Subject: Re: R: hiiiiiiiiii all From: Seisguy@....... Date: Fri, 31 Dec 1999 16:23:21 EST Thanks Dave, that's reassuring fer sure! Just sitting here in a wet Los Angeles waiting for the roll-over WITHOUT incident (bug or otherwise) . Happy New Year to all..... Mike O'Bleness _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Bumps in VBB signal From: S-T Morrissey sean@........... Date: Fri, 31 Dec 1999 15:24:56 -0600 (CST) Barry, Regarding regular periodic bumps in the output of your larger VBB vertical. You mention that they occurr at 5 minute intervals, but you don't say what the period of the event is. So I will assume that it is a single sine (-like?) wave at the operating period, like 60 seconds. This is usually the result of a step in displacement, or a simulation of such in the electronics. To isolate the noise of a seismometer system the obvious method is to clamp the boom or mass so it cannot move and produce real output. This would separate the source possibilities between electronic and mechanical, where mechanical includes the sensor, pier, cover, garage floor concrete slab contracting because it is cold, and the thermostat. Of course, if you have and adjacent seis that doesn't sense the problem, most of these mechanical/environmental sources are eliminated. And if you have two VBB sensors with identical electronics, you can interchange them. Clamping the mass is easy to do with a velocity (moving coil) output system. But any seis with a displacement detector is another matter. Clamping the boom will usually position the detector at an extreme of its range and its electronics will saturate (lock up at a supply voltage). This is ususally not useful since the output is directly coupled. In the triple feedback VBB that you are using, the displacement detector IS the source of the broadband output WHEN the feedback is connected. I don't recall if you are using the VRDT or a capacitive bridge. But clamping a boom so that the detector is at "zero" is quite difficult, especially when "zero" is +,- 0.1 micron, and the detector+amplifier output is 4 volts/micron. Using shims to wedge the sensor to center can create a wide variety of noise, most of which will take days to settle to the micron level. Another test is to remove the sensing vane of the VRDT, which should balance the reactive bridge IF everything else is balanced. This latter is difficult to achieve. I just made another "batch" of VRDT sensors, and after starting with 25 miniature transformers, I ended up with 6 pairs that matched within 0.5 ohm DC, and only one that matched within 1 ohm reactively. Of course, the change caused by the sensing vane still allows a working linear range of several hundred microns at 40 millivolts/micron. For a capacitive sensor, the sensing plate is the output, and can be substituted with a pair of small fixed capacitors if they can be matched. For testing the electronics box, I have an adapter that fits in parallel with the DB-25 connector to the seis that replaces the VRDT coils with their reactive equilavents, namely 365 ohms. The resistors are matched within 0.1 ohm with a meter from a surplus handful of 1% values. Their noise is predominantly thermal, and they produce about 10 times the noise of the earth background. The advantage of this parallel substitution is that the it avoids disturbing the seismometer. I don't know if any of this will help. If you can separate the problem into either mechanical or electronic, it will help. I don't know if the tantalum capacitors can produce spikes if they are operated well within their voltage ratings; and I assume that your DC power supplies are well regulated. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Time From: "JIM MARTIN" jdmartin@.............. Date: Fri, 31 Dec 1999 16:39:25 -0500 Steve, I would also like to have a copy of RightTime, if you are able to locate it. Just send it to my private e-mail (jdmartin@................ thank you and have a happy new year. Jim Martin New Haven, Indiana ----- Original Message ----- From: steve hammond To: PSN-L Mailing List Sent: Friday, December 31, 1999 12:51 PM Subject: Re: Time > Hi Barry, Happy New Year All-- > Barry, I remember you saying at the PSN meeting you were running a 386. If > you are using the system clock for time keeping than you should also be > running RightTime. The program helps you calculate the clock drift over > several days and then controls it via software. I use it in an AT and over > 11 days can keep the drift down to .026 seconds. If you need it, drop me a > note and I can send you the zip file from the old PSN BBS. > Regards, Steve Hammond, PSN San Jose / Aptos California. > -----Original Message----- > From: barry lotz > To: PSN-L Mailing List > Date: Friday, December 31, 1999 9:31 AM > Subject: Time > > > >This is not directly a seismic question but it does affect event > >recording. If my computer(s) are rebooted after a power outage of as > >little as 1 sec the computer clock is several seconds of . Is there a > >correction for this? > >Barry > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman design questions From: "JIM MARTIN" jdmartin@.............. Date: Fri, 31 Dec 1999 16:42:08 -0500 To anyone who wishes to help: Is 18" too tall for the main support with the Lehman? Has anyone used a piece of threaded rod for the boom, or is it better to stick with an aluminum dowel, say 1/2" in dia. ? Is the angle of the boom support wire, in relationship to the boom, a critical item, or is it just desirable to keep it somewhere around 30 degrees? Thanks, and sorry for the elementary questions. Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Happy new year! From: ted@.......... Date: Fri, 31 Dec 1999 17:46:51 -0500 Best wishes to everyone from Portsmouth, NH. We are 6 hours from midnight and having a big party in the street (at 20 degrees F!) Hope all your Y2K bug bites are minor ones, see you next millenium. Ted Blank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Time From: "Dewayne Hill (n0ssy)" n0ssy@.......... Date: Fri, 31 Dec 1999 23:56:15 +0000 You can download an evaluation copy of Rightime from their web site at www.rightime.com. Dewayne >Steve, > >I would also like to have a copy of RightTime, if you are able to locate >it. Just send it to my private e-mail (jdmartin@................ thank you >and have a happy new year. > >Jim Martin >New Haven, Indiana > >----- Original Message ----- >From: steve hammond >To: PSN-L Mailing List >Sent: Friday, December 31, 1999 12:51 PM >Subject: Re: Time > > >> Hi Barry, Happy New Year All-- >> Barry, I remember you saying at the PSN meeting you were running a 386. If >> you are using the system clock for time keeping than you should also be >> running RightTime. The program helps you calculate the clock drift over >> several days and then controls it via software. I use it in an AT and over >> 11 days can keep the drift down to .026 seconds. If you need it, drop me a >> note and I can send you the zip file from the old PSN BBS. >> Regards, Steve Hammond, PSN San Jose / Aptos California. >> -----Original Message----- >> From: barry lotz >> To: PSN-L Mailing List >> Date: Friday, December 31, 1999 9:31 AM >> Subject: Time >> >> >> >This is not directly a seismic question but it does affect event >> >recording. If my computer(s) are rebooted after a power outage of as >> >little as 1 sec the computer clock is several seconds of . Is there a >> >correction for this? >> >Barry >> > >> > >> >_____________________________________________________________________ >> > >> >Public Seismic Network Mailing List (PSN-L) >> > >> >To leave this list email listserver@.............. with the body of the >> >message: leave PSN-L >> >> >> _____________________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email listserver@.............. with the body of the >> message: leave PSN-L >> > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > Dewayne Hill (n0ssy) Westminster, Colorado USA 39.83569n 105.0627w Elev. 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman design questions From: JIm Hannon jmhannon@........ Date: Fri, 31 Dec 1999 19:12:58 -0600 JIM MARTIN wrote: > To anyone who wishes to help: > > Is 18" too tall for the main support with the Lehman? > > Has anyone used a piece of threaded rod for the boom, or is it better to > stick with an aluminum dowel, say 1/2" in dia. ? > > Is the angle of the boom support wire, in relationship to the boom, a > critical item, or is it just desirable to keep it somewhere around 30 > degrees? > > Thanks, and sorry for the elementary questions. > > Jim Martin > New Haven, Indiana > It is best to avoid all magnetic materials in and on the boom. If your threaded rod is steel I would not use it. Otherwise it is a matter of mechanical stability and not having stray mechanical resonances in the system. In other words stiffer is better. The other dimensions are not critical. Except the location of the upper and lower pivot points. The upper pivot, when adjusted for proper period is slightly closer to the mass in the horizontal direction than the lower pivot point. Normally this adjustment is made with the levelling screws on the base. So if you build the pivots to be vertical when the base is horizontal the correct adjustment can be made by slightly inclining the base down at the mass end. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RighTime From: "JIM MARTIN" jdmartin@.............. Date: Fri, 31 Dec 1999 21:12:49 -0500 Is anyone out there running RighTime with either the SDR software package or with the EMON software? Just curious if RighTime is causing any problems with the interrupts. Thanks.... Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman design questions From: "Ed Thelen" ethelen@........ Date: Fri, 31 Dec 1999 20:02:51 -0800 ----- Original Message ----- > > Has anyone used a piece of threaded rod for the boom, or is it better to > > stick with an aluminum dowel, say 1/2" in dia. ? Keep thinking "center of mass", "center of mass", "center of mass", ... And you want the "center of mass" as far as practical from the pivot. Any mass not as far from the pivot is bad - it brings the "center of mass" towards the pivot and shortens the period with no advantages gained. (Let's not get into center of gyration - same principles apply) So - a hollow boom is good - And of course the boom and supports must also be - stiff (raise its resonant frequency above some cutoff) - non-magnetic (you have enough trouble with out stray magnetic attractions confusing you further) - stable, ... so aluminum or copper tubing are among the better choices. I'm biased of course, my all time favorite long period horizontal was made of 1" rigid copper tubing soldered on the family gas stove. Your wife should be so understanding and patient. A small propane torch is probably technically and politically better! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: RighTime From: ted@.......... Date: Sat, 1 Jan 2000 00:56:31 -0500 I've run RighTime with EMON for years without any problem. SDR may be a bit more picky, as it depends on reliably receiving timing interrupts, but Larry will be the final word on that. Ted Blank "JIM MARTIN" on 12/31/99 09:12:49 PM Please respond to PSN-L Mailing List To: cc: Subject: RighTime Is anyone out there running RighTime with either the SDR software package or with the EMON software? Just curious if RighTime is causing any problems with the interrupts. Thanks.... Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 15:02:45 +0000 I was Ctrl R 'ing SDR from last night looking over last nights data and I seen a small event of some sort at 11:15z or so this morning. Nothing on NEIC. But... When I do a save it saves the file my network drive but when I use Winquake (v2.4) it shows the file with a comma in front and won't read the data. By going in and looking at the files and even trying to rename they show no comma at the start in DOS or WINNT, but they still end up showing a comma at the start of the filename in Winquake and naturally can't be read. I guess because it's not the right filename ,000101D.ks1 I've been fooling with this for about an hour, maybe I'm just groggy from working last night, but any one know what gives? I'm giving up and will try again later. Kevin N0CWR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: Dick Webb dwebb2@.............. Date: Sat, 01 Jan 2000 10:11:08 -0500 Kevin, I can't answer your question but did see the event you mentioned. It arrived in Raleigh at 11:23:08 UTC and seemed to be about 710 miles away. When did you see it, where are you and what was your distance estimate? Thanks, Dick At 03:02 PM 01/01/2000 +0000, you wrote: >I was Ctrl R 'ing SDR from last night looking over last nights data and >I seen a small event of some sort at 11:15z or so this morning. Nothing on >NEIC. >But... >When I do a save it saves the file my network drive but when I use Winquake >(v2.4) >it shows the file with a comma in front and won't read the data. >By going in and looking at the files and even trying to rename they show >no comma at the start in DOS or WINNT, but they still end up showing a >comma at the start of the filename in Winquake and naturally can't be read. >I guess because it's not the right filename ,000101D.ks1 >I've been fooling with this for about an hour, maybe I'm just groggy from >working last night, but any one know what gives? I'm giving up and will try >again later. > >Kevin >N0CWR > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's (5.2 at Temiscaming, Quebec) From: Dgw5319@....... Date: Sat, 1 Jan 2000 10:33:02 EST Kevin Looks like a magnitude 5.2 at 11:22 UTC near Temiscaming, Quebec. Here is a link at Natural Resources Canada; Earthquake Report Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 15:41:13 +0000 Hi Dick I think the servers where shutdown at NEIC! :) I can not get Winquake on either a WIN95 or WINNT PC to read my SDR files even when changing the file save to floppy, so I can't say for sure just reading SDR. I even tried the new unregistered version of Winquake D/L'd and same results. I thought I would try to reload my old original version of SDR in another directory instead of SDRv2.7 next. Weird! But it looks like about the same time on SDR by changing the start time aligning the start with my time entered I start to see data at 11:28 My guess would have to be New Madrid, between us? What do you think? I am in Leavenworth, Ks. Appears to be a relatively small event! I went into work checking PC's last night, and frankly not so much in the mood for more troubleshooting this morning. Probably something stupid, so am even ready for a "hey dummy it's...." At 10:11 AM 1/1/00 -0500, Dick Webb wrote: >Kevin, > >I can't answer your question but did see the event you mentioned. It >arrived in Raleigh at 11:23:08 UTC and seemed to be about 710 miles >away. When did you see it, where are you and what was your distance estimate? > >Thanks, >Dick > > > >At 03:02 PM 01/01/2000 +0000, you wrote: >>I was Ctrl R 'ing SDR from last night looking over last nights data and >>I seen a small event of some sort at 11:15z or so this morning. Nothing on >>NEIC. >>But... >>When I do a save it saves the file my network drive but when I use Winquake >>(v2.4) >>it shows the file with a comma in front and won't read the data. >>By going in and looking at the files and even trying to rename they show >>no comma at the start in DOS or WINNT, but they still end up showing a >>comma at the start of the filename in Winquake and naturally can't be read. >>I guess because it's not the right filename ,000101D.ks1 >>I've been fooling with this for about an hour, maybe I'm just groggy from >>working last night, but any one know what gives? I'm giving up and will try >>again later. >> >>Kevin >>N0CWR >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@.............. with the body of the >>message: leave PSN-L > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: Dick Webb dwebb2@.............. Date: Sat, 01 Jan 2000 10:57:10 -0500 Kevin and Dave, Well, I had a 50/50 chance of calling it New Madrid or Quebec since both are about 700 miles from here. Actually, if I had checked the real time helicorder site at CERI I would have seen that they detected little. I am using a restored WWSSN vertical and horizontal long period oriented NS. If I had only gotten the other EW unit installed, I suppose I could have distinguished them from the shape of the emerging wave shapes. Next time. Dave, thanks for directing me to the Canadian site. Looks great and fast. Dick At 03:41 PM 01/01/2000 +0000, you wrote: >Hi Dick >I think the servers where shutdown at NEIC! :) > >I can not get Winquake on either a WIN95 or WINNT PC to read my SDR files >even when changing the file save to floppy, so I can't say for sure just >reading SDR. I even tried the new unregistered version of Winquake D/L'd and >same results. I thought I would try to reload my old original version of SDR >in another directory instead of SDRv2.7 next. Weird! > >But it looks like about the same time on SDR by changing the start time >aligning the start with my time entered I start to see data at 11:28 >My guess would have to be New Madrid, between us? What do you think? > >I am in Leavenworth, Ks. > >Appears to be a relatively small event! > >I went into work checking PC's last night, and frankly not so much in the >mood for more troubleshooting this morning. Probably something stupid, so >am even ready for a "hey dummy it's...." > > >At 10:11 AM 1/1/00 -0500, Dick Webb wrote: > >Kevin, > > > >I can't answer your question but did see the event you mentioned. It > >arrived in Raleigh at 11:23:08 UTC and seemed to be about 710 miles > >away. When did you see it, where are you and what was your distance >estimate? > > > >Thanks, > >Dick > > > > > > > >At 03:02 PM 01/01/2000 +0000, you wrote: > >>I was Ctrl R 'ing SDR from last night looking over last nights data and > >>I seen a small event of some sort at 11:15z or so this morning. Nothing on > >>NEIC. > >>But... > >>When I do a save it saves the file my network drive but when I use Winquake > >>(v2.4) > >>it shows the file with a comma in front and won't read the data. > >>By going in and looking at the files and even trying to rename they show > >>no comma at the start in DOS or WINNT, but they still end up showing a > >>comma at the start of the filename in Winquake and naturally can't be read. > >>I guess because it's not the right filename ,000101D.ks1 > >>I've been fooling with this for about an hour, maybe I'm just groggy from > >>working last night, but any one know what gives? I'm giving up and will try > >>again later. > >> > >>Kevin > >>N0CWR > >> > >>_____________________________________________________________________ > >> > >>Public Seismic Network Mailing List (PSN-L) > >> > >>To leave this list email listserver@.............. with the body of the > >>message: leave PSN-L > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: meredith lamb mlamb1@.......... Date: Sat, 01 Jan 2000 09:19:38 -0800 n0cwr@......... wrote: > I do a save it saves the file my network drive but when I use Winquake > (v2.4) > it shows the file with a comma in front and won't read the data. > By going in and looking at the files and even trying to rename they show > no comma at the start in DOS or WINNT, but they still end up showing a > comma at the start of the filename in Winquake and naturally can't be read. > I guess because it's not the right filename ,000101D.ks1 > Kevin > N0CWR Kevin, I figure it must be a Y2K computer problem. My old (circa 1993?) Packard Bell computer does essentially the same thing but with the addition of a digit: ,1000101a.ml1 It did crash on the stroke of Y2K, even though it had a patch, but Packard Bell said it wouldn't be able to keep running constantly with a program that runs all the time. Same results, the floppy names can't be changed via the normal name change route, and the Winquake program says its not there, and pressing the issue crashes the program. There maybe some kind of work-a-round, but the only one I can think of (for future use) is too reset the computer clock to the year 1976 (could be 1978), where the dates match the year 2000. One could then possibly see the data, but, whether the floppy date can be then changed, and then successfully submitted as a PSN event is conjecture for me at this time. Your present Canadian quake is probably "scrap" (me too), but future quakes "maybe" readable. Unfortunately I'am no computer whiz, so, other means maybe available....but the experience is wholly lacking to suggest anything otherwise. Of course, getting another computer thats compliant is obvious. Outside of this setback, Happy New Year anyway..... Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: meredith lamb mlamb1@.......... Date: Sat, 01 Jan 2000 09:39:41 -0800 Y2K non-compliant computers additional note. Apparently Microsoft Windows doesn't go back year wise to 1976. However the year 1983 matches the month of January 2000. One might have to reset the year date to match the month for 2000 every month, via the Windows Date/Time function. I would think recording, and then changing the dates would work (for submission to PSN event files). Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 17:11:27 +0000 I don't think I am detecting any problems with any other files. I've just come back in and tried a few things. All else looks ok. Other file saves are fine. All other files seem to execute through the network when I run them off the PC when running the SDR PC on GUI Win95. At this point I just don't think I am detecting any problems with any other files. It seems that I can do everything file-wise with this WIN95 (the SDR OS) and then be able to work with them on either the other network WIN95 or WINNT PC. Floppy transfer or via network. And the clock does appear ok. I also have a WIN3.11 PC on the network, but it doesn't have any Winqake or SDR software on it, so I haven't tried it with these files. So...my thinking is that the problem may be with the way SDR is saving the file only and the way it is being read by Winquake. With the comma, one of the first things I considered was some sort of virus. Maybe changing the way Winquake viewed these files with some sort of extra data inserted by a virus. But Norton Anti Virus comes up clean with yesterdays updates. I have in my mind that we may not be alone on this, and bet as soon as Larry comes alive from last night he may be able to point us to a fix. Here's hoping anyway. I'm really thinking that for some reason SDR is writing it's file in a way that Winquake interpets it wrong. (sounds like a virus doesn't it) Like adding a string to the file! I've pumped in some breakfast and buckets of coffee so now I've got to go help a guy install a DSS dish. Will keep my fingers crossed for that easy fix! Bet I sleep like a baby tonight! A bit sleep deprived. If anyone has Winquake functioning, I'd like to send them my file to see if they can read it. I did considered just sending it to PSN but maybe a bit dangerous to see if it would convert there ok to html. Better to test and wait. Happy New Year all. Kevin N0CWR At 09:39 AM 1/1/00 -0800, you wrote: >Y2K non-compliant computers additional note. > >Apparently Microsoft Windows doesn't go back year wise >to 1976. However the year 1983 matches the month of >January 2000. One might have to reset the year date to >match the month for 2000 every month, via the Windows >Date/Time function. > >I would think recording, and then changing the dates would >work (for submission to PSN event files). > >Meredith Lamb > > > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: Karl Cunningham karlc@....... Date: Sat, 01 Jan 2000 09:57:50 -0800 Hi All -- My Winquake v2.68 (under NT4 SP3) and SDR v2.71 (under Win95) seem to be working just fine. I've retrieved several event files and replay requests from SDR via network with Winquake with no problems. These include events before and after the date rollover. I didn't try one spanning the rollover. My SDR machine is using UTC with no offset. I don't know if this is related, but in that ASCII table, a comma is 44 (decimal) and '0' is 48. My SDR machine is an old 486 (Shuttle motherboard). I did some Y2K testing a while back and found that if I turned the machine off just prior to the rollover, then turned it on just after and reset the date in BIOS, everything works just fine. You might try rebooting the computer and setting the date using BIOS setup. In earlier testing, I found that an older version of SDR will erase its saved data files if the system date is vastly different from the date of the data files. Such as if the system date is 1980 and the data files are 1999. Larry may have changed this in more recent versions. One trick to renaming files is to copy the file to a floppy disk and make sure the file you want to rename is the only one on the floppy. Then use the DOS command REN *.* newname.ext This will rename the file even if the name contains illegal characters. We used to do this in the old DOS days if a filename got corrupted. If someone wants to send me a file, I'll be happy to try to read it with Winquake. Send it to me directly, not to the list. Regards, Karl At 05:11 PM 1/1/2000 +0000, you wrote: >I don't think I am detecting any problems with any other files. >I've just come back in and tried a few things. All else looks ok. >Other file saves are fine. >All other files seem to execute through the network when I run them off the >PC when running the SDR PC on GUI Win95. > >At this point I just don't think I am detecting any problems with any >other files. > >It seems that I can do everything file-wise with this WIN95 (the SDR OS) >and then be able to work with them on either the other network WIN95 or >WINNT PC. Floppy transfer or via network. >And the clock does appear ok. > >I also have a WIN3.11 PC on the network, but it doesn't have any Winqake >or SDR software on it, so I haven't tried it with these files. > >So...my thinking is that the problem may be with the way SDR is saving the >file >only and the way it is being read by Winquake. > >With the comma, one of the first things I considered was some sort of virus. >Maybe changing the way Winquake viewed these files with some sort of extra >data inserted by a virus. But Norton Anti Virus comes up clean >with yesterdays updates. > >I have in my mind that we may not be alone on this, and bet as soon as >Larry comes alive from last night he may be able to point us to a fix. >Here's hoping anyway. I'm really thinking that for some reason SDR is writing >it's file in a way that Winquake interpets it wrong. (sounds like a virus >doesn't it) >Like adding a string to the file! > >I've pumped in some breakfast and buckets of coffee so now I've got to go >help a guy install a DSS dish. Will keep my fingers crossed for that easy >fix! Bet I sleep like a baby tonight! A bit sleep deprived. > >If anyone has Winquake functioning, I'd like to send them my file to >see if they can read it. I did considered just sending it to PSN but maybe >a bit dangerous to see if it would convert there ok to html. Better to test >and >wait. > >Happy New Year all. >Kevin >N0CWR > >At 09:39 AM 1/1/00 -0800, you wrote: >>Y2K non-compliant computers additional note. >> >>Apparently Microsoft Windows doesn't go back year wise >>to 1976. However the year 1983 matches the month of >>January 2000. One might have to reset the year date to >>match the month for 2000 every month, via the Windows >>Date/Time function. >> >>I would think recording, and then changing the dates would >>work (for submission to PSN event files). >> >>Meredith Lamb >> >> >> >> >> >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@.............. with the body of the >>message: leave PSN-L >> >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Y2K Bug From: The Lahrs JohnJan@........ Date: Sat, 01 Jan 2000 11:12:58 -0700 >The first Y2K bug I've noticed is with the NEIC Bigquake message! The message reads: The following is from the United States Geological Survey, National Earthquake Information Center: preliminary hypocenter for earthquake of 1900 jan 01, WEST OF MACQUARIE ISLAND, about 475 miles (770 km) NW of Young Island, Balleny Islands: latitude 60.8 degrees south longitude 153.6 degrees east origin time 05 58 19.1 utc depth shallow, magnitude 5.6 ms. Apparently the error is in the program that generates this text, as the database itself keeps the full 4-digit year. NEIC is now working on the problem, so it should be fixed soon. John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: david wolny dwolny@............. Date: Sat, 1 Jan 2000 12:49:26 -0700 (MST) Kevin I too recorded the Quebec event. I can see it in SDR, but Winquake won't read the file. That darn comma at the front of the file name. I tried renaming the file but to no avail. I have SDR running in DOS on an old 486. Strange, the computer has the date correctly, 01/01/2000. I guess I will try Karl's suggestion of renaming the file in the DOS program. Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Y2K Bug From: macsmith macsmith@......... Date: Sat, 01 Jan 2000 09:53:56 -1000 The USGS Hawaii List seems to have gone slightly bannanas listing every quake since March 1998 - quite useful! http://quake.wr.usgs.gov/cgi-bin/finger?quake@................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 20:02:29 +0000 Thanks. So, probably not a virus. Winquake or SDR interpretation of all the zeros in the date? My guess? Whats the date in binary? At 12:49 PM 1/1/00 -0700, you wrote: >Kevin > >I too recorded the Quebec event. I can see it in SDR, but Winquake won't >read the file. That darn comma at the front of the file name. I tried >renaming the file but to no avail. I have SDR running in DOS on an old >486. Strange, the computer has the date correctly, 01/01/2000. I guess I >will try Karl's suggestion of renaming the file in the DOS program. > >Dave > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 20:17:35 +0000 In the meantime... I set my F6 "purge Record files" to 14 days. To save my records. You might try the same to till we come up with a solution. My thoughts are now leaning toward the way SDR might save date info in it's save file using older AMIbios even though the OS made the date transfer ok to 2000. I have system commander on that PC and date appears ok even in running DOS 6.22. SDR save in DOS6.22 on that PC and then lookup in Winquake displays the same. Comma and unable to locate the file due to the comma. I haven't tried reloading the old version I have of SDR yet. What version are you using? At 12:49 PM 1/1/00 -0700, you wrote: >Kevin > >I too recorded the Quebec event. I can see it in SDR, but Winquake won't >read the file. That darn comma at the front of the file name. I tried >renaming the file but to no avail. I have SDR running in DOS on an old >486. Strange, the computer has the date correctly, 01/01/2000. I guess I >will try Karl's suggestion of renaming the file in the DOS program. > >Dave > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Y2K Bug From: Canie canie@........... Date: Sat, 01 Jan 2000 12:25:55 -0800 Something similar seems to have happened at this site: http://www.cnss.org/us.epi.gif - Map of US quakes Canie At 09:53 AM 1/1/00 -1000, you wrote: >The USGS Hawaii List seems to have gone slightly bannanas listing every >quake since March 1998 - quite useful! > >http://quake.wr.usgs.gov/cgi-bin/finger?quake@................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismographs for students From: Ruediger Wisskirchen rwisskirchen@....... Date: Sat, 01 Jan 2000 22:52:28 +0200 barry lotz wrote: > Ruediger > It may work as a strong motion sensor. I agree with Ted, usually you want > the natural period of the sensor to be longer than the lowest period you want > to record. Also since the output would be a function of the # of wire coils > turns you may have a very low output signal . Speakers usually have few turns. But is it possible, that the strong magnet more than compensats this disadvantage? A simple test with a big loudspeaker, a simple amplifier with a 741 and amp.factor 100 gives a strong signal, when I just make a bit wind with my hand against the membran. > > What you describe maybe the begining of a force balance sensor but you would > need a displacement sensor included which would complicate matters. I have read the article about the force-balance-seismometer, but due to my oor english I haven`t quite understood the difference between the forcebalance and the lehman-sensor. Why do you need a displacement sensor? > Do you have > access to magnet wire and simple rectangular magnets? You could use an electric > drill and wind your own coil of 1000+ turns on say a old spool like an empty > solder spool. Is it better for a high voltage to have a short coil with much layers or does a long coil with the same number of wires produeces the same effect? > You could then put a rectangular magnet on both sides of the > coil. As Ted says you probable will have more interesting events if you do not > attach the groung to the end of the boom except as I have described above. I > hope this helps a little. Most of us look around to find possible sensor > parts from devices use for other things, for example computer harddrive driver > as sensor/coil pairs. I still have some old harddisks, thanks for that hint. > > Barry > > ted@.......... wrote: > Thanks Ruediger Wisskirchen (rwisskirchen@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 20:54:22 +0000 Thanks for checking Karl. Those were the right files. In that case! I am totally confused. No. The files look fine in everything except when I look at them with Winquake 2.4 using two different PC's. They appear when viewed in Winquake. I don't see a thing wrong with the file name in DOS or WIN OS's. So now I'm wondering, what does this mean? I'm confused and will have to think about this some more. I hope you don't mind. I'm going to cc: this to the list so that other(s) with trouble might see. May need to get more info from other user just responded with same trouble. thanks again. At 12:29 PM 1/1/00 -0800, you wrote: >Kevin -- > >The files attached to your email were 000101a.ks1 and 000101b.ks1. I don't >know if you tried to send the ones that started with a comma, but when they >got here they had no comma in the file name. > >I can open both files just fine with Winquake (v2.6.8). Both appear to be >identical, starting at 11:20:36 on 1/1/00. > >If the filenames you sent started with commas, you might try sending the >files to yourself via email. Maybe that'll strip the commas off. > >Next interesting thing: I renamed the files (using NT4 SP3) and added a >comma to the beginning of both the file names. Winquake still opened the >files without complaint, comma and all. I've attached a .GIF file, which >is a screen dump of Winquake with the ,000101a.ks1 file open. Maybe your >files have more than just a comma at the start. Maybe there are some >hidden characters too. Do you have a program that can do a hex dump of >sectors on a disk. If you could look at the directory entry on a floppy >for the file in question, you might be able to see more there than meets >the eye. > >I seriously doubt that these files contain a contageous virus, since these >aren't executable files and I don't think anyone would bother trying to >make a virus for event files that could affect Winquake in such a way as to >cause it to write bogus files. > >Be happy to work more on it later. I'll be in and out for most of the >afternoon. here. > >Karl > > >At 07:57 PM 1/1/2000 +0000, you wrote: >> >>Thanks Karl! >>Just got back home. >>Lets try it and see what the file looks like to you. >>Here's two saves. They look fine everywhere but Winquake 2.4. >>SDR2.7 did the file save. >>Winquake sees ,000101b.ks1 and ,000101a.ks1 and when you try to open >>them it says ",000101b.ks1 was not found. (Of course! because DOS >>WINNT4.0 SP3 or WIN95 SP1 see it as 000101b.ks1. >>I ran NAV on these PC's. But please be sure to check them with your AV >>software! >>I still am wondering about some Y2K virus writing a string to the files and >>Winquake interpretating the file name differently. >>I hate to think of updating motherboards. This WINNT pc is using a 166 and >>it's the fastest PC in the house! There's just got to be a software fix. >>Hoping... >>Thanks Kevin >> >> >>At 09:57 AM 1/1/00 -0800, you wrote: >>> >>>If someone wants to send me a file, I'll be happy to try to read it with >>>Winquake. Send it to me directly, not to the list. >>> >>> >> >>> >>Attachment Converted: "C:\Eudora\Karl's\attach\000101b.ks1" >> >>Attachment Converted: "C:\Eudora\Karl's\attach\000101a.ks1" >> >Attachment Converted: "F:\DOWNLOADS\wqfile.gif" > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: boom material/size suggestions From: S-T Morrissey sean@........... Date: Sat, 1 Jan 2000 14:57:04 -0600 (CST) Regarding boom material choices: I have experimented with both threaded rod (1/2" aluminum), various tubing, both round and square, and U shaped channels. My experience is that the rod and tubing are difficult to work with, since they are round and/or hollow (=long screws), and the threaded rod really limits the use of fasteners to large nuts and washers, which can be found in aluminum (or brass/stainless, but these may add weight where it is not needed) if your True-Value store has enough of those yellow specialty hardware trays. But aluminum channel is available from most hardware stores, and in a boom dimension of 3/4" wide by 1/2" high and 1/16" wall, provides unlimited fastening opportunities wherever you can drill a hole. As can be seen in the photos of the seismometers on my web site, I use the channel open side up, which provides a place to run the leads to the coils, drop trim/test weights to balance the boom, etc. As can also be seen, I drill rows of holes in all three sides to facilitate experimenting with the design-in-progress as the ideas come together. The hardware stores (Ace, True-value, around here) have a selection of sizes that often nest or fit together closely. A wide channel can be forked at one end to fasten the mass in between, and forked at the mast end to bypass the support mast so the lower hinge can be a short tension wire pulling from the back side (if the mast is narrow enough). Without resorting to specialty suppliers like McMaster-Carr, there is also a good selection of thicker (1/8") aluminum angle that can be drilled and bolted together for the frame. For the base of the large horizontal made up with angles and a flat piece (3" wide x 1/8" thick), I used filled epoxy to glue everything together as well as bolting it (after roughing all the surfaces with 200 grit sandpaper), and it made a very robust frame in liew of buying thick aluminum plate. And since True-Value sells the 1/8" x 3" in 6 foot lengths, you can laminate (with the aluminum-filled epoxy and lots of weight (park on it)), several thicknesses with what you have to buy (or make 4 seismometers!). As for the relative dimensions of a horizontal boom length to support post height, most designs have about a 30-60-90 triangular relation, with about 30 degrees at the mass/tension wire end or 60 degrees at the upper hinge at the top of the mast. Higher hinge supports that make up closer to a 45-45-90 triangle push the clearance height problem of providing a sealed cover for the instrument, and more acute angles increase the stresses on the mass/boom support wire and/or hinges. However, some strictly "garden-gate" designs using crossed flexure or boxed flexure hinges have very shallow heights, like 6" for an 18" boom. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 21:17:14 +0000 Thinking out loud. If your able to read the files. What is different about your hardware/software? I should be able to read them too. What version and PC are you using? I am using a 486DX50(WIN95)the SDR PC, 486DX120(WIN95) and P166(the WINNT PC that receives the SDR save files over the network). I might mention again that saving the file to disk and then looking at them on any of these PC's and Winquake still see's them with a comma in front of the file name. I tried Winquake v 2.5.2 and 2.4 32 bit versions on the 486DX120. Only Winquake v 2.4 32 bit on the other two. I have a Win95(486DX100), my daughters PC upstairs, and a 386DX40 (WIN3.11) on the network here as well. The 386DX is used for Packetcluster and ham radio databases. This gives me some hope though. My file is useable. Just not by me! :) ha But hasn't make the solution any more obvious at this point. At 12:29 PM 1/1/00 -0800, you wrote: >Kevin -- > >The files attached to your email were 000101a.ks1 and 000101b.ks1. I don't >know if you tried to send the ones that started with a comma, but when they >got here they had no comma in the file name. > >I can open both files just fine with Winquake (v2.6.8). Both appear to be >identical, starting at 11:20:36 on 1/1/00. > >If the filenames you sent started with commas, you might try sending the >files to yourself via email. Maybe that'll strip the commas off. > >Next interesting thing: I renamed the files (using NT4 SP3) and added a >comma to the beginning of both the file names. Winquake still opened the >files without complaint, comma and all. I've attached a .GIF file, which >is a screen dump of Winquake with the ,000101a.ks1 file open. Maybe your >files have more than just a comma at the start. Maybe there are some >hidden characters too. Do you have a program that can do a hex dump of >sectors on a disk. If you could look at the directory entry on a floppy >for the file in question, you might be able to see more there than meets >the eye. > >I seriously doubt that these files contain a contageous virus, since these >aren't executable files and I don't think anyone would bother trying to >make a virus for event files that could affect Winquake in such a way as to >cause it to write bogus files. > >Be happy to work more on it later. I'll be in and out for most of the >afternoon. here. > >Karl > > >At 07:57 PM 1/1/2000 +0000, you wrote: >> >>Thanks Karl! >>Just got back home. >>Lets try it and see what the file looks like to you. >>Here's two saves. They look fine everywhere but Winquake 2.4. >>SDR2.7 did the file save. >>Winquake sees ,000101b.ks1 and ,000101a.ks1 and when you try to open >>them it says ",000101b.ks1 was not found. (Of course! because DOS >>WINNT4.0 SP3 or WIN95 SP1 see it as 000101b.ks1. >>I ran NAV on these PC's. But please be sure to check them with your AV >>software! >>I still am wondering about some Y2K virus writing a string to the files and >>Winquake interpretating the file name differently. >>I hate to think of updating motherboards. This WINNT pc is using a 166 and >>it's the fastest PC in the house! There's just got to be a software fix. >>Hoping... >>Thanks Kevin >> >> >>At 09:57 AM 1/1/00 -0800, you wrote: >>> >>>If someone wants to send me a file, I'll be happy to try to read it with >>>Winquake. Send it to me directly, not to the list. >>> >>> >> >>> >>Attachment Converted: "C:\Eudora\Karl's\attach\000101b.ks1" >> >>Attachment Converted: "C:\Eudora\Karl's\attach\000101a.ks1" >> >Attachment Converted: "F:\DOWNLOADS\wqfile.gif" > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Amplitude From: "Marchal van Lare" vanlare@.............. Date: Sat, 1 Jan 2000 22:20:42 +0100 Hi all, When I approach my Lehman seismograph, what is the average amplitude I can expect? At this time I see an average amplitude of 3500 on a 16 = bit card. Best regards, Marchal van Lare
Hi all,
 
When I approach my Lehman seismograph, = what is the=20 average amplitude
I can expect? At this time I see an = average=20 amplitude of 3500 on a 16 bit card.
 
Best regards,
 
Marchal van Lare
 
 
Subject: Re: Comma's From: Mauro Mariotti mariottim@...... Date: Sat, 1 Jan 2000 23:07:08 +0100 The problems seems to be a bug of Winquake 16 bit version. I actually trying a demo version of winquake32 and 16. I use a BASIC software that generate text file like PSN record map. If I insert in the text file a date over 12/31/1999 the Winquake insert a comma in head of the filename. The real reason is that the DOS name is NOT changed. The problem is that winquake reorder the filename in his internal memory allocation for variable and the year 2000 is treated by the program in some wrong way that corrupt the filename that winquake use to retrieve the file. So the file cannot be opened. Make this test: 1. Using WQuake32 Open one quake file in PSN binary format of a date before 1/1/2000. 2. Save it as PSN TEXT format. 3. Open it by a text editor and change the date in a 2000 year. 4. Open this new file using Winquake32 and save it as BINARY PSN format. 4. Retry to open this binary file using Winquake16. 5. The file can not be opened! Larry i think meny needs your help... Regards Mauro At 20.54 01/01/2000 +0000, you wrote: >Thanks for checking Karl. >Those were the right files. >In that case! I am totally confused. > >No. The files look fine in everything except when I look at >them with Winquake 2.4 using two different PC's. They appear >when viewed in Winquake. I don't see a thing wrong with >the file name in DOS or WIN OS's. > >So now I'm wondering, what does this mean? >I'm confused and will have to think about this some more. > >I hope you don't mind. >I'm going to cc: this to the list so that other(s) with >trouble might see. May need to get more info from other user just >responded with same trouble. >thanks again. > > >At 12:29 PM 1/1/00 -0800, you wrote: >>Kevin -- >> >>The files attached to your email were 000101a.ks1 and 000101b.ks1. I don't >>know if you tried to send the ones that started with a comma, but when they >>got here they had no comma in the file name. >> >>I can open both files just fine with Winquake (v2.6.8). Both appear to be >>identical, starting at 11:20:36 on 1/1/00. >> >>If the filenames you sent started with commas, you might try sending the >>files to yourself via email. Maybe that'll strip the commas off. >> >>Next interesting thing: I renamed the files (using NT4 SP3) and added a >>comma to the beginning of both the file names. Winquake still opened the >>files without complaint, comma and all. I've attached a .GIF file, which >>is a screen dump of Winquake with the ,000101a.ks1 file open. Maybe your >>files have more than just a comma at the start. Maybe there are some >>hidden characters too. Do you have a program that can do a hex dump of >>sectors on a disk. If you could look at the directory entry on a floppy >>for the file in question, you might be able to see more there than meets >>the eye. >> >>I seriously doubt that these files contain a contageous virus, since these >>aren't executable files and I don't think anyone would bother trying to >>make a virus for event files that could affect Winquake in such a way as to >>cause it to write bogus files. >> >>Be happy to work more on it later. I'll be in and out for most of the >>afternoon. here. >> >>Karl >> >> >>At 07:57 PM 1/1/2000 +0000, you wrote: >>> >>>Thanks Karl! >>>Just got back home. >>>Lets try it and see what the file looks like to you. >>>Here's two saves. They look fine everywhere but Winquake 2.4. >>>SDR2.7 did the file save. >>>Winquake sees ,000101b.ks1 and ,000101a.ks1 and when you try to open >>>them it says ",000101b.ks1 was not found. (Of course! because DOS >>>WINNT4.0 SP3 or WIN95 SP1 see it as 000101b.ks1. >>>I ran NAV on these PC's. But please be sure to check them with your AV >>>software! >>>I still am wondering about some Y2K virus writing a string to the files and >>>Winquake interpretating the file name differently. >>>I hate to think of updating motherboards. This WINNT pc is using a 166 and >>>it's the fastest PC in the house! There's just got to be a software fix. >>>Hoping... >>>Thanks Kevin >>> >>> >>>At 09:57 AM 1/1/00 -0800, you wrote: >>>> >>>>If someone wants to send me a file, I'll be happy to try to read it with >>>>Winquake. Send it to me directly, not to the list. >>>> >>>> >>> >>>> >>>Attachment Converted: "C:\Eudora\Karl's\attach\000101b.ks1" >>> >>>Attachment Converted: "C:\Eudora\Karl's\attach\000101a.ks1" >>> >>Attachment Converted: "F:\DOWNLOADS\wqfile.gif" >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SDR problems From: "Alan and Jocelyn Munro" mjpad@.............. Date: Sun, 2 Jan 2000 11:55:21 +1300 Hi everybody Happy New Year Like others I too have problems. Being in New Zealand we got them first. SDR V 1.8 worked ok on 486 machine. Date changed ok. Can't set BIOS = earlier than 1980. Got small quake 1:36 am 1/1/00. Wouldn't save Got Belleny quake did save but could'nt open file. Had local NZ event 9;12 pm local time saved ok and opened ok Win98 = machine. SDR seemed to be working much better today. Could save easily. Maybe time might help us. Alan Munro Invercargill New Zealand
Hi everybody
Happy New Year
Like others I too have = problems.
Being in New Zealand we got them=20 first.
SDR V 1.8 worked ok on 486 machine. = Date changed=20 ok. Can't set BIOS earlier than 1980.
Got small quake 1:36 am 1/1/00. = Wouldn't=20 save
Got Belleny quake did save but could'nt = open=20 file.
Had local NZ event 9;12 pm local time = saved ok and=20 opened ok Win98 machine.
SDR seemed to be working much better = today. Could=20 save easily.
Maybe time might help us.
 
Alan Munro
Invercargill New = Zealand
Subject: Re: RighTime From: Larry Cochrane cochrane@.............. Date: Sat, 01 Jan 2000 15:09:04 -0800 Jim and others... RighTime should NOT be used with SDR. Since SDR keeps its own time based on the 1 millisecond interrupt from the A/D card running programs like RighTime may cause problems. Like RighTime, SDR compensates for the crystal oscillator being off frequency by either adding or subtracting time. And like RighTime you still need some time reference like WWV, WWVB or GPS... -Larry Cochrane Redwood City, PSN At 09:12 PM 12/31/99 -0500, you wrote: >Is anyone out there running RighTime with either the SDR software package or >with the EMON software? Just curious if RighTime is causing any problems >with the interrupts. > >Thanks.... > >Jim Martin >New Haven, Indiana > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: RighTime From: "JIM MARTIN" jdmartin@.............. Date: Sat, 1 Jan 2000 18:42:07 -0500 Thanks, Larry. Was just curious if it WOULD indeed cause problems with the interrupts. Thanks again for the info. I will be e-mailing you privately with an order, shortly. Jim Martin ----- Original Message ----- From: Larry Cochrane To: PSN-L Mailing List Sent: Saturday, January 01, 2000 6:09 PM Subject: Re: RighTime > Jim and others... > > RighTime should NOT be used with SDR. Since SDR keeps its own time based on > the 1 millisecond interrupt from the A/D card running programs like > RighTime may cause problems. Like RighTime, SDR compensates for the crystal > oscillator being off frequency by either adding or subtracting time. And > like RighTime you still need some time reference like WWV, WWVB or GPS... > > -Larry Cochrane > Redwood City, PSN > > > At 09:12 PM 12/31/99 -0500, you wrote: > >Is anyone out there running RighTime with either the SDR software package or > >with the EMON software? Just curious if RighTime is causing any problems > >with the interrupts. > > > >Thanks.... > > > >Jim Martin > >New Haven, Indiana > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sat, 01 Jan 2000 23:53:16 +0000 I found a way to open my files. Try this. Right click on the file. Tell it to open. It will bring up the usual list. Winquake isn't there. Click other then bring up Winquake. I told it to use this all the time for .ks1 Why not? Now it will open the files. Why? I've got to think a bit what this means? I still can't open them through Winquake even after modify header and saving , but at least I can access my data. Happy, but.... Things like this drive me crazy! At 12:49 PM 1/1/00 -0700, David wolny wrote: >Kevin > >I too recorded the Quebec event. I can see it in SDR, but Winquake won't >read the file. That darn comma at the front of the file name. I tried >renaming the file but to no avail. I have SDR running in DOS on an old >486. Strange, the computer has the date correctly, 01/01/2000. I guess I >will try Karl's suggestion of renaming the file in the DOS program. > >Dave > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Comma problem From: Larry Cochrane cochrane@.............. Date: Sat, 01 Jan 2000 16:00:19 -0800 All, Unfortunately theres not much I can do about the problem if you are running old software. If you are having any Y2K problems please run the current releases of SDR and WinQuake. The current version of SDR is 2.71 and WinQuake 2.6 is in beta and ready for a full release. I'm holding off making the official 2.6 release for a few more weeks to make sure there aren't any Y2K problems lurking around in the code. I realize this is going to cause some problems with people still running the old Windows 3.1 OS since the new WinQuake release will only run under Win9X, Win NT and Win2k. Given the amount of time I can devote to software design and maintenance, I just don't the time needed to support both 16 and 32 bit versions. If you are running the new versions of my software and see any problems please let me know. I'm running two SDR systems both with Y2K problems when they first boot up. So far I haven't seen any problems, but I haven't reboot the systems yet. I'm pretty sure all I will have to do is set the time at the DOS prompt and restart SDR. I have a Y2K fix it board that I bought awhile back that I will install in one of my system. Since one of the systems acts as a time server, it keeps it's time accurate using WWV, I'm thinking of adding a little more code to SDR so that the year month and day are sent over the serial port so that the other system can set the proper date when it first starts up. Currently only the hour, minute, seconds and milliseconds are sent over the RS-232 serial port. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: seismic hazard maps From: BOB BARNS roybar@........ Date: Sat, 01 Jan 2000 21:13:50 -0500 Hi gang, Science mag. (24 dec '99, p2423) gives the URL of an interesting site which shows seismic hazard maps among other things. It is seismo.ethz.ch/GSHAP Bill Scolnik and I are also having the comma problem. I am using WinQuake ver. 2.5.2 and SDR ver. 2.71. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Comma problem From: "JIM MARTIN" jdmartin@.............. Date: Sat, 1 Jan 2000 21:49:50 -0500 Gentlemen, I visited the following site (http://psn.quake.net/cgi-dos/event.exe) and downloaded the 000101a.gr2 file that is listed under the 01/01/00 05:58 UTC listing. I then loaded this file into WinQuake (32-bit version 2.5.2) and lo and behold, it showed up in the list with the predeeding comma !!!! Sure would like to know what's up !! Jim Martin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Comma problem From: "JIM MARTIN" jdmartin@.............. Date: Sat, 1 Jan 2000 22:06:38 -0500 Gentlemen, I owe you an apology, and Larry as well. I upgraded WinQuake from 2.5.2 to 2.6.8 and the previous post of mine, relating to the preceeding comma problem, is now nonexistent. I reloaded the questionable file into the new version of WinQuake and now everything is just fine. Again, please accept my apologies for an errant post, and Larry, everything on this end is now working just fine. Jim Martin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: n0cwr@......... Date: Sun, 02 Jan 2000 03:38:17 +0000 Since I started this: I'll repeat what most all of you have probably figured out. The latest software works. Older versions may or may not. I've downloaded the latest software and I am sending for the newer registration keys for the SDR PC and the network file receiver. Thanks to Larry for all his efforts in simplifying and making this hobby available to us. It truly is spectacular software... not to mention his making available great hardware! I am sure Brian and I would never had such a great sensor without it. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Lehman design questions From: mbrewer mbrewer@...... Date: Sun, 2 Jan 2000 11:42:29 -0400 Jim, I am using threaded rod on my two Lehmans. One is brass the other is stainless steel (stainless steel is non-magnetic). I drilled and tapped home-cast lead weights for both. This makes it easy to position the weights on the boom. I locked the weights in place with stainless steel nuts and washers. I use two weights either side of the magnet so that the balance point of the boom assembly, when suspended vertically by the support wire, is close to the magnet itself. Regards, Martin Brewer, Bermuda -----Original Message----- From: JIM MARTIN [SMTP:jdmartin@............... Sent: Friday, December 31, 1999 5:42 PM To: PSN-L@.............. Subject: Lehman design questions To anyone who wishes to help: Has anyone used a piece of threaded rod for the boom, or is it better to stick with an aluminum dowel, say 1/2" in dia. ? Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: geothermal resource map From: Tobin Fricke tobin@....... Date: Sun, 2 Jan 2000 11:06:10 -0800 (PST) This isn't directly related to seismology, but I thought someone on this list might know: I'm looking for a copy of the "California State Geothermal Resource Map". Anyone have any pointers? Tobin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geothermal resource map From: Stephen & Kathy mortskm@....... Date: Sun, 02 Jan 2000 11:33:04 -0800 Tobin Fricke wrote: > > This isn't directly related to seismology, but I thought someone on this > list might know: I'm looking for a copy of the "California State > Geothermal Resource Map". Anyone have any pointers? > > Tobin I would also like to know,,,, I've been searching but haven't found the magic words yet!!! Stephen PSN #55 38.828N 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geothermal resource map From: Stephen & Kathy mortskm@....... Date: Sun, 02 Jan 2000 11:55:13 -0800 Stephen & Kathy wrote: > I would also like to know,,,, I've been searching but haven't > found the magic words yet!!! > > Stephen > PSN #55 > 38.828N 120.978W > Let me clear that up a little,, You can get hardcopy maps from the dept of mines and geology. What I'm looking for are web sites with daily or better yet hourly satellite images dedicated to geothermal activity,, not just IR weather images. Stephen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geothermal resource map From: "John Miller" cimarron@.......... Date: Sun, 2 Jan 2000 13:59:13 -0600 Try http://www.oit.osshe.edu/~geoheat/state/ca/ca.htm . http://www.oit.osshe.edu/~geoheat/images/colstate/califor.gif http://www.oit.osshe.edu/~geoheat/califor.htm#alpine This page also has collated resources by county. John Miller Denver, MO Cimarron Co. LLC cimarron@.......... ----- Original Message ----- From: Tobin Fricke To: PSN-L Mailing List Sent: Sunday, January 02, 2000 1:06 PM Subject: geothermal resource map > > This isn't directly related to seismology, but I thought someone on this > list might know: I'm looking for a copy of the "California State > Geothermal Resource Map". Anyone have any pointers? > > Tobin > > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geothermal resource map From: Canie canie@........... Date: Sun, 02 Jan 2000 12:01:44 -0800 You might start here: http://www.consrv.ca.gov/dog/officespersonnel.htm The bottom half of the page lists the offices for geothermal districts in california - they'll know how to get the maps... Canie At 11:06 AM 1/2/00 -0800, you wrote: >This isn't directly related to seismology, but I thought someone on this >list might know: I'm looking for a copy of the "California State >Geothermal Resource Map". Anyone have any pointers? > >Tobin > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: USA Map From: Seisguy@....... Date: Sun, 2 Jan 2000 20:04:09 EST Check out the USA Current EQ Map, it's gone goofy, shows lots of Midwest activity! Mike http://cires.colorado.edu/people/jones.craig/EQimagemap/us.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman tilt sensitivity From: S-T Morrissey sean@........... Date: Sun, 2 Jan 2000 20:00:25 -0600 (CST) Marchal, Regarding estimating the sensitivity of a horizontal seismometer: The question you ask is somewhat ambiguous since many unknowns are involved. It is very hard to guess what a seis will do as you walk up to it, the main variable being the strength of the local support: floor, pier, isolated pier, rock outcrop, etc. And the orientation of the sensor with respect to the supporting medium and the induced disturbance is very important. For example, if the horizontal seis is located on a concrete flooring slab near a basement wall or foundation, the wall/foundation will provide more support than the open area and act as a hinge to the resulting tilting. So if the boom of the horizontal seis is parallel to the wall, the offset will be much more than if the boom is at a right angle to the wall or foundation. Tilting a horizontal seis along the axis of the boom only changes the mechanical period, while tilting across the boom axis can cause large displacements of the mass depending on the boom length and the operating period. Of course, since a horizontal seis is generally longer than it is wide, it is tempting to set up the seis with the boom axis parallel to the wall rather than sticking out into the room. And, also of course, all this depends on where you park your car. I showed and explained the applicable equations a few days ago. The most important point is that the tilt sensitivity is a function of the square of the period, like a 20-second seis is 4 times as sensitive as a 10-second sensor. The formulas also showed how the displacement sensitivity of eith a horizontal or vertical can be calibrated by tilting the base. A general method of estimating the sensitivity of any long-period seismometer (as is the Lehman design) is to look for the background 6-second microseisms. While these vary in amplitude by x 10 to x 100 depending on the seasons, locations in the world, hurricanes, typhoons, and storms in the North Sea, they are always present. The period ranges form 3 to 12 seconds, 6 being dominant, so a 10-second seis will be particularly sensitive if it under damped. (The flat velocity response of a VBB broadband system makes them obvious, but a 1-second seis will only show them at high (100k) magnifications. Today at St. Louis the microseisms started out at about 2 microns, but have decreased to about 0.4 microns as the storm causing them moved away from the New England coast. With my sensitivity of 5.29 mv/u/sec (millivolts/micron/second), 5 mv is about 1 u/sec, which is about 1 micron at 6 seconds (since omega = 2*pi/T = 1 if T = 2*pi). With my simple 12-bit digitizer, 5 mv is 50 counts out of 2048, or about 2.5%. If I had a 16-bit digitizer, I would want the microseisms to be about 5%, or 1600 counts, which would provide nanometer resolution at 1 second. You mention that your system shows 3500 counts of tilt as you walk up to it. A 16-bit system maximum is about 32000 counts, so your tilt noise is about 9%. Unless you have a very competent site, I would expect a much larger tilt. I would look for the microseisms to be at least 1000 counts. Maybe someone who is operating the Lehman design can let us know what their microseism levels are, or even what their experience is with induced tilting. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: "David A. Nelson" davenn@........ Date: Tue, 4 Jan 2000 00:18:07 +1300 unfortunately we have a bunch of SDR's in NZ that wont run the later versions of SDR we are using ver1.8 which is the latest version that can be run anothe fix for this comma problem would be appreciated as we cant get our files into winquake Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: BOB BARNS roybar@........ Date: Mon, 03 Jan 2000 09:51:41 -0500 Hi, The comma problem looks to be a problem with WinQuake, not SDR. When I downloaded and installed WQ2.6.8, the problem went away. Bob Barns "David A. Nelson" wrote: > > unfortunately we have a bunch of SDR's in NZ that wont run the later > versions of SDR > we are using ver1.8 which is the latest version that can be run > > anothe fix for this comma problem would be appreciated as we cant get > our files into winquake > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 23 Duncan St., > Dunedin, > South Is.. New Zealand. > > http://www.seismicnet.com/dave/home.htm > > IF there indeed are other parallel universes... I can now rest in the > knowledge, that in at least one of them, I am filthy rich and drive a red > Ferrari > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Comma's From: meredith lamb mlamb1@.......... Date: Mon, 03 Jan 2000 10:14:16 -0800 "David A. Nelson" wrote: > unfortunately we have a bunch of SDR's in NZ that wont run the later > versions of SDR > we are using ver1.8 which is the latest version that can be run > > anothe fix for this comma problem would be appreciated as we cant get > our files into winquake > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 23 Duncan St., > Dunedin, > South Is.. New Zealand. > Hi Dave, I'd still try one gambit with older SDR recording computers, and that is too just use a year date the computer can work with. Then change the event file date later on your Winquake file reading computer. I'd strongly suggest reformatting the old drive and entering in a year date as old as the computer itself, and, a year date MONTH that matchs 2000 itself. If you need to change year date thereafter, one must use a year date beyond the bios I think (or it will likely crash). 1976 I think matches the year 2000 for each month. If the computer doesn't accept that, one will have to consult the Windows "date/time" calender for a month that matches 2000. Currently Windows 95 system shows the years 1983 and 1994 as only matching the month of January 2000. Of course another method is too do the above, leave the system running as is, and take careful note of the files date as related too the real date...then change the files data date. Very inconvenient approach....but it might work until other reparations arrive, or, newer systems can be obtained. Yes, this is nothing new......but I don't see any other approach magically fixing old systems otherwise. I don't think anyone or a program will arrive concerning older systems in this regard normally. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: From: "Finke, John E." Finke@........... Date: Mon, 3 Jan 2000 12:25:26 -0500 I am looking for a copy of the following publication, which I understand to be out of print, and thought that perhaps someone within this group might have some information or even an extra copy they are willing to part with. Incidentally, I have been to all the major online book wholesalers and retailers even some minor ones. Also I tried the actual publisher all to no avail. The publication is "The Assessment and Mitigation of Earthquake Risk" Published by UNESCO (United Nations Educational, Scientific, and Cultural Organization). The ISBN is 92-3-101451-X. Thanks, John Finke, P.E., S.E. finke@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismographs for students From: Ruediger Wisskirchen rwisskirchen@....... Date: Sun, 02 Jan 2000 23:43:34 +0200 barry lotz wrote: > Ruediger > It may work as a strong motion sensor. I agree with Ted, usually you want > the natural period of the sensor to be longer than the lowest period you want > to record. Also since the output would be a function of the # of wire coils > turns you may have a very low output signal . Speakers usually have few turns. But is it possible, that the strong magnet more than compensats this disadvantage? A simple test with a big loudspeaker, a simple amplifier with a 741 and amp.factor 100 gives a strong signal, when I just make a bit wind with my hand against the membran. > > What you describe maybe the begining of a force balance sensor but you would > need a displacement sensor included which would complicate matters. I have read the article about the force-balance-seismometer, but due to my oor english I haven`t quite understood the difference between the forcebalance and the lehman-sensor. Why do you need a displacement sensor? > Do you have > access to magnet wire and simple rectangular magnets? You could use an electric > drill and wind your own coil of 1000+ turns on say a old spool like an empty > solder spool. Is it better for a high voltage to have a short coil with much layers or does a long coil with the same number of wires produeces the same effect? > You could then put a rectangular magnet on both sides of the > coil. As Ted says you probable will have more interesting events if you do not > attach the groung to the end of the boom except as I have described above. I > hope this helps a little. Most of us look around to find possible sensor > parts from devices use for other things, for example computer harddrive driver > as sensor/coil pairs. I still have some old harddisks, thanks for that hint. > > Barry > > ted@.......... wrote: > Thanks Ruediger Wisskirchen (rwisskirchen@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SDR and Replay Mode From: meredith lamb mlamb1@.......... Date: Tue, 04 Jan 2000 09:58:24 -0800 Hi all, Am running SDR V2.71 and trying to use the replay mode and consistently getting the "not found" screen notice. Actually, I've had older versions and unfortunately have never been successful. Otherwise the program itself runs fine. Checking under the windows 95 system, the program shows the SDR program contents as: (file)0001(year/month) chan1.002 chan1.003 chan1.004 chan1 etc........showing other channels The replay mode screen shows: File C:\SDR\Chan1.001 not found. - Press Any Key NOW......under SDR is a listed year date subfile: 0001 With nothing in it. Maybe this is where the data should be, but its empty. Any resolutions or suggestions? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Comma's From: "Randall Pratt" randallpratts@.............. Date: Tue, 4 Jan 2000 09:30:43 -0800 I have changed the format for file naming in EMON to move the year to a later portion of the name and I get the same result. For example file P0300AN.rlp has a comma also. By using the windows option to open file type ..rlp the file will open but the date of the file start is shown as 1/03/100. It appears that a fix might be to read the file into a structure and change the year field or at least find out what is being saved as a year in the header of the event file. Randy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A "wonder magnet" really is... From: meredith lamb mlamb1@.......... Date: Tue, 04 Jan 2000 15:08:13 -0800 Hi all, Looking at Wondermagnets products I see item #16 as a mystery magnet....I can't envision what it was ever used for? http://www.wondermagnet.com/dev/magnet16.html I've seen these before and they are basically two thick sheets of ferrite glued together and (sometimes) painted. Essentially they are 2 magnets together or using another phrase they are a 4 pole magnet. Although somewhat "U" shaped, with a semi-circular cut-out, the conflicting fields present problems with uses like seismic instruments.......they are way too big to handle anyway. The center cutout offers no outstanding field as is. Nothing is known of any accessory soft iron core material exactly. Robert Lamb says he's seen them with a backing plate, and, with a plate that covers roughly the circumference of the hole with two magnets. They almost look like they were originally designed to go part way around a pipe (roughly 3.7" diameter). Some kind of plumbing use? Some kind of early day accelerator use? Dinosaur (cow) pill from swallowing magnetic metorites? OK.....OK....I get carried away....ha. Carry on with your computer glitches.... Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A "wonder magnet" really is... From: "Dewayne Hill (n0ssy)" n0ssy@.......... Date: Wed, 05 Jan 2000 00:01:09 +0000 These magnets are out of an IBM 3360(?) disk drive. I have three of them and the are VVVVVVVVVVVVVVVery strong. The poles are across (side to side) and not end to end. You don't want to get your fingers between two of them... Dewayne Hill >Hi all, > >Looking at Wondermagnets products I see item #16 as a >mystery magnet....I can't envision what it was ever used for? > >http://www.wondermagnet.com/dev/magnet16.html > >I've seen these before and they are basically two thick sheets >of ferrite glued together and (sometimes) painted. Essentially >they are 2 magnets together or using another phrase they are a >4 pole magnet. Although somewhat "U" shaped, with a >semi-circular cut-out, the conflicting fields present problems >with uses like seismic instruments.......they are way too big to >handle anyway. The center cutout offers no outstanding field >as is. Nothing is known of any accessory soft iron core >material exactly. Robert Lamb says he's seen them with a >backing plate, and, with a plate that covers roughly the >circumference of the hole with two magnets. > >They almost look like they were originally designed to go >part way around a pipe (roughly 3.7" diameter). Some kind of >plumbing use? Some kind of early day accelerator use? >Dinosaur (cow) pill from swallowing magnetic metorites? >OK.....OK....I get carried away....ha. > >Carry on with your computer glitches.... > >Meredith Lamb > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > Dewayne Hill (n0ssy) Westminster, Colorado USA 39.83569n 105.0627w Elev. 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A "wonder magnet" really is... From: meredith lamb mlamb1@.......... Date: Tue, 04 Jan 2000 20:38:31 -0800 "Dewayne Hill (n0ssy)" wrote: > These magnets are out of an IBM 3360(?) disk drive. I have > three of them and the are VVVVVVVVVVVVVVVery strong. The > poles are across (side to side) and not end to end. > You don't want to get your fingers between two of them... > > Dewayne Hill > Hi Dewayne, I'am kind of amazed at this answer. Maybe I shouldn't be, perhaps they are like 60's or 70's vintage age? I've messed with them before somewhat, and although their gauss isn't terrific, their mass bulk (about 4 lbs) certainly contributes a great deal of hazard/finger wise. Thanks for a answer...it's one of those things I've wondered about for some time. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: Earth Science Student- Looking for A Siesmic Station From: Bill Scolnik wls@......... Date: Tue, 04 Jan 2000 23:28:55 -0500 I received this today and I'm afraid I can't help him. Can anyone here help him with some photographs, etc? >From: BlueRoxy26@....... >Date: Tue, 4 Jan 2000 18:39:59 EST >Subject: Earth Science Student- Looking for A Siesmic Station >To: wls@......... >X-Mailer: AOL 4.0 for Windows 95 sub 26 > >Dear Mr. Scolnic, > > Hello, wy name is Whitney and I am a ninth grade, Earth Science >Student at a Catholic High School. I am doing a Science Fair Project for my >2nd semester project, it has to do with seismographs. My teacher, Bro. Nigel >Pratt, said that I should visit a seismic station. When I looked seismic >stations on-line the closest one I found was this one in Oakland, NJ. If you >could send me some information on this seismic station, and many pictures of >it, I would be very greatful! Thank you for your time. > >P.S.- The project is due on January 14, so the sooner you respond the happier >I'll be thank you so much! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Fwd: Earth Science Student- Looking for A Siesmic Station From: "Robert W. Avakian" ravakian@............ Date: Tue, 04 Jan 2000 23:39:27 -0600 But where is he located? His best bet for a real time visit is a college or University, but without knowing where he is located, that's hard to recommend. Bob Avakian ?Bill Scolnik wrote: > > I received this today and I'm afraid I can't help him. Can anyone here help > him with some > photographs, etc? > > >From: BlueRoxy26@....... > >Date: Tue, 4 Jan 2000 18:39:59 EST > >Subject: Earth Science Student- Looking for A Siesmic Station > >To: wls@......... > >X-Mailer: AOL 4.0 for Windows 95 sub 26 > > > >Dear Mr. Scolnic, > > > > Hello, wy name is Whitney and I am a ninth grade, Earth Science > >Student at a Catholic High School. I am doing a Science Fair Project for my > >2nd semester project, it has to do with seismographs. My teacher, Bro. Nigel > >Pratt, said that I should visit a seismic station. When I looked seismic > >stations on-line the closest one I found was this one in Oakland, NJ. If you > >could send me some information on this seismic station, and many pictures of > >it, I would be very greatful! Thank you for your time. > > > >P.S.- The project is due on January 14, so the sooner you respond the happier > >I'll be thank you so much! > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Fwd: Earth Science Student- Looking for A Siesmic Station From: BOB BARNS roybar@........ Date: Wed, 05 Jan 2000 10:30:00 -0500 Hi, I will reply to this directly to BlueRoxy26@....... and suggest that he come see my rig in Berkeley Heights. There are some pictures of my seis and another one on my web site at members.home.com/roybar Bob Barns Bill Scolnik wrote: > > I received this today and I'm afraid I can't help him. Can anyone here help > him with some > photographs, etc? > > >From: BlueRoxy26@....... > >Date: Tue, 4 Jan 2000 18:39:59 EST > >Subject: Earth Science Student- Looking for A Siesmic Station > >To: wls@......... > >X-Mailer: AOL 4.0 for Windows 95 sub 26 > > > >Dear Mr. Scolnic, > > > > Hello, wy name is Whitney and I am a ninth grade, Earth Science > >Student at a Catholic High School. I am doing a Science Fair Project for my > >2nd semester project, it has to do with seismographs. My teacher, Bro. Nigel > >Pratt, said that I should visit a seismic station. When I looked seismic > >stations on-line the closest one I found was this one in Oakland, NJ. If you > >could send me some information on this seismic station, and many pictures of > >it, I would be very greatful! Thank you for your time. > > > >P.S.- The project is due on January 14, so the sooner you respond the happier > >I'll be thank you so much! > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: computer power supply From: cparker@............... (Christian Parker) Date: Wed, 5 Jan 2000 08:56:03 -0700 (MST) Has anyone here ever tried to use the power supply from an old PC to power their seismometer electronics? I have one laying around so I was going to give this a try. The power supply outputs +12vdc and -12vdc from one of the connectors that normally connects to the motherboard. The pinouts of this connector are as follows: Pin Name Color Description 1 PG Orange Power Good, +5 VDC when all voltages has stabilized. 2 +5V Red +5 VDC (or n/c) 3 +12V Yellow +12 VDC 4 -12V Blue -12 VDC 5 GND Black Ground 6 GND Black Ground I'm wondering if this power is suitable for powering op amps? Christian Parker Boulder, CO cparker@............... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: "Raul J. Alvarez" ralvarez@........ Date: Wed, 05 Jan 2000 09:28:30 -0700 Christain, I suspect that you would have a lot of problems with hash (electrical noise) from this supply. This type of supply is a switcher. You probably be better off getting a +- 12 or 15 volt transformer type supply. Raul Alvarez Bellvue, CO Christian Parker wrote: > Has anyone here ever tried to use the power supply from an old PC to power > their seismometer electronics? I have one laying around so I was going to > give this a try. The power supply outputs +12vdc and -12vdc from one of the > connectors that normally connects to the motherboard. The pinouts of this > connector are as follows: > > Pin Name Color Description > 1 PG Orange Power Good, +5 VDC when all voltages has stabilized. > 2 +5V Red +5 VDC (or n/c) > 3 +12V Yellow +12 VDC > 4 -12V Blue -12 VDC > 5 GND Black Ground > 6 GND Black Ground > > I'm wondering if this power is suitable for powering op amps? > > Christian Parker > Boulder, CO > cparker@............... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: To see a seismograph in New Jersey From: CapAAVSO@....... Date: Wed, 5 Jan 2000 12:10:22 EST Whitney can see an excellent amateur-built seismograph at the Nature Center in Rifle Camp County Park in West Paterson, NJ. Call 201 523 0024 to check visiting hours. Just across the NJ boarder in Palisades, NY is Columbia University's Geological Observatory which is the Eastern Networks seismic center with many professional seismographs. There is only one visiting day a week but I'm sure they would be happy to show Whitney their seismographs for his science fair project. Cap _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: "Charles R. Patton" crpatton@...... Date: Wed, 05 Jan 2000 10:11:08 -0800 Christian, In addition to Raul J. Alvarez=92s quite accurate comment to be concerned= about hash from the supply due to the switcher topology used, two other important points come to mind: 1) Many of those PC type P/S require a minimum load. Without that minimum load, regulation and in some cases, the P/S itself fails catastrophically. A typical technique we often used when trying to do certain types of tests on the P/S itself was to load the 5V to about 2A or more or the 12V to 1A with a fixed resistor. 2) Cross regulation is often less than satisfactory. I.e., the +12 V and +5 V are sometimes regulated by the ratio of the windings in the transformer and only the +5 V is actually feedback to the switcher control circuits, so consequently the +12 V is subject to greater variation since the voltage drops in the P/S circuit under changing load are not compensated for. Anecdotal notes about P/S hash. 1) Solving EMI (ElectroMagnetic Interference problems, i.e., hash) was one of the main aspects of my job at a disk drive manufacturing company. There were multiple incidents where a poorly designed switcher was putting out incredibly difficult to remove hash on the supply=92s output lines that found its way into the disk drive effecting the read performance. One way of looking at it is that a disk drive consists of a magnetic field sensor (a read head) generating tens of microvolts of signal in the 10 MHz to-50 MHz region inside a shielded enclosure. If this can be effected, then so can a seismometer. 2) I just finished putting together a new PC with all new parts. My wife was not happy with the fact that whenever it was on she could not receive a certain AM station. The cure turned out to be that I had to add a Corcom line filter on the AC power cord entering the computer, which completely cured my problem. The point, though, was that the tower case I bought was cheap (the only correct word for a $69 tower case with P/S) and so did not have adequate line filtering on the AC line side, and this is a brand new, ATX level P/S. So hash problems are not confined to old designs or just the load side. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: meredith lamb mlamb1@.......... Date: Wed, 05 Jan 2000 11:19:27 -0800 Christian Parker wrote: > Has anyone here ever tried to use the power supply from an old PC to power > their seismometer electronics? I have one laying around so I was going to > give this a try. The power supply outputs +12vdc and -12vdc from one of the > connectors that normally connects to the motherboard. The pinouts of this > connector are as follows: > > Pin Name Color Description > 1 PG Orange Power Good, +5 VDC when all voltages has stabilized. > 2 +5V Red +5 VDC (or n/c) > 3 +12V Yellow +12 VDC > 4 -12V Blue -12 VDC > 5 GND Black Ground > 6 GND Black Ground > > I'm wondering if this power is suitable for powering op amps? > > Christian Parker > Boulder, CO > cparker@............... > > Christian, I'am sure I'am stepping into this subject where I don't belong, but from my recollection from my brother, he has used these very supplys for various electronic experiments. Without further details, I would think that they might need additional power supply filters (capacitors) on the output. Usually one of the switching supply voltages is very limited on current capacity; so, one would have to watch that. Also "if" I recollect right.....(ahem), he stated that they are better than the regular power supplys for transient protection (spikes). J.B. Saunders surplus there in Boulder also has a wide variety of various types of power supplys there in Boulder; which might work. Of course the normal dual voltage supplys are somewhat rare compared to the switching supplys in quanity. One might consider buying 2 regular transformer DC supplys to join together to make the dual supply. Radio Shack also has these cheap single supplys available. The one remaining subject of power supplys is their regulation performance. Perhaps for amateur projects this can be fairly passed over, as the normal use involved doesn't normally cause problems where the sensor/s is coil/magnet and ampifier. I actually used one switching supply on my Hall seismometers for awhile, till it went kapoot. (I still saw transient spikes.... mainly from the house furnace motor...ha) Without knowing specifically what you are trying to do, its hard to recommend something. If you intend to lean toward a coil and magnet affair; I would suggest buying from Larry. His stuff works fine. The trouble with home brew is that one can usually end up spending more than buying commercially; and, end up with something less than the quality they would get if they had only just bought the stuff to begin with. Yes....electronics and computers drive me bugs....ha. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: ted@.......... Date: Wed, 5 Jan 2000 14:00:08 -0500 Meredith, You're not the only one that gets driven buggy by electronics and computers. My first Lehman amplifier would not work right for a year, but when I would send it to friends who knew what they were doing it would work fine. It finally dawned on me that it takes more than 2 6-volt lantern batteries in series to get +/- 12V. Like maybe 4? Duh... Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: output of speaker coil From: S-T Morrissey sean@........... Date: Wed, 5 Jan 2000 13:36:46 -0600 (CST) Ruediger, Re the output of a large speaker for potential use as a seismometer: Your experiment with the 100x amplifier and speaker does show that the moving coil can generate a voltage with indescernable motions, like fanning air against the speaker. This, however, is a very large signal when compared with seismic ground motions. In fact, even miniscule thermal convection WITHIN the case of a seismometer can be a large signal, and we have resorted to small (10 watt) heaters in the topmost part of large seismometer cases to try to stratify (hotter at the top) the air within the case. We also put insulation between the pier and the bottom of the case, since earth heat transmitted through the pier would cause a thermal inversion within the case. Some modern and pricy VBB sensors are installed in a vacuum bell. Here are some numbers that may help clarify the sensitivity question. I have measured the coil constant of several large speakers, and the constants run from 10 to 20 Volts/meter/second. By comparison, small high-frequency geophones run about 40 V/M/s, larger 1 hz and up seismometers run 200 to 500, and fedback (electronic) seismometers have an output of 1000 V/m/s and up. In our normal use of a 1 hz seismometer with 270 V/m/s (the L-4C with a 5500 ohm coil), remote station sites have required amplifier gains of 60 to 78 db (x 1000 to x 8000) for optimal sensitivity to both near-field and distant earthquakes. We use a damping/attenuation network that provides 100V/m/sec into the amplifier, which after the gain of 4000, gives 0.4 volt/micron/second. With an electronic noise level of around 1 millivolt, our resolution is about 2.5 nanometers/second, and our maximum signal is 4 volts = 10 microns/second. (I have such a "short period" telemetered station in the back field of the farm here). The station is sensitive to any Mb 3.0 event within several hundred kilometers, and most 1-second p-waves from teleseisms. So to use a speaker with 10 V/m/sec, an amplifier gain of about 10 times what we use for the L4-C would be needed, or something like 8000 to 80,000. This could result in a fairly noisy amplifier since several stages would be required (we use two stages for the 78db amplifier; the schematic of which is posted). But this is workable with proper filtering. But a low output from the coil/magnet is not the main problem with a speaker. The compliance of the speaker suspension is rather stiff for seismometer use. I chopped a speaker cone and the back webbing into spider strips to still support the coil, but was unable to sense the earth microseism background of about 1 micron at 6-seconds. Since I had glued on about 10 each 1/4" lead shot balls as a mass, eventually the speaker suspension sagged and the coil dragged. I think that carefully winding a coil (ie forget the drill) for a maximum number of turns within the magnet gap, but enough length either side to have a linear output, will produce the best signal. The output increases with the square root of the coil resistance if all the other dimensions are the same (ie more turns means smaller wire in the same volume so the resistance increases; see the Riedesel paper). But given unlimited space, it is a function of the number of turns within the magnet gap. Various trade-offs seem to favor using wire about #36 size to achieve coils of a few thousand turns and several hundred ohms for strong magnets. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Antique Seismographs From: Larry Cochrane cochrane@.............. Date: Wed, 05 Jan 2000 14:42:44 -0800 Anyone know what this is? Please CC the sender since they are not on the list. Thanks, -Larry >Date: Wed, 05 Jan 2000 17:34:51 -0800 >From: Paul Hayton >Organization: interlog.com >X-Mailer: Mozilla 4.08 [en] (Win95; I) >To: cochrane@.............. >Subject: Antique Seismographs > >Hi there.. enjoyed looking through your site today. > >I have a mystery instrument, that I am guessing has something to do with >seismology... if you could have a look and give me your opinion, much >appreciated. > >http://www.concept.ca/mystery1.jpg > >Thanx again > >Cassie >>^..^<< > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Antique Seismographs From: "steve hammond" shammon1@............. Date: Thu, 6 Jan 2000 00:09:36 -0800 Is there magnets or a compass inside it? Is that an eye cup in the top? What is in the lower window? a mirror? Please reply to the PSN-L@.............. Regards, Steve Hammond PSN San Jose/Aptos California -----Original Message----- From: Larry Cochrane To: PSN-L@.............. Date: Wednesday, January 05, 2000 2:43 PM Subject: Antique Seismographs >Anyone know what this is? Please CC the sender since they are not on the list. > >Thanks, > >-Larry > >>Date: Wed, 05 Jan 2000 17:34:51 -0800 >>From: Paul Hayton >>Organization: interlog.com >>X-Mailer: Mozilla 4.08 [en] (Win95; I) >>To: cochrane@.............. >>Subject: Antique Seismographs >> >>Hi there.. enjoyed looking through your site today. >> >>I have a mystery instrument, that I am guessing has something to do with >>seismology... if you could have a look and give me your opinion, much >>appreciated. >> >>http://www.concept.ca/mystery1.jpg >> >>Thanx again >> >>Cassie >>^..^<< >> >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: Mystery1.jpg From: DGentry509@....... Date: Thu, 6 Jan 2000 15:51:24 EST Additional info on the subject item. Very interesting. Hope someone can figure this out. DRG Hi there... Thank you for your email.... here is my layman's (woman's) description of this mystery object. Made of brass, the main tube is 7 inches long, it has three legs that unfold from the base, independent of each other. (I believe so it can be made level on any surface.) There is a smaller brass tube suspended inside the main tube. There are cross hairs at the top, a rather thick metal cross with a conical type center that is about a 1/2inch in depth. The glass viewing lens at the top is gimbaled. I do not believe this to be a microscope as the magnification is very slight. When looking in, you see the bottom of the inner brass tube. It is silvered with etched concentric circles. You can also see 4, equally spaced screws jutting inwards from the tube about half way down. There is a slide lever on the outer tube (near the bottom) to raise and lower the inner tube, however it is stiff. It is much easier to twist the outer brass tube and the lever slides accordingly. There is also an inner glass tube which forms the windows, this glass tube slides up, I assume to allow access to the inside. There are holes in the brass tube which appear to allow for the glass to be held up in place if needed simply by inserting something to hold it in place. When I have it sitting on a still surface and I shake the surface slightly, the inner tube sways in a pendulum motion. It is very sensitive, as I type on my keyboard I can see the inner brass tube swaying in a circular motion. The lable on the inside of the box reads as follows (and I'm guessing as the handwriting is not clear) Presented to A.S.E Ackerman Esquire (it could be Dr. S.E) by Horatio Nelsin Crelliun June 1910 The lable on the outside of the box reads H. England The wooden box has a hinged lid, the hinges read P Moore Patent #2 Thanking you in advance for your time and energy in looking at this mysterious item. Look forward to hearing from you soon. Cassie >>^..^<< ==== DGentry509@....... wrote: > Paul, am trying to figure out what this unit is. > > Do you have it? The paper looks like it says Dr. S.E. ............Esquire > and the date June 1910 > > Looks to me like a microscope of some sort and uses the 90 degree slanted > slot for focus (depth adjustment) just like my router. > > I'm not able to get to anywhere past your initial web page index. > > Do you have dimensions? > > Was directed to your page by a group of amateur seismologists. > > Thanks, Don Gentry Subject: Re: Mystery1.jpg From: ChrisAtUpw@....... Date: Thu, 6 Jan 2000 17:20:14 EST Cassie, If you could put a clear photo of the label on your site, it might help. I think that the letter before S.E. is probably Lt (Lieutenant) indicating either a military or naval origin ?Level meter ?Surveying. Is there anything to indicate that the instrument is not complete, or that formerly mirrored surfaces have corroded? Have you asked any of the Science Museums if they can recognise it? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: barry lotz gbl@....... Date: Thu, 06 Jan 1983 03:05:59 -0800 What I'd like to find is an inexpensive dual output "wall wart" rather than a single output one and have to split the output with an opamp. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR and Replay Mode From: barry lotz gbl@....... Date: Thu, 06 Jan 1983 05:30:02 -0800 Meredith, Larry I think I have a similar situation. With the Santa Cruz 6.0 event , the event spanned over a two day local (Pacific) time. When I replayed or tried to save the event with a display window that spanned the full event time, it stopped at the end of the first days record and I couldn't save the file. If I set the replay display window to a short time( ie stop before the end of the first day ) but saved a 60-70 sec window, it save the file fine. It may be in the display routine and not the save section. Barry meredith lamb wrote: > Hi all, > > Am running SDR V2.71 and trying to use the replay mode and > consistently getting the "not found" screen notice. Actually, I've > had older versions and unfortunately have never been successful. > Otherwise the program itself runs fine. > > Checking under the windows 95 system, the program shows > the SDR program contents as: > > (file)0001(year/month) > chan1.002 > chan1.003 > chan1.004 > chan1 > etc........showing other channels > > The replay mode screen shows: > > File C:\SDR\Chan1.001 not found. - Press Any Key > > NOW......under SDR is a listed year date subfile: > > 0001 > > With nothing in it. Maybe this is where the data should be, > but its empty. > > Any resolutions or suggestions? > > Thanks, Meredith Lamb > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: Re: Antique Seismographs] From: Steve Hammond Shammon1@............. Date: Thu, 06 Jan 2000 20:01:32 -0800 Hi there, thanx for the email.... okay the mystery item is as follows... Made of brass, the main tube is 8inches long, it has three legs that unfold and are independent of each other, I believe so it can be made level on any surface. There is another brass tube suspended inside the main tube. There are cross hairs at the top, a rather thick metal cross with a conical type center. the glass lens at the top is gimbaled. The base of the inner suspended brass tube i silvered with etched concentric circles. There is a slide lever on the outer tube to raise and lower the inner tube. When I have it sitting on a still surface and I shake the surface slightly, the inner tube sways like pendulum and you can see how far it has moved by the rings at the bottom. The little window of curved glass slides up to give access to the area inside. I really have no idea what this thing is! The lable on the inside of the box reads as follows (and I'm guessing as the handwriting is not so clear) Presented to A.S.E Ackerman Esquire by Horatio Nelson Crelliun June 1910 The lable on the outside of the box reads H. England Thanx for any help you can give, Cassie >>^..^<< steve hammond wrote: > Is there magnets or a compass inside it? Is that an eye cup in the top? What > is in the lower window? a mirror? > Please reply to the PSN-L@.............. > Regards, Steve Hammond PSN San Jose/Aptos California > > -----Original Message----- > From: Larry Cochrane > To: PSN-L@.............. > Date: Wednesday, January 05, 2000 2:43 PM > Subject: Antique Seismographs > > >Anyone know what this is? Please CC the sender since they are not on the > list. > > > >Thanks, > > > >-Larry > > > >>Date: Wed, 05 Jan 2000 17:34:51 -0800 > >>From: Paul Hayton > >>Organization: interlog.com > >>X-Mailer: Mozilla 4.08 [en] (Win95; I) > >>To: cochrane@.............. > >>Subject: Antique Seismographs > >> > >>Hi there.. enjoyed looking through your site today. > >> > >>I have a mystery instrument, that I am guessing has something to do with > >>seismology... if you could have a look and give me your opinion, much > >>appreciated. > >> > >>http://www.concept.ca/mystery1.jpg > >> > >>Thanx again > >> > >>Cassie >>^..^<< > >> > >> > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: [Fwd: Re: Antique Seismographs] From: "steve hammond" shammon1@............. Date: Thu, 6 Jan 2000 21:32:41 -0800 -----Original Message----- From: Steve Hammond To: psn-l@.............. Date: Thursday, January 06, 2000 9:02 PM Subject: [Fwd: Re: Antique Seismographs] Paul, is the bottom a plate or is there a hook or loop at the bottom of the inner tube. Also, looking in the window, I can see metal. is it attached to the tube and could it have been or is it magnetic? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: SDR and Replay Mode From: "Giovanni Rotta" rottag@.......... Date: Fri, 7 Jan 2000 06:30:03 +0100 With the version 2.7 of SDR I have not problem. Have a nice day. Giovanni Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.resianet.org ----- Original Message ----- From: barry lotz To: PSN-L Mailing List Sent: Thursday, January 06, 1983 2:30 PM Subject: Re: SDR and Replay Mode > Meredith, Larry > I think I have a similar situation. With the Santa Cruz 6.0 event , the > event spanned over a two day local (Pacific) time. When I replayed or tried > to save the event with a display window that spanned the full event time, > it stopped at the end of the first days record and I couldn't save the > file. If I set the replay display window to a short time( ie stop before > the end of the first day ) but saved a 60-70 sec window, it save the file > fine. It may be in the display routine and not the save section. > Barry > > > meredith lamb wrote: > > > Hi all, > > > > Am running SDR V2.71 and trying to use the replay mode and > > consistently getting the "not found" screen notice. Actually, I've > > had older versions and unfortunately have never been successful. > > Otherwise the program itself runs fine. > > > > Checking under the windows 95 system, the program shows > > the SDR program contents as: > > > > (file)0001(year/month) > > chan1.002 > > chan1.003 > > chan1.004 > > chan1 > > etc........showing other channels > > > > The replay mode screen shows: > > > > File C:\SDR\Chan1.001 not found. - Press Any Key > > > > NOW......under SDR is a listed year date subfile: > > > > 0001 > > > > With nothing in it. Maybe this is where the data should be, > > but its empty. > > > > Any resolutions or suggestions? > > > > Thanks, Meredith Lamb > > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: AC-DC, DC-DC modules From: S-T Morrissey sean@........... Date: Fri, 7 Jan 2000 00:37:32 -0600 (CST) Barry, I have recently purchased some DC supply components from Newark and Jameco: Newark: 83F9250 Dual DC-DC, +,- 15V, 67ma, 12-18Vin $14.47 83F9256 Single DC-DC, +15V, 133ma, 12-18Vin $14.47 (Many other 2-watt options are available, like 12 Vout at higher I; I then further regulate the +,- 15 V to +,-12, to 0.001%.) (I use a AC-DC wall-brick for the raw DC source.) Jameco has the DATEL 3-watt "BWR-15/100 D12" DC-DC supply: 12Vin, +,- 15Vout, at 100ma, Cat# 155782, for $7.25 (usually about $40 from Newark) Also a collection of AC/DC wall modules, like #129331, 12V,800ma output, $6.95. They also have lower I for as low as $4, so use two. (Jameco: 1 800 831 8242) These last two will let you make a well (0.1%) regulated supply for under $15. Regulation at 0.1% is adequate for most seismic amplifiers, but better stability is needed for a fedback instrument. The DATEL unit is 3cm x 2cm x 1cm high. Regards, Sean-Thomas !p _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR and Replay Mode From: Larry Cochrane cochrane@.............. Date: Thu, 06 Jan 2000 23:08:49 -0800 Barry, The problem Meredith is having is he can't get the replay mode work at all. I just email him a list of instructions to try to debug the problem. SDR should be able to create an event file that spans over midnight but you can not create an event file longer then one day, or 23 hour 59 minute 59 seconds in length. If you are having problems with creating a file the spans over midnight, either local or UTC, please let me know. This works fine on my SDR systems, but I run my systems on local time and supply a UTC offset. This problem may have to do with running the system on UTC time and setting the UTC offset to 0. So, if you run into this problem please let me know if you are running your system on local time or UTC time. -Larry Cochrane Redwood City, PSN At 05:30 AM 1/6/83 -0800, you wrote: >Meredith, Larry > I think I have a similar situation. With the Santa Cruz 6.0 event , the >event spanned over a two day local (Pacific) time. When I replayed or tried >to save the event with a display window that spanned the full event time, >it stopped at the end of the first days record and I couldn't save the >file. If I set the replay display window to a short time( ie stop before >the end of the first day ) but saved a 60-70 sec window, it save the file >fine. It may be in the display routine and not the save section. >Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: "Jim Cristiano" cristiano@........... Date: Fri, 7 Jan 2000 07:50:38 -0800 -----Original Message----- From: barry lotz To: PSN-L Mailing List Date: Thursday, January 06, 2000 5:59 PM Subject: Re: computer power supply >What I'd like to find is an inexpensive dual output "wall wart" rather than a >single output one and have to split the output with an opamp. >Barry Hi, Just buy two 12V wall adapters and tie the + of one to the - of the other and that is your ground. Now you've got a +/- w/ gnd power supply. Slap on some regulators if you want. Jim Cristiano _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: ted@.......... Date: Fri, 7 Jan 2000 11:31:20 -0500 Larry sells a "wall wart" power supply for his amplifier cards which provides +/- 15V AC with ground from a single module. I guess he rectifies that to DC on the amplifier card. I like this arrangement because there is no 115V power anywhere any of us (or a kid) can reach it. I don't know if he has an unlimited supply of these or not. Regards, Ted "Jim Cristiano" on 01/07/2000 10:50:38 AM Please respond to PSN-L Mailing List To: "PSN-L Mailing List" cc: Subject: Re: computer power supply -----Original Message----- From: barry lotz To: PSN-L Mailing List Date: Thursday, January 06, 2000 5:59 PM Subject: Re: computer power supply >What I'd like to find is an inexpensive dual output "wall wart" rather than a >single output one and have to split the output with an opamp. >Barry Hi, Just buy two 12V wall adapters and tie the + of one to the - of the other and that is your ground. Now you've got a +/- w/ gnd power supply. Slap on some regulators if you want. Jim Cristiano _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: Larry Cochrane cochrane@.............. Date: Fri, 07 Jan 2000 16:22:23 -0800 I have them in stock and can get more. The cost is $15.00 + shipping. -Larry Cochrane Redwood City, PSN At 11:31 AM 1/7/00 -0500, you wrote: > > >Larry sells a "wall wart" power supply for his amplifier cards which >provides +/- 15V AC with ground from a single module. I guess he rectifies >that to DC on the amplifier card. I like this arrangement because there is >no 115V power anywhere any of us (or a kid) can reach it. I don't know if >he has an unlimited supply of these or not. > >Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: computer power supply From: barry lotz gbl@....... Date: Fri, 07 Jan 2000 17:44:49 -0800 Ted Yea, that's probably the way to go. I'll put a full bridge rectifier etc... Currently ( no pun intended) I use a 24 vt center tap transformer to 115 vts. I agree with the wall power concern. I like Sean Thomas's idea of higher voltages. I have been so brainwashed into lower voltages that I lost the advantage of higher voltages in AD resolution. Barry Larry Cochrane wrote: > I have them in stock and can get more. The cost is $15.00 + shipping. > > -Larry Cochrane > Redwood City, PSN > > At 11:31 AM 1/7/00 -0500, you wrote: > > > > > >Larry sells a "wall wart" power supply for his amplifier cards which > >provides +/- 15V AC with ground from a single module. I guess he rectifies > >that to DC on the amplifier card. I like this arrangement because there is > >no 115V power anywhere any of us (or a kid) can reach it. I don't know if > >he has an unlimited supply of these or not. > > > >Regards, Ted > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR and Replay Mode From: barry lotz gbl@....... Date: Fri, 07 Jan 2000 18:11:36 -0800 Larry I have no (direct) problem saving an event that spans midnight (local time). I just have to go thru a little more to do it. First I'm using V2.7. My usual routine is to replay a time window which spans the event. I then go back and save the same. The problem I encountered was when I tried to replay a time window which spanned midnight the computer plotted the time til midnight and then said "End of file- Press esc to quit , S to save data, N for next day". The S option gives an "err : unable to save data- press any key ". Only esc works. The way I got around this was to -replay- a time window that stopped before midnight( say only 10 min) so I didn't get that message, but -save- the time window I desired (say 80 min). I have the "UTC" offset set to -8. I don't know if this has anything to do with it but I can't seem to be able to free enough conventional memory to run DOS while in SDR . It is perhaps that I am running 5 channels @ 25 sps with a 5min save before and after the trigger. The program is great as it is. I only brought it to you attention for your use. Barry Larry Cochrane wrote: > Barry, > > The problem Meredith is having is he can't get the replay mode work at all. > I just email him a list of instructions to try to debug the problem. > > SDR should be able to create an event file that spans over midnight but you > can not create an event file longer then one day, or 23 hour 59 minute 59 > seconds in length. > > If you are having problems with creating a file the spans over midnight, > either local or UTC, please let me know. This works fine on my SDR systems, > but I run my systems on local time and supply a UTC offset. This problem > may have to do with running the system on UTC time and setting the UTC > offset to 0. So, if you run into this problem please let me know if you are > running your system on local time or UTC time. > > -Larry Cochrane > Redwood City, PSN > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New event From: barry lotz gbl@....... Date: Fri, 07 Jan 2000 18:23:20 -0800 I happen to be looking at SDR. An event is coming in ; surface waves now @ 01/08/00 02:16 UTC. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: Canie Brooks canie@........... Date: Fri, 07 Jan 2000 18:26:10 -0800 At 06:23 PM 1/7/00 -0800, barry lotz wrote: >I happen to be looking at SDR. An event is coming in ; surface waves now >@ 01/08/00 02:16 UTC. >Barry From what I can tell from this site: http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm It may be in the Indonesia area... Nothing on any lists so far... Canie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: Roger Griggs rdg8@......... Date: Fri, 07 Jan 2000 18:34:05 -0800 I happened to have the monitor on and have a nice trace but it doesn't look like the Indonesia area. It looks alot closer. Still waiting for save to finish and put into winquake. Roger in Oakley At 06:23 PM 01/07/2000 -0800, you wrote: >I happen to be looking at SDR. An event is coming in ; surface waves now >@ 01/08/00 02:16 UTC. >Barry > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: barry lotz gbl@....... Date: Fri, 07 Jan 2000 18:49:13 -0800 I spoke to soon. There is a much closer event coming in also. Barry Roger Griggs wrote: > I happened to have the monitor on and have a nice trace but it doesn't look > like the Indonesia area. > It looks alot closer. Still waiting for save to finish and put into winquake. > Roger in Oakley _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: "David A. Nelson" davenn@........ Date: Sat, 8 Jan 2000 15:50:25 +1300 definately SW pacific very large on CTAO possibly anothe santa cruz event Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: Roger Griggs rdg8@......... Date: Fri, 07 Jan 2000 18:52:33 -0800 Barry, Just a wild guess, Mexico MI 6.5 or Southern Alaska. Looks like 950 miles from my station. But just a guess. Roger At 06:49 PM 01/07/2000 -0800, you wrote: >I spoke to soon. There is a much closer event coming in also. >Barry > > >Roger Griggs wrote: > >> I happened to have the monitor on and have a nice trace but it doesn't look >> like the Indonesia area. >> It looks alot closer. Still waiting for save to finish and put into winquake. >> Roger in Oakley > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New event From: barry lotz gbl@....... Date: Fri, 07 Jan 2000 20:04:00 -0800 I agree. The second one appears to be ~450k from me; Maybe ~4.7 off the coast of N Calif. or south of Mammoth. Barry David A. Nelson wrote: > definately SW pacific very large on CTAO > > possibly anothe santa cruz event > > Dave > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 23 Duncan St., > Dunedin, > South Is.. New Zealand. > > http://www.seismicnet.com/dave/home.htm > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Tonga Islands precursor From: Charlie Plyler cplyler@............. Date: Sat, 08 Jan 2000 17:27:40 -0500 It seems that the Tonga Island and Chile quakes had a recordable electrical precursor. If you wish to take a look go to: http://www.elfrad.com/Quake/Qinfo13.htm Charlie Plyler Elfrad Group _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tonga Islands precursor From: Karl Cunningham karlc@....... Date: Sat, 08 Jan 2000 17:46:09 -0800 Hi Charlie -- That's very interesting. For comparison, would it be possible to see a comparable chart (using the same vertical sensitivity, the same recording duration, and the same starting time) showing the background noise on a day when there were no major earthquakes? Thanks, Karl Cunningham At 05:27 PM 1/8/2000 -0500, you wrote: >It seems that the Tonga Island and Chile quakes had a recordable >electrical precursor. > >If you wish to take a look go to: >http://www.elfrad.com/Quake/Qinfo13.htm > >Charlie Plyler >Elfrad Group _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tonga Islands precursor From: Charlie Plyler cplyler@............. Date: Sat, 08 Jan 2000 21:54:20 -0500 Certainly Karl, To insure the same exact parameters, I will post a graph consisting of the results of tomorrow's recording. Hopefully, seismic activity will be minimal. Charlie Plyler Karl Cunningham wrote: > > Hi Charlie -- > > That's very interesting. For comparison, would it be possible to see a > comparable chart (using the same vertical sensitivity, the same recording > duration, and the same starting time) showing the background noise on a day > when there were no major earthquakes? > > Thanks, > Karl Cunningham _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tonga Islands precursor From: ajbv@............ Date: Sun, 09 Jan 2000 11:29:49 +0800 Hi Charlie, Most interesting, I also, would be interested to see the data prior to the event. Anyhow, this may be of interest to you, I'm putting together a fluxgate magnetometer , and the supplier of the fluxgate devices sent me this article. Long-term ELF background noise measurements, the existence of window regions, and applications to earthquake precursor emission studies. (Physics of the Earth and Planetary Interiors, 77 (1993) 109-125 Elsevier Science Publishers B,V, Amsterdam) You probably aware of the article, but, if you or a PSN reader is unable to obtain a copy through your library then email me and I'll "PDF" the document or fax it to you. (PSN Reader) I'm taking a stand alone digital approach to recording the earths magnetic field but with the aid of a simple circuit (F/V converter) you can record the magnetic field as analogue signal. Maybe another channel on SDR or EMON. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Measuring Time Delay From: Karl Cunningham karlc@....... Date: Sun, 09 Jan 2000 12:41:35 -0800 SDR has a time delay parameter that can be entered for each channel, to compensate for time delay in the seismometer. I'd like to make some measurements to be able to enter accurate values for these, and I'm curious how time delay of a seismometer is measured. I can easily see how it could be done with a shaker table, but not having that luxury, what are some other methods? One could, of course, test the electronics using a function generator, but I would really like to include the mechanical components as well. If all the filtering in the seismomter electronics is of the equal time delay (Bessel) characteristic, time delay is probably not a function of frequency in these circuits. But this probably doesn't apply to the mechanical response or to the overall response of the instrument to ground velocity. What about measuring the response to dropping some large object on the floor near the seismometer? The falling object could easily actuate a contact closure as a time reference when it hits the floor, but how are the results to be interpreted? What about a time delay measurement using real earthquakes? Could a simple reference instrument (geophone?) be used to do the calibration? Could a calculated time delay for a geophone be trusted? My questions are: 1. Given that the instrument probably does not have equal time delay response, is there a standardized frequency for which seismometer time delay measurements are made? 2. If pulse response is used (dropping the object on the floor), can the seismometer output just be bandpass filtered to the desired frequency, and the delay measured? If so, what kind of bandpass filtering should be used, and should its delay be considered? 3. In doing the pulse response measurement, is the proper delay measurement made to the first noticable change in the output, or to some other point in the output waveform? Any help or suggestions are appreciated. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: GeE777@....... Date: Sun, 9 Jan 2000 19:50:13 EST In a message dated 1/9/00 12:42:38 PM Pacific Standard Time, karlc@....... writes: >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> My questions are: 1. Given that the instrument probably does not have equal time delay response, is there a standardized frequency for which seismometer time delay measurements are made? 2. If pulse response is used (dropping the object on the floor), can the seismometer output just be bandpass filtered to the desired frequency, and the delay measured? If so, what kind of bandpass filtering should be used, and should its delay be considered? 3. In doing the pulse response measurement, is the proper delay measurement made to the first noticable change in the output, or to some other point in the output waveform? Any help or suggestions are appreciated. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I have invented a device to do just that on a vertical geophone. I use a DC voltage and apply it to the geophone output. This lifts the coil (or depresses it depending on the polarity), then this voltage is switched off and the output is connected to an oscilloscope or some othe devicee that can immediately measure the coil voltage output as it returns to the normal resting place. One can use this to measure the natural frequency and relative amplitude of the geophone. You can also measure the damping factor. George Erich on the + side http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: Arie Verveer ajbv@............ Date: Mon, 10 Jan 2000 09:06:43 +0800 Hi Karl, I used a coil connected to a battery and switch, when the switch was pressed it triggered a "CRO". After the delay period the seismographs output was measured directly on the "CRO". The coil was placed some 4 feet from the seismograph, this gave the necessary mechanical force via the magnetic pulse. The battery was 1.5 volts. The dampening adjustment was also set by this method. Arie > SDR has a time delay parameter that can be entered for each channel, to > compensate for time delay in the seismometer. I'd like to make some > measurements to be able to enter accurate values for these, and I'm curious > how time delay of a seismometer is measured. I can easily see how it could > be done with a shaker table, but not having that luxury, what are some > other methods? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman help From: "JIM MARTIN" jdmartin@.............. Date: Sun, 9 Jan 2000 20:20:47 -0500 Gentlemen, I am experiencing rather frustrating problems in getting my Lehman set up. I just finished the construction, and am now trying to get the boom to center. The boom is setup so that it has a VERY slight downward slant from level. I have leveled the base plate and it seems that no matter what I do to the leveling screws, the boom either performs a major swing to either the right or left. It takes almost NO turning of the leveling screw and the boom will go from a center of about 30 degrees to the right, to a center that is about the same except to the left. It seems as though I just can't get the darn thing to center up. I know a lot of you out there have built the Lehman, so I'm hoping that maybe someone can give me some assistance. Please help if you can.... Jim D. Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: JIm Hannon jmhannon@........ Date: Sun, 09 Jan 2000 19:49:53 -0600 JIM MARTIN wrote: > Gentlemen, > > I am experiencing rather frustrating problems in getting my Lehman set up. > I just finished the construction, and am now trying to get the boom to > center. The boom is setup so that it has a VERY slight downward slant from > level. I have leveled the base plate and it seems that no matter what I do > to the leveling screws, the boom either performs a major swing to either the > right or left. It takes almost NO turning of the leveling screw and the boom > will go from a center of about 30 degrees to the right, to a center that is > about the same except to the left. It seems as though I just can't get the > darn thing to center up. > > I know a lot of you out there have built the Lehman, so I'm hoping that > maybe someone can give me some assistance. > > Please help if you can.... > > Jim D. Martin > New Haven, Indiana Jim, The important tilt is the position of the upper and lower pivot points with respect to vertical. The action you describe is consistant with the upper pivot point being further from the mass in the horizontal direction than the lower pivot point. The angle of the boom itself is not particulary important. You should be able to use the leveling screws to adjust out your problem by lowering the mass end of the instrument. Then you can adjust the screws for tilt right or left to center the mass. There are actually two different adjustments made with the leveling screws. The centering which you are trying to do, and the period adjustment which you now have set to somewhere beyond infinite. Lowering the mass end of the instrument will decrease the period. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: ChrisAtUpw@....... Date: Sun, 9 Jan 2000 21:45:48 EST In a message dated 10/01/00 00:52:44 GMT Standard Time, GeE777@....... writes: >> I have invented a device to do just that on a vertical geophone. I use a DC voltage and apply it to the geophone output. This lifts the coil (or depresses it depending on the polarity), then this voltage is switched off and the output is connected to an oscilloscope or some other device that can immediately measure the coil voltage output as it returns to the normal resting place. Well, no actually. What you will get is a transient as you turn the bias current off which depends on the L, C and R of the geophone and it's circuit. This will be followed by the induced voltage transient as the system physically returns to it's rest position, which will again depend on the damping etc. of any connected circuit. I would not like to guess what you will actually see at the output end of a six pole Butterworth filter. I'm puzzled at the general use of Butterworth and not Bessel filters in the circuits on PSN. There won't be much difference on second order filters, but sixth order filters are another matter. >>One can use this to measure the natural frequency and relative amplitude of the geophone. Agreed. >>You can also measure the damping factor. Yes if the damping is sub critical. Over damped systems just show a broadening of the response, which is difficult to measure accurately. Have you tried testing a geophone by sitting it on a flat plate on small li-lo cushion filled with water? Then use a syringe to inject a ml of water. An impulse could be given to a horizontal seismometer by discharging a capacitor through a nearby coil of wire. The induced currents give a repulsive force. I'm puzzled why such accurate timing would be needed anyway for our use. With V = 6000 ft / sec, even 100 milliseconds will give an error of ~ 0.1 mile. Using geophones and explosives to do depth surveys is another ball game entirely. A piezo sounder disk makes quite a good accelerometer if you want to thump the floor. Attach the case with plasticene, bluetack, chewing gum etc and feed the output directly into the 'scope. I compared a 38mm sounder disk with a $200+ accelerometer and up to 300 Hz, the only difference was that the sounder disk gave the bigger signal. Otherwise you could overlay the traces on a dual beam 'scope. Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman help From: "JIM MARTIN" jdmartin@.............. Date: Sun, 9 Jan 2000 23:31:29 -0500 Thanks to Jim and Kevin, I now have a Lehman boom that is beginning to behave correctly. Thank you both for you help. In measuring the 'period' of the boom, is this the measurement of time it takes the boom to swing "out and back", when pushed, or the time it takes for the oscillations to die out completely? If I manually deflect the boom ~1" off of center, is the period the time it takes the boom to come back to center, or the time it takes the boom to move out to one side and then back past center to the other side? I know these are VERY elementary questions for this list, but hey, I've got to start somewhere, don't I ? My thanks in advance to anyone who wishes to help me out. Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: Karl Cunningham karlc@....... Date: Sun, 09 Jan 2000 23:03:25 -0800 Hi Jim -- We all had to start at the beginning. The period is the time it takes the boom to move from one side, through the rest position to the other side, and back to its starting point. Karl At 11:31 PM 1/9/2000 -0500, you wrote: >Thanks to Jim and Kevin, I now have a Lehman boom that is beginning to >behave correctly. Thank you both for you help. > >In measuring the 'period' of the boom, is this the measurement of time it >takes the boom to swing "out and back", when pushed, or the time it takes >for the oscillations to die out completely? If I manually deflect the boom >~1" off of center, is the period the time it takes the boom to come back to >center, or the time it takes the boom to move out to one side and then >back past center to the other side? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Scientific American magazine From: meredith lamb mlamb1@.......... Date: Mon, 10 Jan 2000 09:17:40 -0800 Hi all, Check out Roger Bakers article in the Amatuer Scientist section of the January 2000 issue. A much fuller description of the same is found at his web site: http://www.eden.com/~rcbaker If you copy such; its ~26 pages long (on my printer). The magazine title is: Detecting Extraterrestrial Gravity, while the web site is titled: The Hi-Q Gravimeter/Seismometer. The Society for Amateur Scientists (SAS) maintains a web discussion section on this topic at: http://earth.thesphere.com/sas/WebX.cgi I signed in as a "Guest", then, look for "The Amateur Scientist Column", then, again, "The Amateur Scientist column (#folders), then, "For 2000 (1 discussion), then "Detecting Extraterrestrial Gravity January (# discussions). Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: Paul Jebb pfjebb@.............. Date: Mon, 10 Jan 2000 11:31:41 -0500 Dear Jim, I just went through this pickle. If this solution doesn't do it I'll be surprised. I was in touch with a Prof. who built one at Kean College. I followed his suggestion and had no trouble. The pivot point for the wire coming down off the cross-piece must be ahead of the pivot point for the knife blade. So if you can picture the following triangle ABC where A is the end of the boom, B is the edge of the knife at the other end of the boom, and C is the upper point where the guy-wire leaves the upper horizontal cross-piece: Angle ABC must be less than 90 degrees. So what we did was to drill a hole in the upper cross-piece and put an extension through the cross piece to get the fulcrum out ahead of the knife edge at the bottom. If this is confusing, please send me an email and I will, send a picture. pfjebb@.............. It was a major stumbling block for us, please let me know if you get stuck. Paul Jebb JIM MARTIN wrote: > Gentlemen, > > I am experiencing rather frustrating problems in getting my Lehman set up. > I just finished the construction, and am now trying to get the boom to > center. The boom is setup so that it has a VERY slight downward slant from > level. I have leveled the base plate and it seems that no matter what I do > to the leveling screws, the boom either performs a major swing to either the > right or left. It takes almost NO turning of the leveling screw and the boom > will go from a center of about 30 degrees to the right, to a center that is > about the same except to the left. It seems as though I just can't get the > darn thing to center up. > > I know a lot of you out there have built the Lehman, so I'm hoping that > maybe someone can give me some assistance. > > Please help if you can.... > > Jim D. Martin > New Haven, Indiana > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: GeE777@....... Date: Mon, 10 Jan 2000 14:15:41 EST In a message dated 1/9/00 6:46:37 PM Pacific Standard Time, ChrisAtUpw@....... writes: > > Have you tried testing a geophone by sitting it on a flat plate on small > > li-lo cushion filled with water? Then use a syringe to inject a ml of water. > An impulse could be given to a horizontal seismometer by discharging a > capacitor through a nearby coil of wire. The induced currents give a > repulsive force. Hello All, Any pulse you record by droping water or beads records too much of the enviroment around the geophone. If you take a step function response like I recorded it, and get the second derivative of this signal, you will have an impulse response of the geophone with little effects of the surrounding area. Use a pulse generator to get the imulse response of the rest of your electronic system. With thee two signals, you can derive an entire system response and remove any undesired system response from your seismic data. Exploration seismoligists like to work with data that has not been phase distorted by geophones and/or amplifiers, etc. I have also used this same method to record the step function of horizontal geophones. George Erich on the + side http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: ChrisAtUpw@....... Date: Mon, 10 Jan 2000 14:59:57 EST Erich, >> Any pulse you record by droping water or beads records too much of the environment around the geophone. Are you saying that a hydraulic shaker table can't be used to determine the overall response of a geophone? I wasn't proposing to drop water or beads. Injecting one ml of water into a li-lo cushion would move a geophone placed on top upwards by about 10 microns. It can easily be made a lot less. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman construction From: "JIM MARTIN" jdmartin@.............. Date: Mon, 10 Jan 2000 19:56:43 -0500 Gentlemen, Well, things seem to be going along quite nicely, but I think I've hit a roadblock. I can now setup the boom for a very repeatable 11sec period, but I just can't seem to coax anymore out of it. I've tried tilting the base with the front screw and bringing the rear boom pivot point closer to the vertical plane of the wire pivot. Just doesn't seem to want to slow down any more than about 11sec. I am using a 1/2" dia. threaded brass boom, with a sharpened point on the pivot end. This point is pivoting in a VERY small dimple at the end of a 3/8" bolt. I even tried applying a small amount of lube to the pointed pivot, in an attempt to reduce any friction. Any suggestions? Jim Martin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Measuring Time Delay From: GeE777@....... Date: Mon, 10 Jan 2000 20:07:03 EST In a message dated 1/10/00 12:00:31 PM Pacific Standard Time, ChrisAtUpw@....... writes: > > Are you saying that a hydraulic shaker table can't be used to determine > the overall response of a geophone? > > I wasn't proposing to drop water or beads. Injecting one ml of water > into > a li-lo cushion would move a geophone placed on top upwards by about 10 > microns. It can easily be made a lot less. > I am not familar with a li-lo cushion. Al I know is that the experiments I made at an oil company research center for years showed me that any motion made to a geophone recorded data from the surrounding enviroment. We had a heavy cement shake table and kept recording reflections and refractions from the sides and bottom of the table. Recording the step function response worked very well and was cheep to do. George Erich on the + side http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: "Frank Cooper" fxc@....... Date: Mon, 10 Jan 2000 19:49:33 -0600 Hi Jim, You might try John Cole's ball bearing method. Look at his web site at http://freeweb.pdq.net/fxc/four.htm or mine at http://freeweb.pdq.net/fxc/ I increased the period of my seismic pendulum from 12 to 16 seconds quite easily by using his method. Frank Cooper, Friendswood, Texas -----Original Message----- From: JIM MARTIN To: PSN-L@.............. Date: Monday, January 10, 2000 7:03 PM Subject: Lehman construction >Gentlemen, > >Well, things seem to be going along quite nicely, but I think I've hit a >roadblock. I can now setup the boom for a very repeatable 11sec period, >but I just can't seem to coax anymore out of it. I've tried tilting the >base with the front screw and bringing the rear boom pivot point closer to >the vertical plane of the wire pivot. Just doesn't seem to want to slow >down any more than about 11sec. > >I am using a 1/2" dia. threaded brass boom, with a sharpened point on the >pivot end. This point is pivoting in a VERY small dimple at the end of a >3/8" bolt. I even tried applying a small amount of lube to the pointed >pivot, in an attempt to reduce any friction. > >Any suggestions? > >Jim Martin > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: john c cole johnccole@........ Date: Mon, 10 Jan 2000 21:11:44 -0600 jim i have been reading your mail with interest. i read the reply submitted by frank and agree with his reply as well as the others. here is what i have to say. eleven to twelve seconds is about all that you can expect out of the detector as it is constructed. i could not get any more out of mine and it was built the same way. the time period is controlled by the upper and lower pivot point. even the smallest amount of friction or resistance at these two points is critical . we are talking about extremely small amounts. to lower the friction at the lower pivot point, cut the end off flat,drill a hole in the end of the pendulum ,drill a hole large enough for a 1/4" ball bearing to fit in. about half of the bearing protruding from the pendulum. the surface that the ball bearing rest against should be sanded with no.400 paper then with no600 paper. the smoother the better. absolutely no holes drilled to keep the pendulum from migrating. the weight of the coil and the lead weight will keep it in place. it will never ,never slide out while it is in operation. it will slide off sometime while it is being adjusted. put a drop of super glue in the hole before inserting the ball bearing. if you like, put a l;little more around the edge of the ball bearing after the first has hardened. the top pivot point. i use .015 music wire for the lower section up to the turn buckle . the upper wire from the turnbuckle to the top pivot point is .010 thousandth. are you with me? the best source for the wire of the correct diameter is ,your local music store. the e string of a guitar is used. that is the first small string. cost,50 cents to a dollar .. the diameter of the strings aer written on the package .the smaller diameter on the string at the top the longer the period. using this method i can get any time that i desire. i usually run mine at about sixteen seconds . twelve seconds or even less is ok. i think that most professional detectors run at fifteen seconds. any higher and you will be adjusting all the time . ps i have four detectors up and running at this time. your friend john ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: meredith lamb mlamb1@.......... Date: Mon, 10 Jan 2000 21:09:18 -0800 JIM MARTIN wrote: > Gentlemen, > > Well, things seem to be going along quite nicely, but I think I've hit a > roadblock. I can now setup the boom for a very repeatable 11sec period, > but I just can't seem to coax anymore out of it. I've tried tilting the > base with the front screw and bringing the rear boom pivot point closer to > the vertical plane of the wire pivot. Just doesn't seem to want to slow > down any more than about 11sec. > > I am using a 1/2" dia. threaded brass boom, with a sharpened point on the > pivot end. This point is pivoting in a VERY small dimple at the end of a > 3/8" bolt. I even tried applying a small amount of lube to the pointed > pivot, in an attempt to reduce any friction. > > Any suggestions? > > Jim Martin > Jim, Suspect your boom/pivot junction (3/8"s bolt). Does the 3/8" bolt allow movement both toward or away from the front of the mast? Is it very secure in the mast? Another question... what is the weight of the mass? (Its remotely possible too much weight could be bending your boom, and influencing the period adjustment) Also, a question is of the mast; is it very sturdy or does it bend during its swing? Its possible it needs additional support. Overall, if the frame/mast is built like a tank, then the stresses have less influence. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: time/phase delay From: S-T Morrissey sean@........... Date: Mon, 10 Jan 2000 22:22:33 -0600 (CST) Regarding a concern for the time delay of a seismic system: This has generally been a "don't care" for seismology. THe primary reason is that the measurable phase delays are usually small when compared with the needed accuracy of determining the arrival time of a seismic wave. The "pick" of the arrival time of an impulsive wave is where the trace first diverges from the background trace, so is at the most impulsive or high frequency portion of the waveform. (emergent phases are another story). The high frequency delay is usually determined by the low-pass filters in the data, which include the pre-amplifier, the telemetry or digitizer input, and the discriminator or digital-to-analog output. The phase response of the seismometer mass itself ranges from 0 to pi, as the driving force ranges from very long periods to high frequencies, where the phase lag is equal to pi/2 at the period of the seismometer. If the seis natural period Tn is 1 second, a phase lag of pi/2 is 90 degrees or 0.25 seconds. A lag of 0 means that the mass follows the ground motion, which is also the case as would be expected if nothing is moving. And if the damping is set to 0.7 of critical, the phase response is linear about Tn, resulting in no phase distortion in the output. By saying that the phase of the motion of the mass lags the ground motion at frequencies higher than Tn (the seis period), it means that the mass essentially stays put as the ground moves, which in an moving coil seis, means that the voltage output has minimum delay (and maximum level) at high frequencies. The natural dispersion of seismic waves (the farther they travel, the longer their period becomes), means that generally the arrival times for many stations are being read from data from similar instruments that all would have a similar phase delay. Electronic filters would add additional delays, but these would usually be low-pass filters at for example, 25hz, which would have a delay of up to 10 milliseconds. But again, even a closely spaced network would be using nearly identical equipment, so the delays would all be the same, and not affect the hypocenter determination. In using data from both close (20km spacing) stations and near field (100 to 300km) stations, the data from the more distant stations would have significant propagation variables that generally are much greater than instrumental errors. Even electronic broadband stations have phase delays, which can be significant. For example, a 120 second VBB sensor will have a 90 degree lag at periods of 120 seconds, which is 30 seconds. But for purposes of timing, ie determining the relative arrival times between stations, any station registering a 120 second wave will have a similar delay IF the phase delay is linear which is only true IF the damping is set to (0.707) of critical. (Which is why we use this damping value). So this is why phase delays are not a concern in timing of seismic waveforms. Modern digital systems have their own problems with long FIR and IIR digital filters, but usually correct for the delays of the filters in the output timing. High frequency multi-channel systems have identical delays for every channel (which can be fine tuned), so there is no net relative time difference between the outputs. Even variations of 10% in natural frequency between geophones are not a major problem. The phase delay (and other parameters) of a seismometer can be easily determined using the calibration coil or the signal coil in a bridge circuit (unless you have access to a shake table: we have a pair (vertical and horizontal) at St. Louis Univ. that I can help anyone use; it runs from DC to 50hz, 1 to 100 microns at 0.5%, supporting seismometers up to 100 kgm). I have previously described how to use a calibration bridge, which we permanently install in the circuit of many short period stations; I can repeat it if necessary. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: George Harris gjharris@............. Date: Mon, 10 Jan 2000 22:31:06 -0500 Jim, It is important that the point and the dimple are properly matched. That is, the point must be sharper than the angle on the dimple. Flexure pivots are much better. It may not be possible to get much better operation out of point/dimple pivots. George Harris JIM MARTIN wrote: > Gentlemen, > > Well, things seem to be going along quite nicely, but I think I've hit a > roadblock. I can now setup the boom for a very repeatable 11sec period, > but I just can't seem to coax anymore out of it. I've tried tilting the > base with the front screw and bringing the rear boom pivot point closer to > the vertical plane of the wire pivot. Just doesn't seem to want to slow > down any more than about 11sec. > > I am using a 1/2" dia. threaded brass boom, with a sharpened point on the > pivot end. This point is pivoting in a VERY small dimple at the end of a > 3/8" bolt. I even tried applying a small amount of lube to the pointed > pivot, in an attempt to reduce any friction. > > Any suggestions? > > Jim Martin > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: NewEvent and NewFile mailing lists From: Larry Cochrane cochrane@.............. Date: Tue, 11 Jan 2000 03:20:14 -0800 Greetings, Do too spam email being sent to the two event notification mailing lists I maintain, I tightened up on security so that bogus messages should no longer be sent out. Some background for the new members; PSN station operators send in event files for archiving by email them as an attachment to event@.............. (or event@................ Valid PSN format event files are then processed and archived on my system. Besides the archiving, email messages are sent out on two mailing lists. One is called NewFile and the other NewEvent, see http://www.seismicnet.com/maillist.html for more info. The NewFile list only has links to the files on my system as part of the message, so these messages are small. The NewEvent list resends the event file as an attachment, so these messages can be large. The problem was that spammers could send messages to event@... or directly to the mail list. Today I redid things so that only one email address could post to the two mailing lists. Also, I modified the program that does the archiving so that messages to the lists only get sent out if there is one or more (up to 4 messages can be sent in one message) valid event file as part of the incoming message. This should stop the spamming since they won't contain a PSN event file as part of their message. If you send in event files please check to see if my system received it correctly. If you are a member of one of the lists please let me know if you see anything strange or get any spam messages from my systems. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Kudos From: offutt@............ (Warren Offutt) Date: Tue, 11 Jan 2000 10:37:16 -0700 (MST) Re the spam protection problem: this list is darned fortunate to have Larry as the overseer. I'm sure many feel as I do: Larry thanks for your great efforts. warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: BOB BARNS roybar@........ Date: Tue, 11 Jan 2000 15:46:20 -0500 Jim, If you have the magnet of a Lehman, it may be attracted to some magnetic material in the area, for example, steel reinforcing rods in a concrete floor. It doesn't take much iron nearby to cause a problem. Bob Barns JIM MARTIN wrote: > > Gentlemen, > > Well, things seem to be going along quite nicely, but I think I've hit a > roadblock. I can now setup the boom for a very repeatable 11sec period, > but I just can't seem to coax anymore out of it. I've tried tilting the > base with the front screw and bringing the rear boom pivot point closer to > the vertical plane of the wire pivot. Just doesn't seem to want to slow > down any more than about 11sec. > > I am using a 1/2" dia. threaded brass boom, with a sharpened point on the > pivot end. This point is pivoting in a VERY small dimple at the end of a > 3/8" bolt. I even tried applying a small amount of lube to the pointed > pivot, in an attempt to reduce any friction. > > Any suggestions? > > Jim Martin > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: BOB BARNS roybar@........ Date: Tue, 11 Jan 2000 15:58:38 -0500 Hi, I agree with John about using a ball against a flat surface (although I use a disk with a small radius edge) for the pivot. I think that a 1/8" ball or smaller would be better than a 1/4" ball. I disagree that a "12 sec. or even smaller" period would be OK. As Sean-Thomas has pointed out, the sensitivity of a Lehman varies as the of the period, i.e., a 20" period would be 4 times better than a 10" period. I usually run my Lehman at about 20" and have gone as high as 24". At 20", I have to adjust the level about twice a week with the Lehman sitting on a concrete basement floor. Bob Barns john c cole wrote: > > jim > i have been reading your mail with interest. i read the reply submitted > by frank and agree with his reply as well as the others. > here is what i have to say. eleven to twelve seconds is about all that > you can expect out of the detector as it is constructed. i could not get > any more out of mine and it was built the same way. > the time period is controlled by the upper and lower pivot point. even > the smallest amount of friction or resistance at these two points is > critical . we are talking about extremely small amounts. > to lower the friction at the lower pivot point, cut the end off > flat,drill a hole in the end of the pendulum ,drill a hole large enough > for a 1/4" ball bearing to fit in. about half of the bearing protruding > from the pendulum. the surface that the ball bearing rest against should > be sanded with no.400 paper then with no600 paper. the smoother the > better. absolutely no holes drilled to keep the pendulum from migrating. > the weight of the coil and the lead weight will keep it in place. it will > never ,never slide out while it is in operation. it will slide off > sometime while it is being adjusted. put a drop of super glue in the hole > before inserting the ball bearing. if you like, put a l;little more > around the edge of the ball bearing after the first has hardened. > the top pivot point. i use .015 music wire for the lower section up to > the turn buckle . the upper wire from the turnbuckle to the top pivot > point is .010 thousandth. are you with me? the best source for the wire > of the correct diameter is ,your local music store. the e string of a > guitar is used. that is the first small string. cost,50 cents to a dollar > . the diameter of the strings aer written on the package .the smaller > diameter on the string at the top the longer the period. > using this method i can get any time that i desire. i usually run mine > at about sixteen seconds . twelve seconds or even less is ok. i think > that most professional detectors run at fifteen seconds. any higher and > you will be adjusting all the time . > ps i have four detectors up and running at this time. > > your friend john > > ________________________________________________________________ > YOU'RE PAYING TOO MUCH FOR THE INTERNET! > Juno now offers FREE Internet Access! > Try it today - there's no risk! For your FREE software, visit: > http://dl.www.juno.com/get/tagj. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ted@.......... Date: Tue, 11 Jan 2000 16:29:46 -0500 If you use a ball bearing or small disk as the base support for the boom, remember that this single-point support allows the boom to rotate around its long axis. In fact if you mount your coil off to one side of the boom (like the pictures of the Lehman in the original SciAm article) the off-center mass of the coil applied to the boom will drag it down until the coil is hanging straight down, or more likely dragging on the base. I had to use counterweights to get it to hang straight. Drilling your 5 lb. lead weight slightly off center and then using it as a counterweight works (tighten it when it balances the coil). I always recommend that people use a "Y" attachment to suspend the boom, where the two wires join into one just before attaching to the crosspiece. This has greatly lessened the rotational movement for me - and this is a source of noise since it causes relative movement of the magnet and coil. Flexible connectors can resist a torque but I believe it is best not to have any torque applied to the boom at all. Sean-Thomas, have you noticed whether it is really important to make sure the coil and magnet are lined up with the swing plane of the boom, to eliminate any rotational impulse imparted by the resistive damping, or is this simply too small to measure? Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: Danie Overbeek danieo@............ Date: Wed, 12 Jan 2000 04:39:32 +0000 Jim and John A ball rolling on a flat is fine for the lower pivot point but my ball is attached to the mast and the flat is a small polished hardened steel flat attached to the pendulum. This way, the pendulum is less sensitive to the position of the ball on the flat. The flat is made from the handle of a small flat file which was also hardened. Cheers all Danie Overbeek. locationTo: psn-l@.............. Date: Mon, 10 Jan 2000 21:11:44 -0600 Subject: Re: Lehman construction From: john c cole Reply-to: PSN-L Mailing List jim i have been reading your mail with interest. i read the reply submitted by frank and agree with his reply as well as the others. here is what i have to say. eleven to twelve seconds is about all that you can expect out of the detector as it is constructed. i could not get any more out of mine and it was built the same way. the time period is controlled by the upper and lower pivot point. even the smallest amount of friction or resistance at these two points is critical . we are talking about extremely small amounts. to lower the friction at the lower pivot point, cut the end off flat,drill a hole in the end of the pendulum ,drill a hole large enough for a 1/4" ball bearing to fit in. about half of the bearing protruding from the pendulum. the surface that the ball bearing rest against should be sanded with no.400 paper then with no600 paper. the smoother the better. absolutely no holes drilled to keep the pendulum from migrating. the weight of the coil and the lead weight will keep it in place. it will never ,never slide out while it is in operation. it will slide off sometime while it is being adjusted. put a drop of super glue in the hole before inserting the ball bearing. if you like, put a l;little more around the edge of the ball bearing after the first has hardened. the top pivot point. i use .015 music wire for the lower section up to the turn buckle . the upper wire from the turnbuckle to the top pivot point is .010 thousandth. are you with me? the best source for the wire of the correct diameter is ,your local music store. the e string of a guitar is used. that is the first small string. cost,50 cents to a dollar .. the diameter of the strings aer written on the package .the smaller diameter on the string at the top the longer the period. using this method i can get any time that i desire. i usually run mine at about sixteen seconds . twelve seconds or even less is ok. i think that most professional detectors run at fifteen seconds. any higher and you will be adjusting all the time . ps i have four detectors up and running at this time. your friend john ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ChrisAtUpw@....... Date: Tue, 11 Jan 2000 21:48:35 EST I just knew that if I waited long enough, someone would come up with a really neat solution to the Lehman suspension problems.... Congratulations Danie!! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: PSN meeting] From: Edward Cranswick cranswick@........ Date: Tue, 11 Jan 2000 21:06:07 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Subject: Seismograph Interpretation Booklet From: Doug Crice dcrice@............ Date: Tue, 11 Jan 2000 22:45:40 -0800 A copy of Principals Underlying The Interpretation of Seismograms- 1966 edition.. released by the US Dept of Commerce is for sale on eBay at: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=234138378 -- Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman notes From: S-T Morrissey sean@........... Date: Wed, 12 Jan 2000 01:04:42 -0600 (CST) Ted and Jim and co. Regarding the boom/mass/coil/hinge questions. Symmetry is very important in the design of the boom. The geometric center of the mass and of the coil(s) should be carefully aligned with boom axis. This is important since the damping force of the coil should act on the center of mass of the mass and boom; otherwise torques about the boom axis will result. For perfect symmetry, a "dummy" coil form or equalavent mass is often installed on the opposite side of the mass from the main signal coil. Sometimes tis is an independent calibration coil and magnet, or a second signal coil. A boom suspension made with an inverted Y wire yoke, with the split lower ends attached to the widest portions of the mass, will help control any rotations and keep the coil aligned in the magnet gap. At the upper mast end the Y wire goes through a saddle that is attached to the mast top by a fine wire as the upper pivot. The magnet MUST be mounted to the frame if good resolution and low noise are expected. Some attempts at a moving magnet seis were made, but even with massive shielding, like the 1/4" steel tank that is the cover for the Johnson-Mattheson seis, geomagnetic and cultural magnetics (from steel boot shanks to hunting knives) were still a problem. I would certainly go the extra effort of using a flat flexure or taught wire for the boom pivot, rather than any bearing device. The mast end of the boom must fork and pass the mast so the taught wire pulls from the back. An example is shown on my web site in the diagram of the classic Sprengnether long-period horizontal. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Antique Seismograph From: "Randall Pratt" randallpratts@.............. Date: Wed, 12 Jan 2000 08:50:09 -0800 I forwarded you information to a military historian friend. He confirmed my suspicion that you have a part from the sight of an artillery piece possibly back to the Spanish American war. Randy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ChrisAtUpw@....... Date: Wed, 12 Jan 2000 13:35:38 EST In a message dated 12/01/00 02:41:46 GMT Standard Time, danieo@............ writes: >> A ball rolling on a flat is fine for the lower pivot point but my ball is attached to the mast and the flat is a small polished hardened steel flat attached to the pendulum. This way, the pendulum is less sensitive to the position of the ball on the flat. The flat is made from the handle of a small flat file which was also hardened. Cheers all Danie Overbeek. Jim I have been reading your mail with interest. I read the reply submitted by Frank and agree with his reply as well as the others. Eleven to twelve seconds is about all that you can expect out of the detector as it is constructed. I could not get any more out of mine and it was built the same way. The time period is controlled by the upper and lower pivot point. Even the smallest amount of friction or resistance at these two points is critical. We are talking about extremely small amounts. To lower the friction at the lower pivot point, cut the end off flat, drill a hole in the end of the pendulum large enough for a 1/4" ball bearing to fit in. About half of the bearing protruding from the pendulum. The surface that the ball bearing rests against should be sanded with no: 400 paper then with no: 600 paper. The smoother the better. Absolutely no holes drilled to keep the pendulum from migrating. The weight of the coil and the lead weight will keep it in place. It will never, never slide out while it is in operation. It will slide off sometimes while it is being adjusted. Put a drop of super glue in the hole before inserting the ball bearing. If you like, put a little more around the edge of the ball bearing after the first has hardened. The top pivot point. I use .015 music wire for the lower section up to the turn buckle. The upper wire from the turnbuckle to the top pivot point is ..010 thousandth. are you with me? the best source for the wire of the correct diameter is, your local music store. The e string of a guitar is used. That is the first small string. Cost 50 cents to a dollar. The diameter of the strings are written on the package. The smaller diameter on the string at the top the longer the period. Using this method I can get any time that I desire. I usually run mine at about sixteen seconds. Twelve seconds or even less is OK. I think that most professional detectors run at fifteen seconds. Any higher and you will be adjusting all the time . PS I have four detectors up and running at this time. John Cole Great contributions!! Let's think them through further. We need to have the vertical hinge axis fixed, so that the seismometer level can be trimmed easily and also so that it can be disassembled and reassembled without too much difficulty. Attaching a ball bearing to the top of the fixed vertical frame and fitting a rigid flat load plate on the suspension should do this well enough. The load plate can be marked with the approximate correct position. With a ball bearing in the end of the horizontal swinging arm and a flat plate on the frame, this lower point of rotation is NOT fixed laterally. Would it not be better to fix this by mounting the flat plate on the end of the horizontal arm and fit the ball bearing into the frame? I suspect that one reason for difficulties in setting up a Lehman for long swing periods may be that the 'hinge axis' of a flexing suspension wire at the top of the frame may change as the wire flexes through different angles. It also assumes that the wire can't move in the clamp jaws. You really need both jaws to be aligned vertically, so that the wire flexes at right angles to the jaws. If you use identical lengths of the same wire for the top and bottom flexures as Sean suggested, there should be no problem. Likewise for rolling contact (John Cole). The rolling resistance of a ball on a plate may depend on the surface finish of plate. A small disk of polished sapphire (optical stockist / ex IR sensor window?) would certainly be OK, but a small glass flat (part of a microscope slide?) glued on with epoxy should also work. Hard glass or polished Quartz or Agate would probably be better. Agate flats and triangles are used in some Laboratory Balances and sometimes in 'grandfather' clocks. We also need to consider the long term operation of the system. Unlubricated rolling contacts (such as steel bearings) can corrode (and probably will in time). Lubricated corrosion protected contacts can attract dust and 'particulate matter' and may need to be covered. You can get stainless steel ball bearings (from a bearing stockist) and sapphire spheres are also made (they are used in some vertical tapered column gas flowmeters). Another alternative is to make a crossed shim flex suspension for both, but making these may present rather more difficulties for the amateur constructor. I hope that these thoughts may be helpful. Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: hinge. From: "wesgee" wesgee@........... Date: Wed, 12 Jan 2000 13:48:43 -0800 Chris, when you talk about a crossed hinge is that made out of shim stock? Do you have a diagram ? John Gee wesgee@........... http://hambone2.engr.csufresno.edu Subject: Re: Lehman construction From: n0cwr@......... Date: Wed, 12 Jan 2000 22:22:23 +0000 Our Lehman is in a room off the garage. Two cars in the garage great... Fine with one car in the garage but, if I attain too high of a period (16 sec plus) with both cars out of the garage the boom rolls over to the side - flatline till ones back! 12 - 16 second period = no problems. Just things one has to consider in amateur seismology I guess. :) Just for your amusement. Kevin. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: box flexure From: S-T Morrissey sean@........... Date: Wed, 12 Jan 2000 17:36:43 -0600 (CST) A compact 3-element crossed flexure can be made in a 3/4" square box from a 4 3/8" strip of 3/4" wide 0.002" to 0.005" phosphor bronze. Thinner material is more advantageous but fragile. I have used 0.001" stainless steel. For an initial pattern that is fairly robust: Inside flexure yyy is 1/4" wide; outer flexures zzz are 3/16" wide, ("slot B" can be started with a paper punch and widened to 3/8") Folds are made at the lines "|"; initially crease x|y and z|x down about 45 deg, and y|b and b|z upwards about 90 deg. Then "tab A" is carefully twisted and inserted through "slot B". Then all the bends are increased to 45 degree inside angles. "tab A" flexure base "slot B" top < 3/4" >|< 1 1/16" >|< 3/4" >|< 1 1/16" >|< 3/4" > x x x x x| |b b b b b b|z z z z z z z z|x x x x x x x x x x x| |b b b b b b|z z z z z z z z|x x x x x x x x x x x x|y y y y y y y y|b b b b b b| |x x x x x x x x x x x x|y y y y y y y y|b b b b b b| |x x x x x x x x x x x x| |b b b b b b|z z z z z z z z|x x x x x x x x x x x| |b b b b b b|z z z z z z z z|x x x x x x x x x x x x x x x x x < xxx overlies xxx and are soldered together. y z y z y z y z y z < the center of rotation is where z y < the flexures cross z y z y z y z y b b b b b b b b b b b b For installation, 3/4" wide strips of 1/16" brass can be soldered or epoxied to the insides of xxx and bbb with extensions for mounting holes. Note that this flexure ONLY works properly in tension, ie side bbbbbb pulled away from side xxxxxx. But it will actually work as a miniature horizontal seismometer when made with 0.005" brass, with side bbbbb as the base and a small weight, like a quarter, placed on top of xxxxx. You can print this and then cut out the strip to make a paper demo. Also, for lighter loads and reduced restoring forces, thinner material can be used, and the flexure strips made as small as 1/16" wide. This makes a pretty floppy assembly, so V-shaped inserts (of 0.005" brass) are fitted inside the flexures and the strips are lightly soldered to them. NOTE the flattened end of the V where the flexures cross. This flat is about 1/16" wide, and the free length of the strips at the crossover is about 1/8". The V inserts more precisely control the center of rotation, but reduce the overall flexibility of the hinge. At the risk of pushing this diagraming style, a complete flexure would look like: where BBBBBBB are the mounting bars, and VVVVVV are the inserts. x x x x x x x x x x x x < xxx overlies xxx and are soldered together. yVBBBBBBBBBBBBBBBBBBBVy yV Vz yV Vz yV Vz yVVVVVz y z < the center of rotation is where z y < the flexures cross zVVVVVy zV Vy zV Vy zV Vy zVBBBBBBBBBBBBBBBBBBBVy b b b b b b b b b b b b BBBBBBBBBxxxxxxxxBBBBBBBB < "top view" showing brass mounting bar B Bzz yy zzB B with holes HH. B HH Bzz yy zzB HH B B HH Bzz yy zzB HH B B Bzz yy zzB B BBBBBBBBBxxxxxxxxBBBBBBBB A proper drawing with all the details will be posted on the web site. ...... Sometime .... I have used a pair of these to make a 12" base horizontal seis with a 10" boom. A S shaped bracket on the end of the boom has the upper flexure pulling forward toward the mass, and the lower flexure pulling away. Separate uprights are used for each, with the short lower flexure post in front of the tall upper flexure post. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: meredith lamb mlamb1@.......... Date: Wed, 12 Jan 2000 17:06:30 -0800 Hi all, With specific reference to the pivot area, I would really recommend the variety like used with a number of professional instruments like the Sprengnether horizontals. Probably the best I've ever seen is John Lahr's home brew variation: http://lahr.org/john-jan/psn/pivot.jpg Here the above is a very good picture. Another variation is also shown on the same site: http://lahr.org/john-jan/psn/horizvt.html; except the diagram doesn't match the picture, and it wouldn't work as is. John's complete web site related to amateur seismology is: http://lahr.org/john-jan/psn/gldn_psn.html Another picture site of the exact same pivot is also shown at: http://www.geocities.com/ResearchTriangle/Facility/1739/page22.html Here the pivot is photographed with 3 additional views. An additional mention should be made in regards to the connection wires in the photographs. As is they create a slight drag, on the boom. Copper wires looped to create a visual effect of a spring like Sean-Thomas suggested some time back, will help alot here. A lesser alternative, is to create a high looping copper wire connection to lessen the drag. The wire used is piano/music wire, available at a variety of hobby shops. Sorry, but the exact size escapes me at the moment. One could install terminals on the round pivot assembly for this "spring" copper wire connection; between the mass and the output. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: box flexure From: Steve Hammond Shammon1@............. Date: Thu, 13 Jan 2000 00:44:34 -0800 That's a post worht keeping. Thanks-- You don't happen to have a photo of one of the box flexures you built? Regards, STeve Hammond PSN Aptos, California S-T Morrissey wrote: > > A compact 3-element crossed flexure can be made in a 3/4" square box _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: twleiper@........ Date: Thu, 13 Jan 2000 04:18:38 -0500 On Wed, 12 Jan 2000 22:22:23 +0000 n0cwr@......... writes: >Our Lehman is in a room off the garage. >Two cars in the garage great... >Fine with one car in the garage but, >if I attain too high of a period (16 sec plus) with both cars >out of the garage the boom rolls over to the side - flatline till >ones back! 12 - 16 second period = no problems. My daughter's Lehman is on a pier cast atop what is either an immovable huge bolder or exposed bedrock in the root / wine cellar. It is a very stable environment with natural temperature control and the seismo is made from thermally stable materials, such as a granite tool and die makers slab for a base. With a natural period of 50 seconds it only needs seasonal centering adjustment for what I theorize is increased weight of the frame house (the foundation rests on said bolder about 15 feet away) due to higher relative humidity in the summer, or the presence of leaves on a rather large beach tree about 30 feet away. My wife will not let us cut the tree down to see... With this level of sensitivity I can not only tell when the oil truck backs into the driveway (about 75 ft away), but I can also tell whether I am at the beginning or the end of his run based on the weight of the truck. When the truck is empty I have to know he is there to pick out the offset in the six second noise level, but full is a clear LP tilt event of about 8 times the background amplitude. He is a friend of mine and I have verified it. So is the insanity worth it? Not really. Only in the case of the most distant surface waves have we been able to see higher performance than with her original unit (http://www.seismicnet.com/leiper/seismograph.html) running end to end, and in no case did it detect anything that was not discernable on the "science fair unit". That first unit is no slouch and can be adjusted to about a 40 second period, but dimensional instability and perhaps magnetometry effects of the suspended magnet design limit the "seasonally adjusted" period to about 15 to 18 seconds. It can only see the oil truck when it is full. So here is the challenge question: Assuming identical detector,gain and filtration (they are) and only the difference in period, can you calculate the capacity of the oil truck? (ST, Give everybody else a day before posting the correct answer, please...) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Magnet Wire From: Paul Jebb pfjebb@.............. Date: Thu, 13 Jan 2000 10:56:30 -0500 Gentlemen: Regarding a Lehman seismometer: Is 30 gauge copper wire satisfactory for the coil, if so, how much should I use. I plan to put the wire on with a drill, but counting the number doesn't seem possible. The original design called for 400 ohms of resistance. Can anyone speak to this issue? Yours truly, Paul Jebb NCS _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: Karl Cunningham karlc@....... Date: Thu, 13 Jan 2000 08:36:54 -0800 Paul -- I would try to use something smaller than 30 gauge wire. I don't think you can get enough turns of 30 gauge wire in a small enough size. Something like AWG 40 or 42 would be better. As far as counting, how about rigging up a bicycle speedometer, using the odometer part to count turns. You probably can't count every turn, but you may be able to get it within 50 or 100. Karl Cunningham At 10:56 AM 1/13/2000 -0500, you wrote: >Gentlemen: >Regarding a Lehman seismometer: > >Is 30 gauge copper wire satisfactory for the coil, if so, how much >should I use. I plan to put the wire on with a drill, but counting the >number doesn't seem possible. The original design called for 400 ohms >of resistance. Can anyone speak to this issue? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Counting Magnet Winding Turns From: ChrisAtUpw@....... Date: Thu, 13 Jan 2000 12:39:01 EST If you look up Radio Shack, they sell 5 digit LCD debounced counters that run off a 1.5 V battery for ~$16. Use a minature reed switch and put a reed switch magnet on the armature. You are unlikely to exceed the maximum count rate of about 7 pps. It is actually not too hard to count the number of times you turn the handle if you are using a geared up hand drill. An estimate good to a few % will be adequate. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: Doug Crice dcrice@............ Date: Thu, 13 Jan 2000 10:50:34 -0800 >So here is the challenge question: >Assuming identical detector,gain and filtration (they are) and only the >difference in period, can you calculate the capacity of the oil truck? >(ST, Give everybody else a day before posting the correct answer, >please...) If you going to do the math, you should also calculate whether the drift is caused by mutual gravitational attraction between the oil truck and seismometer, as opposed to tilt of the bedrock. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: "Charles R. Patton" crpatton@...... Date: Thu, 13 Jan 2000 12:13:19 -0800 twleiper@........ wrote: >So here is the challenge question: >Assuming identical detector,gain and filtration (they are) and only the >difference in period, can you calculate the capacity of the oil truck? >(ST, Give everybody else a day before posting the correct answer, >please...) Doug Crice wrote: "...whether the drift is caused by mutual gravitational attraction between the oil truck and seismometer..." And just for fun, another idle thought, what about the distortion to the Earth's magnetic field due to the large diamagnetic body (the oil) in the vicinity. Just as a helpful hint, I have estimated that fuel oil might be cycloheptane (C7H14) (see also: http://www.bowdoin.edu/dept/es/200/guide/oil.html and search for cycloalkanes). Based on that, the Chemistry Physics handbook says the diamagnetic suseptibility is minus 73.9 e-6 for cycloheptane. Also I think the the problem statement is incomplete. Don't I need to know the bedrock composition so I can estimate the strain coefficient? I must have too much time on my hands. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ChrisAtUpw@....... Date: Thu, 13 Jan 2000 16:04:03 EST In a message dated 13/01/00 20:15:40 GMT Standard Time, crpatton@...... writes: twleiper@........ wrote: So here is the challenge question: Assuming identical detector, gain and filtration (they are) and only the difference in period, can you calculate the capacity of the oil truck? Doug Crice wrote: "...whether the drift is caused by mutual gravitational attraction between the oil truck and seismometer..." >> And just for fun, another idle thought, what about the distortion to the Earth's magnetic field due to the large diamagnetic body (the oil) in the vicinity. >> I must have too much time on my hands. Regards, Charles R. Patton How has it escaped Mr.Patton's notice that trucks frames are made of a lot mild steel, which has a huge magnetic susceptibility cf. oil? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 40 Gauge Wire From: Paul Jebb pfjebb@.............. Date: Thu, 13 Jan 2000 16:20:42 -0500 Dear Members, Karl suggested that I use 40 or 42 gauge wire for the coil which leads me to two further questions: Where can you find such fine wire, Radio Shack doesn't carry it? How many turns do you recommend? Thanks, Yours truly, Paul Jebb NCS _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: "Charles R. Patton" crpatton@...... Date: Thu, 13 Jan 2000 13:54:12 -0800 ChrisAtUpw@....... wrote: > How has it escaped Mr.Patton's notice that trucks frames are made o= f a > lot mild steel, which has a huge magnetic susceptibility cf. oil? No, obviously the frame is a strong magnetic effect, but the question is phrased that the oil load made a difference so theoretically all we have = to consider is the delta effect, as the question was, =93=85can you calculat= e the capacity of the oil truck?=94 Doug and I are just speculating about othe= r possible effects than just the weight of the oil on the bedrock. I was speculating primarily tongue-in-cheek, as probably for any possibility of= the effect to be significant, the Lehman would have to be constructed with th= e magnet on the arm, and we weren=92t given that information. I haven=92t = done the calculations on Doug=92s speculation to know if it=92s too minute to be a= significant effect or not. That=92s the fun of the question. As a side note, there was a paper on the use of the gravitational attract= ion method to calibrate some seismometers. A several kilogram mass was moved= around a seismometer and the deflection measured to give an actual sensitivity. I have the article somewhere in my files. So that=92s why = I don=92t discount Doug=92s speculation as quickly. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ChrisAtUpw@....... Date: Thu, 13 Jan 2000 18:09:28 EST >> No, obviously the frame is a strong magnetic effect, but the question is=20 phrased that the oil load made a difference so theoretically all we have to=20 consider is the delta effect, as the question was, =E2=80=9C=E2=80=A6can you= calculate the=20 capacity of the oil truck?=E2=80=9D Doug and I are just speculating about o= ther=20 possible effects than just the weight of the oil on the bedrock. I was=20 speculating primarily tongue-in-cheek, as probably for any possibility of th= e=20 effect to be significant, the Lehman would have to be constructed with the=20 magnet on the arm, and we weren't given that information. My point is that there is such a huge ratio between the diamagnetic=20 susceptability of oil and the ferromagnetic susceptability of iron that the=20 oil could not have any effect. I don't discount the gravitational attraction. G=3D 6.67x10^ -11 m^3 / K= g=20 s^-2 according to my quick calculations. Force F newtons =3D GxM1xM2/ d^2 wh= ere=20 M's are in Kg and d is in m. =20 Regards, Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: Greg ghost@............. Date: Thu, 13 Jan 2000 16:22:01 -0700 Some smart person wrote: > I don't discount the gravitational attraction. G= 6.67x10^ -11 m^3 / Kg Let's not forget the amount of rain in the soil, the toxic waste dump in the back yard, the color of the cheese I'm eating, the phase and position of the moon, the astrological sign of the seismometers and it's builders, and the gas pressure inside the neon side on the far side of the moon. Yes I'm the silly one that put the sign there. Guess what it says? ;P ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seking the source of Yellowstone's Heat From: GeE777@....... Date: Thu, 13 Jan 2000 18:41:29 EST Hello all I thought this is a very interesting article I don't know if this is too big to send or not. If it doesn't transmit, write me direct & I will send it to you if you wish <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Thursday, January 6, 2000 | Print this story Seeking Source of Yellowstone's Heat Does it come from deep in the Earth's core, or is it the result of crust stretching, as one theory suggests? A network of seismometers to record distant quakes could settle the issue. By MICHAEL MILSTEIN, Special to The Times YELLOWSTONE NATIONAL PARK, Wyo.--Heat from deep within the Earth undoubtedly keeps Yellowstone's geysers simmering. But even after years of research, geologists still puzzle over two questions as large as all of Yellowstone: How deep does the park's heat source dwell, and how does all that heat find its way to the surface? They are fundamental questions that also apply to the world's many other volcanic hot spots, including Hawaii, Iceland and the Galapagos Islands. Some theorists imagine chimneys of hot rock emerging from the Earth's fiery core, more than 1,800 miles down, to feed long-lived chains of volcanoes on the surface. But others argue that hot spots are merely spots--lonely pockets of hot rock seeping through thin spots in the crust. Last fall, geologists began laying a network of seismometers and global positioning system units in and around Yellowstone. They hope the three-year, $1-million project will settle the question by producing the most complete image yet of the deep roots of a hot spot. "This is our first opportunity to really see what's happening down there," said Robert Smith, a professor of geophysics at the University of Utah and co-leader of the Yellowstone Hot Spot Geodynamics Project, funded primarily by the National Science Foundation. "Up until now, it's all been modeling and educated guesswork." Using the seismic network as a kind of geological looking glass to see below the surface, geologists will scan underground for a chimney of molten rock that may feed the hot spot. The absence of such a subterranean supply line would suggest that Yellowstone--and perhaps other volcanic hot spots--do not draw their heat from such a deep-seated furnace but that they are born at the surface. "Our most important goal is to try to image a plume, which may or may not exist," said Gene Humphreys, a professor of geology at the University of Oregon and Smith's partner in the project. "We should be able to tell if it does exist. That's the big question." The answer should give scientists clues about how long the hot spots will last and enable better predictions of when they might trigger eruptions. Eruptions of the Yellowstone hot spot over the last 10 million years or more have left a string of ancient craters stretching southwest across the North American continental plate, which is grinding slowly over the hot spot in the same direction. * * * The hot spot last punched through the plate in a catastrophic eruption about 600,000 years ago. It was a monstrous event that spewed 1,000 times as much ash and debris as the 1991 eruption of Mt. Pinatubo in the Philippines. Many geologists believe a balloon of hot rock rising from the core and through the mantle bumped up against the underside of the crust about 15 million or more years ago, creating the Yellowstone hot spot. According to the theory, a narrow plume of hot rock trailing the balloon like a string still ties the hot spot to the scorching core and continues to pump it full of heat. A competing hypothesis contends that the hot spot's driving force lies not at the Earth's core, but above it. This line of thinking suggests that stretching of this part of the country thinned the continental crust like pizza dough pulled tight. This reduces the pressure, allowing the underlying mantle rock to soften and subsequently melt to form the hot spot. Without the thick continent to hold it in check, the theory goes, the frothy rock surges up like champagne from a newly uncorked bottle, punching through the flimsy crust without any encouragement from below. Measurements over many decades have found that the caldera dating to Yellowstone's last eruption rises and falls in a continuing cycle. After dropping since 1985, it is now rising again, possibly inflating with gases and fluid escaping from the hot spot. A series of new global positioning system units will track such ups and downs, giving scientists a clearer view of how the hot spot helps to mold the surface above it. "We know there's some sort of upwelling of mantle material; we know that process is going on," said Kenneth Pierce, a U.S. Geological Survey geologist who was one of the first to propose the plume theory for the Yellowstone hot spot but is not involved in the new research project. "What's causing the upwelling is what's sort of uncertain." By spring, the project's full array of 70 to 80 seismometers will encircle Yellowstone, listening for the seismic signatures of earthquakes rattling the distant Pacific, mainly around the volcanic islands of Tonga and Fiji. As waves from the earthquakes race through the Earth, some will find their way beneath Yellowstone and will slow down in the slushy hot rock of the hot spot. Data from the seismometers will show precisely where the waves slow down, letting researchers generate a three-dimensional computer image of the hot spot just as a CT scan builds a similar computer image of tissues in the human body. * * * Expanding the seismic network has the same effect as pulling a camera back from the subject: A broader picture comes into view. Geologists attempting to construct a similar seismic image of the hot spot beneath Iceland found themselves handicapped; because Iceland is a solitary island, they were limited in how far they could spread their net of instruments. Around Yellowstone that's obviously not a problem: The expansive network now going into place will stretch 300 miles wide and may detect traces of the hot spot up to 600 miles beneath the surface, Smith said. This should be deep enough to tell if a mantle plume really does fuel the hot spot and, in turn, Yellowstone's steaming surface wonders. Initial signs are that neither the hot spot nor its plume seems to extend deeper than 150 miles, Smith said. But Pierce notes that models suggest that the chimney-like plume could be as narrow as 6 miles wide; trying to spot it with sketchy seismic data could be like trying to spot a spider web in fog. "Whatever they learn will undoubtedly be a contribution," Pierce said, "but it will be very interesting to learn if they can really see as much as they hope to see." * * * A String of Ancient Calderas' As the North American plate has slid to the southwest at about 4.5 centimeters per year, eruptions of the underlying Yellowstone hot spot have blasted giant holes up through it. A string of holes stretches from Yellowstone into Idaho in the form of volcanic calderas--broad craterlike basins of a volcano formed by an explosion or collapse of the cone--shown on this map. Source: Robert Smith, University of Utah [Unable to display image] >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seking the source of Yellowstone's Heat From: John Hernlund hernlund@....... Date: Thu, 13 Jan 2000 17:50:15 -0700 (MST) Good article, thanks for sending it! I had the pleasure of listening to Humphreys give a lecture on the same issue and he had some really interesting views not listed in the article. In particular I remember his idea that the huge amount of basalts erupted in the northwest US may have depleted the upper mantle of iron, which would cause physical and chemical shifts that would buoy the material upwards to the surface due to a lower density (less garnet also). This would in turn create melt in the same manner as other upwellings through decompression. If this idea is correct, then the root of the heat should be very shallow, but perhaps seismically indistinguishable from pure extension related volcanism...perhaps an electrical tomography experiment is also in order here. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman period improvement From: "JIM MARTIN" jdmartin@.............. Date: Thu, 13 Jan 2000 19:45:13 -0500 Gentlemen, I am now able to repeatedly achieve at least a 15.3 sec period on my Lehman. I am now using .020 music wire for the attachment from the boom to the lower part of turnbuckle, and .015 music wire from the upper part of turnbuckle to the upper pivot on the pipe frame. I am still using the 1/2" threaded brass rod, sharpened to a point on the pivot end. The point pivots on the polished head of a Grade 8 hardened steel hex bolt. This bolt head has no dimple. I found that the dimple was causing a LOT of friction. I am quite sure that with a little more fine tuning, I will be able to easily achieve a 20 sec. period. Just my 2 cents..... Jim Martin New Haven, Indiana _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: ChrisAtUpw@....... Date: Thu, 13 Jan 2000 20:07:50 EST In a message dated 13/01/00 23:26:17 GMT Standard Time, ghost@............. writes: << Some smart person wrote: > I don't discount the gravitational attraction. G= 6.67x10^ -11 m^3 / Kg Let's not forget the amount of rain in the soil, the toxic waste dump in the back yard, the color of the cheese I'm eating, the phase and position of the moon, the astrological sign of the seismometers and it's builders, and the gas pressure inside the neon side on the far side of the moon. Yes I'm the silly one that put the sign there. Guess what it says? ;P Thanks for the contribution "Greg" If you use G= 1.07x10^ -9 and put in pounds and feet, you will get the answer in poundals. I know it's a bit difficult, but do you think that you can cope with the arithmetic? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman construction From: Malcolm Purves malcolmp@.............. Date: Fri, 14 Jan 2000 02:22:04 +0000 At 04:18 13/01/00 -0500, Tom wrote: >My daughter's Lehman is on a pier cast atop what is either an immovable >huge bolder or exposed bedrock in the root / wine cellar. snip >Assuming identical detector,gain and filtration (they are) and only the >difference in period, can you calculate the capacity of the oil truck? >(ST, Give everybody else a day before posting the correct answer, >please...) Hi Tom, great post, interesting web page and entertaining question. Many thanks for the good read and the info. Being just a humble telecommunications engineer I got as far as deciding on the leverage to your truck but then I got hung up on the matter of the spring constant of your ground. :-( I guess that comes out of the fact that the loaded tanker was at the threshold in the noise of your short period but way above the noise in your long period, but I am not a seismologist, so I await with interest Sean-Thomas's input. By the way, what is a root cellar ? :-( Not roots impinging from that tree outside is it ? I know about wine cellars. Malcolm, SW England. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: coils and wire size From: S-T Morrissey sean@........... Date: Thu, 13 Jan 2000 21:22:16 -0600 (CST) Re counting turns when winding a coil: I don't bother to count, but I know the approximate number. First of all, I turn the coil by hand on a short shaft under good light, placing each turn EXACTLY adjacent to the previous, and delimiting each layer with correction tape strips as I described a few weeks ago. (need a repeat??). It takes about 2 minutes to make about 100 turns. And another 10 minutes to epoxy the layer. A 12-layer coil takes me over 2 hours, depending on distractions while the epoxy cures. This lets you know the number of turns by knowing the diameter of the wire and the winding length. I use #36 wire from Newark (need a repost of that info??; they take MasterCard!). "Beldsol" enameled #36 wire has a diameter of 0.0055", so if I have a winding length of 0.5" with EVERY TURN exactly placed, I have 91 turns in that layer. Since I don't use a bobbin form, I step back the end of each layer by one turn, or conversely start with a slightly larger number in the first layer. So I use a starting length of 0.615" ( slightly under 5/8") to start with 111 turns; subsequent layers are 109, 107, 105, 103, 101, 99, 97, 95, 93, 91, and 89 turns in the 12th layer, for a total of 1200 turns. The average length of a turn with a 5/8" initial diameter is 2.17", so there is 217 feet of wire in the coil, and at 414.8 ohms per 1000 ft, I should get 90 ohms, which is about what I measure. For your info: other wire diameters and resistances: (diameter for enamel insulation) NEWARK roll length, ft cost #36 0.0055 414.8 ohms/1000 ft. #36E1321 1/2lb 6400 $27.33 #38 0.0044 659.6 #36F779 1 lb 19300 $73.49 #40 0.0034 1049.0 #42 0.0028 1659 #44 0.0023 2593 Actually, the exact number of turns is not important. What is important is to get the maximum number of turns inside the gap of the magnet, which cannot be done with a "scramble wound" bobbin that often results from using a drill. The required bobbin alone will take up an appreciable amount of the volume. Also a target resistance value is not necessary. The trade-off in my opinion is how small a wire you want to work with to get the maximum number of turns into a given space. #40 and up wire is probably not amenable to precise layering, but will give more turns and more resistance. But remember that the output increases only with the square root of the resistance. 200 ohms will produce 1.4x the signal of 100 ohms. If I use the same dimensions as above and #42 enameled wire, which is about half the diameter of #36, I will get twice the turns per layer, and twice the number of layers, for about 4800 turns. With the same mean length per turn, this will be 868 feet of #42, which will measure 1440 ohms. So I get only 4 times the output (4 x 1200 turns) at 16 times the resistance (16 x 90 = 1440 ohms). BUT I also have 16 times the Johnson noise due to the resistance, and it may be difficult to damp with a resistor if the magnet is not strong enough. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 40 Gauge Wire From: Danie Overbeek danieo@............ Date: Fri, 14 Jan 2000 06:30:34 +0000 Date: Thu, 13 Jan 2000 16:20:42 -0500 From: Paul Jebb Organization: Newcomb Central School To: "PSN-L@.............." Subject: 40 Gauge Wire Reply-to: PSN-L Mailing List Dear Members, Karl suggested that I use 40 or 42 gauge wire for the coil which leads me to two further questions: Where can you find such fine wire, Radio Shack doesn't carry it? How many turns do you recommend? Thanks, Yours truly, Paul Jebb NCS _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) A scrap automobile ignition coil secondary is wound with #42 or thinner wire, usually copper but sometimes aluminium. I found my coil easy to strip. Number of turns, as many as you can get into the available space! Good luck Danie Overbeek. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: coils and wire size From: Paul Jebb pfjebb@.............. Date: Fri, 14 Jan 2000 10:09:44 -0500 Hi Sean, Thanks for those suggestions, a lot of nuggets in there. Cheers, Paul S-T Morrissey wrote: > Re counting turns when winding a coil: > > I don't bother to count, but I know the approximate number. > > First of all, I turn the coil by hand on a short shaft under > good light, placing each turn EXACTLY adjacent to the previous, > and delimiting each layer with correction tape strips as I described > a few weeks ago. (need a repeat??). It takes about 2 minutes to > make about 100 turns. And another 10 minutes to epoxy the layer. > A 12-layer coil takes me over 2 hours, depending on distractions > while the epoxy cures. > > This lets you know the number of turns by knowing the diameter of the > wire and the winding length. I use #36 wire from Newark (need a repost > of that info??; they take MasterCard!). "Beldsol" enameled #36 wire has > a diameter of 0.0055", so if I have a winding length of 0.5" with EVERY > TURN exactly placed, I have 91 turns in that layer. Since I don't use > a bobbin form, I step back the end of each layer by one turn, or conversely > start with a slightly larger number in the first layer. So I use a starting > length of 0.615" ( slightly under 5/8") to start with 111 turns; subsequent > layers are 109, 107, 105, 103, 101, 99, 97, 95, 93, 91, and 89 turns in > the 12th layer, for a total of 1200 turns. The average length of a turn > with a 5/8" initial diameter is 2.17", so there is 217 feet of wire in the > coil, and at 414.8 ohms per 1000 ft, I should get 90 ohms, which is about > what I measure. > > For your info: other wire diameters and resistances: > > (diameter for enamel insulation) NEWARK roll length, ft cost > #36 0.0055 414.8 ohms/1000 ft. #36E1321 1/2lb 6400 $27.33 > #38 0.0044 659.6 #36F779 1 lb 19300 $73.49 > #40 0.0034 1049.0 > #42 0.0028 1659 > #44 0.0023 2593 > > Actually, the exact number of turns is not important. What is important > is to get the maximum number of turns inside the gap of the magnet, which > cannot be done with a "scramble wound" bobbin that often results from > using a drill. The required bobbin alone will take up an appreciable amount > of the volume. Also a target resistance value is not necessary. The > trade-off in my opinion is how small a wire you want to work with to get > the maximum number of turns into a given space. #40 and up wire is probably > not amenable to precise layering, but will give more turns and more > resistance. But remember that the output increases only with the square > root of the resistance. 200 ohms will produce 1.4x the signal of 100 ohms. > > If I use the same dimensions as above and #42 enameled wire, which is > about half the diameter of #36, I will get twice the turns per layer, > and twice the number of layers, for about 4800 turns. With the same mean > length per turn, this will be 868 feet of #42, which will measure 1440 > ohms. So I get only 4 times the output (4 x 1200 turns) at 16 times the > resistance (16 x 90 = 1440 ohms). BUT I also have 16 times the Johnson > noise due to the resistance, and it may be difficult to damp with a > resistor if the magnet is not strong enough. > > Regards, > Sean-Thomas > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seking the source of Yellowstone's Heat From: GeE777@....... Date: Fri, 14 Jan 2000 13:46:59 EST In a message dated 1/13/00 4:50:53 PM Pacific Standard Time, hernlund@....... writes: > This would in turn > create melt in the same manner as other upwellings through decompression. > If > this idea is correct, then the root of the heat should be very shallow, but > perhaps seismically indistinguishable from pure extension related > volcanism...perhaps an electrical tomography experiment is also in order > here. > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.public.asu.edu/~hernlund/ > Yes, I do think all this is very interesting.. Those of you using aol, I can send you by direct e-mail a map of the area. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Data Acquisition From: Phil Giannini pgiannini@........ Date: Fri, 14 Jan 2000 16:49:11 -0800 Hi Gang, For those of you that were at the PSN December meeting... You might remember the topic of obtaining a FREE data acquisition starter kit from Dataq being tossed around. Well, I got another bingo card today with the web address for obtaining a free kit. For those of you that might want to try your hand at another approach to data gathering here is the address for the free stuff: www.dataq.com/61.htm FYI Regards, Phil SFN & Z _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Data Acquisition From: meredith lamb mlamb1@.......... Date: Fri, 14 Jan 2000 19:08:18 -0800 Phil Giannini wrote: > Hi Gang, > For those of you that were at the PSN December meeting... You might > remember the topic of obtaining a FREE data acquisition starter kit from > Dataq being tossed around. Well, I got another bingo card today with the > web address for obtaining a free kit. For those of you that might want > to try your hand at another approach to data gathering here is the > address for the free stuff: > www.dataq.com/61.htm > > FYI > Regards, Phil SFN & Z > Hi Phil and others, I should make mention that this company primarily is courting the purchasing agents of companys, on the free kits, or is making an evaluation based on information that suggests the applicant has a position of enough stature to somewhat influence sales. I know, I tried to get one....no success. I'am not an engineer, purchasing agent, profession etc., etc. This kind of set back is common unfortunately for those of us, without sufficient titles, or ownership to qualify. I think the correct address is: http://www.dataq.com/025.htm, but the original address will get one there. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Used Seismometer From: "John Miller" cimarron@.......... Date: Fri, 14 Jan 2000 20:38:46 -0600 I have located a used TELEDYNE GEOTECH S-500, 1HTZ Seismometer for $ 275.00. It is supposedly in working condition. Is this a good buy? TIA John Miller Denver, MO Cimarron Co. LLC cimarron@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Data Acquisition From: The Lahrs JohnJan@........ Date: Fri, 14 Jan 2000 19:56:05 -0700 Meredith, I did get one of the free AD from Dataq. The problem is that 8 bits is just not enough for seismology purposes. Also, the gain is low, so even for a seismology demonstration using a small geophone one would need an amplifier. If you want to try it out, I'll give it to you. I've not tried out the diamagnetic carbon disks yet. So many projects and so little time. John At 08:08 PM 1/14/00 , you wrote: >Phil Giannini wrote: > > > Hi Gang, > > For those of you that were at the PSN December meeting... You might > > remember the topic of obtaining a FREE data acquisition starter kit from > > Dataq being tossed around. Well, I got another bingo card today with the > > web address for obtaining a free kit. For those of you that might want > > to try your hand at another approach to data gathering here is the > > address for the free stuff: > > www.dataq.com/61.htm > > > > FYI > > Regards, Phil SFN & Z > > > >Hi Phil and others, > >I should make mention that this company primarily is courting >the purchasing agents of companys, on the free kits, or is >making an evaluation based on information that suggests the >applicant has a position of enough stature to somewhat >influence sales. > >I know, I tried to get one....no success. I'am not an engineer, >purchasing agent, profession etc., etc. This kind of set back is >common unfortunately for those of us, without sufficient titles, >or ownership to qualify. > >I think the correct address is: http://www.dataq.com/025.htm, >but the original address will get one there. > >Take care, > >Meredith Lamb > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: barry lotz gbl@....... Date: Fri, 14 Jan 2000 19:22:00 -0800 Paul 2=A2 : Regarding counting turns, I have a Radio Shack digital counter.= It has a 4 digit LCD display with reset etc. It counts contact between two pins. I set ,securely, the counter on the bench. I attached one pin,thru = a wire to my vice. I secured the other pin via a wire to a wiper on the dri= ll chuck. The drill was held horizontally in the vice with the spool in the chuck. Each revolution of the chuck contacted the two wires an counted a revolution. I ran several hundred turns when I constructed my LVDTS. I haven't used the counter with the Lehman though. I just recorded the overall DC resistance of the completed coil. I agree with Karl. Finer wir= e will result in a larger output. 36-40+ ga is good. I have tried to wind 4= 9+ gage and found it very frustrating. I breaks easily and hard to solder wh= en broke. Patience is a good tool also. Keep the faith :) Barry Paul Jebb wrote: > Gentlemen: > Regarding a Lehman seismometer: > > Is 30 gauge copper wire satisfactory for the coil, if so, how much > should I use. I plan to put the wire on with a drill, but counting the > number doesn't seem possible. The original design called for 400 ohms > of resistance. Can anyone speak to this issue? > > Yours truly, > > Paul Jebb > NCS > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: "steve hammond" shammon1@............. Date: Sat, 15 Jan 2000 09:42:25 -0800 I like the counter idea and will try it. I do have a question. I was wondering if anybody had the wire constant i= nfo for enamel insulation #52 wire. My little Electronic Pocket Handbook stop= s at #44. I really enjoyed reading the information that Sean-Thomas presented abou= t coil making and was wondering if he could explain what Johnson noise due = to resistance is and how to measure it. I have been making scramble wound coils using #52 wire mainly because Pe= te Rowe came to a PSN meeting in 93' and gave me some large bobbins of the stuff. I played with this wire for awhile and after breaking enough of it= to clutter up the floor in my garage, figured out a method to get it onto a coil form. I used the white 2-inch plastic spools from RadioShack 22-gaug= e wire. First sand the frame so that the wire won't snag on an edge when be= ing wound. I use a small Drumel lathe with a wall light dimmer controlling th= e speed. Hang the wire above the frame so it can fall off the bobbin. Cut a hole on the inside of the white frame and feed the wire through the hole. Tape the wire down on the outside for winding. Pull some extra wire down from the bobbin, hold your breath, start the Drumel lathe, feed with one hand and pull wire down with the other. Breath when you think you have it under control or are going to pass out. In about five minuets, you'll hav= e a coil. I have made several coils this way. They all have been in the 17K range. Even without electronics, they will drive a galvanometer on a drum record= er. I unwind a little wire when I want to match two coils for a pair of seismographs. I like to use a cow magnet inside the center hole of the plastic frame (1/2-dim - length 2.5-inch) and just mount the magnet to th= e boom of the Lehman. If you do mount the magnet on the boom, make sure the= re is no steel in the floor or seismograph enclosure walls that will draw th= e boom to the steel. To make the connecting wires portion, wrap a few inche= s of wire around a 6-inch piece of 22 gauge wire and then solder them together. Epoxy the connector wire to side of the frame. Then wrap the complete coil assembly in black electrical tape to protect it when it's being installed or when your working around the seismograph. I've got two= in use today that have lasted 8 years. My 2C worth. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: barry lotz To: PSN-L Mailing List Date: Friday, January 14, 2000 7:16 PM Subject: Re: Magnet Wire Paul 2=A2 : Regarding counting turns, I have a Radio Shack digital counter.= It has a 4 digit LCD display with reset etc. It counts contact between two pins. I set ,securely, the counter on the bench. I attached one pin,thru = a wire to my vice. I secured the other pin via a wire to a wiper on the dri= ll chuck. The drill was held horizontally in the vice with the spool in the chuck. Each revolution of the chuck contacted the two wires an counted a revolution. I ran several hundred turns when I constructed my LVDTS. I haven't used the counter with the Lehman though. I just recorded the overall DC resistance of the completed coil. I agree with Karl. Finer wir= e will result in a larger output. 36-40+ ga is good. I have tried to wind 4= 9+ gage and found it very frustrating. I breaks easily and hard to solder wh= en broke. Patience is a good tool also. Keep the faith :) Barry Paul Jebb wrote: > Gentlemen: > Regarding a Lehman seismometer: > > Is 30 gauge copper wire satisfactory for the coil, if so, how much > should I use. I plan to put the wire on with a drill, but counting the > number doesn't seem possible. The original design called for 400 ohms > of resistance. Can anyone speak to this issue? > > Yours truly, > > Paul Jebb > NCS > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Noise From: ChrisAtUpw@....... Date: Sat, 15 Jan 2000 18:09:20 EST Since seismologists need to measure very small signals, there are several sources of noise which may interfere with our measurements. If a sensor such as a coil has a resistance R Ohms, it generates a noise voltage across it's output (due to the internal movements of the electrons) 'en' where en = SQRT(4xKxTxRxB) where K is a constant, T is the absolute temperature in Deg K (=293 at 20 Deg C) and B is the bandwidth (say 10 for a frequency range from 0 to 10 Hz). at room temperature en = 1.27x(10^ -10)xSQRT(RxB) so for a 1000 ohm coil and a 10 Hz bandwidth the noise voltage will be en = 12.7 nano volts This doesn't sound much, but we then have to amplify our signals a lot and there are TWO additional types of noise in the amplifier itself. You may see a figure of 3.8 nano volts per root Hz quoted for an OP27 OP-AMP at 10 Hz. This means that the average noise voltage for a 10 Hz bandwidth will be 3.8xSQRT10 = 12 nano volts. Unfortunately, most semiconductor amplifiers also generate additional noise at low frequencies called '1/f' noise. It is called this because the amplitude increases as the frequency decreases and it is the biggest interfering signal below about 10 Hz. There are two ways of controlling amplifier noise problems. You can fit a pair of low noise transistors on the OP-AMP input and get down to less than 1 nano volt per root Hz. The best you can do this way, with a lot of effort, is about 0.3 nano volts per root Hz. You can use a 'chopper stabilised amplifier' like the MAX422 or the LTC1050 which, by the way that they work, eliminate the 1/f noise. They do add some high frequency noise above about 5 KHz, but this is easily filtered out. This is good news in general for seismolgists, but the price tag is not such good news. You will notice that I have quoted the AVERAGE noise voltage. When you look at the amplifier output with an oscilloscope, you may wonder what has gone wrong. You soon realise that the maximum voltage, which is the one you tend to notice, is probably at least twice the average that you expected and quite 'lumpy' as well. That is the nature of averages. FET and CMOS amplifiers also have other types of noise which limit their performance. The final noise output is the sum of the various components. If you do wind a huge coil, while the output may go up with the number of turns, so does the noise. To wind a larger number of turns in a given space, you need finer wire which has a higher resistance per turn and since it is more difficult to wind it evenly, the wasted space also increases. The likelyhood of picking up mains other types of electrical interferance also increase and screening may be difficult. The 'rare earth' and 'neodymium' magnets have the strongest magnetic fields and enable you to get more volts out of your coil than a similar sized alnico magnet would give. To estimate the total average noise voltage, you square the calculated / measured values from the various sources, add them together and then take the square root. You need to get the best signal to noise ratio that you can, so, if you have a high resistance coil, adding an expensive chopper amplifier will probably not do much good. Buying a samarium magnet might be much more cost effective. Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WinQuake 2.6 Release is ready From: Larry Cochrane cochrane@.............. Date: Sat, 15 Jan 2000 20:29:01 -0800 Greetings, Well it's been in the works for over a year, the official WinQuake 2.6 release is ready and finally out of beta! The last few weeks I have been working on the documentation, the part I hate the most! I finally finished this task and today I created the setup program contain all of the files needed to install and run the program. I actually had to create three files. One is a large 2.6 meg file that can be used to install the program (really two programs with the PSN Explorer Web browser that is now part of the release) on systems connected to the Internet. Since 2.6 meg is to large to fit on a floppy, and some users may have a system not connected to the Internet, I had the program I use to create the setup break the files into two parts. This way users can download the two files, transfer them to floppies and then install WinQuake on another system. Users running the current beta release will have to download and install this version because the beta program will time out next month. See http://www.seismicnet.com/software.html for download links and installation information. Please let me know if you run into any problems installing or running the program. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise From: Ed Thelen ethelen@........ Date: Sun, 16 Jan 2000 05:35:45 -0800 ChrisAtUpw@....... wrote: > .... > There are two ways of controlling amplifier noise problems. You can fit a > pair of low noise transistors on the OP-AMP input and get down to less than 1 > nano volt per root Hz. The best you can do this way, with a lot of effort, is > about 0.3 nano volts per root Hz. You can use a 'chopper stabilised > amplifier' like the MAX422 or the LTC1050 which, by the way that they work, > eliminate the 1/f noise. They do add some high frequency noise above about 5 > KHz, but this is easily filtered out. This is good news in general for > seismolgists, but the price tag is not such good news. > .... Arrow - www.arrow.com - has commercial temperature range LTC1050 for $5.55 If you really want to run it above 85 degrees C, the LTC1050AMH883 is $24.00 I love 'choppers' - a GREAT improvement over my original 741's (which were great in the early 1970's :-) Cheers Ed Thelen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise From: "D. Hill" n0ssy@.......... Date: Sun, 16 Jan 2000 14:24:03 +0000 If someone want to use a chopper amp there is a good circuit at the URL below. There are two amps on this page. I have built and currently us the amp that has the 1hz filter with no problems. What I like is there is no drift of the output voltage, which mean fewer re-adjustments. I have modified the the off set adjustment section of the circuit which makes it easier to adjust. If you are interested in my mod please contact me. http://www.info2000.net/~aloomis/seismom.htm Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: From: Nick & Sophie Caporossi nickcap@............. Date: Sun, 16 Jan 2000 10:44:53 -0500 Hi all: Does anyone what is the problem with Pacific Northwest Seismograph Network? Specifically the "LON LHZ UW : Longmire (Mt. Rainier) long-period" It's at: http://www.geophys.washington.edu/SEIS/PNSN/WEBICORDER/welcome.html I view that site quiet often to see when a quake is starting. Thanks Nick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Howard Grebin From: George Bush gbush@....... Date: Sun, 16 Jan 2000 09:50:23 -0800 For those of you who knew Howard, I have to sadly report that he died last Tuesday at the age of 92. Many years ago Howard built the seismometer that I am presently using from refurbished salvaged equipment. He was quite active in ametuer radio and seismography, building his first seismometer in 1978. His obituary appeared in the Jan 14th edition of the Press Democrat of Santa Rosa, CA. George _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: barry lotz gbl@....... Date: Sun, 16 Jan 2000 10:24:53 -0800 Hi Steve Thanks for the input. If I break a wire during winding I would try to "side lap" the wires and try to solder. I was always concerned about whether the connecting was made. I had the beginning of the coil as one end for checking continuity. I would then go away from the joint and bare ,with heat, the wire to check for continuity. I have two types of magnet wire coatings, red and orange. The red appears to be easily removed with heat. the orange is more difficult. Do you have and suggestions on heat temp required for coating removal? I seem to remember it being mentioned in the recent past. The reason I was having problems with winding fine wire was one of two reasons. If one tries to allow the source spool to turn then inertia fluctuations from changes in rotational speed causes breaking. Secondly if I let the wire feed off the end of a stationary source coil then the wire seems to snag on adjacent windings of the source coil due to the steep angle as it comes off the coil. Barry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Howard Grebin From: "steve hammond" shammon1@............. Date: Sun, 16 Jan 2000 11:13:56 -0800 Thanks for letting me know George. I had the pleasure of meeting Howard a few years back at his home in Sebastopol. He gave me a picture of his seismograph and showed me how to make an ink pen for my drum recorders. About 1950, as the story would go, the Berkley Lab would call Howard to get a second reading on distant events. He was a pioneer. It's good to hear that his seismograph is still on-line. Regards, Steve Hammond -----Original Message----- From: George Bush To: psn-l@............. Date: Sunday, January 16, 2000 9:51 AM Subject: Howard Grebin >For those of you who knew Howard, I have to sadly report that he died last >Tuesday at the age of 92. Many years ago Howard built the seismometer that >I am presently using from refurbished salvaged equipment. He was quite >active in ametuer radio and seismography, building his first seismometer in >1978. His obituary appeared in the Jan 14th edition of the Press Democrat >of Santa Rosa, CA. >George > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: Karl Cunningham karlc@....... Date: Sun, 16 Jan 2000 12:03:16 -0800 Barry -- At work, we use a match for stripping high-temperature magnet wire. Play the flame quickly over the last 1/4" (or however much you want to strip) of the wire. It only takes a fraction of a second to do it. Then gently strip the charred insulation from the wire with a pencil eraser. If the wire breaks while winding, it's best to start over. You can splice it, but the bump it causes will disturb the layering of the rest of the coil. Winding with small wire can be tricky. Let the wire feed off the end of the spool and straight up, as you mentioned. Putting the spool on the floor facilitates this. At work we use a "whisker disk" to control the wire feed. This is an aluminum disk (maybe 1/16" thick) with a polished perimeter that is larger in diameter than the ends of the spool, and has "whiskers" extending out from the edge. It looks a little like a rotary wire brush with only a few wires present. The whisker disk sits on top of the end of the spool of wire you are feeding from. The large diameter of the whisker disk forces the magnet wire to feed out from the layers on the spool without snagging on the adjacent turns, and the whiskers (VERY fine stainless wires) keep the magnet wire from moving and getting tangled when the winding operation stops. The whiskers extend about 1" from the perimeter of the disk. I'm not sure how you could make the whiskers, but some bristles from a very fine brush might work if glued to the outside of the disk. Karl At 10:24 AM 1/16/2000 -0800, you wrote: >Hi Steve > Thanks for the input. If I break a wire during winding I would try to "side >lap" the wires and try to solder. I was always concerned about whether the >connecting was made. I had the beginning of the coil as one end for checking >continuity. I would then go away from the joint and bare ,with heat, the wire to >check for continuity. > I have two types of magnet wire coatings, red and orange. The red appears to >be easily removed with heat. the orange is more difficult. Do you have and >suggestions on heat temp required for coating removal? I seem to remember it >being mentioned in the recent past. The reason I was having problems with >winding fine wire was one of two reasons. If one tries to allow the source spool >to turn then inertia fluctuations from changes in rotational speed causes >breaking. Secondly if I let the wire feed off the end of a stationary source >coil then the wire seems to snag on adjacent windings of the source coil due to >the steep angle as it comes off the coil. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: Magnet Wire From: angel rodriguez angel@............ Date: Sun, 16 Jan 2000 17:34:28 -0500 Hi All, Check out this seismograph on ebay. http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=239007825 I hope it doesn't waste too much of your time. Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnet Wire From: barry lotz gbl@....... Date: Sun, 16 Jan 2000 17:17:47 -0800 Karl Thanks for the idea about the larger disk. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: bridge transformer From: S-T Morrissey sean@........... Date: Sun, 16 Jan 2000 21:37:54 -0600 (CST) Barry, You asked about the 600 ohm transformer between the excitation oscillator and the bridge in the displacement transducer: The reason that an isolation transformer is used in all reactive bridge circuits (VRDT, LVDT, and capacitive) is to remove any DC component from the excitation signal. Even the most perfect amplifier at the output of the oscillator circuit will have some small DC offset voltages present at the output, and these will be modulated by all the noises present at its input and amplified to the output. Without a transformer, these DC noise currents flowing in the inductors of the VRDT or LVDT will cause magnetic forces on the moving transducer sensing element, causing noise forces on the seismometer mass. Magnetic forces are not a problem for capacitive sensors, but electrostatic forces are, especially for large plate areas and sub-millimeter spacing. And even sub-millivolt DC noise can have large electrostatic effects. So there is nothing more simple than the transformer to isolate the DC noise. And some bridge circuits actually use a transformer in the output to provide a 10x to 100x voltage gain prior to the bridge AC amplifier, which also prevents input offset currents of the AC amplifier from getting back into the transducer. Often large capacitors are also used between the bridge and the amplifier to block any DC noise. This is particularly important for electrolytic tiltmeter bubbles, where any DC current will plate the electrodes off the vial walls. So it is also necessary to use an op-amp at the bridge output amplifier with minimal input current noise and DC offset. The 600/600 ohm transformers are available from Mouser, Newark, and others for a few dollars. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: n0cwr@......... Date: Mon, 17 Jan 2000 14:49:56 +0000 Hi Jim I seen your post was 1/9/2000 and appeared ready to start getting some reads. My last "clean" read of an event was 1/8/2000 (M 7.1 from Tonga Islands) I see a lot of events superimposed in the noise but not worth sending to the group. In the midwest, I think, readable events are a bit slower than for those that are out in the Pacific or California. But I am wondering?, you may have been able to see the Maine 3.4? I came in this morning to find the boom of the Lehman over to it's stop. Flat line on the screen. I have the period set to 16/17 seconds and I am considering dropping it back. This has happened several times now. The concrete, I guess that it is setting on shift's. Or, things change somewhere just a micron here or there. I didn't have to adjust it even at 14 second period. Sensitivity compared to when I started and I had it set to it's easy to attain 12 second period?... I don't think I've noticed a difference other than the noise floor is much higher now and I have to adjust it periodically. I'd think that location is everything. There isn't an abonded gold mine on my city lot! Darn! I guess the point is, if the thing has set over night flat lined, what good did the longer period do. With local noise, most of the weaker reads I get have to happen during the quiet time of night. I was hoping to see if I could of detected the Maine 3.4 superimposed in the noise but...., _______________________________________________ ! At 11:31 PM 1/9/00 -0500, you wrote: >Thanks to Jim and Kevin, I now have a Lehman boom that is beginning to >behave correctly. Thank you both for you help. > >In measuring the 'period' of the boom, is this the measurement of time it >takes the boom to swing "out and back", when pushed, or the time it takes >for the oscillations to die out completely? If I manually deflect the boom >~1" off of center, is the period the time it takes the boom to come back to >center, or the time it takes the boom to move out to one side and then >back past center to the other side? > >I know these are VERY elementary questions for this list, but hey, I've got >to start somewhere, don't I ? > >My thanks in advance to anyone who wishes to help me out. > >Jim Martin >New Haven, Indiana > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Period adjustment From: S-T Morrissey sean@........... Date: Mon, 17 Jan 2000 14:44:33 -0600 (CST) Jim, Regarding instability at long natural periods: For your information and encouragement, I would like to point out that when the WWNSS (Worldwide network of standardized seismograph stations) was first deployed, the horizontal long period (LP) seismometers (Sprengnether 5100s) were set at 30 seconds period. But after about a year, it became evident that this resulted in many against the stops for much of the time, in spite of being an elegant instrument installed on massive piers in carefully designed vaults (with notable exceptions). So the standard period for the long-period WWNSS was set to 15 seconds. Recording was done with a 90-second galvanometer on photographic paper. The seis, galvo, and coupling/attenuation network impedances were 500 ohms. So I would also suggest that strong over-damping coupled with a good amplifier can achieve a similar result as a much longer period, since over-damping makes a somewhat broad response, but at reduced output, hence the need for a proper amplifier, especially one with very low input offset current, since such currents WILL flow through the signal coil of the seis and push the mass around. These alone may cause substantial apparent drift of the mass position. In two stations where I am currently operating LP seismometers (with natural periods set to 15 seconds), I am damping them with 500 ohms (the same as the coil resistance), which is a damping coefficient of 2 times critical. I am using the amplifier posted on the web site. With no galvanometer, the response is fairly broadband from 10 hz to 25 seconds. Regards, Sean-Thomas PS: You have not mentioned the thermal protection that you are providing for your seismometer. Even the large 5100 LP seismometers have 4" to 8" of insulation. I use an indoor/outdoor thermometer to monitor the instrument temperature, which changes no more than 1 degree C / week, and about 1/10th that per day. PS2: I notice that you mention moving your boom 1" off center to measure the period. This may result in major non-linearities in the restoring forces that control the period. The period is rarely measured visually; when it is, displacements of less than a mm are used, and a magnifying reticule is used to time the zero crossings going in the same direction (a full cycle of motion represents the period). Preferably an oscilloscope or the seismic digitizer is used to measure the period from the output of the moving coil, using very small displacements. It may be that your period is actually much longer than what you get by moving it 1". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: updates and my move From: "David A. Nelson" davenn@........ Date: Tue, 18 Jan 2000 14:18:44 +1300 hi all, trust everyone's new yr is going well. I'm winging it outta new zealand again. monday 24th Jan i will be flying to sydney, australia, looking for work and a new start. my e-mail addy will be davenelson39@........... ok 2 additions to map and list and one update have been done Don Wheeler and Brian Schavee welcome to the group to both of u Steve Hammond i updated ur data too cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: barry lotz gbl@....... Date: Mon, 17 Jan 2000 20:37:20 -0800 Hi If your sensor isn't in non-stable equibrilium (returns to zero when offset) then you may be experiencing slab tilting due to moisture gradients of the soil due to winter weather. Is your sensor on a slab? It happens to my Lehman this time of year in my garage. Just another possibility. See which way it moves relative to the exterior, considering the fact that soil swells when wet,more or less depending on the soil type. Mine usually stabilizes once the first several rains finish. It goes the other way in the spring time. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman help From: BOB BARNS roybar@........ Date: Tue, 18 Jan 2000 11:47:39 -0500 Jim, My calculation (approximate) predicts that the Maine 3.4 was much too small to see above the noise in NJ and I did not see it. That most likely means that it is far too small to see in the midwest. Bob Barns, Berkeley Heights, NJ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: ChrisAtUpw@....... Date: Tue, 18 Jan 2000 20:32:29 EST In a message dated 13/01/00 09:23:33 GMT Standard Time, twleiper@........ writes: >> My daughter's Lehman is on a pier cast atop what is either an immovable huge bolder or exposed bedrock in the root / wine cellar. It is a very stable environment with natural temperature control and the seismo is made from thermally stable materials, such as a granite tool and die makers slab for a base. With a natural period of 50 seconds it only needs seasonal centering adjustment.... Dear Mr.Leiper, This all sounds great, but what is the price of granite engineering slabs and how do you go about boring holes in them? I read through your account of the construction of the original seismograph with interest. I have been trying to think of a relatively cheap, heavy and robust base material for a seismograph. I noted that people who used plate Aluminium seemed to have put weights on them, so presumably, some weight can be an advantage. I was driving past some roadworks yesterday, when I had a bright idea. You can get 2" thick paving slabs made out of high density 'vibrated' concrete, with a reasonably flat finish on both sides. The workmen were cutting 3' x 2' slabs to size with a disk as I passed and I wondered if anyone had thought of using part of one for a seis base? You could probably stick flat metal base plates onto the concrete with epoxy. The smallest diamond core drill that I can hire is 1/2", which seems a bit too big. I haven't yet tried drilling a slab with a hammer drill and a carbide bit, but from past experience, high silica aggregates are quite drill resistant. Do you know if anyone has used a paving slab and if so, were there any problems? The price and weight seem about right. Can you comment, please, in comparison the granite block? Regards, Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: Rick Bitto rbitto@........... Date: Tue, 18 Jan 2000 20:53:36 -0500 I had thought of pouring a concrete base from scratch with threaded inserts cast in place. I too was wondering what drawbacks this base would have (other than weight). Rick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: "steve hammond" shammon1@............. Date: Tue, 18 Jan 2000 19:36:25 -0800 Chris, I just used a cheap cement drill to do this. Here is what i did on mine and how I applied the design and set it all up. Regards, Steve Hammond I used a combination of cement and Aluminum for the base of my Lehman. I made 12 x 12 x 20 -inch deep hole in the ground and filled it with cement. 50/50 mix. I added a 12x12x4-inch box at above ground level so the cement would extend above ground level by 4-inches. After the cement set, I drilled three 3/8-inch holes and installed (3) 6-inch x 3/8 machine anchors in the cement in a triangular pattern. I then drill 3 holes to match the pattern in the 1/2 x 8 x 14-inch Aluminum base plate on the Lehman. Using 6 nuts and 12 washers I 'm able to suspend the plate a few inches above the cement and level it by adjusting the tripod captured nut arrangement. This works very well for me. My Lehman has a 40-inch boom and a 5lbs mass weight. The upright wire angel is 42 degrees. The three bolt pattern provides the initial coarse adjustment. I then added two 4-40 machine screws that extend through the left and right rear corners of the aluminum plate. They butt into two metal blocks placed atop the cement pad and under the plate. By applying equal amounts of force the Lehman pipe uprights remain vertical at 90 degrees. When the ground conditions change and the boom goes to stop, I apply a bit more force to one or the other to adjust the boom back to center by tweaking the aluminum plate slightly giving me very fine control over the vertical 90 degree adjustment. My Lehman uses the standard oil nozzle in the upper cross pipe for the upper guide wire, so I added a large hexhead screw as the lower pivot stop which I use for positioning the boom forward and back in relation to the upper wire oil nozzle. A turnbuckle is used in the upper guide wire to adjust the 0' leveling of the boom. Installed in alluvium soil, I maintain an operational period of 21 seconds. I have had the period as high as 40+ seconds, but I needed to check it each day to keep it off the stops which become demanding after a few months. I have found that with a 12-25 seconds period you can record from California to New Zealand events in the range of 6.0 and higher. If you would like to see a picture of the seismograph on the bench, there is one on the PSN web site in San Jose. http://pw2.netcom.com/~shammon1/equip.htm However this picture is taken when I was making some measurements in the shop but it helps to visualize my comments above. To set it all up, I follow the following steps until I obtain the period I'm after. It takes about 2 hours to dial-in 21 seconds the first time and over the next 30 days the seismograph will find its own natural shape and require readjusting several times. Once operational stag is reached, you only need to adjust it as the ground conditions change. The adjustments Take a look at the web site picture this should help the discussion below. The lower pivot screw is hidden by the lower cross plate that has been drilled and tapped to receive the screw. The head of the screw is in the back of the unit and by turning it in, you push the boom away from the pipe uprights increasing the angel or increasing the pendulum angel and reducing the period of the pendulum. Initialization 1) Remove all damping. 2) Before starting, make sure the lower pivot nut is turned in well past the imaginary vertical line passing between the the point in the oil nozzle where the upper guide wire enters it and the pivot point on the end of the boom. (I use a very fine point set in a cup drilled in the end of the lower pivot screw.) If the position of the lower pivot screw gets to absolute zero or - zero the boom will hang perfectly still or want to roll-off to the left or the right and go to the stops and you will never be able to center it at 90-degrees to the pipe uprights. If you are unsure, turn the screw all the way in and start there. Adjustment loop 3) level the boom to 00' degrees using the turnbuckle. 4) center the boom to the pipe uprights at 90 degrees. 5) check the period. When you start it will be less than 1 second. 5A) Exit -- go to damping adjustment step 7. Quit if the period is where you want it (mine is at 18 seconds undapened). 6) Unscrew the lower pivot screw 1/8 turn. 7) GoTo step #3 Section Adjusting the damping. 7) If you are using a magnet damping, a rule of thumb is to adjust your damping to stop the seismograph after 3.5 cycles. A simple way to do this is the breath method. Blow slightly on the side of the boom to set it in motion. The center of the boom should come to rest after passing through the imaginary center center line under the horizontal edge of the boom 8 times. After blowing on it, the swing back would be numbered swing #1 passing center on the initial swing back from being blown off center. Swing #2 is the first half cycle swing #3 is the first full cycle swing back #4 is 1 1/2 cycles and so-on. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: ChrisAtUpw@....... To: psn-l@.............. Date: Tuesday, January 18, 2000 5:33 PM Subject: Re: Lehman base material? >In a message dated 13/01/00 09:23:33 GMT Standard Time, twleiper@........ >writes: > >>> My daughter's Lehman is on a pier cast atop what is either an immovable >huge bolder or exposed bedrock in the root / wine cellar. It is a very stable >environment with natural temperature control and the seismo is made from >thermally stable materials, such as a granite tool and die makers slab for a >base. With a natural period of 50 seconds it only needs seasonal centering >adjustment.... > >Dear Mr.Leiper, > > This all sounds great, but what is the price of granite engineering slabs >and how do you go about boring holes in them? I read through your account of >the construction of the original seismograph with interest. > > I have been trying to think of a relatively cheap, heavy and robust base >material for a seismograph. I noted that people who used plate Aluminium >seemed to have put weights on them, so presumably, some weight can be an >advantage. > > I was driving past some roadworks yesterday, when I had a bright idea. >You can get 2" thick paving slabs made out of high density 'vibrated' >concrete, with a reasonably flat finish on both sides. The workmen were >cutting 3' x 2' slabs to size with a disk as I passed and I wondered if >anyone had thought of using part of one for a seis base? You could probably >stick flat metal base plates onto the concrete with epoxy. The smallest >diamond core drill that I can hire is 1/2", which seems a bit too big. I >haven't yet tried drilling a slab with a hammer drill and a carbide bit, but >from past experience, high silica aggregates are quite drill resistant. > > Do you know if anyone has used a paving slab and if so, were there any >problems? The price and weight seem about right. Can you comment, please, in >comparison the granite block? > > Regards, Chris Chapman > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: "Jan D. Froom" froom@............. Date: Tue, 18 Jan 2000 20:04:21 -0800 At the past PSN meeting at the Berkeley Seismological Laboratory, Robert Uhrhammer told us that their Seismic Pads were made of concrete and sand... No rocks or steel. And the seismometers SAT on the top of block; in other words, they were not attached. Jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Georgia Shake From: DGentry509@....... Date: Wed, 19 Jan 2000 00:52:44 EST From the NEIC bulletin, some East Coast action. 00/01/18 22:19:31 32.94N 83.27W 5.0 3.5Lg GEORGIA, USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: "steve hammond" shammon1@............. Date: Tue, 18 Jan 2000 21:53:57 -0800 Hi Rick, Hay Jan-- call me kuz we need to talk. Rick, I designed my Lehman base because I wanted to use some scrap aluminum plate I got from a salvage yard that was kind of small. It needed to be bolted to something because the unit would not have worked if It wasn't. The mass would have just sat on the ground after the pipe uprights tipped forward. I settled on the 50/50 cement sand mix because that is what my dad taught me to use some years back for making castings. During the PSN meeting Robert Uhrhammer, of the Berkeley Seismological Lab mentioned that the Broadband network uses a 50/50 mix as Jan just posted earlier and they just sit their equipment on the slabs. He also said they sometimes just sit them on window glass to eliminate even more expansion. It turns out that a 50/50 mix has the best stability / expansion ratio due to the ratio of elements and density. He also said they never use any ag-rock in it. Of course I just knobbed my head in agreement as Bob explained all this and acted like I always new that... and told myself something about having dumb-luck. All in all, the design works real well for me. I was even able to put a second slab around the mounting cube and keep an air gap between them so I could stand next to the device and work on it without too much extra effort. Later, I also added 3-inch insulation to the sides and tops of the covers. I only checked them from time to time after that through a window in the top. About once a year the upper wire would rust and break and about every 2-3 months I would tweak the 4-40 screw to center the boom. By the way, I think I said this before, did I mention SPIDERS!!! Never just reach down into the darkness... One night I came up with the biggest blackest angriest fattest spider at the end of my elbow you ever saw. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: Rick Bitto To: PSN-L Mailing List Date: Tuesday, January 18, 2000 5:54 PM Subject: Re: Lehman base material? >I had thought of pouring a concrete base from scratch with threaded >inserts cast in place. I too was wondering what drawbacks this base >would have (other than weight). > >Rick > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: twleiper@........ Date: Wed, 19 Jan 2000 18:49:03 -0500 On Tue, 18 Jan 2000 20:32:29 EST ChrisAtUpw@....... writes: >In a message dated 13/01/00 09:23:33 GMT Standard Time, >twleiper@........ >writes: snip.... > >Dear Mr.Leiper, > > This all sounds great, but what is the price of granite >engineering slabs >and how do you go about boring holes in them? snip In my case the price was ten bucks many years ago at a scrap yard. It is two by three and 4" thick and already had the leveling mechanism. All my attachment points are with PC-7 epoxy, so no drilling was required. The idea was to preserve the geometry of the components to the most rediculous degree possible over long term temperature drifts (days/weeks). I had tried all manners of insulation, stratified heating elements, baffles, etc. with less than ideal success. In addition, there is a principle in amateur seismology that states that the more you make the instrument immune to the environment, the more it is immune to YOU. Trying to experiment with it, ie; uncovering, adjusting, restabilizing and analyzing, becomes more of a pain in the ass. Since my vault is highly stable, I decided to focus primarily on reducing drafts (relatively simple) and preserving geometric integrity over long period temperature swings through materials selection. I am experimenting with bimetallic boom and support elements and hope to be able to preserve the geometry (and adjustments) over a twenty degree differential. I'll post something if it leads to anything worthwhile. One thing I would suggest if you don't have a complete machine shop in the garage...Make everything out of sealed particle board and other composites. My brother has a very high end custom furniture manufacturing operation in San Diego, and his tolerances with this material are getting down to the thousanths, and it is extremely stable. Like the Dobsonian telescope mount compared to an elegant German Equatorial mount, it promises excellent performance at a price attainable to the masses. I think my next project will be a complete seismometer and recorder constructed entirely off materials available at Home Depot and Radio Shack, so that great silent majority of teaming millions who want to become amateur seismologists can realize their unfulfilled dream... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: Keith Payea kpayea@...................... Date: Wed, 19 Jan 2000 18:25:46 -0800 I've used a similar tactic, making the base of my STM style vertical unit out of garden variety (literally!) 8" x16" x2" concrete stepping stones. I used three, cut one in half, and made a 24" long base out of two layers of 1 + 1/2 pieces. I used "liquid nails" as an adhesive and it works great. For fasteners, I mostly used "T-nuts" epoxied into holes in the concrete which I made with ordinary masonry drill bits. I chose mostly #8 hardware, and it turned out that a 1/4" drill bit was just about perfect to drill a hole to glue the T-nut into. I found that the drill bit wants to wander as you drill, so I shoot for a slightly sloppy fit. Then, I fill the holes about half way with epoxy and set the entire assembly to be attached, with the t-nuts threaded on, right into the holes. I use wax paper to make sure only the t-nuts get epoxied to the base. In five minutes, the epoxy is set and I back out the screws and remove the assembly. I usually clean up the epoxy overflow with an exacto knife, and wait a full day before putting any real strain on the fitting. It makes the base heavy, but extremely heavy! One other note. Concrete is porous, so before final assembly, I coated the entire base with a high quality sealer/primer paint. It has the benefit of making the base a nice neat white color. Good Luck, Keith Payea ChrisAtUpw@....... wrote: > In a message dated 13/01/00 09:23:33 GMT Standard Time, twleiper@........ > writes: > > >> My daughter's Lehman is on a pier cast atop what is either an immovable > huge bolder or exposed bedrock in the root / wine cellar. It is a very stable > environment with natural temperature control and the seismo is made from > thermally stable materials, such as a granite tool and die makers slab for a > base. With a natural period of 50 seconds it only needs seasonal centering > adjustment.... > > Dear Mr.Leiper, > > This all sounds great, but what is the price of granite engineering slabs > and how do you go about boring holes in them? I read through your account of > the construction of the original seismograph with interest. > > I have been trying to think of a relatively cheap, heavy and robust base > material for a seismograph. I noted that people who used plate Aluminium > seemed to have put weights on them, so presumably, some weight can be an > advantage. > > I was driving past some roadworks yesterday, when I had a bright idea. > You can get 2" thick paving slabs made out of high density 'vibrated' > concrete, with a reasonably flat finish on both sides. The workmen were > cutting 3' x 2' slabs to size with a disk as I passed and I wondered if > anyone had thought of using part of one for a seis base? You could probably > stick flat metal base plates onto the concrete with epoxy. The smallest > diamond core drill that I can hire is 1/2", which seems a bit too big. I > haven't yet tried drilling a slab with a hammer drill and a carbide bit, but > from past experience, high silica aggregates are quite drill resistant. > > Do you know if anyone has used a paving slab and if so, were there any > problems? The price and weight seem about right. Can you comment, please, in > comparison the granite block? > > Regards, Chris Chapman > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: Danie Overbeek danieo@............ Date: Thu, 20 Jan 2000 07:26:22 +0000 Don't talk to me about spiders! In the early days I was caught out several times by events that resembled magnitude 7+ teleseisms, only to discover that miniature daddy long legs busy spinning webs between the seismic mass and the frame. The way a spider no more than 2mm across its body can throw around a a seismic mass at least a million times heavier than itself is awesome. Cheers all arachnidphobes, Danie Overbeek. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Geophone layout From: "Thomas" tlooi@........... Date: Thu, 20 Jan 2000 01:26:44 -0500 Hi everyone, I am 4th year student working a project using geophones to measure ice thicknes. Is there a special method to layout the geophones to get an accurate profile an induced vibration? The purposal is to generate an acoustic pulse through possibly several kilometers of ice and have the geophones detect this pulse and derive the ice thickness. Would anyone have suggestions on a detonation mechanism? I've heard people use 1 kg of dynamite for 1 km of ice. As you can see, I am not too familiar with geophones but I do know they work like an accelerator. If anyone knows of a good book, please suggest it because none of our group members are geology people. Thanks alot for your time. Thomas Looi Aerospace Engineering University of Toronto _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Geophone layout From: Doug Crice dcrice@............ Date: Thu, 20 Jan 2000 06:39:49 -0800 Thomas, The standard method of measuring ice thickness is ground-penetrating radar. Not only does it work well, you can even do it from a helicopter. You can also do it with geophones using standard seismic reflection methods, though it would be harder. A second problem is that the velocity of sound waves in glacier ice may be less well defined than that of microwaves. The name of the technique is a seismic reflection survey. The University of Toronto has a perfectly good Department of Geophysics, where you will find the equipment and expertise to use either method. Start by visiting your library and opening up any book with "Geophysics" in the title. There is no doubt information on the Internet as well, but some problems are better solved at the library because it's harder to find tutorial information on the internet. I am not familiar with any work on ice thickness with seismic, but visit the web site of the Society of Exploration Geophysicists www.seg.org and look into their data base of articles. If the full article isn't there, they will be in your library. A geophone is a vibration transducer with a moving coil and magnet that senses velocity (as opposed to acceleration). They are more sensitive than accelerometers at the low frequencies encountered in seismic. Good luck. Thomas wrote: > > Hi everyone, > > I am 4th year student working a project using geophones to measure ice > thicknes. Is there a special method to layout the geophones to get an > accurate profile an induced vibration? The purposal is to generate an > acoustic pulse through possibly several kilometers of ice and have the > geophones detect this pulse and derive the ice thickness. Would anyone have > suggestions on a detonation mechanism? I've heard people use 1 kg of > dynamite for 1 km of ice. > > As you can see, I am not too familiar with geophones but I do know they work > like an accelerator. If anyone knows of a good book, please suggest it > because none of our group members are geology people. > > Thanks alot for your time. > > Thomas Looi > Aerospace Engineering > University of Toronto > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Doug Crice http://www.georadar.com 19623 Via Escuela Drive phone 408-867-3792 Saratoga, California 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Geophone layout From: John Hernlund hernlund@....... Date: Thu, 20 Jan 2000 10:25:29 -0700 (MST) On Thu, 20 Jan 2000, Thomas wrote: > I am 4th year student working a project using geophones to measure ice > thicknes. Is there a special method to layout the geophones to get an > accurate profile an induced vibration? The purposal is to generate an > acoustic pulse through possibly several kilometers of ice and have the > geophones detect this pulse and derive the ice thickness. Would anyone have > suggestions on a detonation mechanism? I've heard people use 1 kg of > dynamite for 1 km of ice. Yes, there is a general rule of thumb, but dynamite in ice will probably be messy, not to mention all the permits and other difficulties involved. In addition, if you are recording on a triggered system you may destroy the trigger each time... The hard thing in explosives is that for the energy to be transmitted into the solid they must be buried to a certain depth, so that you aren't just blowing up the ground. However, a deeper source will give you a slightly more complicated waveform and at greater depths reflections become broader as reflections from the surface are super-imposed onto the signal. Also, far better results are obtained from various different shot locations. > As you can see, I am not too familiar with geophones but I do know they work > like an accelerator. If anyone knows of a good book, please suggest it > because none of our group members are geology people. Honestly, if you are able to switch methods I would strongly suggest using electromagnetic methods, which will be able to discern changes in conductivity between ice and rock quite well. You won't have to deploy fidgety geophones and worry about the complicated routine of getting a nice source. The drawback here is the cost of the equipment, unless you can borrow it some how. We use a $60,000 instrument from Zonge Engineering in Tucson, which has a very good square wave generator (quick turnoff). Several methods exist that simply require you to make a loop on the surface and place an antenna in the middle (another coil or special device). A square wave is sent through the large loop and the response recorded on the antenna can be fourier transformed to give a conductivity vs. depth profile. The deeper you want to probe, the larger the outer loop must be. Depending on the resistance of your loop, at some point a large loop will require a gas powered generator to drive the current, because batteries will only do so much. But all of this can be put into a single vehicle and carted around. The moving of the coil is the hardest part. There are many academic books on the method of reflection seismology, but from experience many people can tell you that there are a lot of practical difficulties that are mostly learned from doing it. Some of these problems will be specific to the equipment you are using. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehman base material? From: ChrisAtUpw@....... Date: Thu, 20 Jan 2000 16:35:43 EST Dear Mr.Leiper, Thanks for the quick reply. I thought that it might be something like this, for the last time that I looked at the price of a large piece of engineering quality polished granite, the cost was $ thousands, not hundreds. >> In my case the price was ten bucks many years ago at a scrap yard. It is two by three and 4" thick and already had the levelling mechanism. All my attachment points are with PC-7 epoxy, so no drilling was required. The idea was to preserve the geometry of the components to the most ridiculous degree possible over long term temperature drifts (days/weeks). I had tried all manners of insulation, stratified heating elements, baffles, etc. with less than ideal success. Have you tried a heater in the top of the enclosure which is accurately regulated to a few degrees above the actual floor temperature? >> Since my vault is highly stable, I decided to focus primarily on reducing drafts (relatively simple) and preserving geometric integrity over long period temperature swings through materials selection. I am not making the following points to quiz you, but just so that you can yourself reject any obviously inapplicable ones and maybe cross check on some others. What are you observing in the behaviour of the seismograph which you think is a fault / wish to correct? Did you measure and plot the inside and outside temperature changes actually occurring and were the events correlated with temperature changes? Do the bottom arm, the uprights and the diagonal support arm materials have the same temperature expansion coefficient? Do you also record air pressure, wind velocity, sunshine and rainfall? I am just thinking of other factors which might contribute to drift. You seem to be convinced that it is a temperature problem.... what if it isn't? How do you arrange the venting of the seis enclosure? If the air pressure falls suddenly, what flow can it cause inside the case? Do any of the effects tend to occur at around the same time of day? Are there any large electrical supply cables nearby? What sort of suspension systems do you use? Is there any magnetic material on the arm at all? I remember having to use Al rather than brass in one application because of it's weak magnetic properties. >>With a natural period of 50 seconds it only needs seasonal centring adjustment for what I theorise is increased weight of the frame house (the foundation rests on said bolder about 15 feet away) due to higher relative humidity in the summer, or the presence of leaves on a rather large beach tree about 30 feet away. With a 50 second response, the suspension angle is of the order of 0.1 Deg, which has to be maintained to parts per thousand.... In winter, a large Beech tree will use very little water. In summer it may, a very rough figure, use >50 galls a day. Say you have three weeks of fine weather, could a reduction of 1000 galls on that side of the house be in agreement with an observed shift? Just after I had sent my last EMail, I remembered where I had come across polished granite slabs before. A monumental stonemason.... Speaking gravely you say 'Yes, the array of holes is for security and to allow for flower baskets to be fitted.... No, no inscription please - in our situation, we consider it advisable that the stone should remain anonymous....' You might even get a partially engraved one cheap.... even some stonemasons make monumental mistakes.... It is late and I am getting tired... >> I think my next project will be a complete seismometer and recorder constructed entirely off materials available at Home Depot and Radio Shack..... I was looking at an old 4 lb glass bottling jar (Kilner) the other day and wondered if a mini S-G seis. could be fitted inside.... Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VRDT vane From: S-T Morrissey sean@........... Date: Thu, 20 Jan 2000 21:04:48 -0600 (CST) Barry, Regarding the vane in the VRDT: It is electrically passive, (as is the core on the LVDT). The sensitivity of the sensor is due to the fact that the vane changes the inductance and therefore the reactance of both of the inductances on either side of it. As it moves between the pole faces, it increases one inductance as it decreases the other, and therefore changes the balance of the bridge. The reactance change is of the order of 2 ohms per micron with a 2mm gap between the inductors at 600hz excitation frequency. (using the TL021 transformers modified as in the drawing). The relative inductance change depends on the initial distance from the pole face, so a smaller gap between both is more sensitive. The gross effect of the inductance change is quite non-linear, but the balanced effect over a small distance can be very linear, especially if the vane dimensions are about 20% larger than the pole faces. I dismantle a larger, like 1-watt, audio transformer and use the center of the E laminates as the vane; audio transformers have thinner laminates with higher permitivity to reduce hysteresis losses compared with AC transformers. An advantage of the VRDT is that there are minimal forces acting on the vane, compared to a LVDT, where magnetic forces from the central driving winding are measurable, and a capacitive sensor, where electrostatic forces can be appreciable. Speaking of which, the VRDT vane should be grounded to the frame to prevent static problems. Naturally, it should be suspended with non-magnetic material, like brass brazing rod or small diameter hobby-metals tubing (ACE hdwe) which can be finely slit from the end on one side and the vane soldered or epoxied in. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: twleiper@........ Date: Thu, 20 Jan 2000 22:12:58 -0500 On Thu, 20 Jan 2000 16:35:43 EST ChrisAtUpw@....... writes: >Dear Mr.Leiper, > > Thanks for the quick reply. I thought that it might be something >like this, for the last time that I looked at the price of a large piece of >engineering quality polished granite, the cost was $ thousands, not >hundreds. big snip >I was looking at an old 4 lb glass bottling jar (Kilner) the other >day and wondered if a mini S-G seis. could be fitted inside.... > > Regards Chris Chapman > Interesting. Why not use a Klein bottle to achieve infinite period? And if you recorded on a Mobius strip, you would only need to find a pen with a bottomless inkwell... Actually there is no problem. Having tested the insane route I am certain the effect I am seeing (and saw with the first instrument to a lesser degree) is in fact seasonal tilt due to the weight of the house and/or the beech tree. The tree is known to induce artifact in gale force winds, and I am sure it weighs thousands more when foliated. What I have now requires slight centering only twice yearly, which is pretty good for an instrument of such period, and what I have concluded (and independently has been confirmed in ST's recent post about the LP instruments used in global system) is that periods in excess of 15 to 20 seconds are not worth the effort...it is much simpler to use force balance/feedback techniques and get all the period you want. (or perhaps the Klein bottle...get to work on that one) My principle reason for experimentation is to learn what is important and try to come up with something more realistic for the weekend mechanic accountant who wants to do something with his kid. Most of the discussion and experimentation here is an order of magnitude (or two) above what I have in mind. Nobody uses a pair of tin cans and a string anymore...they just go to radio shack and buy some walkie talkies. What happened to train sets? For instance, if we cut the grass around that old '74 Impala wagon on blocks and cram it with all the half empty cans of hardened blacktop sealant, that bag of setting concrete you never used to plant the new mailbox, the old bikes and other crap from the garage... Then remove the wheels and set the brake drums/disks directly onto steel plates...Attach a twenty foot cantilevered and balanced truss beam (made of 2X2) to the trailer hitch with a magic marker attached to the other end and the fulcrum about a foot from the hitch end. Modify the treadmill you got for your wife (never used) by replacing the tread with deli paper (preferably also unused) and change the gearing or motor to achieve desired recording speed. Point the car NS or EW and away you go...no longer the neighborhood eyesore, the ingenious new application makes you the neighborhood madman. Instead of carving out "S" turns it traces out "S" waves... Speaking of madmen, drill down from the following link to "tim working out", the "antenna farm" and "this" for a good laugh. Note the innovative use of the fridge... http://members.localnet.com/~wa1sov/meet_the_amers/schoolbus.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: John Miller, used seismometers From: yeraltiaramaclk@............... (Ahmet Ercan) Date: Fri, 21 Jan 2000 09:12:00 +0200 Dear Miller, Thanks for informing us Teledyne Geotech S-500. If it is a set of = seismograph(seismometer+recorder+etc) we could be interested. We can buy following; a. Microtremor device, b. Acceloremeters, c. Pressiometers, d. Crack monitoring devices. Prof. Dr. Ahmet ERCAN yeraltiaramaclk@...............
Dear Miller,
 
Thanks for informing us Teledyne = Geotech S-500. If=20 it is a set of seismograph(seismometer+recorder+etc) we could be=20 interested.
We can buy following;
a. Microtremor device,
b. Acceloremeters,
c. Pressiometers,
d. Crack monitoring = devices.
 
Prof. Dr. Ahmet ERCAN
yeraltiaramaclk@superonli= ne.com
Subject: Re: Etc. From: ChrisAtUpw@....... Date: Fri, 21 Jan 2000 17:07:11 EST In a message dated 21/01/00 03:27:11 GMT Standard Time, twleiper@........ writes: >> Why not use a Klein bottle to achieve infinite period? You have lost me there. What is a Klein bottle? Has it anything to do with the 'Happy Hour'? >> Actually there is no problem. I am certain the effect I am seeing is in fact seasonal tilt due to the weight of the house and/or the beech tree. What I have now requires slight centring only twice yearly, which is pretty good for an instrument of such period.... Great. It sounded pretty good to me too.... but it is an 'open loop' device. >> It is much simpler to use force balance/feedback techniques and get all the period you want. Agreed, but not everyone understands / is happy with the electronics involved. My wife is useless with a soldering iron.... It is difficult enough getting her to use a steam iron.... >> My principle reason for experimentation is to learn what is important and try to come up with something more realistic for the weekend mechanic accountant who wants to do something with his kid. How about devising an auto-zero circuit for the seismometer, so that you never have to readjust it? >> Nobody uses a pair of tin cans and a string anymore.... Probably because they never did work well anyway.... >> They just go to radio shack and buy some walkie talkies. Which do work.... some of the time.... >> What happened to train sets? Plastic was invented, metal toys became 'collectors items' and they now cost a fortune.... Like the fridge, but is it cool? Like the typical US citizen too. Pass on his aerial farm.... Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Unattended operations From: ted@.......... Date: Fri, 21 Jan 2000 17:55:02 -0500 Just fill the Klein bottle with ink so you never run out while recording on the Mobius strip. Where's that patent form? Regards, Ted (in cold, windy, but rock-solid New Hampshire) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: twleiper@........ Date: Fri, 21 Jan 2000 18:29:46 -0500 >>> Why not use a Klein bottle to achieve infinite period? > You have lost me there. What is a Klein bottle? > Has it anything to do with the 'Happy Hour'? A Klein bottle is a three dimensional Mobius strip. Search on "topology" >Great. It sounded pretty good to me too.... but it is an 'open >loop' device. Yes. there is no feedback, just damping (resistive) >How about devising an auto-zero circuit for the seismometer, so >that you never have to readjust it? Basically, a force balanced instrument (using a displacement sensor to create an "error" signal used to apply a balancing force to "hold" the mass in a fixed position relative to earth) would never need adjustment, except perhaps for optimum performance. The error signal may not be "zeroed" because of non-centered mechanics, but dynamic element of that signal (variation) would still reflect the acceleration required to hold the mass stationary with respect to the quivering earth. All one has to do is pass a sample of that error voltage through a high pass filter (only dynamic elements with a period LESS than say 300 seconds are measured) and on to the signal processing circuittry. After one or two integrations (this always seems to kick up a few postings...let's see. The first integration of acceleration would give velocity and then integrating velocity gives displacement...I think. But there again, is the high pass filter actually the first integration? I think so, so the signal at that point would be velocity. See what I mean? ). So, with the "natural" adjustments out of whack, the instrument would still remain centered with the only consequence being some non-linearity in signal response and reduced dynamic range. Several good examples of this type instrument are described on Larry's site. I frankly could care less whether the squiggles on my adding machine paper are acceleration, velocity or displacement, and my mechanical drive for the pen is deliberately non-linear to maximize the dynamic range, so accuracy in signal and timing has never mattered to me. I just like watching that thing come alive and speculating on the "where" and "how big". Chelsea and I have recordings of all the major quakes of '99 (Mexico(s), Turkey(s), Taiwan, Greece, etc.) and probably 90% of all the mag 6 and above quakes worldwide. The most inporatnt thing is that this can coexist with N'Sync. I just want to make somethinng that is simple, cheap, and gets good squiggles for others. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Unattended operations From: twleiper@........ Date: Fri, 21 Jan 2000 18:38:45 -0500 I should have thought of that... By the way Ted, welcome to New England. My paraents are up there in North Sandwich. We'll have to try to hitch up sometime. Did you ever get anywhere on that DAS-8 info I gave you last year? On Fri, 21 Jan 2000 17:55:02 -0500 ted@.......... writes: > > >Just fill the Klein bottle with ink so you never run out while >recording on the Mobius strip. Where's that patent form? > >Regards, Ted (in cold, windy, but rock-solid New Hampshire) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: amazing picture From: Joe Irvine jirvine@.............. Date: Tue, 21 Dec 1999 18:39:51 -0800 Hi guys: Passing through the sound barrier. >> This is extraordinary photograph, a once in a life time photo. Hope >> you >> enjoy. Every so often, just the right combination of conditions and >> events occur to create an unbelievable event-in this case an F-18 >> passing through the sound barrier. >> >> Not only were the water vapor, density and temperature just right, >> but there just happened to be a camera in the vicinity to capture the >> moment. >> >> The F-18 is actually in transonic flight, with normal shock waves >> emanating from behind the canopy and across the wings and fuselage. >> >> The condition will last for only an instant, and once supersonic flow >> exists completely around the aircraft, sharp-angled sonic cones >> replace the normal shock waves. The odds of getting a shot like this >> are staggering. This is a little out of our territory, but as an old retired pilot I just had to share it. Joe Subject: Re: VRDT vane From: barry lotz gbl@....... Date: Fri, 21 Jan 2000 19:23:10 -0800 Sean Thomas Thanks for the clarification on the vane. I have been using lvdts with on end of both the primary and secondary coils attached to ground. I think because of this the core had to be isolated from ground. I haven't noticed any particular problems and the calibration was quite linear. I did this by providing a acrylic tube break in the core brass extension shaft. I think if I provided a floating excititation and output condition I would have been able to ground the lvdt core. I will try this condition when I receive the transformers from Mouser next week and construct the vrdt Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc From: Danie Overbeek danieo@............ Date: Sat, 22 Jan 2000 06:25:53 +0000 About TW Leiper's modest expectations for his and Chelsea's seismograph: Full of admiration as I am of those who go deeply into the finer points of seismography, I also salute those who are just content to see it when Gaia shivers, without getting too technical about it all. The Edenvale South Africa "observatory" operates a seismograph and a magnetograph on the above basis. Cheers Danie Overbeek _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc From: "Jan D. Froom" froom@............. Date: Fri, 21 Jan 2000 21:21:04 -0800 Hear! Hear! Jan Danie Overbeek wrote: > About TW Leiper's modest expectations for his and > Chelsea's seismograph: > > Full of admiration as I am of those who go > deeply into the finer points of seismography, > I also salute those who are just content to see > it when Gaia shivers, without > getting too technical about it all. > > The Edenvale South Africa "observatory" operates > a seismograph and a magnetograph on the above basis. > > Cheers > > Danie Overbeek > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: amazing picture From: SW6079@....... Date: Sat, 22 Jan 2000 09:31:23 EST Wow!!! That really is an incredible shot. Just curious, but did you ever have an opportunity to fly the SR-71??. Thanks, Mike _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: amazing picture From: Norman Davis WB6SHI wb6shi@........ Date: Sat, 22 Jan 2000 08:11:41 -0800 Love the picture... To reply remove the REMOVE in my email address. Sorry but I get too much spam. Norman M. Davis WB6SHI Shingle springs, CA mailto:wb6shi@........ http://www.directcon.net/normd/index.htm ICQ: 7192318 How to Know God... http://www.harvest.org/knowgod/index.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: Karl Cunningham karlc@....... Date: Sat, 22 Jan 2000 10:47:08 -0800 At 06:29 PM 1/21/2000 -0500, you wrote: >All one has to do is pass a sample of that error voltage through a high >pass filter (only dynamic elements with a period LESS than say 300 >seconds are measured) and on to the signal processing circuittry. >After one or two integrations (this always seems to kick up a few >postings...let's see. The first integration of acceleration >would give velocity and then integrating velocity gives >displacement...I think. But there again, is the high pass filter >actually the first integration? I think so, so the >signal at >that point would be velocity. See what I mean? ). I guess I'll have to start going to those meetings again... Poster's Anonymous. I thought I was strong and could resist posting a reply about integration. But alas, I've succumbed to temptation... Integrating the signal is not always as easy as it seems, especially twice. Sure, the integrators can be built, but the gain of an integrator is inversely proportional to frequency. So, using your example, to obtain a range of period from 300 seconds to 0.2 seconds (5Hz) requires a range of 1500:1 in the gain of the stage. That means any low-frequency instability in stages before the integrator will be multiplied by as much as 1500 on the way to the output. Integrate a second time and it's the square of that value -- 2.25 million. That's bad news. I tried this one time and found out the hard way -- after I had constructed the circuits. Also, I don't think the high-pass filter is the same as integration. It's closer to a derivative function over some range of frequencies (gain increases with frequency), but still isn't really that either. I think there is an answer to this problem, though. The VBB design puts a derivative function in the feedback, in the path to the feedback coil. And since (in the bandwidth of interest) the current in the feedback coil is proportional to acceleration (guaranteed by the mechanical dynamics, and the fact that loop gain is kept fairly high), the signal ahead of the derivative function has to be velocity. You can then integrate this function once to get displacement. Karl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: twleiper@........ Date: Sat, 22 Jan 2000 15:39:17 -0500 On Sat, 22 Jan 2000 10:47:08 -0800 Karl Cunningham writes: >At 06:29 PM 1/21/2000 -0500, you wrote: >>All one has to do is pass a sample of that error voltage through a >high >>pass filter (only dynamic elements with a period LESS than say 300 >>seconds are measured) and on to the signal processing circuittry. >>After one or two integrations (this always seems to kick up a few >>postings...let's see. The first integration of acceleration >>would give velocity and then integrating velocity gives >>displacement...I think. But there again, is the high pass filter >>actually the first integration? I think so, so the >signal at >>that point would be velocity. See what I mean? ). > >I guess I'll have to start going to those meetings again... Poster's >Anonymous. I thought I was strong and could resist posting a reply >about integration. But alas, I've succumbed to temptation... Typical complex discussion follows focussing on the difficulties of 300 sec to .2 sec period signal processing... Actually the 300 sec high pass was suggested as a simple way to eliminate drift. I am sure that a 50 sec floor would be just as good. That's why I prefer direct acceleration detection (coil and magnet) instead of loop derivative detection. To be sure, my circuits and component values are almost always SOT (select on test) and often don't get off the breadboard for years. But it certainly is good to know that what I have found to actually work can also be backed up by the theory... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetism and Wondermagnet notes From: meredith lamb mlamb1@.......... Date: Sat, 22 Jan 2000 17:07:50 -0800 Hi all, I just completed acouple additional pages on a web site for those interested in diamagnetism....with a bend toward using it in possible seismic tiltmeter/seismometer applications. See: http://users2.50megs.com/diamagnetics/page008.html http://users2.50megs.com/diamagnetics/page009.html The index for the above is at: http://users2.50megs.com/diamagnetics/ ......................... I note Wondermagnet/Forcefield has added afew magnets to their listing at: http://www.wondermagnet.com Items #27, 30, 31, 32, all have possible copper coil induction sensing use, as do previously shown magnets. Item #26, is mentioned on the web page 9, above; a very interesting item currently with diamagnetism potential. Items# 2, 4, 21 and 29, all seem to be the four pole or 2 magnets in one piece variety. Item 2, most closely matches the neo magnets I use in my S-G type Hall seismometers. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: LVDT question From: S-T Morrissey sean@........... Date: Sat, 22 Jan 2000 20:59:52 -0600 (CST) Barry, You say that the LVDT core had to be electrically isolated for your LVDT to work. So I am mystified. The effect in the LVDT is entirely electromagnetic: (for the benefit of the reader): the AC excitation signal of the central winding is coupled transformer-style to the windings at both sides of center. When the sensing core cylinder is centered, equal voltages are induced in both of the outside windings, which are connected in opposite directions so the net output is zero; a displacement of the core increases the voltage induced in one as the other is reduced, resulting in the displacement voltage output. Grounding or floating the core should make no difference except for some weak electrostatic forces that may be present. The floating or grounding condition of the excitation and output windings should make no difference as far as the core is concerned. As I mentioned before, the excitation is usually transformer coupled to prevent any DC currents from magnetically moving the core around. Maybe there is something else going on with your LVDT. A common problem is that the moving core can touch and drag on the inside of the winding forms, possibly making contact with a winding in a formless configuration; the clearance on commercial LVDTs is really minimal, like less than 0.5 mm, which is why I don't like to use them. But I assume that yours is not dragging or the seismometer wouldn't work. So, as I said, I am mystified. Regards, Sean-Thomas. PS: a good treatment of the LVDT and its' noise can be found in: Agnew, D.C., "Strainmeters and Tiltmeters", Reviews of Geophysics, vol 24, No 3, 579-634, 1986 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: ChrisAtUpw@....... Date: Sat, 22 Jan 2000 23:41:15 EST In a message dated 21/01/00 23:41:48 GMT Standard Time, twleiper@........ writes: C>>the Lehman.... is an 'open loop' device.... T>There is no feedback, just damping (resistive) C>> How about devising an auto-zero circuit for the seismometer, so that you never have to readjust it? T> Basically, a force balanced instrument (using a DISPLACEMENT SENSOR to create an "error" signal used to apply a balancing force to "hold" the mass in a fixed position relative to earth) would never need adjustment, except perhaps for optimum performance. C>> Agreed, but you described a moving coil sensor, which gives a signal proportional to the rate of movement of the coil in the magnetic field, but it is not sensitive to the position of the coil in that field.... T> All one has to do is pass a sample of that error voltage through a high pass filter .... and on to the signal processing circuitry.... The first integration of acceleration would give velocity and then integrating velocity gives displacement...I think. See what I mean? C>> Suppose that you have a Lehman arm offset from zero and it then moves a bit. A coil pickup moving in a magnetic field will give you the differentiated movement signal, which could then be integrated to give the approximate movement, less any non linearity's, integrator drifts etc., or in a force balance system, used to hold the arm in a fixed position with respect to the base. What the integrated signal cannot give you is the initial offset (or integration constant). Unless you have some sort of position signal available, even if it is quite rough and ready, you can't correct for slow drifts. You used to be able to buy photo potentiometers which could have done this job nicely for your +/- 0.75" movements, but I haven't seen any about recently. They were made on an alumina strip ~2" long x ~0.15" wide. On one face, a conductive strip was deposited along one long edge and a resistance element on the other long edge. The strips were completely bridged by CdS photo conductor. If you put a voltage across the resistance and shone a narrow spot of light on the element, the CdS conducted only under the light spot and the conducting strip picked up that voltage. Does anyone know if they are still available, please? In the S-G seismometers, the arm is stabilised by gravity and you need to measure micron movements. In Karl Cunningham's force balance seismometer, the position is sensed by an +/- 0.1" LVDT transducer and used for the feedback. It would be nice to have an 'add on' device for a mechanical garden gate Lehman which would stabilise the arm, particularly for people who are interested in seismology but do not have access to a highly stable site. > I just want to make something that is simple, cheap, and gets good squiggles for others. >> It is the 'good' which may be the difficult bit, but since you have done such an admirable job with the standard Lehman design.... and I do mean that most sincerely. Regards Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LVDT question From: barry lotz gbl@....... Date: Sun, 23 Jan 2000 13:17:08 -0800 Sean Thomas I agree with what you have said(I think). As I remember it, (it happened with the first lvdt I constructed), The output was considerably reduced with my configuration. As a consequence all the later versions I constructed with isolated cores. Since the isolated core worked I left it at that. I make lvdts with acrylic tubing. They have ~ 1/16 space around the core. My thought was if the secondary coils were attached to ground at one end that providing a ground(core) near the coils would drag the output down. Bwt now that I think of it, how can the secondary coils be induced by the primary if the field is grounded by the core? I have another one on the bench. I'll try a calibration both ways. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: barry lotz gbl@....... Date: Sun, 23 Jan 2000 13:29:11 -0800 Hi I'm kind of entering this thread in the middle. I have a force balance horizontal and lehman adjacent to each other. I use the output of the FB sensor to tell when to check my Lehman position (due to slab tilt). I previously used infared emitter detector combination (radio shack). I attached narrow target to the end of my Lehman. It shadowed the emitter from hitting the detector. However when the Lehman drifted 1/2 the target width the emitter hit the detector and lit an led in my house. It didnt't tell which direction but did tell when attention was required. Barry ChrisAtUpw@....... wrote: > In a message dated 21/01/00 23:41:48 GMT Standard Time, twleiper@........ > writes: > > C>>the Lehman.... is an 'open loop' device.... > > T>There is no feedback, just damping (resistive) > > C>> How about devising an auto-zero circuit for the seismometer, so that you > never have to readjust it? > > T> Basically, a force balanced instrument (using a DISPLACEMENT SENSOR to > create an "error" signal used to apply a balancing force to "hold" the mass > in a fixed position relative to earth) would never need adjustment, except > perhaps for optimum performance. > > C>> Agreed, but you described a moving coil sensor, which gives a signal > proportional to the rate of movement of the coil in the magnetic field, but > it is not sensitive to the position of the coil in that field.... > > T> All one has to do is pass a sample of that error voltage through a high > pass filter .... and on to the signal processing circuitry.... The first > integration of acceleration would give velocity and then integrating velocity > gives displacement...I think. See what I mean? > > C>> Suppose that you have a Lehman arm offset from zero and it then moves a > bit. A coil pickup moving in a magnetic field will give you the > differentiated movement signal, which could then be integrated to give the > approximate movement, less any non linearity's, integrator drifts etc., or in > a force balance system, used to hold the arm in a fixed position with respect > to the base. What the integrated signal cannot give you is the initial offset > (or integration constant). Unless you have some sort of position signal > available, even if it is quite rough and ready, you can't correct for slow > drifts. > You used to be able to buy photo potentiometers which could have done > this job nicely for your +/- 0.75" movements, but I haven't seen any about > recently. They were made on an alumina strip ~2" long x ~0.15" wide. On one > face, a conductive strip was deposited along one long edge and a resistance > element on the other long edge. The strips were completely bridged by CdS > photo conductor. If you put a voltage across the resistance and shone a > narrow spot of light on the element, the CdS conducted only under the light > spot and the conducting strip picked up that voltage. Does anyone know if > they are still available, please? > In the S-G seismometers, the arm is stabilised by gravity and you need to > measure micron movements. In Karl Cunningham's force balance seismometer, the > position is sensed by an +/- 0.1" LVDT transducer and used for the feedback. > It would be nice to have an 'add on' device for a mechanical garden gate > Lehman which would stabilise the arm, particularly for people who are > interested in seismology but do not have access to a highly stable site. > > > I just want to make something that is simple, cheap, and gets good > squiggles for others. > > >> It is the 'good' which may be the difficult bit, but since you have done > such an admirable job with the standard Lehman design.... and I do mean that > most sincerely. > > Regards Chris > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: twleiper@........ Date: Sun, 23 Jan 2000 18:42:35 -0500 On Sun, 23 Jan 2000 13:29:11 -0800 barry lotz writes: >Hi > I'm kind of entering this thread in the middle. ...continued. The problem with all this stuff is differentiating drift from legitimate signal. In the example you cited, you simply have an indicator which alerts the human (you) when attention MIGHT be required. After all, those LEDs might be blinking due to a large quake. My feeling is that with proper materials, reasonable periods (10 -15 sec) and good use of damping and filtration, drift can be minimal with little to no effect in performance. You will note also that I use the "solenoid" type pickup which has tremendous advantages over the typical "edge driven" coil in that there are no inverse square problems (as coil is moved to and from magnet) and no internal cancellation (far side of coil fights the near side). But the main difference is that the sensitivity of the detector is quite flat across a +/- .7" deflection. I can usually tell when the coupling is drifting too close because the gain will increase quite dramatically when the coil is less than .05" from the face of the magnet, where normally it is "centered" about .75" from the magnet. Drift of +/- .5" can be ignored, and that range should be readily achievable with a sensible and low cost design. HOWEVER, since not all are interested in such designs, let me tell you how I WOULD do it if I thought it was worth the effort: It is logical to assume that, over a long period, a mechanically centered boom will make as many excursions to the left of center as to the right. There will be short term exceptions much as a bridge with double tolls one way and toll free the other will carry "free" travelers who never return, and paying travelers who always return via some other route. With this in mind, I would simply put a "null" differentiator with adjustable hysteresis (one quad OpAmp) on the "pen motor" signal (signal in your design that is around 0 to +/- a volt or two) and have it clock a chip (such as 74191) up and down. If the chip count is preset at 1/2 its total (depends on how many bits) the perfectly centered boom will stay around that count. In other words, each time it moves left you increment and right you decrement. In addition you would need to clock for a permanent shift (no return across center) by adding one increment per X minutes the boom is off center. When the counter clocks UP to maximum or DOWN to minimum (again, easily done with a couple NAND gates) you then increment a stepper motor (one step) with a lead-screw that moves a lead weight side to side either on your seismo base or on the slab itself. Since you would be doing this for a very long period instrument the weight and deflection required are probably less that one would think. By adjusting the hysteresis (possibly to ignore six second noise) and the count total (through use of divide by "N" counters), as well as the pitch and/or gearing of the stepper you would have a simple and cheap method that closely approximates the human operator. In normal operation the count may reach max/min in a couple days of slab tilt, adjust the weight a little and then again a couple days (or weeks) later. If you put the new piano in the room overhead and the boom swings permanently to one side, the "X" minutes increment will eventually roll over enough motor steps to correct for the condition. You want to try it? Go knock yourself out... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: AP Article-Earthquake Noise From: Seisguy@....... Date: Sun, 23 Jan 2000 22:36:52 EST Scientist-Musician Digs Earthquakes By MATTHEW FORDAHL ..c The Associated Press SAN FRANCISCO (AP) - The hills are alive with the sound of music - and so are the Earth's valleys, mid-ocean ridges and volcanoes. Earthquake waves that topple buildings, raise mountains and split the ground have long been used to study tremors and the structure of the Earth. Now, they're being turned into sound to make truly hard-rock music that can help teach seismology. Though seismic waves make no noise on their own, their motions as recorded by seismometers can be sped up to produce sounds, says Andrew Michael, a trombone-playing seismologist at the U.S. Geological Survey and composer of a quake quartet. ``The music came from a concept of how the Earth strains to create earthquakes and earthquakes providing a backdrop to civilization,'' he said. ``The general population is almost completely unaware until there's a very large earthquake.'' Michael's piece for trombone, cello, vocalist and earthquake is about the strain that leads to quakes as well as their impact on society. It premiered last month at the annual meeting of the American Geophysical Union. The two-minute quartet begins with a trombone and cello glissando punctuated by the thundering roars generated from the 1992 Landers, Calif., earthquakes. The sliding noise represents the buildup in the Earth before a quake strikes. A jazzy movement, which borrowed from a Bach cello sonata, is interrupted by the quakes' thunder-like rumbling. The glissando then returns and the piece ends with the thud of a big quake. ``It made a good percussion track,'' said Stephanie Ross, Michael's wife who sings the quartet's vocal line. She's also a researcher at the USGS in Menlo Park. Michael's interest in music and earthquakes began in 1997, when he was preparing a lecture on earthquake waves trapped in fault zones. It struck him that the situation was similar to sound waves trapped and vibrating inside a trumpet. The parallels didn't work for that lecture because of the fleeting nature of earthquake waves in a small area. ``But I started thinking more about the comparisons and decided to do a whole lecture on the analogy,'' he said. Seismic waves are much more complex than sound waves, but both transmit energy from a source through a path like the ripples from a pebble dropped in a pond or a spring compressing or decompressing. Earthquake waves move too slowly to make audible sound, though many people hear the rumbling of objects being shaken. To actually hear a quake, Michael speeds up recordings of their waves. Seismograms - the squiggly line graphs that show ground motion - measure several types of waves. To become sound, the entire range of a quake's motion is reduced to the in-out motion of a speaker, which vibrates to make sound. ``We are playing fast and loose by taking the whole seismogram and turning it all into compressions and noncompressions,'' he said. ``But it works well enough.'' And it has scientific value. ``It puts us in the position of being the music critic to the Earth,'' said Michael, a trombonist since childhood. By listening, scientists can tell how much a fault slipped. Smaller faults, like small musical instruments such as trumpets, produce higher frequency waves than longer faults, or big instruments like tubas. So a magnitude-6.3 quake from a small fault has a higher pitch than a magnitude-6.5 quake generated along a larger fault. Quakes recorded from a distance have a much deeper sound resembling thunder. Closer quakes, on the other hand, sound more like a gunshot. The reason? High frequency waves dissipate more quickly over distance, leaving only a low rumble. It's not unlike the boom heard through the wall from a neighbor's stereo. The higher-pitch lyrics and melodies don't travel as far. Michael so far has presented his lecture less than a dozen times at universities and scientific conferences. He hopes someday to make it available on video. ``There's actually been a good reaction from the general public,'' he said. ``It's spoken to different people in different ways. People are actually learning some seismology and music.'' EDITOR'S NOTE: Sounds generated from earthquakes are available on the World Wide Web at http://quake.wr.usgs.gov/more/listen/ AP-NY-01-23-00 1202EST _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Etc. From: Ed Thelen ethelen@........ Date: Mon, 24 Jan 2000 02:09:27 -0800 twleiper@........ wrote: > > On Sun, 23 Jan 2000 13:29:11 -0800 barry lotz writes: > >Hi > > I'm kind of entering this thread in the middle. ...continued. > > The problem with all this stuff is differentiating drift from legitimate > signal. In the example you cited, you simply have an indicator which > alerts the human (you) when attention MIGHT be required. After all, those > LEDs might be blinking due to a large quake. > > ... > Drift of +/- .5" can be ignored, and that range should be readily > achievable with a sensible and low cost design. > > HOWEVER, since not all are interested in such designs, let me tell you > how I WOULD do it if I thought it was worth the effort: > > It is logical to assume that, over a long period, a mechanically centered > boom will make as many excursions to the left of center as to the right. > There will be short term exceptions much as a bridge with double tolls > one way and toll free the other will carry "free" travelers who never > return, and paying travelers who always return via some other route. With > this in mind, I would simply put a "null" differentiator with adjustable > hysteresis (one quad OpAmp) on the "pen motor" signal (signal in your > design that is around 0 to +/- a volt or two) and have it clock a chip > (such as 74191)... the count total > (through use of divide by "N" counters), as well as the pitch and/or > gearing of the stepper you would have a simple and cheap method that > closely approximates the human operator. > > In normal operation the count may reach max/min in a couple days of slab > tilt, adjust the weight a little and then again a couple days (or weeks) > later. If you put the new piano in the room overhead and the boom swings > permanently to one side, the "X" minutes increment will eventually roll > over enough motor steps to correct for the condition. > > You want to try it? Go knock yourself out... Ah - it was fun ;-) I did roughly the same thing with a little BASIC STAMP computer (programmed in BASIC :-) http://www.parallaxinc.com/ which can be set to: - turn on LEDs - to do rough A-to-D (for the photo-transistors) - and programed to drive a stepper motor which drove something like a 36 to 1 gear box 'cus the adjustment screws take so little turning, and the torque of the stepper not very much. Added considerations are : - enable the actual adjustment only a fixed time of the day (to help prevent confusion about what might be happening} - short the pickup coil to - prevent massive signals from the electrical and mechanical noise from scaring you - damp the pendulum way above critical so it restores more smoothly after adjustment (I use resistive damping). It works - however, I still want to do a 3 axis force balance thing ;-) Cheers Ed Thelen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB Drawings From: barry lotz gbl@....... Date: Mon, 24 Jan 2000 19:31:10 -0800 Hi Rex I was reviewing your drawings and had a question about the bridge and subsequent circuit. STM's drawing shows the ref oscillator going into an inverting configured amp with gain of 100, followed by an inverting amp with gain of one. They both go into different pins of the demodulator. As I read your drawing , you have two inverting amps with gain of 100 connected to the bridge ends. Is this equivalent? I don't know. It seems in your circuit that the two amps would have the same sign where in STM's circuit they are of opposite sign. Karl's lvdt demodulator( which I currently use) is more like STM's in that one uses the switch to selectively choose one signal or the other depending on sign ( a rectifier). Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB Drawings From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Mon, 24 Jan 2000 22:45:41 -0500 I haven't had time to get to the electronics of the VBB. I just changed jobs in early December and just getting settled in. I will take a look at my schematics and get back to you. barry lotz wrote: > Hi Rex > I was reviewing your drawings and had a question about the bridge and > subsequent circuit. STM's drawing shows the ref oscillator going into an > inverting configured amp with gain of 100, followed by an inverting amp with > gain of one. They both go into different pins of the demodulator. As I read > your drawing , you have two inverting amps with gain of 100 connected to > the bridge ends. Is this equivalent? I don't know. It seems in your circuit > that the two amps would have the same sign where in STM's circuit they are > of opposite sign. Karl's lvdt demodulator( which I currently use) is more > like STM's in that one uses the switch to selectively choose one signal or > the other depending on sign ( a rectifier). > Regards > Barry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: S-G construction From: "Randall Pratt" randallpratts@.............. Date: Tue, 25 Jan 2000 09:52:08 -0800 Hi, I'm looking at the S-G construction notes on the PSN file. Does anyone have advice or experience with component substitution, operation on 12 volts instead of the 16 volts shown or other general comments? What about using the XTAL from a TV picture tube which I think is about 3.49 MHz? Would any of the diodes in the TV also be suitable? Does the design require further amplification and how much? Thanks for any advice. Randy randallpratts@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: S-G construction From: Larry Cochrane cochrane@.............. Date: Tue, 25 Jan 2000 19:18:13 -0800 Randy, I use a standard 4 Mhz TTL oscillator rather then making one. Any frequency in the 2-6 mhz range will work. Yes, you will need some amplification after summing the two receivers together. Not sure how much gain you will need, so you will need to experiment with that.... Regards, Larry Cochrane Redwood City, PSN At 09:52 AM 1/25/00 -0800, you wrote: >Hi, > >I'm looking at the S-G construction notes on the PSN file. Does anyone have >advice or experience with component substitution, operation on 12 volts >instead of the 16 volts shown or other general comments? What about using >the XTAL from a TV picture tube which I think is about 3.49 MHz? Would any >of the diodes in the TV also be suitable? Does the design require further >amplification and how much? Thanks for any advice. > >Randy >randallpratts@.............. > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: S-G construction From: ChrisAtUpw@....... Date: Wed, 26 Jan 2000 06:41:58 EST In a message dated 25/01/00 18:37:12 GMT Standard Time, randallpratts@.............. writes: << I'm looking at the S-G construction notes on the PSN file. Does anyone have advice or experience with component substitution, operation on 12 volts instead of the 16 volts shown or other general comments? What about using the XTAL from a TV picture tube which I think is about 3.49 MHz? You need two L/C tuned circuits + diode rectifiers + smoothing capacitors for your two position sensor plates. These have to resonate with a stabilised amplitude crystal oscillator drive voltage on the central plate. The devices that Larry sells are already set up and tuned. If you don't have quite a bit experience of electronics (if you were completely confident of your abilities, would you ask?), buying the ready made sensor plates etc. would give you the certainty of success. The S-G circuit in my copy of the notes operates on +/- 12 V. The new design is a considerable advance on the original Scientific American circuit, which used 16 V supplies. Have you considered it? Regards Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VBB response, contd. From: S-T Morrissey sean@........... Date: Wed, 26 Jan 2000 14:50:06 -0600 (CST) Allan and co: Some questions about the VBB response: If you are looking at the response by using MATHCAD to calculate the transfer function and plot the response, you should get exactly what I get. This assumes that you are using exactly the same formulations, constants, etc, as the worksheets I have shown. Have you noted that the frequency (or period) variable is a complex number, ie s(i) = j*w(i), where w is omega? The result you get should not be "approximate", but exactly the same as I get with the same inputs. The other question that makes me suspect that you are not getting the proper response is that you ask about the "high end" response: the VBB response IS the total response, as is shown by the MATHCAD plot. The VBB response is flat to velocity over a wide range of periods, not just the long periods. If you change the integrator time constant and/or the feedback capacitor the long period corner can be changed. The short period corner frequency is largely determined by "r", the output of the displacement detector. Larger is better until the instabilities show up. I have one VBB that audibly humms until I strap in a RC filter into the displacement detector output. (that most likely produces a proper phase shift so the oscillation doesn't start). I don't know of anyone else who has had problems with the transfer function and MATHCAD worksheet expressions. They do work. The only way I can address the question about the resulting response is to point to the calibration data on my web site, where the independent calibration data overlay the response predicted by the transfer function. What you see is what you get. In fact, the broadband response at the short period/high frequency end can cause problems with local site noise. My site here in the basement is about 15 meters from a busy street, so I have considerable low-pass filtering to reduce the cultural noise, as well as that of the dogs romping through the house; however, I still pick up a railroad about 3 km away. And I can record a Mb 3.+ at New Madrid 300 km away, as well as the long period data that I am more interested in. Since I am using a vertical sensor, the long period noise is factors of 100 less than the tilt noise a horizontal LP would be subject to. Which is why I wish that more PSN people would build vertical long period instruments. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response, contd. From: barry lotz gbl@....... Date: Wed, 26 Jan 2000 20:58:17 -0800 2=A2 I got Sean Thomas's equations to work in Mathcad. I haven't been able = to confirm the velocity output vs frequency for my sensor since I haven't constructed the excitation mechanism as yet. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response, contd. From: ChrisAtUpw@....... Date: Thu, 27 Jan 2000 05:48:50 EST In a message dated 26/01/00 20:52:58 GMT Standard Time, sean@........... writes: << In fact, the broadband response at the short period/high frequency end can cause problems with local site noise. My site here in the basement is about 15 meters from a busy street.... Since I am using a vertical sensor, the long period noise is factors of 100 less than the tilt noise a horizontal LP would be subject to. Which is why I wish that more PSN people would build vertical long period instruments. Has there been any use of piezo electric accelerometers, either directly or with the output integrated to give velocity? (I am not talking about silicon chip devices.) What period would you recommend, please? I can extend the response out to ~15 sec without problems. Are there any other types of vertical seismometer that we can usefully construct, please? I was looking at your STM-8, but I can't get the spring and the whole project seems a bit too ambitious for me at the moment. Regards Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response, contd. From: barry lotz gbl@....... Date: Thu, 27 Jan 2000 20:07:13 -0800 Hi Well a few years ago I was very interested in those piezoelectric disks. Radio Shack has them for one. I thought they would make a good sensor without the use of magnets or excitation electronics. To give you the end of the story first, I got confused as to what I was measuring and gave up. The sensor: I'll try to describe the sensor with the dimensions from memory. There is a plastics shop near me that sells acrylic plate and tubing. The sensor exterior was a ~2.5" diameter tube about 5" long. At the ends I made caps of the next size larger tube that telescoped over the main tube about 0.5". To form the end I glued a ~3" square plate at the end of the cap tube. I now had a "sealed" tube. For the sensor(s) I bought two radio shack piezo disks. Each disk was the same diameter as the main tube. I put the disk at the end of the main tube them put the cap over that. I did leave a small spacer inside the cap so the disk wouldn't touch the cap plate. Ok, for the mass I used a ~1" diameter steel round stock. The idea was to position the round stock inside the main tube and have it attached to the disks at both ends. When the mass moved relative to the tube there would be an output from both disks. I wired them so the flex output would sum rather than cancel. I won't go to much into the disk mechanical attachment to the mass at this time. It did give an output when put it on my work bench and applied a tilt to the bench top. The problem: As I understand it, for short period sensors(accelerometers) , the displacement output is a directly proportional to the ground acceleration for periods below the natural period of the sensor & at ~ 0.7 damping. Peizoelectric material seems to output velocity. Therefore was the sensor I described above outputing the differential of acceleration since I was measuring velocity rather than displacement? I'm not sure. I also wasn't sure about how to apply damping to the sensor short of maybe filling the interior with oil or some such material. I would like any feedback as to what I was measuring. Could piezoelectric mat'l be used for hinge material and their output measured? I still think there maybe some possibilities for them in strong motino sensors. Regards Barry ChrisAtUpw@....... wrote: > In a message dated 26/01/00 20:52:58 GMT Standard Time, sean@........... > writes: > --snip--- > Has there been any use of piezo electric accelerometers, either directly > or with the output integrated to give velocity? (I am not talking about > silicon chip devices.) What period would you recommend, please? I can extend > the response out to ~15 sec without problems. > > > Regards Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Article on California's Long Valley caldera From: RLLaney@....... Date: Thu, 27 Jan 2000 21:34:34 EST A very readable article titled "When Magma's on the Move" is in the February 2000 edition of Smithsonian magazine. The relation of earthquakes, volcanic activity, locals and the USGS is discussed. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: KURILI From: "Francesco" franuc@............. Date: Fri, 28 Jan 2000 16:48:02 +0100 Mw 6.8 North of Hokkaido - Kurili
Mw 6.8
North of Hokkaido - Kurili
 
Subject: Winding a Coil From: Paul Jebb pfjebb@.............. Date: Fri, 28 Jan 2000 10:57:28 -0500 Dear Members, Someone in the group posted a note about winding a coil in layers separated by paper and epoxy glue using a hand turning method. Would that member mind sending that information to me? Could you also please direct me some information on the guidelines for using this list serve? Thanks. Yours truly, Paul Jebb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response, contd. From: George Harris gjharris@............. Date: Fri, 28 Jan 2000 20:01:54 -0500 barry lotz wrote: > I would like any feedback as to what I was measuring. Could piezoelectric mat'l > be > used for hinge material and their output measured? A piezo sensor can be thought of as a capacitor which is sensitive to force (or acceleration). It is a relatively high impedance device, so any resistance across the output will quickly discharge the voltage. Since the frequency response is normally high, it would be hard to see most seismo signals. The most likely would be a bender element with a mass on the free end. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response cont., Piezo Acc. From: ChrisAtUpw@....... Date: Sat, 29 Jan 2000 07:33:38 EST In a message dated 29/01/00 01:03:53 GMT Standard Time, gbl@....... writes: >> I was very interested in those piezoelectric disks. Radio Shack has them for one. I thought they would make a good sensor without the use of magnets or excitation electronics. >> The sensor exterior was a ~2.5" diameter tube about 5" long. For the sensor(s) I bought two radio shack piezo disks. I put the disk at each end of the main tube. For the mass I used a ~1" diameter steel round stock inside the main tube and had it attached to the disks at both ends. When the mass moved relative to the tube there would be an output from both disks. I wired them so the flex output would sum rather than cancel. It did give an output when put it on my work bench and applied a tilt to the bench top. >> The problem: As I understand it, for short period sensors (accelerometers), the displacement output is a directly proportional to the ground acceleration for periods below the natural period of the sensor & at ~ 0.7 damping. Peizoelectric material seems to output velocity. I also wasn't sure about how to apply damping. I would like any feedback as to what I was measuring. To give you the end of the story, I got confused as to what I was measuring and gave up. C> As you put a load on the center of a piezo disk the capacitative element of ~15 nF charges up. The more the load the bigger the voltage. If you have a very high impedance voltmeter, the charge just sits there, otherwise it leaks away. If you then unload the disk, you get a charge of the opposite polarity. The first resonant frequency of a large size unloaded disk is usually ~500 Hz. >>Could piezoelectric material be used for hinge material and their output measured? C> small piezo laminated bars are sold just for this job, but their capacity is low at 750 pF, which makes long period response sensing more difficult. 100 M Ohm in // with 750 pF has a decay time of 0.075 sec. You can exchange capacity for sensitivity if you place additional capacity in parallel with the piezo element. There are also well established feedback techniques for increasing the input impedance by up to x100. The larger disk elements with 15 NF capacity look much more promising at 1.5 sec. It is not too difficult to increase this by another order of magnitude. They also seem to be more robust than the small bar elements. C> I have been using a modified PZT 'sounder' disk mounted on a spike to find leaks in water mains, by pushing the spike into the ground and listening for the water hiss and the clink of pebbles. It seems to be an effective technique. You use an audio amplifier and if you turn up the gain, you can easily hear someone walking by. I could also hear the noise of traffic on the road 100 yards away quite loudly. The response extends to over 1 KHz if you don't filter it and it can be extended down to a few tens of seconds without much difficulty. I don't know is how this device would compare in sensitivity to a geophone, but it seems to have a respectably high sensitivity and it is a lot cheaper. As it is, the disks give a pure acceleration output. This could be integrated to give a vertical velocity output. The disk temperatures need to be quite closely regulated to eliminate drifts. Chris. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Satellite re-entry to Seismic record From: ajbv@............ Date: Sat, 29 Jan 2000 21:46:38 +0800 Hi On the night of the 27th of January at 14:50 UT we had a really bright meteor-like event visible over a wide part of Western Australia. Using naked eye reports (at around 2000/01/271450 UT) from the public we have determined the object was probably travelling along a trajectory starting a little west of south (crossing the coast east of Albany) and finishing a little east of north. Apparently the object disintegrated in "mid-air" over the sea approximately north of Kunnunura (near the border with the Northern Territory). It was seen by people spread out about 2,000km across the state. This is very unusual for a meteor as it suggests a 'grazing' trajectory. We believe it was the entry of the Molniya 1-67, a Russian communications satellite that was launched in 1986. Its last published data is: Molniya 1-67 7938 x 87 km 1 16885U 86057A 00024.49418620 .02629495 48244-5 10000-3 0 7350 2 16885 62.1358 132.2173 3778027 263.7491 79.4965 8.19716859 99080 It also turned out that my seismic station picked up a "noise" event at "approximately" the same time of the sighting. Visual Observations are to the nearest minute. It may be a coincidence, but maybe there is some infra-sound to seismic shake or even some magnetic disturbance that caused an effect in the seismometers. The N-S (S-G) seismometer showed the disturbance, E-W did not and the vertical showed it well. This leads me to think is a magnet disturbance. I thought this may be of interest, any comments? I've posted to record to the P.S.N events. ( 000127a.au2 ) Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response cont., Piezo Acc. From: Karl Cunningham karlc@....... Date: Sat, 29 Jan 2000 10:02:56 -0800 Barry & Chris -- Piezo devices are often used with charge amplifiers, which is just an op-amp with capacitive feedback and a parallel resistor to keep it from drifting off scale. When the input is connected to the Piezo device (a capacitor) the op-amp circuit acts as an amplifier with gain of CZ/C1. The low-frequency limit is given by the time constant of the resistor and C1. Op-amps with very low input bias and offset currents must be used. This circuit provides a low-impedance output to drive other circuitry cabling, etc. With some of today's op-amps having input currents in the picoamp range, this type of thing is quite viable. Use teflon standoffs for the connections at the inverting input of the op-amp. And any cabling used between the piezo device and the circuit should be made with wire having insulation with very low dielectric absorption. Karl +--------------\/\/\/\------------+ | | +----------------||---------------+ | C1 | | |\ | | | \ | | | \ | | | \ | +-------------| - \ | | | \ | | | \ | Piezo --- | >------+------------O CZ --- | / | | / | +-----| + / | | | / | | | / --- --- |/ \ / \ / V V _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response cont., Piezo Acc. From: "steve hammond" shammon1@............. Date: Sat, 29 Jan 2000 11:59:42 -0800 I'm working from memory here so I can't be too specific. In 1991 Bob Ogborn in San Jose who later moved to Texas, but who may still be lurking around the list, built a number of piezoelectric sensors and was thinking about building an array with them. I seem to remember that he tried the RS device but they would break because they were brittle. Bob told me this. #1 they are only good for very local events because they are velocity devices and "need to have the ground moving around you to induce an output". At the time, Bob, Dick, Bruce and I all lived within close proximity and there were a number of event Bob never recorded. I've often thought that the device might be more suited for strong motion designs. There are a number of thing I can tell you about the characteristics of Bob's design. One of the first things you notice is that if you held one in your hand and shook it while holding the bare wires, you got a shock. Bob is an excellent electronics tech and would grin at you every time you did it. He used 1/2 of a whisper fan out of an original Mac that was a piezoelectric device that had 2 flippers sticking out of one end that were 3x1/2x1/16-inch that sandwiched and isolated a piezoelectric disk at the other. When power was applied, the free ends of the flippers would flutter freely in the air from the current applied to the piezoelectric disk and move the air around them. Bob, simply broke off one flipper and epoxied a 1-oz. fishing weight to the free-end of the flipper. Walla -ka-zam, the remaining 1/2-fan was now transformed into the pendulum and mass creating a velocity transducer. Next he took 4-inches of common PVC 1-inch pipe and capped one end of it off with a pipe cap which he had drilled a 1/4-hole into it for filling the device with damping oil. In the second pipe cap he drilled another hole, put the single wires through it and filled the cap 1/2-full with enough cement to seal-up the hole and hold the piezoelectric block in the center so the mass weight would extend into the PVC pipe without contacting the walls of the pipe. Once both caps were mounted, he filled the device with 10W oil and capped the fill-hole off with a rubber plug. Bob, tried an number of weights of oil for damping, but he also spent time trying different mass weights and damping flags. By adding a copper flag at the end of the pendulum, he could drill different hole patterns in it and achieve different degrees of damping. If you took a 4x4 wood block and placed it on the ground a few feet away and stood on it with both feet and hit the end once with a slug hammer (without falling off...), you could calibrate each of the devices output magnitude to different combinations of oil and drill patterns. Bob really knew electronics and I won't even go there. I'm sure there are a lot of people within the forum that can talk about the circuit for this kind of device. I know this, if you play with it, be sure to use a pair of clamping zineor diodes to protect the electronics from being charbroiled by the output because the ones that Bob built could really put out high current and draw a good spark when you smacked them. Another characteristic is that they were EXTREMELY directional. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: ChrisAtUpw@....... To: psn-l@.............. Date: Saturday, January 29, 2000 4:34 AM Subject: Re: VBB response cont., Piezo Acc. >In a message dated 29/01/00 01:03:53 GMT Standard Time, gbl@....... writes: > >>> I was very interested in those piezoelectric disks. Radio Shack has them >for one. I thought they would make a good sensor without the use of magnets >or excitation electronics. > >> The sensor exterior was a ~2.5" diameter tube about 5" long. For the >sensor(s) I bought two radio shack piezo disks. I put the disk at each end of >the main tube. For the mass I used a ~1" diameter steel round stock inside >the main tube and had it attached to the disks at both ends. When the mass >moved relative to the tube there would be an output from both disks. I wired >them so the flex output would sum rather than cancel. It did give an output >when put it on my work bench and applied a tilt to the bench top. > >> The problem: As I understand it, for short period sensors >(accelerometers), the displacement output is a directly proportional to the >ground acceleration for periods below the natural period of the sensor & at >~ 0.7 damping. Peizoelectric material seems to output velocity. I also wasn't >sure about how to apply damping. I would like any feedback as to what I was >measuring. To give you the end of the story, I got confused as to what I was >measuring and gave up. > >C> As you put a load on the center of a piezo disk the capacitative element >of ~15 nF charges up. The more the load the bigger the voltage. If you have a >very high impedance voltmeter, the charge just sits there, otherwise it leaks >away. If you then unload the disk, you get a charge of the opposite polarity. >The first resonant frequency of a large size unloaded disk is usually ~500 Hz. > >>>Could piezoelectric material be used for hinge material and their output >measured? > C> small piezo laminated bars are sold just for this job, but their capacity >is low at 750 pF, which makes long period response sensing more difficult. >100 M Ohm in // with 750 pF has a decay time of 0.075 sec. You can exchange >capacity for sensitivity if you place additional capacity in parallel with >the piezo element. There are also well established feedback techniques for >increasing the input impedance by up to x100. > >The larger disk elements with 15 NF capacity look much more promising at 1.5 >sec. It is not too difficult to increase this by another order of magnitude. >They also seem to be more robust than the small bar elements. > >C> I have been using a modified PZT 'sounder' disk mounted on a spike to find >leaks in water mains, by pushing the spike into the ground and listening for >the water hiss and the clink of pebbles. It seems to be an effective >technique. You use an audio amplifier and if you turn up the gain, you can >easily hear someone walking by. I could also hear the noise of traffic on the >road 100 yards away quite loudly. >The response extends to over 1 KHz if you don't filter it and it can be >extended down to a few tens of seconds without much difficulty. I don't know >is how this device would compare in sensitivity to a geophone, but it seems >to have a respectably high sensitivity and it is a lot cheaper. As it is, the >disks give a pure acceleration output. This could be integrated to give a >vertical velocity output. The disk temperatures need to be quite closely >regulated to eliminate drifts. > > Chris. > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: John Hernlund hernlund@....... Date: Sun, 30 Jan 2000 11:41:36 -0700 (MST) It seems pretty difficult to explain your recording by magnetic arguments, since they are a type of force that falls away as 1/r^3 which means it takes an extremely powerful source to make any recording at distances of more than a hundred meters. These observations can be made, but they usually involve huge perturbations of the entire Earth's magnetic field as it interacts with radiation or from the core itself. So for a dinky little satellite...probably just some interesting noise around the same time. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response cont., Piezo Acc. From: barry lotz gbl@....... Date: Sun, 30 Jan 2000 19:59:14 -0800 Karl It sounds suspiciously like an integrator. If this is the case then maybe the output of the short period piezo sensor would be acceleration. I'll have to pull the sensor out of the dust and see if it will work again. Regards Barry Karl Cunningham wrote: > Barry & Chris -- > > Piezo devices are often used with charge amplifiers, which is just an > op-amp with capacitive feedback and a parallel resistor to keep it from > drifting off scale. When the input is connected to the Piezo device (a > capacitor) the op-amp circuit acts as an amplifier with gain of CZ/C1. The > low-frequency limit is given by the time constant of the resistor and C1. > Op-amps with very low input bias and offset currents must be used. This > circuit provides a low-impedance output to drive other circuitry cabling, > etc. With some of today's op-amps having input currents in the picoamp > range, this type of thing is quite viable. > > Use teflon standoffs for the connections at the inverting input of the > op-amp. And any cabling used between the piezo device and the circuit > should be made with wire having insulation with very low dielectric > absorption. > > Karl > > +--------------\/\/\/\------------+ > | | > +----------------||---------------+ > | C1 | > | |\ | > | | \ | > | | \ | > | | \ | > +-------------| - \ | > | | \ | > | | \ | > Piezo --- | >------+------------O > CZ --- | / > | | / > | +-----| + / > | | | / > | | | / > --- --- |/ > \ / \ / > V V > > _ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: L4 From: Mauro Mariotti mariottim@...... Date: Mon, 31 Jan 2000 09:21:59 +0100 Someone knows how is build an L4? Thanks Mauro _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: Ken Navarre kjn@.......... Date: Mon, 31 Jan 2000 09:10:29 -0800 (PST) On Sat, 29 Jan 2000 ajbv@............ wrote: > Apparently the object disintegrated in "mid-air" over the sea > approximately north of Kunnunura (near the border with the Northern > Territory). It was seen by people spread out about 2,000km across the > state. This is very unusual for a meteor as it suggests a 'grazing' > trajectory. We believe it was the entry of the Molniya 1-67, a Russian > communications satellite that was launched in 1986. Was there a sonic boom associated with the reentry event? If so, the "noise" you described could be related to that. Several years ago when "AREA 51" in Nevada was an active source of classified aerial activity southern California seismometers tracked several events that seemed to be associated with high altitude sonic booms headed from out over the Pacific and flying toward the Nellis Test facility in the Nevada desert. The booms left a "seismic footprint" across the seismic network. I recall some work being done to determine the altitude and direction of travel of the aircraft that produced the sonic booms. There were several events like this that occurred over several months. No one stepped forward to claim responsibility and it was assumed that the booms resulted from the operation of some classified project at the test site. Ken Navarre _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB response cont., Piezo Acc. From: Karl Cunningham karlc@....... Date: Mon, 31 Jan 2000 11:00:54 -0800 Hi Barry -- It isn't an integrator since the piezo device is a capacitor. The combination of the capacitive input and capacitive feedback make it flat with frequency (above the cutoff of the resistor and C1). Below this cutoff, it's actually a derivative function. Looking at a couple of articles about piezoelectricity, it appears it is a change in electric polarization with change in applied stress. On the surface, I think this would imply it is an acceleration device. Is there more to the story? Karl At 07:59 PM 1/30/2000 -0800, you wrote: >Karl > It sounds suspiciously like an integrator. If this is the case then maybe >the output of the short period piezo sensor would be acceleration. I'll have to >pull the sensor out of the dust and see if it will work again. >Regards >Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: ajbv@............ Date: Tue, 01 Feb 2000 19:20:14 +0800 Hi, I asked around and nobody heard any sounds except an observer in the north of the state who claimed to hear a "hissing sound". This type of comment does occur on some Fireball sightings. But no rattling of windows or the like. So alas, I'll just have to say the measured "noise" at the time of satellite entry will be put in the Hmmmm basket. I do agree that the magnet effect is not really possible given the 1/r^3 decline in the magnet strength with distance. Anyhow unit the next event. Thanks to John Hernlund and Ken Navarre. Arie Ken Navarre wrote: > On Sat, 29 Jan 2000 ajbv@............ wrote: > > Apparently the object disintegrated in "mid-air" over the sea > > approximately north of Kunnunura (near the border with the Northern > > Territory). It was seen by people spread out about 2,000km across the > > state. This is very unusual for a meteor as it suggests a 'grazing' > > trajectory. We believe it was the entry of the Molniya 1-67, a Russian > > communications satellite that was launched in 1986. > > Was there a sonic boom associated with the reentry event? If so, the > "noise" you described could be related to that. Several years ago when > "AREA 51" in Nevada was an active source of classified aerial activity > southern California seismometers tracked several events that > seemed to be associated with high altitude sonic booms headed from > out over the Pacific and flying toward the Nellis Test facility in > the Nevada desert. The booms left a "seismic footprint" across the > seismic network. I recall some work being done to determine the altitude > and direction of travel of the aircraft that produced the sonic booms. > There were several events like this that occurred over several months. > No one stepped forward to claim responsibility and it was assumed that > the booms resulted from the operation of some classified project at the > test site. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: Ed Thelen ethelen@........ Date: Tue, 01 Feb 2000 12:12:27 -0800 I knew a guy who lived under the landing pattern for Los Angles International air port. He ran a garden gate type seismograph adjusted to about 20 seconds natural period. He said that even though it was in a little shed in the back yard, the seismograph had to be carefully covered with a good box or he would be affected by planes flying low overhead. Could there have been an non-audible pressure wave from the fireball that pushed the boom of the seismometer a tiny bit? I don't know if a shock wave from say 50 Km high event (presumably a very audible sharp step in pressure) gets converted to a slow rising pressure wave that humans don't hear at ground level. (I do know that a supersonic Hustler bomber flying at say 30,000 feet makes a very audible window rattling "BOOM" at ground level.) "Grasping at straws" Ed Thelen ajbv@............ wrote: > > Hi, I asked around and nobody heard any sounds except an observer > in the north of the state who claimed to hear a "hissing sound". This > type of comment does occur on some Fireball sightings. But no rattling > of windows or the like. So alas, I'll just have to say the measured "noise" > at the time of satellite entry will be put in the Hmmmm basket. I do agree > that the magnet effect is not really possible given the 1/r^3 decline in the > magnet strength with distance. Anyhow unit the next event. > > Thanks to John Hernlund and Ken Navarre. > > Arie > > Ken Navarre wrote: > > > On Sat, 29 Jan 2000 ajbv@............ wrote: > > > Apparently the object disintegrated in "mid-air" over the sea > > > approximately north of Kunnunura (near the border with the Northern > > > Territory). It was seen by people spread out about 2,000km across the > > > state. This is very unusual for a meteor as it suggests a 'grazing' > > > trajectory. We believe it was the entry of the Molniya 1-67, a Russian > > > communications satellite that was launched in 1986. > > > > Was there a sonic boom associated with the reentry event? If so, the > > "noise" you described could be related to that. Several years ago when > > "AREA 51" in Nevada was an active source of classified aerial activity > > southern California seismometers tracked several events that > > seemed to be associated with high altitude sonic booms headed from > > out over the Pacific and flying toward the Nellis Test facility in > > the Nevada desert. The booms left a "seismic footprint" across the > > seismic network. I recall some work being done to determine the altitude > > and direction of travel of the aircraft that produced the sonic booms. > > There were several events like this that occurred over several months. > > No one stepped forward to claim responsibility and it was assumed that > > the booms resulted from the operation of some classified project at the > > test site. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BINGO! Satellite re-entry to Seismic record From: Arie Verveer ajbv@............ Date: Wed, 02 Feb 2000 21:21:04 +0800 Hi , After Ed's suggestion on the infra sound possibility, I did some more investigation on the 'noise' spike when the Molniya 1-67, Russian communications satellite re-entered above my location. (27th Jan 2000 at 14:50:28 UT). I checked the professional Seismometers via an AutoDrm request, and this showed no event. Then as the final check I looked at the magnet recordings form a magnetic observatory some 900 km away. Bingo, at the time of my observation there is a distinct spike in the magnetic records at 14:50UT. All three component's of the magnetic field showed the effect. That data is available for the next week or so at: ftp://ftp.ips.gov.au/asfc/data/mag/lea/rawdata/images/learaw.000127.gif I cant explain what caused the effect but it looks very interesting against the seismometer recordings and the visual observation. Arie Ed Thelen wrote: > I knew a guy who lived under the landing pattern for Los Angles > International air port. He ran a garden gate type seismograph > adjusted to about 20 seconds natural period. He said that > even though it was in a little shed in the back yard, > the seismograph had to be carefully covered with a good box > or he would be affected by planes flying low overhead. > > Could there have been an non-audible pressure wave from the > fireball that pushed the boom of the seismometer a tiny bit? > > I don't know if a shock wave from say 50 Km high event > (presumably a very audible sharp step in pressure) > gets converted to a slow rising pressure wave that > humans don't hear at ground level. > > (I do know that a supersonic Hustler bomber flying at > say 30,000 feet makes a very audible window rattling > "BOOM" at ground level.) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BINGO! Satellite re-entry to Seismic record From: offutt@............ (Warren Offutt) Date: Wed, 2 Feb 2000 07:38:45 -0700 (MST) Arie, When a decaying satellite or meteorite reenters the atmosphere, there is a fairly long column of ionized gas following its path. That column could easily be hundreds of miles long. A potential difference along that path would naturally produce a current with concomitant magnetic effects detectable at distances larger than likely if one considers the 1/r^3 factor based on the distance to the entering object itself. warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: Ken Navarre kjn@.......... Date: Wed, 2 Feb 2000 09:31:00 -0800 (PST) On Tue, 1 Feb 2000, Ed Thelen wrote: [snip] > Could there have been an non-audible pressure wave from the > fireball that pushed the boom of the seismometer a tiny bit? Didn't the NRC use microbarographs to monitor for nuclear explosions worldwide? I've wanted to find the time to build one of the microbarographs described in Scientific American but haven't been able to... yet. Maybe in the next lifetime... :( Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: ddiffenderfer@........ Date: Wed, 2 Feb 2000 09:52:30 -0800 Yes, we monitored all nuclear events with microbarographs. David W. Diffenderfer P. O. Box 427 Palo Verde, CA 92266 760-854-2140 ddiffenderfer@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: Danie Overbeek danieo@............ Date: Thu, 03 Feb 2000 02:59:04 +0000 Date: Tue, 01 Feb 2000 12:12:27 -0800 From: Ed Thelen Reply-to: PSN-L Mailing List Organization: @Home Network To: PSN-L Mailing List Subject: Re: Satellite re-entry to Seismic record I knew a guy who lived under the landing pattern for Los Angles International air port. He ran a garden gate type seismograph adjusted to about 20 seconds natural period. He said that even though it was in a little shed in the back yard, the seismograph had to be carefully covered with a good box or he would be affected by planes flying low overhead. Could there have been an non-audible pressure wave from the fireball that pushed the boom of the seismometer a tiny bit? I don't know if a shock wave from say 50 Km high event (presumably a very audible sharp step in pressure) gets converted to a slow rising pressure wave that humans don't hear at ground level. (I do know that a supersonic Hustler bomber flying at say 30,000 feet makes a very audible window rattling "BOOM" at ground level.) "Grasping at straws" Ed Thelen ajbv@............ wrote: > > Hi, I asked around and nobody heard any sounds except an observer > in the north of the state who claimed to hear a "hissing sound". This > type of comment does occur on some Fireball sightings. But no rattling > of windows or the like. So alas, I'll just have to say the measured "noise" > at the time of satellite entry will be put in the Hmmmm basket. I do agree > that the magnet effect is not really possible given the 1/r^3 decline in the > magnet strength with distance. Anyhow unit the next event. > > Thanks to John Hernlund and Ken Navarre. > > Arie > > Ken Navarre wrote: > > > On Sat, 29 Jan 2000 ajbv@............ wrote: > > > Apparently the object disintegrated in "mid-air" over the sea > > > approximately north of Kunnunura (near the border with the Northern > > > Territory). It was seen by people spread out about 2,000km across the > > > state. This is very unusual for a meteor as it suggests a 'grazing' > > > trajectory. We believe it was the entry of the Molniya 1-67, a Russian > > > communications satellite that was launched in 1986. > > > > Was there a sonic boom associated with the reentry event? If so, the > > "noise" you described could be related to that. Several years ago when > > "AREA 51" in Nevada was an active source of classified aerial activity > > southern California seismometers tracked several events that > > seemed to be associated with high altitude sonic booms headed from > > out over the Pacific and flying toward the Nellis Test facility in > > the Nevada desert. The booms left a "seismic footprint" across the > > seismic network. I recall some work being done to determine the altitude > > and direction of travel of the aircraft that produced the sonic booms. > > There were several events like this that occurred over several months. > > No one stepped forward to claim responsibility and it was assumed that > > the booms resulted from the operation of some classified project at the > > test site. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) << Go to the electronics page, scroll down till you find the article title "Infrasound monitoring with a micrbarograph" Cheers Danie Overbeek.>>> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry to Seismic record From: Peter & Beth pho@........... Date: Wed, 02 Feb 2000 19:56:09 -0500 Ken, Do you have a source for a microbargraph? Peter Ken Navarre wrote: > On Tue, 1 Feb 2000, Ed Thelen wrote: > > [snip] > > Could there have been an non-audible pressure wave from the > > fireball that pushed the boom of the seismometer a tiny bit? > > Didn't the NRC use microbarographs to monitor for nuclear explosions > worldwide? > > I've wanted to find the time to build one of the microbarographs > described in Scientific American but haven't been able to... yet. > Maybe in the next lifetime... :( > > Ken > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BINGO! Satellite re-entry to Seismic record From: Peter & Beth pho@........... Date: Wed, 02 Feb 2000 20:04:53 -0500 What kind of sensor could you make to build a magnetometer to monitor magnetic anomalies? What kind of period would you look for? Peter Arie Verveer wrote: > Hi , After Ed's suggestion on the infra sound possibility, I did some more > investigation > on the 'noise' spike when the Molniya 1-67, Russian communications satellite > re-entered > above my location. (27th Jan 2000 at 14:50:28 UT). I checked the professional > Seismometers > via an AutoDrm request, and this showed no event. Then as the final check I > looked > at the magnet recordings form a magnetic observatory some 900 km away. > > Bingo, at the time of my observation there is a distinct spike in the magnetic > records at > 14:50UT. All three component's of the magnetic field showed the effect. That data > is > available for the next week or so at: > > ftp://ftp.ips.gov.au/asfc/data/mag/lea/rawdata/images/learaw.000127.gif > > I cant explain what caused the effect but it looks very interesting against the > seismometer > recordings and the visual observation. > > Arie > > Ed Thelen wrote: > > > I knew a guy who lived under the landing pattern for Los Angles > > International air port. He ran a garden gate type seismograph > > adjusted to about 20 seconds natural period. He said that > > even though it was in a little shed in the back yard, > > the seismograph had to be carefully covered with a good box > > or he would be affected by planes flying low overhead. > > > > Could there have been an non-audible pressure wave from the > > fireball that pushed the boom of the seismometer a tiny bit? > > > > I don't know if a shock wave from say 50 Km high event > > (presumably a very audible sharp step in pressure) > > gets converted to a slow rising pressure wave that > > humans don't hear at ground level. > > > > (I do know that a supersonic Hustler bomber flying at > > say 30,000 feet makes a very audible window rattling > > "BOOM" at ground level.) > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BINGO! Satellite re-entry to Seismic record From: ChrisAtUpw@....... Date: Wed, 2 Feb 2000 22:24:10 EST Arie, >> warren wrote:- When a decaying satellite or meteorite reenters the atmosphere, there is a fairly long column of ionized gas following its path. That column could easily be hundreds of miles long. A potential difference along that path would naturally produce a current with concomitant magnetic effects detectable at distances larger than likely if one considers the 1/r^3 factor based on the distance to the entering object itself. I seem to remember the transient effects of meteors on the earth's magnetic field being described in Amateur Radio Mags. (RadCom). The wind blown ionised path left by the meteor interacts with the earth's magnetic field generating a current and the conducting track also reflects radio waves. For that part of the path above about 50 Km, it is unlikely that any shockwave would have been heard on the ground. The most likely area to experience a sonic boom would be near the end of the trajectory, which is reported to be over the sea. Is a SSW/NNE track possible for a meteorite anyway, bearing in mind that cosmic debris is likely to be moving roughly in the plane of the earth's orbit and would therefore have had to come in over the South Pole? Did the Infrasound Station at Warramunga get anything? See http://rses.anu.edu.au/seismology/ Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: ChrisAtUpw@....... Date: Wed, 2 Feb 2000 22:58:24 EST In a message dated 03/02/00 01:03:51 GMT Standard Time, pho@........... writes: << Do you have a source for a microbargraph? Peter >> For a general review of Infrasound sources, applications and developments, see www4.etf.noaa.gov/infra/infrasonic.html There is an Infrasound detector described at http://www.tiac.net/users/shansen/belljar/content.htm which used an MKS Instruments Barotron Type 223 0.2 mm Hg detector. www.mksinst.com. I can suggest some improvements. Arie has a prototype Infrasound detector on his site. I am also interested and have quite a lot of further info. I wasn't feeling very rich either. For magnetic fluxgate sensors, Arie reported :- >>The design is based around the sensitive FGM-3 and FGM-3h sensor. They are good buy, around $40 US. http://fqs.dconn.com/Electronics/sensors.htm Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: new version of Seismogram Viewer From: The Lahrs JohnJan@........ Date: Wed, 02 Feb 2000 21:22:33 -0700 >------------- Begin Forwarded Message ------------- > >Date: Wed, 02 Feb 2000 17:34:46 +0100 >From: Antony Lomax >X-Accept-Language: en >MIME-Version: 1.0 >To: Philippe Volant , Pierre Henry >, Torild van Eck , Douglas Wright ><73024.3237@..............>, Alberto Michelini , >Jean-Luc BERENGUER , " Catherine Berge-Thierry - >DPRE/SERGD/BERSSIN - 86.71" , James Pope >, Willie Lee , Laslo= =20 >Evers >, Francesco , Guy Marquis >, Pascal Amand ,= Philip >Crotwell , Andre Herrero ,=20 >Bradley >White , Philippe Beys = , >Askold , Victor Huerfano - PRSN >, Miki Moore , Paul Morin >, John Lahr , Anne Deschamps >, Stephane Gaffet , Lee >Hee-il , Gary Gibson ,=20 >"D.Giardini" >, gsa-sismo , David >Kerridge , riviere ,=20 >Mariano >GARCIA-FERNANDEZ , Bob Uhrhammer >, "St=E9phane Dietrich" ,= Doug >Dreger , Genevieve Roult=20 >, >Bouin Marie Paule , Tim Ahern=20 >, >Agecodagis >Subject: new version of Seismogram Viewer >Content-Transfer-Encoding: 7bit > >Hello to all who have expressed interest in Java for seismolgy and the >Seismogram Viewer, > >I would like to inform you that you can learn about and try a >"pre-release" copy of version 2 of the SeisGram2K Seismogram Viewer at: >http://www-geoazur.unice.fr/~lomax/seisgram/ver2/SeisGram2K.html > >I hope that you find this of interest! > >Best regards, > >Anthony > >-- > >--------------------------------------- >Anthony Lomax, UMR Geosciences Azur >250 Rue Albert Einstein, bat 4, 06560 Valbonne, FRANCE >http://www-geoazur.unice.fr/~lomax mailto:lomax@............... >tel: 33 (0) 4 92 94 26 25 fax: 33 (0) 4 92 94 26 10 >----------------------------------------- >Software for Seismology: >NonLinear EQ location: http://www-geoazur.unice.fr/~lomax/nlloc >Java Seismogram Viewer: >http://www-geoazur.unice.fr/~lomax/seisgram/SeisGram2K.html >Java 3D Seismicity Viewer: >http://www-geoazur.unice.fr/~lomax/nlloc/seismicity.html >----------------------------------------- > > > > >------------- End Forwarded Message ------------- * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: microbarographs , Infra-sound From: Arie Verveer ajbv@............ Date: Thu, 03 Feb 2000 21:14:10 +0800 Hi, This may be of interest, It deals with a Infra sound detector I constructed a few years ago. See: http://www.iinet.net.au/~ajbv/Infra/Infra.html Chris ( ChrisAtUpw@....... ) on this mailing list made some good suggestions and improvements. As yet I haven't entered them on the site. But soon. A friend asked me this: could it be used to hear earthquakes.? Now that was a good question. I didn't really have a good answer. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Worldwide magnetic recordings of satellite reentry From: CapAAVSO@....... Date: Thu, 3 Feb 2000 10:02:36 EST Here is a message from Al McWilliams who designed the McWilliams magnetometer, a simple easy-to-build device used by amateurs for over 20 years to make recordings of magnetic storms that match those of professional observatories. He mentions a web site where you can see that the 27 January satellite reentry was recorded worldwide. You must act fast though. The records last only 7 days on this site. Cap ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Subj: Re: Magnetometer recording of a satellite reentry. Date: 02/02/2000 9:23:11 PM Eastern Standard Time From: amcwill417@............. (Alex_McW) To: CapAAVSO@........ zygo@.............. JWink38223@........ kstrait@........... Hi Cap and All, At this site: http://geomag.usgs.gov/wwwplots/plots.html one sees that at least nine of the ground based geomagnetic observatories (Boulder, Guam, Fredericksburg, San Juan, Newport, Honolulu, Tucson, Fresno, and Sitka) clearly show the 1450UT event on 27 January 2000. This site only goes back 7 days so you have to view it immediately. My record shows no clear event (just a small blip which could very well be noise). Al _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: BOB BARNS roybar@........ Date: Thu, 03 Feb 2000 10:17:39 -0500 Is there a link to construction details, etc. about McWilliams magnetometer? Bob CapAAVSO@....... wrote: > > Here is a message from Al McWilliams who designed the McWilliams > magnetometer, a simple easy-to-build device used by amateurs for over 20 > years to make recordings of magnetic storms that match those of professional > observatories. He mentions a web site where you can see that the 27 January > satellite reentry was recorded worldwide. You must act fast though. The > records last only 7 days on this site. > Cap > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Subj: Re: Magnetometer recording of a satellite reentry. > Date: 02/02/2000 9:23:11 PM Eastern Standard Time > From: amcwill417@............. (Alex_McW) > To: CapAAVSO@........ zygo@.............. JWink38223@........ > kstrait@........... > > Hi Cap and All, > At this site: http://geomag.usgs.gov/wwwplots/plots.html one sees that at > least nine of the ground based geomagnetic observatories (Boulder, Guam, > Fredericksburg, San Juan, Newport, Honolulu, Tucson, Fresno, and Sitka) > clearly show the 1450UT event on 27 January 2000. This site only goes back > 7 days so you have to view it immediately. My record shows no clear event > (just a small blip which could very well be noise). > Al > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: delete From: Linda Kovach linda2@............. Date: Thu, 03 Feb 2000 12:15:52 -0800 how can i be deleted from e0mail list for awhile. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: delete From: Spencer817@....... Date: Thu, 3 Feb 2000 14:09:40 EST PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: CapAAVSO@....... Date: Thu, 3 Feb 2000 14:40:27 EST In a message dated 02/03/2000 10:19:54 AM Eastern Standard Time, roybar@........ writes: << Is there a link to construction details, etc. about McWilliams magnetometer? Bob >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Hi Bob, There is no link but I can tell you briefly how it works. Later I could send you detailed drawings and instructions how to build it. These are from the August 1998 Solar Bulletin published by the American Association of Variable Star Observers (AAVSO). I would need a postal address or FAX number. The basic design is a torsion magnetometer consisting of a bar magnet suspended on a torsion wire that can be a piece of guitar string 0.2 mm diameter and about 25-40 cm long. The bar magnet should be about 6 mm diameter and 5 cm long. The magnet is mounted with epoxy in the middle of a thin wooden vane about 1cm wide and 20cm long. The torsion wire can be epoxied to the center of the magnet so the vane hangs horizontal. The upper mount for the torsion wire is then rotated to provide enough torque to make the wooden vane point east and west instead of its preferred north-south direction that it seeks as a compass. The vane is now torsion balanced against the Earths magnetic field and will rotate in response to changes in the strength of the field due to magnetic storms. Beneath one end of the wooden vane are two Radio Shack photocells and above it is a 12-volt automobile bulb, the kind with a straight filament. The bulb and the photocells are arranged so the shadow vane shades one half of each photocell from the lamp above. The linear design of the photocells should be oriented so the lines are perpendicular to the edge of the shadow vane. The photocells are variable resistors. their resistance varies in direct relation to how much light falls on them. If they are equally shaded their resistance is equal. They are made two legs of a four-leg Wheatstone bridge. The other two legs can be 5000 ohm 1/4 Watt resistors. A regulated 9-volt power supply is connected across the bridge and also lights the 12-volt automobile lamp (9-volts is plenty for this application). A chart recorder or A/D converter and computer is connected between the centers of the two legs of the bridge. The two resistors in series have 9-volts across them but at the center the voltage is half as much or 4 1/2-volts. There is also 9-volts across the two photocells that are also connected in series. At the center where they are connected together the voltage is also 4 1/2-volts provided the shadow vane shades the photocells equally which is the way it should be set initially. The recorder is connected between these two 4 1/2-volt points and since they are of equal potential, no current flows and the recorder reads zero (adjust it or bias it so the zero point is in the middle of the chart). When the strength of the Earth's magnetic field changes in response to a solar flare of coronal mass ejection, the shadow vane's balance by the torsion wire becomes unbalanced and rotates the position of the shadow vane above the photocells. this increases the resistance of one photocell and lowers the resistance of the other and unbalances the Wheatstone bridge so current flows in the recorder. It moves it up or down depending on whether the flare-induced current in the Earth's magnetosphere adds to or subtracts from the normal earth magnetic field strength. The beautiful part of the McWilliams magnetometer is its simplicity. It produces recordings equal to those of professional flux gate magnetometers at the USGS magnetic observatories. Furthermore it needs no amplification and can easily drive a 0 to 1 milliamp recorder directly and is sensitive enough to spread a magnetic storm over the full chart. Most AAVSO magnetic storm observers use Rustrak strip chart recorders running 1/4 inch/hr but it can also be recorded on a computer using Windaq. For details on recording with Windaq email Jerry Winkler at . He will be glad to help you. I should mention that the shadow vane must be damped like a seismograph and for the same reason. A damper in an oil cup under the shadow vane will do the trick. Don't use magnetic damping for obvious reasons and place it as far as possible from big steel objects. Place the magnetometer far from driveways. Cars passing by at a distance of ~40m will put tiny blips on the chart but moving a car in your driveway will send it off scale. The McWilliams photocell sensor would probably work quite well on a seismograph. Have fun, Cap _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Magnetometry links (including McWilliams) From: Doug Welch welch@................... Date: Thu, 3 Feb 2000 15:12:11 -0500 (EST) Please see: http://www.macho.mcmaster.ca/DLW/Magnetometry.html Cheers, Doug Welch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: BOB BARNS roybar@........ Date: Thu, 03 Feb 2000 15:32:39 -0500 Cap, Many thanks for your very lucid description of the magnetometer--it sounds like a good thing to build. If you mail me the drawings, I will make them avail. as gifs on my web site. Bob Barns 63 Martins La. Berkeley Heights, NJ 07922 CapAAVSO@....... wrote: > > In a message dated 02/03/2000 10:19:54 AM Eastern Standard Time, > roybar@........ writes: > > << Is there a link to construction details, etc. about McWilliams > magnetometer? > Bob >> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Hi Bob, > There is no link but I can tell you briefly how it works. Later I could > send you detailed drawings and instructions how to build it. These are from > the August 1998 Solar Bulletin published by the American Association of > Variable Star Observers (AAVSO). I would need a postal address or FAX number. > The basic design is a torsion magnetometer consisting of a bar magnet > suspended on a torsion wire that can be a piece of guitar string 0.2 mm > diameter and about 25-40 cm long. The bar magnet should be about 6 mm > diameter and 5 cm long. The magnet is mounted with epoxy in the middle of a > thin wooden vane about > 1cm wide and 20cm long. The torsion wire can be epoxied to the center of the > magnet so the vane hangs horizontal. The upper mount for the torsion wire is > then rotated to provide enough torque to make the wooden vane point east and > west instead of its preferred north-south direction that it seeks as a > compass. The vane is now torsion balanced against the Earths magnetic field > and will rotate in response to changes in the strength of the field due to > magnetic storms. Beneath one end of the wooden vane are two Radio Shack > photocells and above it is a 12-volt automobile bulb, the kind with a > straight filament. The bulb and the photocells are arranged so the shadow > vane shades one half of each photocell from the lamp above. The linear design > of the photocells should be oriented so the lines are perpendicular to the > edge of the shadow vane. The photocells are variable resistors. their > resistance varies in direct relation to how much light falls on them. If they > are equally shaded their resistance is equal. They are made two legs of a > four-leg Wheatstone bridge. The other two legs can be 5000 ohm 1/4 Watt > resistors. A regulated 9-volt power supply is connected across the bridge and > also lights the 12-volt automobile lamp (9-volts is plenty for this > application). A chart recorder or A/D converter and computer is connected > between the centers of the two legs of the bridge. The two resistors in > series have 9-volts across them but at the center the voltage is half as much > or 4 1/2-volts. There is also 9-volts across the two photocells that are also > connected in series. At the center where they are connected together the > voltage is also 4 1/2-volts provided the shadow vane shades the photocells > equally which is the way it should be set initially. The recorder is > connected between these two 4 1/2-volt points and since they are of equal > potential, no current flows and the recorder reads zero (adjust it or bias it > so the zero point is in the middle of the chart). When the strength of the > Earth's magnetic field changes in response to a solar flare of coronal mass > ejection, the shadow vane's balance by the torsion wire becomes unbalanced > and rotates the position of the shadow vane above the photocells. this > increases the resistance of one photocell and lowers the resistance of the > other and unbalances the Wheatstone bridge so current flows in the recorder. > It moves it up or down depending on whether the flare-induced current in the > Earth's magnetosphere adds to or subtracts from the normal earth magnetic > field strength. > The beautiful part of the McWilliams magnetometer is its simplicity. It > produces recordings equal to those of professional flux gate magnetometers at > the USGS magnetic observatories. Furthermore it needs no amplification and > can easily drive a 0 to 1 milliamp recorder directly and is sensitive enough > to spread a magnetic storm over the full chart. Most AAVSO magnetic storm > observers use Rustrak strip chart recorders running 1/4 inch/hr but it can > also be recorded on a computer using Windaq. For details on recording with > Windaq email Jerry Winkler at . He will be glad to help > you. I should mention that the shadow vane must be damped like a seismograph > and for the same reason. A damper in an oil cup under the shadow vane will do > the trick. Don't use magnetic damping for obvious reasons and place it as far > as possible from big steel objects. Place the magnetometer far from > driveways. Cars passing by at a distance of ~40m will put tiny blips on the > chart but moving a car in your driveway will send it off scale. The > McWilliams photocell sensor would probably work quite well on a seismograph. > Have fun, > Cap > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: "Raul J. Alvarez" ralvarez@........ Date: Thu, 03 Feb 2000 17:36:16 -0700 Thanks for your offer to place the .gifs on your page. Raul Alvarez BOB BARNS wrote: > Cap, > Many thanks for your very lucid description of the magnetometer--it > sounds like a good thing to build. > If you mail me the drawings, I will make them avail. as gifs on my web > site. > Bob Barns > 63 Martins La. > Berkeley Heights, NJ 07922 > > CapAAVSO@....... wrote: > > > > In a message dated 02/03/2000 10:19:54 AM Eastern Standard Time, > > roybar@........ writes: > > > > << Is there a link to construction details, etc. about McWilliams > > magnetometer? > > Bob >> > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Hi Bob, > > There is no link but I can tell you briefly how it works. Later I could > > send you detailed drawings and instructions how to build it. These are from > > the August 1998 Solar Bulletin published by the American Association of > > Variable Star Observers (AAVSO). I would need a postal address or FAX number. > > The basic design is a torsion magnetometer consisting of a bar magnet > > suspended on a torsion wire that can be a piece of guitar string 0.2 mm > > diameter and about 25-40 cm long. The bar magnet should be about 6 mm > > diameter and 5 cm long. The magnet is mounted with epoxy in the middle of a > > thin wooden vane about > > 1cm wide and 20cm long. The torsion wire can be epoxied to the center of the > > magnet so the vane hangs horizontal. The upper mount for the torsion wire is > > then rotated to provide enough torque to make the wooden vane point east and > > west instead of its preferred north-south direction that it seeks as a > > compass. The vane is now torsion balanced against the Earths magnetic field > > and will rotate in response to changes in the strength of the field due to > > magnetic storms. Beneath one end of the wooden vane are two Radio Shack > > photocells and above it is a 12-volt automobile bulb, the kind with a > > straight filament. The bulb and the photocells are arranged so the shadow > > vane shades one half of each photocell from the lamp above. The linear design > > of the photocells should be oriented so the lines are perpendicular to the > > edge of the shadow vane. The photocells are variable resistors. their > > resistance varies in direct relation to how much light falls on them. If they > > are equally shaded their resistance is equal. They are made two legs of a > > four-leg Wheatstone bridge. The other two legs can be 5000 ohm 1/4 Watt > > resistors. A regulated 9-volt power supply is connected across the bridge and > > also lights the 12-volt automobile lamp (9-volts is plenty for this > > application). A chart recorder or A/D converter and computer is connected > > between the centers of the two legs of the bridge. The two resistors in > > series have 9-volts across them but at the center the voltage is half as much > > or 4 1/2-volts. There is also 9-volts across the two photocells that are also > > connected in series. At the center where they are connected together the > > voltage is also 4 1/2-volts provided the shadow vane shades the photocells > > equally which is the way it should be set initially. The recorder is > > connected between these two 4 1/2-volt points and since they are of equal > > potential, no current flows and the recorder reads zero (adjust it or bias it > > so the zero point is in the middle of the chart). When the strength of the > > Earth's magnetic field changes in response to a solar flare of coronal mass > > ejection, the shadow vane's balance by the torsion wire becomes unbalanced > > and rotates the position of the shadow vane above the photocells. this > > increases the resistance of one photocell and lowers the resistance of the > > other and unbalances the Wheatstone bridge so current flows in the recorder. > > It moves it up or down depending on whether the flare-induced current in the > > Earth's magnetosphere adds to or subtracts from the normal earth magnetic > > field strength. > > The beautiful part of the McWilliams magnetometer is its simplicity. It > > produces recordings equal to those of professional flux gate magnetometers at > > the USGS magnetic observatories. Furthermore it needs no amplification and > > can easily drive a 0 to 1 milliamp recorder directly and is sensitive enough > > to spread a magnetic storm over the full chart. Most AAVSO magnetic storm > > observers use Rustrak strip chart recorders running 1/4 inch/hr but it can > > also be recorded on a computer using Windaq. For details on recording with > > Windaq email Jerry Winkler at . He will be glad to help > > you. I should mention that the shadow vane must be damped like a seismograph > > and for the same reason. A damper in an oil cup under the shadow vane will do > > the trick. Don't use magnetic damping for obvious reasons and place it as far > > as possible from big steel objects. Place the magnetometer far from > > driveways. Cars passing by at a distance of ~40m will put tiny blips on the > > chart but moving a car in your driveway will send it off scale. The > > McWilliams photocell sensor would probably work quite well on a seismograph. > > Have fun, > > Cap > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@.............. with the body of the > > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: Peter & Beth pho@........... Date: Thu, 03 Feb 2000 20:04:21 -0500 I was looking around on the web and found a good source for magnetic sensors, and others at: http://www.vernier.com Peter ChrisAtUpw@....... wrote: > In a message dated 03/02/00 01:03:51 GMT Standard Time, pho@........... > writes: > << Do you have a source for a microbargraph? Peter >> > > For a general review of Infrasound sources, applications and > developments, see www4.etf.noaa.gov/infra/infrasonic.html > There is an Infrasound detector described at > http://www.tiac.net/users/shansen/belljar/content.htm which used an MKS > Instruments Barotron Type 223 0.2 mm Hg detector. www.mksinst.com. I can > suggest some improvements. > Arie has a prototype Infrasound detector on his site. I am also > interested and have quite a lot of further info. I wasn't feeling very rich > either. > > For magnetic fluxgate sensors, Arie reported :- > >>The design is based around the sensitive FGM-3 and FGM-3h sensor. They are > good buy, around $40 US. http://fqs.dconn.com/Electronics/sensors.htm > > Regards Chris Chapman > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: super sonic objects From: Ken Navarre kjn@.......... Date: Thu, 3 Feb 2000 20:30:01 -0800 (PST) Mike had a problem posting to the list so I'm posting this for him... Ken ---------- Forwarded message ---------- Date: Wed, 2 Feb 2000 16:53:14 -0700 From: Stickney, Mike To: kjn@.......... Subject: super sonic objects Hi Ken: I have seen a lot of traffic on the PSN group discussing atmospheric signals. Some PSN members might be interested in an article in the Sept/Oct 1995 issue of Seismological Research Letters (volume 66, number 5) "Space Shuttle and Meteriod--Tracking Supersonic Objects in the Atmosphere with Seismographs" by Anthony Qamar pages 6-12. Last time I tried to post to the list, my message bounced so I hope you don't mind if I send this to you for possible forwarding. -Mike Stickney Montana Bureau of Mines and Geology _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: ChrisAtUpw@....... Date: Fri, 4 Feb 2000 06:39:27 EST In a message dated 04/02/00 01:12:40 GMT Standard Time, pho@........... writes: << I was looking around on the web and found a good source for magnetic sensors, and others at: http://www.vernier.com Peter >> This is a long list of quite interesting general purpose school level sensors. The audio sensors do not have audio range or sensitivity needed for Infrasound measurements which range from ~4 Hz to 0.02 Hz and at sensitivities down to 0.01 micro Bar. A specialised range of sensors is required, which can be made, but they are expensive to buy. The magnetic sensor listed is of the Hall effect type and does not have the very high stability needed to detect and measure the changes in the earth's magnetic field at parts per million and below. CapAAVSO@....... describes a torsion bar magnetometer by McWilliams, which will work at this level. There was also a "Jam Jar" magnetometer described many years back in popular science articles. It was built entirely inside a fruit bottling jar for protection against air motion. Flux gate or proton resonance sensors are usually used for professional work. Fluxgates of some ferrites can be used, but very soft magnetic alloys like mu metal may be better. Two rods of the magnetic material are each wound with a magnetising coil. They are connected so that the windings oppose and a sense coil is wound over the pair. When the coil is energised at a frequency F, the sense coil output is at 2xF. An external magnetic field will cause one bar to reach magnetic saturation before the other, producing a small difference signal. This signal is filtered and is then passed through a phase sensitive detector, enabling changes at ppm level to be measured. Ring and tube sensors are also available. See site for details of suitable fluxgate sensors:- http://fqs.dconn.com/Electronics/sensors.htm Descriptions of amateur constructed fluxgate equipment have been published. Magnetic field changes may be of interest to Ham Radio operators and to astronomers. Regards Chris. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seis books From: BOB BARNS roybar@........ Date: Fri, 04 Feb 2000 10:27:58 -0500 Hi, For books on science and technology: http://fatbrain.com They offer a v. long list of books on seismology including the incomparable "Earthqukes and Geological Discovery" by Bolt. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: Jim Hannon jmhannon@........ Date: Fri, 04 Feb 2000 17:37:24 -0600 See site for details of suitable fluxgate >sensors:- http://fqs.dconn.com/Electronics/sensors.htm > Descriptions of amateur constructed fluxgate equipment have been >published. Magnetic field changes may be of interest to Ham Radio operators >and to astronomers. > > Regards Chris. > The sensors that Fat Quarters sells are probably not fluxgate sensors. The are most likely magneto inductive sensors. Precision Navagation http://www.precisionnav.com/sensormain.html holds some patents on this technology. See http://www.patents.ibm.com/patlist?icnt=US&patent_number=4851775 and http://www.patents.ibm.com/patlist?icnt=US&patent_number=5239264 Also this link has a brief description of the operation of the magneto inductive sensor. http://www.pacific.net/~brooke/Sensors.shtml#Magneto-Inductive Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: Doug Welch welch@................... Date: Fri, 4 Feb 2000 18:45:32 -0500 (EST) The sensors that Fat Quarters sells are MOST CERTAINLY fluxgates! Doug On Fri, 4 Feb 2000, Jim Hannon wrote: > See site for details of suitable fluxgate > >sensors:- http://fqs.dconn.com/Electronics/sensors.htm > > Descriptions of amateur constructed fluxgate equipment have been > >published. Magnetic field changes may be of interest to Ham Radio operators > >and to astronomers. > > > > Regards Chris. > > > The sensors that Fat Quarters sells are probably not fluxgate sensors. > The are most likely magneto inductive sensors. Precision Navagation > http://www.precisionnav.com/sensormain.html holds > some patents on this technology. See > http://www.patents.ibm.com/patlist?icnt=US&patent_number=4851775 > and http://www.patents.ibm.com/patlist?icnt=US&patent_number=5239264 > > Also this link has a brief description of the operation of the > magneto inductive sensor. > http://www.pacific.net/~brooke/Sensors.shtml#Magneto-Inductive > > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Satellite re-entry, Infrasound, Magnetometers From: Jim Hannon jmhannon@........ Date: Fri, 04 Feb 2000 18:09:30 -0600 At 06:45 PM 2/4/00 -0500, you wrote: > >The sensors that Fat Quarters sells are MOST CERTAINLY fluxgates! > >Doug > > Doug, I admit I am guessing, but have you read the description of the Precision Navagation sensors? They put out a variable frequency square wave just like the Speake sensors. The fluxgate sensors I know about all require demodulating a fixed frequency flux chopping signal and that results in a DC voltage representive of the magnetic flux. This would have to be converted to the variable frequency signal with additional circuitry. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VBB displacement gain From: S-T Morrissey sean@........... Date: Sat, 5 Feb 2000 14:27:57 -0600 (CST) Barry, Re. Your recent question about increasing the gain of the VRDT displacement detector. If the gain is too high, short period oscillations will occur, sometimes strong enough to be visible. They will show up in the MATHCAD model of the transfer function. Also with higher gain, phase shift problems in the displacement amplifier will show up; often changing the capacitor in the low-pass filter will cure them. The value of "r" does not directly affect the zero stability of the VBB system, assuming the loop gain is reasonable. However, if it is changed without adjusting the proportional damping resistor Rp, the system will become undamped and will actually oscillate at the feedback period of several tens of seconds. A partially damped condition would seem to be a zero instability. Use the MATHCAD model to investigate the damping change, and make sure it comes out greater than 0.707. Regarding getting a copy of J. Steim's Harvard thesis: it is 160 pages; It does say that it is copyrighted, so I really don't want to get involved. Maybe Harvard has a way of providing a copy. Regards, Sean-Thomas ----------------------------------------- For the reader, here is a review of what I wrote in April regarding using a vary large feedback capacitor with a low value of "r". Regarding the question of using lower displacement gain "r" and a much larger feedback capacitor Cp: Naturally, you can plug any range numbers into the transfer function and get any response you want. Decreasing "r" by 1/50 and increasing Cp by x50 and adjusting the damping can give a flat response. However, lowering "r" really lowers the high frequency corner, and seismologists really want something flat to above 50 hz., or at least well above the anti- aliasing filters of the digitizer. Reducing "r" and increasing Cp causes a serious reduction of the net output (k=1/(G*Cp), G=Gn/M). This means that an amplifier that adds noise and probably compromises the dynamic range needs to be put ahead of the digitizer. One of the major plusses of a VBB instrument is that the passive-component feedback results in an inherent dynamic range of 120db or more which is not limited by amplifiers. For reference, for the multi-period design I am using a VRDT with 200 millivolts/micron, a 10x amplifier, for an "r" of 2 000 000 volts/meter. With Cp set to 20 uf for all periods, the output is 2100 volts/meter/second, and the -3db upper frequency corner is at 80hz. Also, decreasing "r" really limits the sensitivity to detecting small accelerations, increasing the noise floor. And if Cp is too large, it can cause short-period oscillations, which will be predicted by the MATHCAD worksheet of the transfer function. Making the mass large doesn't help either; the brownian noise of 0.3kg is below the low noise model for any reasonable period and Q. Put as a simplistic concept, a smaller mass is "easier" for the feedback system to "control". Commercial VBB masses range from 0.6 to less than 0.1 kg. You have suggested that you are using 500ufarad with "r" = 42 000. Unless you have won the lottery, I assume that this is a pair of 1000 uf electrolytics. The biggest problem in using a large Cp is that non-polarized electrolytics are not acceptable for the feedback components. They are very temperature sensitive in regard to value and leakage. Polypropolyne or polystyrene are needed. The leakage of these is 10^5 megohm-microfarads or more; electrolytics have a value as little as 1, and being electro-chemical cells, are very temperature dependent. And since the dielectric layer is formed by the imposition of voltage, it degrades with time, or the actual capacitance varies with the voltage and frequency. If you look under the hood of the feedback box of a Streckheisn, it is packed with an array of pricey cubical 10uf poly capacitors, all measured. Years ago, I got into a discussion with Mr. Guralp about using tantalum capacitors in the feedback. THere was a problem with instability with temperature change as the Cp change made the feedback unstable. As far as I can see, poly caps are used for both the feedback and the integrator C in all the commercial instruments. I mentioned the oscillations around 4hz. Aside from the above considerations, a value we like to ignore is the presumably quite short time constant of the displacement detector amplifier. It naturally does have some low-pass filtering with associated phase shifts. My original VBB audibly hummed at about 400 hz until I added a small RC filter to the amplifier input. I used a decade resistor to tweak it until the oscillation stopped, with something like 1200 ohms into 4 uf, which I presume was making a phase correction. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: fluxgates vs Speake and Precision Navigational magnetometers From: "Charles R. Patton" crpatton@...... Date: Sat, 05 Feb 2000 22:55:45 -0800 A flux gate sensor =93modulates=94 the ambient field. Basically it =93attracts=94 the ambient field in a high permeability core, then satura= tes that core with an auxiliary winding =96 the driver winding -- causing its= permeability to approach that of air, therefore the previous ambient field lines in the core are =93pushed=94 out. If the core is surrounded = by another coil which is magnetically orthogonal to the driving coil =96 the= sense coil -- the sense winding is not coupled magnetically to the drive winding, but the flux from the ambient field that is moving in and out induces voltages in the sense coil. A little thought about this process shows that although the drive coil saturates on a positive and negative drive peaks, the result on the sense coil is that the sensed voltage has gone though two positive peaks, i.e., it is the second harmonic =96 it is= two times the frequency -- of the drive waveform. This is why flux gate magnetometers are often called harmonic modulators. Typically to improve sensitivity, the sense winding is resonated with a capacitor to the second harmonic frequency. The Speake and Precision Navigation magnetometers use another effect. Suppose we take a strip of high permeability metal that is easily saturated (easy saturation is not actually necessary, it just makes the effect easier to use.) Now we wrap a coil around this strip of metal and put it in an oscillator circuit that senses the BEMF in the coil. What happens next is that the BEMF collapses when the strip saturates under the drive current. If this is the signal to reverse the current in the drive coil, then the unbalance in the drive current is the measure of the ambient flux. The Speake and Precision Navigation circuits do one more slight variation. Instead of symmetrically sensing and reversing the drive current, they reset the core in one direction very quickly and only sense the saturation in the opposite direction. The result of this tactic is that the time to saturation varies with the ambient field and since this time is the pulse width of the output, therefore the frequency varies roughly proportional to the ambient field. I=92ve been developing a high accuracy, low cost version of the symmetrical form that can be read out with one of the 24 bit DACs that are now so available with a very stable zero and symmetrical plus and minus sense range. The strip of permalloy or Metglas is free to $0.25. A hint for gathering the strips: save all your anti-theft tags such as on CD=92s from Best Buy and other retailers, and make good friends with your local librarian. A curious thing, I have picked up 20 or 30 the tags in the parking lot of my local Best Buy store. I can only surmise that as people leave the store they instantly rip off the cellophane wrapping, along with the tags, in order to start playing their new CD=92s= on the way home. I can easily pick-up 5 to 10 tags in a single trip to the parking lot. Just look down. Current results on the librarian source strips are a noise floor of about 50 pT peak-to-peak to about 30 Hz not counting ambient hum. It=92s actually capable of about a 1 KHz BW= , but I close it down to keep the 60 HZ pick-up manageable. Probably the anti-theft tags, which use Metglas, will not perform as well as the library permalloy strips since the Metglas in the tags is probably annealed to be highly magnetostrictive. This quality interferes with the noise performance from what I=92ve read. I=92ve haven=92t finished t= he experiments in this area to confirm that. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: Peter & Beth pho@........... Date: Thu, 03 Feb 2000 20:46:34 -0500 This sounds like a good experiment. Maybe you could post drawings for everyone to see.. Peter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Worldwide magnetic recordings of satellite reentry From: CapAAVSO@....... Date: Sun, 6 Feb 2000 10:35:13 EST In a message dated 02/06/2000 10:20:24 AM Eastern Standard Time, pho@........... writes: << This sounds like a good experiment. Maybe you could post drawings for everyone to see.. Peter >> ------------------------------------------------------------------------------ -------------- Peter, You can find drawings and the schematic for building the McWilliams magnetometer at the following web site: http://www.regulusastro.com/ This design is by AAVSO magnetic observer,Jim Mandaville, but it is not set in concrete. Much simpler designs will work as well. Have fun, Cap _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB displacement / capacitors From: ChrisAtUpw@....... Date: Sun, 6 Feb 2000 12:11:51 EST In a message dated 05/02/00 20:32:13 GMT Standard Time, sean@........... writes: << The biggest problem in using a large Cp is that non-polarized electrolytics are not acceptable for the feedback components. They are very temperature sensitive in regard to value and leakage. Polypropylene or polystyrene are needed. The leakage of these is 10^5 megohm-microfarads or more; electrolytics have a value as little as 1, and being electro-chemical cells, are very temperature dependent. And since the dielectric layer is formed by the imposition of voltage, it degrades with time, or the actual capacitance varies with the voltage and frequency.... Years ago, I got into a discussion with Mr. Guralp about using tantalum capacitors in the feedback. There was a problem with instability with temperature change as the Cp change made the feedback unstable. You and Mr.Guralp may have been using different components. The original 'Wet Tantalum Electrolytics' that were marketed in the UK had virtually NO leakage. They were sealed metal cans with conc. Sulphuric acid inside. I charged a 100 muF up to 10 V, measured it with an Keithley Electrometer and left it overnight. It read over 9.9 V next morning. Then I believed it! We used them in long period integrators in glider flight computers. Then solid tantalums came along which had leakage's comparable to Al. foil electrolytics, but were much less costly and the wet tantalums became unavailable. Regards Chris Chapman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Sending mail to PSN.QUAKE.NET. From: Larry Cochrane cochrane@.............. Date: Sun, 06 Feb 2000 14:23:55 -0800 All, Yesterday I made a change to my mail server. I am getting a lot of spam email sent to me using psn.quake.net, so I stopped receiving email addressed to this domain name. Please use either seismicnet.com or webtronics.com when sending email to me, this list or the event file archive system (event@................ Thanks. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fluxgates vs Speake and Precision Navigational magnetometers From: "Charles R. Patton" crpatton@...... Date: Sun, 06 Feb 2000 20:09:18 -0800 Jim, I=92ll answer the questions as best I understand them. You wrote: =93How much material are you using in the core? I was thinking that for efficiency the strip should be cut into some narrower strips to make the diameter of the coil smaller and thus having more core and less air.=94 A bit of background to answer this question. As I understand it, there are two major types of magnetic anti-theft systems (as opposed to RF tags and the like.) They both impose a low level AC magnetic field on the area you pass through (the gate like structures at the doorway are the drive and sense coils. In the case of the tags on CD=92s, the strip is magnetostrictive so it actually physically resonates at a multiple of the drive frequency. The sense coil looks for this resonance. The other strip, a mild-steel strip, adjacent to the very shiny, but somewhat pock-marked Metglas, is used to deactivate the tag. On check-out, the sales clerk magnetizes the mild steel, which thereby holds the Metglas in saturation, thereby blocking the resonance effect. The library strip is Permalloy about 4 =93 x 0.1=94 x 0.001=94 and usuall= y visible down in the spline of the book. When it goes through the AC field, it saturates causing a second harmonic to appear, just like the flux gate. This is picked up by the sense coil indicating that there is a strip (and thereby the book it is attached to) in the field. For my experiments, the local librarian was kind enough to give me about 10 of the strips. I took a standard plastic coffee stirrer (the straw style) and wound one and two layer versions with #36 magnet wire. I squeeze the whole coil in a vise to give it an oval shape that the Permalloy strip will slip down inside easily. A single layer arrangement will saturate with about 12 mA. The earth=92s field is equivalent to about 3 mA in this coil structure. With 10 V drive it takes about 15 us to go from plus to minus saturation. I don=92t advise trying to cut narrower strips. It=92s hard to control the cut with homemade equipment and the effect will be to broaden the saturation time as different parts of strip saturate, making it harder to determine saturation. Additionally it is very touchy to cut Metglas. It has many of the characteristics of thin glass. I was only able to cut it two ways. One was a pair stainless steel scissors that I would very carefully hone between cuts to make sure there were no nicks in the blade. A nick, and a great big dimple or sometimes a tear would appear. The other method was to scribe the Metglass with a diamond scribe very carefully, then folding and cracking along the scribe. In either case, I did this with a jig I built so I could reasonably control the strip width and hold it constant. But this was from 2=94 wide, several foot long Metglas designe= d for EM shielding so I could get a handle on it and hold it evenly. You then wrote: =93Any thoughts on using the Metglass strips in a parallel core design flux gate device? One would thing the high perm and easy saturation would make for a much lower power device. This question stumped me. Can you elaborate on what you meant by a parallel core design? I have seen so many designs, some with multiple cores, I=92m confused just which one you mean. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fluxgates vs Speake and Precision Navigational From: Jim Hannon jmhannon@........ Date: Mon, 07 Feb 2000 18:16:31 -0600 > >This question stumped me. Can you elaborate on what you meant by a >parallel core design? I have seen so many designs, some with multiple >cores, I=92m confused just which one you mean. > >Regards, >Charles R. Patton > > Charles, Thanks for the info. The parallel core flux gate design (my name for it) consists of two cores such as a rod or wire or strip of metglas. Each cor= e has a excitation winding. The two coils are placed in parallel inside a overall sense winding. The excitation currents in the two coils are arranged to produce cancelling flux in the sense coil. The signal from th= e sense winding is processed as usual. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: fluxgates vs Speake and Precision Navigationalmagnetometers From: "Charles R. Patton" crpatton@...... Date: Mon, 07 Feb 2000 18:37:50 -0800 Jim Hannon wrote: > > > The parallel core flux gate design (my name for it) > consists of two cores such as a rod or wire or strip of metglas. Each c= ore > has a excitation winding. The two coils are placed in parallel inside a= > overall sense winding. The excitation currents in the two coils are > arranged to produce cancelling flux in the sense coil. The signal from = the > sense winding is processed as usual. Sure, the tapes of both the permalloy or Metglas should work fine in that= configuration. One reason I=92ve decided to concentrate on the inductive= version is that the gain of a harmonic modulator style varies according t= o the Q of the tuned sense winding and the drive waveform. There is a paper wh= ich discusses that when conditions are right (or wrong, it depends on your viewpoint) the sense winding can be paramagnetically pumped and actually = go into oscillation, at which point the output has no relationship to the am= bient field. The down side of the inductive version is that for various reason= s it probably will have an inherently higher noise floor due to the current fl= owing in the winding is common to the sense circuit as opposed to a flux gate w= here theoretically none of the noise of the drive winding should show up in th= e sense winding. I think that current noise effect is low enough that I w= ill be limited by other effects first. Anyway,. Back to the paramagnetic pum= ping effect -- unfortunately, this condition corresponds to higher gain, highe= r Q style units. As a side point, this has been used in other areas that peo= ple may not be aware of. There were some high primary to secondary isolation= power supplies manufactured by Wanlass corporation, which depended on thi= s effect. Literally the secondary was pumped by saturating its core in an orthogonal fashion -- they used a pair of C-cores where one core is rotat= ed 90 degrees to the other. In years past, before transistors were available, = the bell ring generator for small business telephone systems was a paramagnetically pumped sub-harmonic generator. Some old books on mag-am= ps discuss the conditions necessary for unstable (read oscillating) mag-amp circuits. I=92ve built a small experimental variation where you take a s= eries combination of a small choke, resonating capacitor and a 110 VAC light b= ulb. When adjusted correctly the bulb will go up and down in brightness in a f= ew second cycle indefinitely. It=92s kind of neat. No transistors or movin= g parts, just an unstable ferroresonance condition. It also has an incarna= tion in pendulum bob drivers for clocks. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 24 bit A/D From: barry lotz gbl@....... Date: Mon, 07 Feb 2000 22:57:24 -0800 I received a new issue of Sensors. There is a new ad for a 24 bit A/D from Cirrus Logic. See http://www.cirrus.com BTW- I have been running the 16 bit Burr Brown A/D at an oversampling rate of 30 readings per sample. Someone mentioned on a previous listing that oversampling was the equivalent of a higher resolution A/D. I agree with the consept that multiple readings will give one a more accurate sample value but I wonder how I would get more than a count of =B1 32768 (higher than 16 bit) ? The only way I see this occuring is to take say 30 readings per sample and then only divide by 15 rather than 30. Is this a valid approach or mathmatical hocus pocus? Could the individual who wrote the way to calculate the effective A/D resolution with oversampling repost the way it's calculated. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 24 bit A/D? >> 16+ bit A/D From: ChrisAtUpw@....... Date: Tue, 8 Feb 2000 09:36:57 EST Hi there Barry, B> I have been running the 16 bit Burr Brown A/D at an oversampling rate of=20 30 readings per sample. Someone mentioned on a previous listing that=20 oversampling was the equivalent of a higher resolution A/D.=20 If you had a constant signal with no noise and a perfect A/D giving 16=20 bits, calling the converter would produce the same integer number n every=20 time. Averaging would produce the same integer. If you have a constant signal, but up to two bits of noise on the=20 converter, you will get a series of 16 bit readings of n-2, n-1, n, n+1, n+= 2=20 in random order. There will be more n readings than either n+1 or n-1 etc.=20 --- you get a statistical distribution and you are down to something like 14= =20 bit confidence accuracy on one reading. This is not good news. To halve the=20 average error on one single reading, you have to average four readings=20 together. For each factor of two, you need to average four times the previou= s=20 number --- to get 1/4 the average error, takes 16 readings. =20 If you add 16 off 16 bit readings together you get a 20 bit integer=20 number. You can a) use this number b) convert to 'real' numbers and divide b= y=20 16 c) stay with integers, div 16 and loose any extra accuracy of a size less= =20 than 1 bit and accept the 'rounding error' on the last bit d) stay with=20 integers, div 4 and use the 18 bit integer --- the last two or three bits of= =20 the 20 bit number will be noise that you don't want to know about anyway. =20 B> I agree with the consept that multiple readings will give one a more=20 accurate sample value but I wonder how I would get more than a count of =20= =B1=20 32768 (higher than 16 bit)?=20 The only way to represent an accuracy of less than 1 bit with a 16 bit=20 integer is to use a larger total number, 17, 18 bits etc.=20 If you have a couple of bits of noise on a 16 bit A/D, you can get more=20 than '16 bit accuracy' by taking and averaging enough readings 128, 512 ??=20 This can take a long time and you also have to ask yourself if your signal i= s=20 going to stay steady for this length of time. You need to have a filter on=20 your analogue input line which rejects any signal or noise of a frequency=20 greater than your sample time.=20 In the real world, it can be an advantage to average enough readings to=20 be reasonably certain of getting an accuracy within the last bit of the=20 converter, but beyond this, it starts to take a lot of time and effort and=20 you are usually better off using a higher accuracy A/D converter. When you have a lot of mains hum on the signal, which maybe changes from= =20 time to time, another technique which may be worth considering is to take an= d=20 average enough samples to exactly cover one mains cycle, but this does limit= =20 the sample rate to less than the mains frequency per second. If you have 60=20 Hz mains and a 20 mu Sec sample rate, you could set the coverter to sample=20 say eight channels in succession, 84 times. The average contribution to all=20 channels from mains hum over this period will be zero. In calculating the=20 sample rate, you have to take into account set-up times and settling times,=20 or you may also loose accuracy that way. Sampling eight channels with=20 suitable pauses 20 times equally spread out over a single cycle would=20 probably be better.=20 =20 Hope that this makes things clearer. Regards Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Wanted: 12-bit A/D card From: ted@.......... Date: Thu, 10 Feb 2000 10:58:03 -0500 I'm looking for a 12-bit A/D card for ISA slot. Does anyone have an extra they'd be willing to sell? I'd prefer if it was one of the cards already supported by EMON since I'm running out of code segment space to add more support. (To gain space I have resorted to making error messages more cryptic. Please begin reading between the lines.) :-) These are the cards supported, but others would be OK too. Metrabyte DAS-4 or DAS-16 PCLab 714 or 711-S Acqutek PA-CP12 Real Time Devices ADA110 CIO-DAS08/Jr/16-AO Axiom AX5210PG BSOFT ANA290 Acrosser B3001 Thanks! Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Wanted: 12-bit A/D card From: "Victor Taylor" victorjtaylor@............. Date: Sat, 12 Feb 2000 10:30:52 -0500 I have a 12 bit metra bite A/D card I will sell you with the program, give me a few days to find it, I will get back to you.. Victor ----- Original Message ----- From: To: "PSN-L Mailing List" Sent: Thursday, February 10, 2000 10:58 AM Subject: Wanted: 12-bit A/D card > > > I'm looking for a 12-bit A/D card for ISA slot. Does anyone have an extra > they'd be willing to sell? I'd prefer if it was one of the cards already > supported by EMON since I'm running out of code segment space to add more > support. (To gain space I have resorted to making error messages more > cryptic. Please begin reading between the lines.) :-) These are the cards > supported, but others would be OK too. > > Metrabyte DAS-4 or DAS-16 > PCLab 714 or 711-S > Acqutek PA-CP12 > Real Time Devices ADA110 > CIO-DAS08/Jr/16-AO > Axiom AX5210PG > BSOFT ANA290 > Acrosser B3001 > > Thanks! > > Regards, Ted > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: RADIOTEL@....... Date: Sun, 13 Feb 2000 18:47:00 EST Meredith, et all I recently visited Meredith Lambs's web page and viewed his SG seismo with a hall effect sensor. Is the SG with hall effect sensor as sensitive as the original SG configuration? What is the period range for an SG with hall effect sensors? Is the electronics easier to make ( it certainly seems so). Any comments anyone has would be appreciated. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: meredith lamb mlamb1@.......... Date: Sun, 13 Feb 2000 19:19:44 -0800 RADIOTEL@....... wrote: > Meredith, et all > > I recently visited Meredith Lambs's web page and viewed his SG seismo with a > hall effect sensor. Is the SG with hall effect sensor as sensitive as the > original SG configuration? Theres alot of variables here that determine sensitivity. Technically I've never tried to measure it on a actual operating SG. Earlier methods used by Bob Lamb showed variations of roughly 25mv on up too ~ 40+mv per each .001", which is dependent on the gain of the amplifier AND, how close the Hall is too the center of the 4 pole magnet/s used. The Hall device itself has a amplifier which I'am guessing the gain is about 350. The circuit on the web site and I use has a gain of 5 which with the amplifier gain ends up around ~1800. I have no idea of how sensitive the capactive model of SG really is; but I wouldn't be surprised if the Hall versus the capacitive model isn't fairly similar. The Hall device is technically overdriven in the circuit, however the linearity is still (?+ - 5%?) very good for this use. > What is the period range for an SG with hall > effect sensors? The physical period is always going to be short, as they are simply a hanging pendulum. However, they are subject to seismic wave tilt like any seismometer, and here is where with the amplifier and its "period" adjusting capacitors, one can pick what they want. Betcha this is confusing to alot of people. The Hall device can be operated in its Tilt mode (relatively linear displacement) or, Frequency mode (with its capacitor, resistor bleed off function). The circuit on the web site uses both aspects, one for mechanical adjustment, and the other frequency mode for normal operation with a null voltage point. At the moment, I use 30mfd mylar caps on the amplifiers; which roughly equates to some 30 seconds max. The output roughly matches the output of the Sprengnether coil & magnet affairs I also operate, and compare too. So....while the physical period is some 1.05s, the actual seismic wave tilt of the seismometer will be followed, up to the value of the capacitors used. I don't think any higher than 30mfd is really necessary. >Is the electronics easier to make ( it certainly seems so). Quite abit easier, but, some of the components like the zenors, mylar caps, and precision pots used could rack up the cost...but, it depends on what you want to financially settle for. Being totally biased for the Hall, it is probably the simpliest, and cheapest route to a non-precision seismometer I've ever seen. I got virtually all the parts via surplus outlets cheaper than commercial outlets prices. One important note...I'am not very technically qualified for much more than simple details, nor has any effort been made to "go for any max" seismo output, nor any extensive followup on alot of specifics. Operationally the 2 Hall S-G's I have been working well over a year now. Once the pier and mechanics settle down, the adjustments have been infrequent, and often done via the amplifier which is away from the seismometers. The hairest part of building the seismometer is the .002" brass hinges and installing them without crimping/bending them. They need to be thin to flex. Thicker hinges didn't work with the ~3.5 pound mass. None have broken from the weight yet. The eddy current damping of the mass is the most unorthodox feature I use. Its probably overdamped but it works well. This is probably the most difficult part to simulate, but with neodymium magnets and certain aluminium, or copper plates it can be done. Its probably easier to do so on a hanging pendulum like this as the movement is so slight, than if it were a normal gatehinge type seismo. The Hall S-G's don't seem to have the range as the Sprengnether coil and magnet affairs. To be fair though, the Sprengnethers do have huge signal generating coil magnets. Being as I have to operate in a city environment....they do very well overall. Big quakes can saturate the Halls output on the SDR program. Roughly 4000 bits is about the limit with the Allegro 3515, but the 3503 could possibly extend this limitation to perhaps twice that capacity; as it has roughly half the sensitivity. The Hall circuit shouldn't be construed as being only useful in a S-G. I've used one on a horizontal Sprengnether for a day or two, and with the Allegro 3503, it did well, as a additional output besides only the coil/magnet output. For its lesser movement range, the seismometer has to be mechanically stable and on a seasoned pier. For all practical purposes the Hall circuit could even serve as a zero point indicator with other sensors on the same seismo; if one wished to do so. Robert Lamb did very well developing this circuit; its a very good one. > Any comments anyone has would be appreciated. > Jim Allen > Cerritos, California Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: RADIOTEL@....... Date: Sun, 13 Feb 2000 22:09:08 EST Meridith Lamb I appreciate the extensive infomation you provided regarding the hall sensor. I have built a STM-8 basic seismo which is presently configured as a coil magnet unit (4 sec. period) since I am not presently skilled enough to tackle the electronics that Sean-Thomas's unit require. I previously exchanged e-mail with Sean-Thomas regarding using the traditional SG electronics with the STM-8 of which he was encouraging for me to try. However, it sounds like the hall effect approach would be almost a natural for this use and especially for someone with very limited electronics skills. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: Norman Davis WB6SHI wb6shi@........ Date: Sun, 13 Feb 2000 20:00:29 -0800 I was just on his page and find no link to an sg... what is the url. > > >RADIOTEL@....... wrote: > >> Meredith, et all >> >> I recently visited Meredith Lambs's web page and viewed his SG seismo with a >> hall effect sensor. Is the SG with hall effect sensor as sensitive as the >> original SG configuration? > Norman M. Davis WB6SHI Shingle springs, CA mailto:wb6shi@........ http://www.directcon.net/normd/index.htm ICQ: 7192318 How to Know God... http://www.harvest.org/knowgod/index.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: meredith lamb mlamb1@.......... Date: Sun, 13 Feb 2000 22:55:31 -0800 Norman Davis WB6SHI wrote: > I was just on his page and find no link to an sg... what is the url. > > > > > > >RADIOTEL@....... wrote: > > > >> Meredith, et all > >> > >> I recently visited Meredith Lambs's web page and viewed his SG seismo > with a > >> hall effect sensor. Is the SG with hall effect sensor as sensitive as the > >> original SG configuration? > > > > Norman M. Davis WB6SHI Shingle springs, CA > mailto:wb6shi@........ > http://www.directcon.net/normd/index.htm > ICQ: 7192318 > How to Know God... http://www.harvest.org/knowgod/index.htm > Hi Norman, All of the Hall denoted stuff is the S-G referenced: http://www.geocities.com/ResearchTriangle/Facility/1739/index.html Isn't that a horrible long address.....ha. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SG SEISMO WITH HALL EFFECT SENSOR From: meredith lamb mlamb1@.......... Date: Sun, 13 Feb 2000 23:43:44 -0800 RADIOTEL@....... wrote: > Meridith Lamb > I appreciate the extensive infomation you provided regarding the hall sensor. > I have built a STM-8 basic seismo which is presently configured as a coil > magnet unit (4 sec. period) since I am not presently skilled enough to tackle > the electronics that Sean-Thomas's unit require. I previously exchanged > e-mail with Sean-Thomas regarding using the traditional SG electronics with > the STM-8 of which he was encouraging for me to try. However, it sounds like > the hall effect approach would be almost a natural for this use and > especially for someone with very limited electronics skills. > Jim Allen > Cerritos, Calif. > Jim, If I read you correctly in regard to using the Hall on the STM-8 frame, that will be most interesting to see how well it does, besides helping elevate the electronics experience somewhat. I also lack a lack a heck of a lot of experience....its just the way it is. I've never tried it on a vertical yet, but I think you will see a more interesting increased "period". One could also use a dual approach here, to make it even more interesting. Simply leave the coil/magnet as is, because it will sense the nearby quakes P & S waves well. After building the circuit, add a very light extension on the same seismo end for the Hall circuit; and that way you can get kind of both worlds, the near by quakes and some more teleseisms you wouldn't normally see very well with the coil/magnet. Suggest building the circuit and getting used to it via a tempory route of wires and hand manipulating of the magnet near and far and from side to side. It takes awhile to get used to it, as its different than a straight amplifier where one only adjusts the gain, filter or etc. Of course on your seismo the Hall would be mounted on the boom, with the 4 pole magnet on the base frame. To be honest.....(ha), I've shorted out more than just afew diodes and capacitors with the wrong polaritys. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehaman boom position From: "D. Hill" n0ssy@.......... Date: Mon, 14 Feb 2000 13:30:56 -0700 I was adjusting my Lehman and got wondering about something. How should the boom be set? Should it be level or should it have a slight downward drop at the at the mass end. If there were a drop at the mass then it would seem that re-adjustments would be less frequent. And as the movement of the base is what produces the wave forms then it would seem that as long as the boom did not touch any of the sensing/supporting hardware then there should not be difference in it's performance. Any comments from anyone? Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Microbargraph From: Peter & Beth pho@........... Date: Mon, 14 Feb 2000 20:57:00 -0500 Has anyone tried to build the Neher micorbargraph as seen in: http://www.sciam.com/1998/0598issue/0598amsci.html I'm wondering about the frequency response and the effects of varying air pressure. Peter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lehaman boom position From: ted@.......... Date: Tue, 15 Feb 2000 09:17:19 -0500 I have always had the best luck adjusting the boom so it makes a 90 degree angle with the upright support. Then adjust the entire base assembly to get the period correct (which means you tilt the base so the base and boom make the same slight angle off of vertical). You are correct that the mass end should be slightly lower, but make this happen by adjusting the leveling screws on the base. Regards, Ted "D. Hill" on 02/14/2000 03:30:56 PM Please respond to PSN-L Mailing List To: PSN cc: Subject: Lehaman boom position I was adjusting my Lehman and got wondering about something. How should the boom be set? Should it be level or should it have a slight downward drop at the at the mass end. If there were a drop at the mass then it would seem that re-adjustments would be less frequent. And as the movement of the base is what produces the wave forms then it would seem that as long as the boom did not touch any of the sensing/supporting hardware then there should not be difference in it's performance. Any comments from anyone? Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Gravimeter used as a vertical motion seismograph? From: RLLaney@....... Date: Tue, 15 Feb 2000 12:07:23 EST Hello all: A friend who is interested in amateur seismology send me a copy of the article "Detecting Extraterrestrial Gravity" from the Amateur Scientist, Scientific American, January 2000. The device measures the gravitational pull of the Sun and Moon and was built by Roger Baker of Austin, Texas who claims it cost less than $100 to build. Baker originally designed the device as a vertical-motion seismograph. My friend has two questions: 1) Could this article be like the one describing the ADXL05 sensors in SA a couple years ago where the readers were mislead into believing that the sensors would work for detecting distant earthquakes, that is, another device that doesn't quite measure up as advertised? 2) More important, could this device be modified back for use as a reasonable vertical-motion seismograph? Would appreciate hearing from anyone who has seen the article and/or is familiar with this device. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Microbarograph ?? From: ChrisAtUpw@....... Date: Tue, 15 Feb 2000 14:20:46 EST From experiments on capacities for gliding applications, you can expect the 'response time' of the gas in a 1 L bottle to changes in the wall temperature to be of the order of 1.5 to 2 minutes. The response to external pressure changes will be limited by the mass of the fluid in the column, by it's viscosity which is also strongly temperature dependant and by the forth power of the bore of the tube. I would expect the response rate to be limited to small fractions of a Hertz. For every 1 C Deg change in the bottle temperature, the internal pressure changes by about 3.5 milli Bar. To be able to measure pressure changes of the order of micro Bars, would require temperature tracking of the whole bottle to milli degree level. How stable is your external air temperature? The first thing that you notice when observing microbarograph traces are the large fluctuations in pressure due to wind and air turbulence. In looking for pressure changes, the sluggish response of the manometer will be beneficial here, but what do you actually want to measure? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Gravimeter used as a vertical motion seismograph? From: GeE777@....... Date: Tue, 15 Feb 2000 14:25:16 EST In a message dated 2/15/00 9:08:13 AM Pacific Standard Time, RLLaney@....... writes: > Baker originally designed the device > as a vertical-motion seismograph. > > My friend has two questions: > > 1) Could this article be like the one describing the ADXL05 sensors in SA a > > couple years ago where the readers were mislead into believing that the > sensors would work for detecting distant earthquakes, that is, another > device > that doesn't quite measure up as advertised? > > 2) More important, could this device be modified back for use as a > reasonable vertical-motion seismograph? > > Would appreciate hearing from anyone who has seen the article and/or is > familiar with this device. > Hello I have made a gravitymeter from a vertical seismometer. Basically, I use dc voltage to lift (or lower) the coil to the stop or the maximum travel position. Then the DC voltage is removeed and the voltage generated by the coil coming to rest is measured. The farther the coil travels to come to the resting position the higher the voltage. Other geophones are in the circuit to reduce normal seismic noise. I am still testing this circuit for sensitivity. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Gravimeter used as a vertical motion seismograph? From: Roger Baker rcbaker@............. Date: Wed, 16 Feb 2000 13:27:09 -0600 Well, actually I designed the Hi-Q seismo, referenced in this article, and I am also a member of this list, although it has been awhile since I last posted. One of my interests up until about a year ago was in hacking better seismograph and geophysical instrument designs, and these have resulted in easily-built designs for a microbariograph, the Hi-Q vertical, a taught wire suspension Bennioff force-feedback horizontal built with a glass and silicone frame published in the Society for Amateur Scientist's Bulletin, and a strong motion sensor now in the possession of Larry Cochrane. I think these designs are in the PSN archives. I believe my Hi-Q design is sound and easily built, and there is a chart of a teleseismic detection on my web page. As always, I invite others to verify my work cited at http://www.eden.com/~rcbaker The original concept for my magnetic suspension vertical (Hi-Q) was based on the fact that the virtue of a force feedback vertical is a function of its "Q", and inversely proportional to damping losses, which obscure slow,low amplitude motion. Magnetic spring suspensions using ceramic magnets take minutes to come to rest, unlike most metal spring arrangements. And so I used this physical novelty as the instrumental basis for my compact magnetic force feedback design. It did introduce the additional complexity that most magnets are pretty temperature sensitive. The Hi-Q is quite good, in my opinion, as a vertical seismo, but just passable as a gravimeter because gravimeters must by nature be highly resistant to slow temperature variations and creep in order to see the slow and very minor fluctuations in gravity caused by earth tides. Therefore, the temperaure sensitive parts of the electronics should be placed inside the isothermal enclosure, and probably the vertical rigidity of the insulated styrofoam enclosure should be improved further so that earth tides are not seen so much as fluctuations on slow background change due to creep -- unless your central heating system is unusually good. The basic instrument strategy is that you should add just enough feedback force to push the optical sensor back into its linear central sensing zone, and then amplify and slow-filter this till you are satisfied with the seismic or gravimetric results, whichever you want to study. It is obvious from the postings of Meridith Lamb on his Hall effect seismo that the selection of workable displacement sensors for seismographs is wider than commonly supposed. It should be obvious from the cantilever sensors of atomic force microscopes that optical sensors can detect displacements down to sub-atomic dimensions. So far as I know, capacitance micrometers are the most ultimately sensitive displacement detectors hackable by amateurs (see the work by R.V. Jones about 1973 in the British Journal of Physics, Scientific Instrument series), although optical sensors are cheap and small and easy to build from Radio Shack parts. I published a hack of a capacitance micrometer from Radio Shack parts in the SAS bulletin a few years ago. (The last issue of SAS described a super-sensitive technique for the detection of trace organics. My next Science Hacker column will be a description of progress in building an amateur vibrating probe scanning microscope, using tiny mica flakes as reflective cantilevers). --Yours, Roger Baker At 12:07 PM 2/15/00 EST, RLLaney@....... wrote: >Hello all: > >A friend who is interested in amateur seismology send me a copy of the >article "Detecting Extraterrestrial Gravity" from the Amateur Scientist, >Scientific American, January 2000. The device measures the gravitational >pull of the Sun and Moon and was built by Roger Baker of Austin, Texas who >claims it cost less than $100 to build. Baker originally designed the device >as a vertical-motion seismograph. > >My friend has two questions: > >1) Could this article be like the one describing the ADXL05 sensors in SA a >couple years ago where the readers were mislead into believing that the >sensors would work for detecting distant earthquakes, that is, another device >that doesn't quite measure up as advertised? > >2) More important, could this device be modified back for use as a >reasonable vertical-motion seismograph? > >Would appreciate hearing from anyone who has seen the article and/or is >familiar with this device. > >Bob Laney >Herndon, VA > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: boom angle of horiz seis From: S-T Morrissey sean@........... Date: Tue, 15 Feb 2000 13:59:41 -0600 (CST) Dewayne, You ask about the proper angle of the boom of a horizontal seismometer. This has to do with the restoring force that makes it swing back to center. This force is a portion of gravity, namely g*sine(i), where i is the angle with respect to the horizontal, measured in radians. In the case of a SG, the boom is vertical, but horizontal in the Lehman design. There it is generally assumed that the boom support is adjusted so the boom is parallel to the base, so the base angle adjusts the period. IF the boom is exactly horizontal, it will experience NO gravitational restoring force, so it will swing back and forth aimlessly. If the mass end is lowered slightly, it will swing in a shallow curve in the gravitational field, with the minimum being at the bottom or center of the swing. Here is a repeat of the calculation of the actual numbers you can expect: SO ... Lets consider some formulae of interest for the horizontal pendulum: (assuming that the restoring force by the hinges and/or pivot are minimal): The natural period: Tn = 2*pi*sqrt(L/(g*sine i)) where L is the boom length in cm, g=980cm/sec^2, i is the angle that the boom makes wrt the horizontal, (if i is measured in radians, (360 degrees = 2*pi radian, or 1 radian = 57.3 degrees), and i is small, sine i = i). For example, a 40 cm boom hanging vertically (mass at the bottom) as a simple tick-tock pendulum ( an SG design at an angle of 90 degrees) has a period of 1.3 seconds. (a one second clock pendulum is 24.8 cm). But the pendulum supports or hinges can be arranged in a "garden gate" configuration as is the Lehman and most long-period horizontals. When tilted horizontally to about 4 degrees, the period is 5 seconds. At about a 1 degree ((2*pi/360) radian) angle, it is 10 seconds, and at about 0.23 deg. it is 20 seconds. However, if we increase the boom length by times 4 to 160cm, (an impractical 60 inches), we also get a period of 20 seconds. So the period is changing with the square root of the boom length as well as the inverse of the square root of the angle the boom makes with the horizontal. In general, a practical boom length is 10" to 15", with a baseplate of 15" to 24" long and about half as wide at the leveling end (for a horizontal; leveling for a vertical, as shown above, is nowhere as critical, and 4" to 8" widths are workable). It is important to note that the size of the mass determines nothing of the period or sensitivity to tilting. Any reasonable size will work; larger is better for overcomming any torque of the hinges or flexures, to the point where the mass/boom structure begins to distort any part of the suspension. (THe size of the mass IS a factor in a VBB fedback system). The total mass of the boom should be less than 10% of the main mass, which includes the sensor coils. The tilt sensitivity of a seismometer is therefore a function of the square of the operating period Tn. For a HORIZONTAL: (where z is the displacement, and phi is the tilt) z = (g * Tn^2 / 4 * pi^2) * phi For a VERTICAL: z = (g * Tn^2 / 8 * pi^2) * phi^2) (vertical) Note the vertical sensor responds to the SQUARE of the tilt. BUT .. Since the angle is always small and less than 1, the square of a small angle (measured in radians) is smaller than the original number. So conversely the horizontal is MORE sensitive to tilt of the base (at a right angle to the boom) by the square of the tilt angle. SO what does this mean in comparing the tilt noise of a vertical compared with a horizontal of the same period. Suppose the seis is in a corner of the garage or basement. Then suppose that when you walk up to the site you deflect the floor by 1 micron (10^-6 meter) when you are 1 meter away (Or your neighbor parks his Humvee 100 meters away and deflects the neighborhood by 0.1 millimeter.) In both cases the tilt is delta(L)/L or 10^-6 radian. So if your horizontal seis has a period of 10 seconds, the mass will offset 24.8 microns. This is a large number; the 6-second microseisms run about 2 to 4 microns. HOWever: if you have a vertical seis, the displacement from a 10^-6 tilt is 10^-6th of the horizontal. Conversely, it takes a floor deflection if 1mm at 1 meter distance to get the same 24.8 microns movement on a vertical. So when you push the operating period from 10 to 20 seconds, the tilt sensitivity increases by 4. Even a modest period increase demands a good site for the instrument. The WWNSS (worldwide network of standard seismographs) originally tried to operate the long period sensors at 30 seconds, but so many were always at the stops that they backed off to 15 seconds as the standard. You can test the tilt sensitivity using your leveling screw, which I guess is something like 40 threads/inch. In the above formula, "phi" is the angle in radians, so if you turn the screw one turn and if the base support width is 10 inches, the tilt is 1/40" divided by 10", or 0.0025 radians. Using the formula above for a horizontal sensor: The displacement then is 0.062cm times the square of the period. If Tn is 10 seconds, it is 6.2cm; if Tn is 100 seconds, one turn of th 40 tpi screw will try to move the boom 620 cm. Even if 1/100 turn can be used, the displacement is still quite large. THis is why VBB instruments have a feature that allows a shorter period to be switched in for setup at installation, and a motor-driven lever of 100:1 to level the sensor in operation. A typical tilt noise level for the 360-second STS-1 is equivalent to about 6 nanoradians. For practical operation of a home-made VBB, an operating period of 20 to 40 seconds would be preferred. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Gravimeter used as a vertical motion seismograph? From: GeE777@....... Date: Tue, 15 Feb 2000 17:54:23 EST In a message dated 2/15/00 11:29:00 AM Pacific Standard Time, rcbaker@............. writes: > > (The last issue of SAS described a super-sensitive technique for the > detection of trace organics. My next > Science Hacker column will be a description of progress in building an > amateur vibrating probe scanning microscope, using tiny mica flakes as > reflective cantilevers). > > Hello My method is trying to balance such things as heat and unwanted vibrations from geophones that do not have their coils offset by DC voltages by the geophone element with the offset coil. This is simple and I have got it sensitive enough to observe earth tides. I have eight patents for geophones or geophone testing equipment. Most were patented during my occupation with an oil company rersearch department, so the patents belong to them. I now would like to study the effects of local gravity changes as a possible precurser to local seismic events. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: boom angle of horiz seis From: Jack Sandgathe jsandgat@....... Date: Tue, 15 Feb 2000 16:57:13 -0800 Sean Thomas: For me to offer a correction to you sir, is like trying to correst Isaac Newton or someone, but here goes. I think you meant to refer to the hinges being vertical rather than the boom being horizontal. respectfully, Jack Sandgathe At 01:59 PM 2/15/00 -0600, you wrote: >Dewayne, >........IF the boom is exactly horizontal, it will experience NO gravitational restoring >force, so it will swing back and forth aimlessly. If the mass end is lowered slightly, it will >swing in a shallow curve in the gravitational field, with the minimum being at the bottom or center >of the swing. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: boom angle of horiz seis From: "steve hammond" shammon1@............. Date: Tue, 15 Feb 2000 20:36:49 -0800 Jack, Sean, Dewayne, Ted, I have to agree with Jack however in reading between the lines, Sean, I think you said the same thing I'm about to say. This is how I view this problem. Let the upper pivot point be point A, the lower pivot point be B, and the point that the upper guide wire intersects the boom be point C. Align A-B to be vertical at 0 degrees. Adjust the length of A-C so the boom is at a 90 degree angel to A-B. This is the infinite critical point and the boom wanders. If I were to swing the boom left to right for 150-degrees the boom would remain at 90 degrees to A-B because A-C is constant and the length remains unchanged. To create the pendulum effect, I must increase the angel between A and B, let's say by tilting the base 1-degree. One result is that point C is fixed in relation to points A and B and has nothing to do with the period. Points A and B control the period. If I swing the boom 150-degrees again, the relationship of A-B and B-C remain constant. The period is then measured in the time it take to make one full cycle. The pendulum effect is created by the angel between A-B not the dip in C. I can prove this to you. If I use a bubble level and a turnbuckle between points A-C and level my boom in relation to the ground, my angel in relation to A-B is now 89-degrees to compensate for the 1-degree tilt however the period remains constant and is unchanged regardless of where I position point C. So you say, why does it work better for some systems to adjust the boom slightly lower as in Ted's case. Well, I happen to know Ted, and his system (the last time I checked) uses a knife edge on his boom. It is the critical contact point and if the stop block is perfectly aligned with the boom then the angel between A-B and B-C is 90-degrees making the knife edge to block align at 0/0. I use a point and a cup in my system and have found that mine works better when the boom is set level using a bubble level. My 2C worth. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: Jack Sandgathe To: PSN-L Mailing List Date: Tuesday, February 15, 2000 4:57 PM Subject: Re: boom angle of horiz seis >Sean Thomas: > > For me to offer a correction to you sir, is like trying to correst >Isaac Newton or someone, but here goes. I think you meant to refer to the >hinges being vertical rather than the boom being horizontal. > > respectfully, Jack Sandgathe > >At 01:59 PM 2/15/00 -0600, you wrote: >>Dewayne, >>........IF the boom is exactly horizontal, it will experience NO >gravitational restoring >>force, so it will swing back and forth aimlessly. If the mass end is >lowered slightly, it will >swing in a shallow curve in the gravitational >field, with the minimum being at the bottom or center >of the swing. >> > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS clocks From: Phil Schmidt pgschmidt@............... Date: Wed, 16 Feb 2000 22:06:54 +1000 G'day all I was out looking for GPS solutions to provide timing for my future seismic station I can across a few possible websites. The main ones being - http://www.trimble.com/ http://www.garmin.com/ http://www.magellan.com.au/ Trimble offered something of particualr interest and that was the ACE II starter kit information on this particular kit can be found at - http://www.trimble.com/cgi/omprod.cgi/ace2gps.htm Or if your are starting and the main Trimble web page it is under Timing & Synchronization Products. There are other products in this page however this particular kit caught my eye because of it's contents. I have not yet obtained the price for this kit, if someone out there does happen to know please let me know. The Garin website offered a few OEM solution these can be found at the following seb site - http://www.garmin.com/oemSensors.html Another Excellent Web site I can across in my travels was the Datum Web site - http://www.datum.com/ a few pieces of equipment in here that might be of use one is the Starclock and the other the PCI Time and Frequency processor. Starclock info is at - http://www.bancomm.com/cstartime.htm PCI T & F processor is at - http://www.bancomm.com/cbc637PCI.htm The Datum offered plenty of other products for GPS timing and the like as well. Hope this information is of some use to others out there please let me know if prices of any products are determined. Philip Schmidt Australia _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: GPS clocks From: "Francesco" franuc@...... Date: Wed, 16 Feb 2000 12:40:13 +0100 Why not Motorola Oncore? Look at PSN web page about GPS kit and his use with SDR software It works very well. Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: more horizontal seis boom angle From: S-T Morrissey sean@........... Date: Wed, 16 Feb 2000 13:21:07 -0600 (CST) Jack, I believe that what I said and what you said are correct: if the boom is horizontal, the hinges must be vertical. This, of course, is in describing the horizontal pendulum configuration, also called the "garden gate" design, as is the Lehman horizontal seis. This is the common configuration for classic long-period horizontal seismometers, as well as some modern broadbands such as the STS-1. (Other VBBs use an inverted pendulum design, where the hinge is horizontal and at the bottom of the boom, the boom is vertical, and the mass is at the top: the hinge provides some restoring force, but with a practical mass, this is inherently unstable, but OK for a fedback instrument). Regarding Steve's question about the angles: For simplicity the horizontal pendulum has always been designed so that the boom and the hinge axis (either upper/lower pivots or more continuous flexures) are at right angles. This then makes the angle of the boom with respect to the horizontal the same as the angle of the axis of rotation with respect to the vertical, so only one variable angle is involved, which greatly simplifies the mathematical description of the pendulum. The angle of the boom and therefore the period can then be adjusted by tilting the base or frame along the axis of the boom, which is usually an external adjustment so the cover does not have to be removed. (The boom is often also designed to be parallel to the base or frame, which facilitates the alignment of magnets, coils, and transducers.) However, Since the boom or axis angle is small, sine(i) = i (radians), and the natural period Tn = 2*pi*sqrt(L/(g*i)). As i gets very small, the period gets very large. Actually, there is usually a small restoring moment from the hinges or pivot wires, so the boom may stay at equilibrium even if perfectly level. Obviously, if the mass end is raised up so that the boom slopes down toward the lower pivot, it will flop over to one side. At the other extreme, if the boom is vertical and hangs straight down from the hinges, it is a simple pendulum, as in the SG design. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: boom angle of horiz seis From: ted@.......... Date: Wed, 16 Feb 2000 16:40:28 -0500 Good memory, Steve! My original Lehman (long since gone, donated to Yamato High School in Japan) used a knife-edge which required perfect adjustment in order for the entire knife edge to contact the base. this adjustment was made via the turnbuckle in the middle of the suspension wire. The other newer designs are far superior but it worked well for a long time. Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: boom angle of horiz seis From: "steve hammond" shammon1@............. Date: Wed, 16 Feb 2000 21:31:31 -0800 Hi Ted, well there is proof, the mind does go first... Now I remember that you did donate that system to the American School in Tokyo. What year was that? 93? At least I still remembered it had a knife edge. Have a good day-- Regards, Steve PSN Aptos, California -----Original Message----- From: ted@.......... To: PSN-L Mailing List Date: Wednesday, February 16, 2000 1:48 PM Subject: Re: boom angle of horiz seis > > >Good memory, Steve! My original Lehman (long since gone, donated to Yamato >High School in Japan) used a knife-edge which required perfect adjustment >in order for the entire knife edge to contact the base. this adjustment >was made via the turnbuckle in the middle of the suspension wire. The >other newer designs are far superior but it worked well for a long time. > >Regards, Ted > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more horizontal seis boom angle From: "steve hammond" shammon1@............. Date: Wed, 16 Feb 2000 22:03:50 -0800 Sean-Thomas, BTW, I take great interest in your formulas, I find them very informative. But I keep coming up with more questions as I think more about the problem. For example, where is the end of the boom? In my case, the boom is 38 1/4-in long tip to tip. I use a 1/4-copper plate for damping and it hang on a L-bracket at the at the end. At the 32-inch point, the upper wire intersects the boom. The coil and magnet are mounted at the 24 3/4-inch point. So in your equation, L=which point? The end of the boom or the intersection point where the guide wire is mounted? Regards, Steve Hammond PSN Aptos, California > >Regarding Steve's question about the angles: > >For simplicity the horizontal pendulum has always been designed so >that the boom and the hinge axis (either upper/lower pivots or more >continuous flexures) are at right angles. This then makes the angle >of the boom with respect to the horizontal the same as the angle of >the axis of rotation with respect to the vertical, so only one variable >angle is involved, which greatly simplifies the mathematical description >of the pendulum. The angle of the boom and therefore the period can then >be adjusted by tilting the base or frame along the axis of the boom, which >is usually an external adjustment so the cover does not have to be removed. >(The boom is often also designed to be parallel to the base or frame, which >facilitates the alignment of magnets, coils, and transducers.) > >However, Since the boom or axis angle is small, sine(i) = i (radians), >and the natural period Tn = 2*pi*sqrt(L/(g*i)). As i gets very small, >the period gets very large. Actually, there is usually a small restoring >moment from the hinges or pivot wires, so the boom may stay at equilibrium >even if perfectly level. Obviously, if the mass end is raised up >so that the boom slopes down toward the lower pivot, it will flop over >to one side. At the other extreme, if the boom is vertical and hangs >straight down from the hinges, it is a simple pendulum, as in the SG design. > >Regards, >Sean-Thomas > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more horizontal seis boom angle From: Jim Hannon jmhannon@........ Date: Thu, 17 Feb 2000 05:58:11 -0600 At 10:03 PM 2/16/00 -0800, you wrote: >Sean-Thomas, BTW, I take great interest in your formulas, I find them very >informative. But I keep coming up with more questions as I think more about >the problem. For example, where is the end of the boom? In my case, the boom >is 38 1/4-in long tip to tip. I use a 1/4-copper plate for damping and it >hang on a L-bracket at the at the end. At the 32-inch point, the upper wire >intersects the boom. The coil and magnet are mounted at the 24 3/4-inch >point. So in your equation, L=which point? The end of the boom or the >intersection point where the guide wire is mounted? >Regards, Steve Hammond PSN Aptos, California > Steve, The description of the "end of the boom" make the assumption that there is a right angle between the line formed by the upper and lower pivot points and the boom. This mainly just simplifies talking aout the arrangment. The important parameter is the vertical alignment of upper and lower pivot points. The line formed by the upper and lower pivot points must tip slightly toward the end of the boom or the mass. Then if there is a right angle between the pivot line and the line defined by the boom you can say that the boom has to be tipped down slightly. How the mass is distributed at the end of the boom really doesn't make a lot of difference. Talking about the position of the end of the boom causes some confusion in that it leads you to think (for example) that by adjusting the length of the supporting wire you can adjust the period. It may have some effect but the real adjustment is the angle of the line formed by the pivot points. That is why the period is adjusted by the leveling screws in the base of the insrument. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more horizontal seis boom angle and 'L' From: ChrisAtUpw@....... Date: Thu, 17 Feb 2000 13:08:13 EST In a message dated 17/02/00 05:57:02 GMT Standard Time, shammon1@............. writes: >> I keep coming up with more questions as I think more about the problem. For example, where is the end of the boom? In my case, the boom is 38 1/4-in long tip to tip. I use a 1/4-copper plate for damping and it hangs on a L-bracket at the at the end. At the 32-inch point, the upper wire intersects the boom. The coil and magnet are mounted at the 24 3/4-inch point. So in your equation, L=which point? The end of the boom or the intersection point where the guide wire is mounted? Regards, Steve Hammond PSN Aptos, California >> In a Lehman 'garden gate' system, the distance 'L' is measured from the HINGE LINE to the 'CENTRE OF GRAVITY' of the whole weight + boom system. If you have a heavy weight and a very light boom and the boom is mounted at right angles to the hinge line, it will be roughly the distance from the hinge line to the CENTER of the weight. With a more complicated system having a heavy boom, a magnet and a weight, you need to take the boom off and holding it horizontal, find the point where it just BALANCES over a horizontal knife edge. You can usually get a rough estimate by balancing it over your finger. L is then the horizontal distance from the balance point to the hinge line at the end of the beam. So long as the beam makes and angle of 90 +/- 8 Degrees with the hinge line, the error is < 1%. [Otherwise you have to calculate the length of the perpendicular from the actual hinge line to the centre or mass.] I hope that this makes it clear. Chris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Ranger seismometers for sale. From: Edward Cranswick cranswick@........ Date: Thu, 17 Feb 2000 15:54:58 -0700 Chris Sanders I have just forwarded your message to the email listserver of one of the Public Seismic Network websites . Good luck! -Edward Chris Sanders wrote: > Hi Ed, > > David Oppenhemier in Menlo Park gave me your e-mail address as a person who > might be able to help me. I believe that we may have met sometime in the > past when I still worked in seismology. Here's what I wrote to David: > > ======= > I have three Ranger seismometers (single component, 1 Hz, excellent > condition, with adjustable legs, and carrying case) that want to sell > at a half price and I am looking for contacts > who might be interesting purchasing them. Any leads you have will be > appreciated (you can pass this email along to them). > ======= > > I would appreciate any information you might have about potential buyers. > David said that you have contacts with the People's Seismic Network. > > Thanks, > > -Chris Sanders > > PS: I was a research seismologist for many years, however recently I jumped > into another field and am a Microsoft employee. That's why I have the > seismometers and why I have them for sale. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: more horizontal seis boom angle and 'L' From: "steve hammond" shammon1@............. Date: Thu, 17 Feb 2000 21:02:01 -0800 Jim Chris, The center balance point is 28.5-inches. I'll be re-installing both of Lehman's in the next few months and measure the natural period then. Thanks for the answers. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: ChrisAtUpw@....... To: psn-l@.............. Date: Thursday, February 17, 2000 10:08 AM Subject: Re: more horizontal seis boom angle and 'L' >In a message dated 17/02/00 05:57:02 GMT Standard Time, >shammon1@............. writes: >>> I keep coming up with more questions as I think more about the problem. >For example, where is the end of the boom? In my case, the boom is 38 1/4-in >long tip to tip. I use a 1/4-copper plate for damping and it hangs on a >L-bracket at the at the end. At the 32-inch point, the upper wire intersects >the boom. The coil and magnet are mounted at the 24 3/4-inch point. So in >your equation, L=which point? The end of the boom or the > intersection point where the guide wire is mounted? Regards, Steve Hammond >PSN Aptos, California >> > > In a Lehman 'garden gate' system, the distance 'L' is measured from the >HINGE LINE to the 'CENTRE OF GRAVITY' of the whole weight + boom system. If >you have a heavy weight and a very light boom and the boom is mounted at >right angles to the hinge line, it will be roughly the distance from the >hinge line to the CENTER of the weight. With a more complicated system having >a heavy boom, a magnet and a weight, you need to take the boom off and >holding it horizontal, find the point where it just BALANCES over a >horizontal knife edge. You can usually get a rough estimate by balancing it >over your finger. L is then the horizontal distance from the balance point to >the hinge line at the end of the beam. So long as the beam makes and angle of >90 +/- 8 Degrees with the hinge line, the error is < 1%. [Otherwise you have >to calculate the length of the perpendicular from the actual hinge line to >the centre or mass.] > > I hope that this makes it clear. Chris > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MAILING LIST From: "Francesco" franuc@...... Date: Tue, 22 Feb 2000 20:10:13 +0100 From some days I don't reicive any messages from PSN mailing-list. Some problem? Francesco
From some days I don't reicive any = messages from=20 PSN mailing-list.
Some problem?
 
Francesco
Subject: Re: MAILING LIST From: steph@.................. Date: Tue, 22 Feb 2000 14:16:35 -0500 Your mail was delivered to Steph. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS Software From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Tue, 22 Feb 2000 18:26:52 -0500 This is a little off topic, but someone posted a link to a site that had software for the Motorola Oncore VP GPS unit (the one used as a time base for Larry's Seismometer software.). I want to us it to test my wiring. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GPS Software From: steph@.................. Date: Tue, 22 Feb 2000 18:28:12 -0500 Your mail was delivered to Steph. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Magnet finish coatings? From: meredith lamb mlamb1@.......... Date: Wed, 23 Feb 2000 14:59:42 -0800 Hi all, Curiosity question here. I've wondered what coatings of metal are applied to alot of neodymium magnets. I've heard that its first copper, then nickel, then if desired very thin gold or rhodium which is kind of dull gray in appearance? Or, is it some other concoction? Another version I've heard is nickel first, then if desired other metals? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Large Event Comming In From: peaches@............ (Donna Whitaker) Date: Thu, 24 Feb 2000 16:17:14 -1000 (HST) This is from the Palmer Alaska Tsunami Warning center: http://lumahai.soest.hawaii.edu/tsunami.html TO ALL TSUNAMI WARNING SYSTEM PARTICIPANTS INFO KWBC/NWS COM CENTER ONLY, NO RELAY REQUIRED UNCLAS TSUNAMI BULLETIN NUMBER 1 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED FEB 25 AT 0210 UTC ....THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 6.8, OCCURRED AT 1644 AST ON FEB 24, OR 1744 PST ON FEB 24, OR 0144 UTC ON FEB 25. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: VANUATU ISLANDS REGION NEAR 19.5S, 174.0E. THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE A TSUNAMI INFORMATION BULLETIN FOR HAWAII AND OTHER AREAS OF THE PACIFIC. EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS WARRANT. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: sdi support for nudaq acl-8112pg From: Norman Davis WB6SHI wb6shi@........ Date: Mon, 28 Feb 2000 13:14:21 -0800 Is anyone using a acl-8112pg a/d card for sdi or is it supported? Norman M. Davis WB6SHI Shingle springs, CA mailto:wb6shi@........ http://www.directcon.net/normd/index.htm ICQ: 7192318 How to Know God... http://www.harvest.org/knowgod/index.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: log amplifiers ?? From: angel rodriguez angel@............ Date: Wed, 1 Mar 2000 15:10:48 -0500 Hello S-T, Tuesday, August 03, 1999, 2:55:35 PM, you wrote: STM> Angel, STM> Regarding your other questions: STM> 1: The current folder of drawings and schematics weighs about 6 ounces. STM> If you send the proper postage to get it to you, I will provide the STM> envelope. I can also provide 1 meter or so of hinge material (0.005" STM> bronze, 0.75" wide). STM> 2: Many have experimented with logrithmic amplifiers to expand the STM> dynamic range of seismic recording. The problem is how to deal with STM> the negative side of the signal. Many schemes of the "invert and add" STM> idea have been tried to handle the bi-polar analog signal, sometimes STM> even developing two log-scaled outputs. These still have problems with STM> low level signals, like near zero voltage. STM> The only successful compression of seismic data has been gain-ranging, STM> where a comparator senses a large signal and knocks down the gain of the STM> amplifier by 1/10 and keeps it there for a duration much longer than STM> the event. Software can find the gain step and restore the gain. Multiple STM> gain-ranging has also worked. It has not been without problems, like STM> dealing with the transient at the gain step. Often it is done at the STM> ADC converter, where the n-bit mantissa is scaled by augmenting the STM> exponent by the inverse of the programmable gain amplifier. Modern STM> 24-bit EDME digitizers avoid the problem altogether for a price. STM> But this means digital telemetry, with all its complications. So STM> multi-level, multi-channel, (40 db separation) analog FM telemetry is STM> the simplest solution. STM> Regards, STM> Sean-Thomas STM> _____________________________________________________________________ STM> Public Seismic Network Mailing List (PSN-L) STM> To leave this list email listserver@.............. with the body of the STM> message: leave PSN-L Hi Sean-Thomas, Greeting from Panama. I will ge going back up to the US in about two weeks and was wondering if you have had a chance to rounf up the materials you mentioined above. I had Susan Kopicki a friend of mine send you a check ($5.00) for postage back in August of 99. The address again in case you miss placed it is: Angel Rodriguez 7318 Linden Ave No. Seattle, WA. 98103 Warmly, angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: using up bandwidth From: angel rodriguez angel@............ Date: Wed, 1 Mar 2000 15:22:53 -0500 Hello all, OOops! Sorry about the last message, it was ment for Sean-Thomas. Warmly angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Log scaling From: Jack Ivey ivey@.......... Date: Thu, 02 Mar 2000 16:20:42 -0500 Has anyone tried to use mu-law or a-law digitizers for seismic use? These schemes are used for telecom applications to compress high dynamic range signals without the sign and zero problems of logs. Jack Ivey KB8SPI _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New mail server From: "Larry Cochrane" cochrane@.............. Date: Fri, 03 Mar 2000 01:26:44 -0800 All, Do too a spammer hijacking my mail server to relay spam email I had to upgrade my mail server to one that will not relay email. More info later.... Currently email to my personal account (cochrane@............... and hopefully this list are working. Also, archiving of this list should be working. What I don't have working yet is the event file archiving, so email to event@.............. (or event@............... is not working. The new email server I am using is different so I need to change how the automatic archiving of event files works. I should have this working in a few days. This also means that the NewFile and NewEvent lists are not. Regards, Larry Cochrane Redwood City PSN ___________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: nudaq cards? From: Norman Davis WB6SHI wb6shi@........ Date: Fri, 03 Mar 2000 15:21:07 -0800 is anyone out there using a nudaq card with sdr or emon? not having much luck with sdr... Norman M. Davis WB6SHI Shingle springs, CA mailto:wb6shi@........ http://www.directcon.net/normd/index.htm ICQ: 7192318 How to Know God... http://www.harvest.org/knowgod/index.htm ___________________________________________________________ Public Seismic Network Mailing List (PSN-L) leave-l ___________________________________________________________ Public Seismic Network Mailing List (PSN-L) LEAVE PSN-L ___________________________________________________________ Public Seismic Network Mailing List (PSN-L) Has NASA landed any seismo equipment on Mars? A comet is going to fly past Mars in March. http://www.astroarts.com/comets/2000/0076P/java-orbit.html Be interesting to know if the equipment could detect any movement caused by the comet. ___________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: test From: Larry Cochrane larry_cochrane@.............. Date: Sat, 04 Mar 2000 21:11:01 -0800 test message Subject: test From: Larry Cochrane larry_cochrane@.............. Date: Sat, 04 Mar 2000 21:21:51 -0800 test message __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: test From: Larry Cochrane larry_cochrane@.............. Date: Sat, 04 Mar 2000 21:26:56 -0800 test message this is a test __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Update on mail server From: Larry Cochrane cochrane@.............. Date: Sun, 05 Mar 2000 00:17:07 -0800 All, I'm still in the process of evaluating email servers. Most of the members of this list received the message below. The mail server I used to send out my last message has some prolems so I am trying a new one. What a pain.... -Larry Last email message: Do too a spammer hijacking my mail server to relay spam email I had to upgrade my mail server to one that will not relay email. More info later.... Currently email to my personal account (cochrane@............... and hopefully this list are working. Also, archiving of this list should be working. What I don't have working yet is the event file archiving, so email to event@.............. (or event@............... is not working. The new email server I am using is different so I need to change how the automatic archiving of event files works. I should have this working in a few days. This also means that the NewFile and NewEvent lists are not. Regards, Larry Cochrane Redwood City PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Update on mail server. event archiving back up... From: Larry Cochrane cochrane@.............. Date: Sun, 05 Mar 2000 21:22:00 -0800 All, It looks like I have everything back to normal, more or less.... This list and the PSN event archive system should be working again, as well as the NewFile and NewEvent lists. If your new to this list PSN stations send their event files, as attachments, to event@............... My system process the email message and places the file(s) on my system so others can download them. There are two event notification mailing lists that send out email messages when a PSN station uploads an event file(s). One is called NewEvent. This list has the event file(s) attached with the new event notification. The other list is called NewFile. This list only has the event file upload notification. It does not have the event file attached with the message so the message is a lot smaller. See http://www.seismicnet.com/maillist.html for more info. If you use the event file archive system please let me know if you run into any problems. Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: thanks to Larry From: S-T Morrissey sean@........... Date: Mon, 6 Mar 2000 13:33:10 -0600 (CST) Larry, Just a note of appreciation for your efforts to maintain a real professional mailing list system. All of us are thankful for your efforts to spare us the servings of SPAM. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A/D and log amp posting From: barry lotz gbl@....... Date: Mon, 06 Mar 2000 17:26:28 -0800 Hi I'll try to send this again since I'm not sure it went thru and it was an interesting converter with possibilities. F.w.i.w.- Crystal (Cirrus Logic) has a 24 bit A/D with a 1x- 64x programmable instrumentation amp and a 4 channel differential input (CS5531/32/33/34) .. It has a reasonable sample rate and serial communication. I'm just getting familiar with the chip at the present time. The channels can be programmed with different sample rates and gains, even for the same sensor. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Radio Shack WWV Clock From: Rick Bitto rbitto@........... Date: Mon, 06 Mar 2000 21:50:52 -0500 Several months ago, I purchased a Radio Shack WWV clock with the intent of sacrificing it to obtain timing signals for Larry's A-to-D board. Unfortunately, I've grown fond of the device - it is the only clock in the house that's accurate! (No one can set the clock 10 or 15 minutes early so they can get to work/school on time) Has anyone fed the timing signal back into the display? If so, could you provide some details? I also just received my JDR Microdevices catalog and they are selling a WWV receiver kit for $34.99. Does anyone have experience with this kit? TIA, Rick Bitto __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: Larry Cochrane cochrane@.............. Date: Mon, 06 Mar 2000 20:07:57 -0800 Rick, At 09:50 PM 3/6/00 -0500, Rick wrote: >Several months ago, I purchased a Radio Shack WWV clock with the intent of >sacrificing it to obtain timing signals for Larry's A-to-D board. >Unfortunately, I've grown fond of the device - it is the only clock in the >house that's accurate! (No one can set the clock 10 or 15 minutes early so >they can get to work/school on time) > >Has anyone fed the timing signal back into the display? If so, could you >provide some details? The Radio Shack clock uses WWVB not WWV. WWVB transmits on one frequency down at 60khz (I think). The problem with sharing the unit with the display and SDR is power drain on the batteries. The display turns the receiver on only when needed. SDR needs the receiver on all of the time. If you power the unit with something other then batteries you should be able to force the receiver on all of the time by grounding the PON line and sharing the output signal between the display and SDR. > >I also just received my JDR Microdevices catalog and they are selling a WWV >receiver kit for $34.99. Does anyone have experience with this kit? Sounds interesting. Can you post some more info on it like what frequency or frequencies it receives etc. -Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: n0cwr@......... Date: Tue, 07 Mar 2000 04:14:45 +0000 I was looking for a replacement for the expensive ICOM receiver I was using for SDR. I did look at hamtronics kit at over 50 dollars. But I found it in a WWV Radio Shack TimeKube that I found on Ebay for about 12 dollars. They were made till about the early 80's but they show up on Ebay periodically and make a great and inexpensive receiver for wwv. They pick up 5, 10 and 15 mhz. I replaced the 9volt battery with an inexpensive 9v p.s. 5mhz signal is receivable here 24hours. Works as well, if not better, than the expensive ICOM receiver. Keyword search (description and text) WWV should show them on Ebay. I have not heard that many good results from the newer type "clock" receivers, and that probably depends more on your location. At 09:50 PM 3/6/00 -0500, Rick Bitto wrote: >Several months ago, I purchased a Radio Shack WWV clock with the intent of >sacrificing it to obtain timing signals for Larry's A-to-D board. >Unfortunately, I've grown fond of the device - it is the only clock in the >house that's accurate! (No one can set the clock 10 or 15 minutes early so >they can get to work/school on time) > >Has anyone fed the timing signal back into the display? If so, could you >provide some details? > >I also just received my JDR Microdevices catalog and they are selling a WWV >receiver kit for $34.99. Does anyone have experience with this kit? > >TIA, > >Rick Bitto > > > > > > > > > > > > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: Rick Bitto rbitto@........... Date: Tue, 07 Mar 2000 21:32:39 -0500 Larry Cochrane wrote: > Rick, > > At 09:50 PM 3/6/00 -0500, Rick wrote: > >Several months ago, I purchased a Radio Shack WWV clock with the intent of > >sacrificing it to obtain timing signals for Larry's A-to-D board. > >Unfortunately, I've grown fond of the device - it is the only clock in the > >house that's accurate! (No one can set the clock 10 or 15 minutes early so > >they can get to work/school on time) > > > >Has anyone fed the timing signal back into the display? If so, could you > >provide some details? > > The Radio Shack clock uses WWVB not WWV. WWVB transmits on one frequency > down at 60khz (I think). The problem with sharing the unit with the display > and SDR is power drain on the batteries. The display turns the receiver on > only when needed. SDR needs the receiver on all of the time. If you power > the unit with something other then batteries you should be able to force > the receiver on all of the time by grounding the PON line and sharing the > output signal between the display and SDR. > You're undoubtedly right, the Radio Shack Owner's Manual should be corrected because it reads - "It automatically updates the clock setting by receiving a 60 kHz longwave radio signal from station WWV......." I was planning to power the clock from the 5 VDC source on your A/D board through the two voltage dropping diodes. If I left the receiver connected to the clock, is the 22K pull-up resistor still required? If so, should the resistor be connected to the 3.8 V line? > > > >I also just received my JDR Microdevices catalog and they are selling a WWV > >receiver kit for $34.99. Does anyone have experience with this kit? > > Sounds interesting. Can you post some more info on it like what frequency > or frequencies it receives etc. > > -Larry Cochrane > Redwood City, PSN > The information in the catalog is pretty sketchy. It does say that it receives the 10 MHz WWV signal. It has a built-in speaker and an audio output jack. It also says that no tuning is necessary. It makes no mention of any required antenna. The catalog number is RK-HFRC-1. An optional case for the receiver is offered for $14.99, catalog number RK-CHRFC. I could not find these items on their web page (www.jdr.com). Rick __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: Rick Bitto rbitto@........... Date: Tue, 07 Mar 2000 21:38:33 -0500 n0cwr@......... wrote: > I was looking for a replacement for the expensive ICOM receiver I was > using for SDR. I did look at hamtronics kit at over 50 dollars. > But I found it in a WWV Radio Shack TimeKube that I found > on Ebay for about 12 dollars. They were made till about the early > 80's but they show up on Ebay periodically and > make a great and inexpensive receiver for wwv. They pick up 5, 10 and > 15 mhz. I replaced the 9volt battery with an inexpensive 9v p.s. > 5mhz signal is receivable here 24hours. > Works as well, if not better, than the expensive ICOM receiver. > Keyword search (description and text) WWV should show them on Ebay. > I have not heard that many good results from the newer type "clock" > receivers, and that probably depends more on your location. Thanks for the info on the TimeKube, I'll start checking Ebay. However, the Radio Shack 'Atomic Clock' that I have does not appear to have any problems locking on to the WWVB signal. Rick __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: "Jan D. Froom" froom@............. Date: Tue, 07 Mar 2000 21:38:47 -0800 An outfit called BRG Precision Products carries these atomic wwwb clocks with pc interface.... I use one on my school system, running windows95 and Ted's EMON program. Currently they say they are out of stock, but check them out at http://www.brgproducts.com/arc30.html Jan An outfit called BRG Precision Products carries these atomic wwwb clocks with pc interface....  I use one on my school system, running windows95 and Ted's EMON program. Currently they say they are out of stock, but check them out at
http://www.brgproducts.com/arc30.html

Jan Subject: Re: Radio Shack WWV Clock From: barry lotz gbl@....... Date: Wed, 08 Mar 2000 19:14:59 -0800 Rick I've been using it for both for several months now. It works fine. I still use the battery for the clock. I haven't changed it yet. I'll read your other postings and also try to remember how I wired it up. It was really simple. Regards, Barry PS It's the only accurate clock in my house also! Rick Bitto wrote: > Several months ago, I purchased a Radio Shack WWV clock with the intent of > sacrificing it to obtain timing signals for Larry's A-to-D board. > Unfortunately, I've grown fond of the device - it is the only clock in the > house that's accurate! (No one can set the clock 10 or 15 minutes early so > they can get to work/school on time) > > Has anyone fed the timing signal back into the display? If so, could you > provide some details? > > I also just received my JDR Microdevices catalog and they are selling a WWV > receiver kit for $34.99. Does anyone have experience with this kit? > > TIA, > > Rick Bitto > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: barry lotz gbl@....... Date: Wed, 08 Mar 2000 19:56:14 -0800 Rick What I did was to use Larry's interface schematic #2 with the 74HC14. I didn't use the led though. The only wires going to the clock display were to DCF and ground. I used the wire pair from a trashed set of head phones. They were fine and fit thru the antenna hole. I connected DCF to pin #1 of the 74hc14 . I left the batteries in. I use the diodes to knock the 5 vts to 3.8 as Larry shows. Barry Rick Bitto wrote: > Several months ago, I purchased a Radio Shack WWV clock with the intent of > sacrificing it to obtain timing signals for Larry's A-to-D board. > Unfortunately, I've grown fond of the device - it is the only clock in the > house that's accurate! (No one can set the clock 10 or 15 minutes early so > they can get to work/school on time) > > Has anyone fed the timing signal back into the display? If so, could you > provide some details? > > I also just received my JDR Microdevices catalog and they are selling a WWV > receiver kit for $34.99. Does anyone have experience with this kit? > > TIA, > > Rick Bitto > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Shortwave Radio From: Stephen & Kathy mortskm@....... Date: Wed, 08 Mar 2000 19:57:17 -0800 All, I happened to notice a "while supplys last" deal for an inexpensive 10 band shortwave radio. $15.99 I don't know why?? But might be worth a chance to find out!! It might work as a WWV source??? We have done buisness with these people and have been treated fairly and haven't been burnt "yet". Check it out at the following: http://www.screaminghotdeals.com/index2.shtml Stephen PSN Station #55 near Pilot Hill Ca __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: Karl Cunningham karlc@....... Date: Thu, 09 Mar 2000 07:51:02 -0800 Rick -- One small thing I'd like to add... I've been using the Radio Shack clock also, and have had good luck with it. I added a "wall wart" type of power supply. Initially, there was a lot of RF coming from the computer running SDR that made WWVB reception almost impossible in that area. So I extended the wire to the antenna to about 30 feet using shielded cable and used an optical isolator between the RS clock and the computer. That did the trick. -- Karl __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack WWV Clock From: Rick Bitto rbitto@........... Date: Thu, 09 Mar 2000 17:23:10 -0500 Barry, Karl, et al, Thanks for all your experiences and comments, I hope to start experimenting this weekend with the clock. Rick Karl Cunningham wrote: > Rick -- > > One small thing I'd like to add... I've been using the Radio Shack clock > also, and have had good luck with it. I added a "wall wart" type of power > supply. > > Initially, there was a lot of RF coming from the computer running SDR that > made WWVB reception almost impossible in that area. So I extended the wire > to the antenna to about 30 feet using shielded cable and used an optical > isolator between the RS clock and the computer. That did the trick. > > -- Karl > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Check this From: "wesgee" wesgee@........... Date: Thu, 9 Mar 2000 16:07:20 -0800 Have fun with these links. Bye. Subject: Re: Check this - possible virus alert! From: Larry Cochrane cochrane@.............. Date: Thu, 09 Mar 2000 16:13:17 -0800 PLEASE DO NOT SEND ATTACHMENTS TO THE LIST! I have no idea what this file is and it may contain a virus. I suggest users delete it. -Larry Cochrane Redwood City, PSN At 04:07 PM 3/9/00 -0800, you wrote: >Have fun with these links. >Bye. >Attachment Converted: "C:\NET\NEW\LINKS2.VBS" > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN-L List Rules - Please read From: Larry Cochrane cochrane@.............. Date: Thu, 09 Mar 2000 16:31:03 -0800 All, I need to send this out more often... Here are the list rules for this list. You receive this info as part of the welcome message when you joined the list. PSN-L List Rules: 1) Keep all posts as short as possible and to the point. (I only have a certain amount of bandwidth to send out email messages) 2) If you are including words from someone else's post (that you are referring or responding to), do NOT include more than a line or two of that post... we have already seen what they wrote. When replying, please edit out the following message appended to each outgoing PSN-L message: __________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email PSN-L-REQUEST@.............. with the body of the message: unsubscribe PSN-L 3) Do not send personal messages through the list. - post to the list if you think your information would be beneficial for everyone to read (this is how we all can learn) - post directly to the individual if it is a personal note, an "I agree with what you said" or "Thank you" type notes. 4) Do not send "me too's", "I agree's" or such to the list (it just wastes my bandwidth and other peoples time). 5) Do NOT send computer virus warnings (such as the "good times" virus) to the list; these are spams and not true (again, don't waste our time "warning" us of these) 6) Send only TEXT messages to the list. Do not include any attachments, HTML tags (this is referring to HTML code not links), or so forth. If you have a picture, or other binary type files to share with the group, you can uploaded when using FTP to ftp://ftp.seismicnet.com/info. 7) ALWAYS treat everyone here with respect and post with professionalism. Any abusive, sarcastic, or berating behavior on the list will be cause for list suspension and will not be tolerated. Please report any occurrences of this to the listowner (cochrane@................ 8) This list is closed meaning only list members can post to the list. This is done to prevent spammers from sending messages to the list. When you post to the list the From: address must match the address you used when subscribing to the list. Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More on the file LINKS2.VBS... From: Larry Cochrane cochrane@.............. Date: Thu, 09 Mar 2000 16:37:25 -0800 All, It looks like this file is or has a virus in it. I received several email messages from email servers that automatically test for viruses in attachments. Below is what I got from one of the servers. DO NOT OPEN THIS FILE. DELETE IT! -Larry The mail message (file: LINKS2.VBS) you sent to dgammon@......... contains virus VBS_FREELINK. The infected file(s) was deleted by Trend InterScan VirusWall on avsrv2. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Check this - possible virus alert! From: Don Stevens xor@........ Date: Thu, 09 Mar 2000 19:45:01 -0500 Larry, This is my first time posting and I realize this is a bit of topic, but let me explain what happened. That was indee a virus post by someone not on the list. They were able to hijack your server. Here is something you might find of intrest, as well as others on the list. It was posted to another list I am a member of, and offers a possible answer to this problem. I use this software and it works great. Check it out. It is worth the time. Don Stevens Sender: owner-radobs@........................ From: Tom Hanson To: radobs@........................ Subject: Internet Protection Against Hackers Demonstrated X-Sender: tahanson@.......................... X-Mailer: QUALCOMM Windows Eudora Pro Version 3.0.3 (32) Some members of the Radobs List may have noticed an article in Friday's Columbus Dispatch, in the Business section, entitled: "Firewalls can help secure your home of office computer" The article is part of the series "On Computing" by Michael J. Himowitz My client saw this article, and asked if we could check out some of the suggestions. He is running a server on a Warner Cablemodem. We used Steve Gibson's security checking routine at www.grc.com, and found numerous holes in the security on the Microsoft NT 4.0 (Sp 4) server. We then downloaded and installed ZoneAlarm (www.zonelabs.com) and installed it. As the NT server rebooted, the ZoneAlarm package kept me busy for a while, approving the normal functions to be allowed access to the Internet, such as our Internet Information Server package, two browsers, and two email packages. There were a number of permissions requested for several functions which I did not realize were going on, but which make sense, such as permission for the SMTP package to send outgoing email. After all the permissions had been granted, we returned to our normal duties. Not more than half an hour later, an alarm went off. It turned out that a site in Korea was trying to use our server to send email. One of our people took the IP address reported by Zone Alarm, launched a browser at the site, and we got what I ** think ** was 16 bit characters. One of the employees is a native Chinese, and he recognized part of the graphics as Korean. An hour after that, the alarm went off again. This time, there were five alarms accumulated from a different address. We didn't bother following up on the address this time. I now believe I can understand why our cable modem seemed to be frantically busy much of the time, while the visits to our web site did not appear to demonstrate great amounts of activity. The ZoneAlarm package appears to be very effective. It is available for Win95, Win98 and NT, including NT Server. The package is free to private individuals and to non-profit organizations. There is a 60 day free trial period for businesses, after which we will presumably receive notice of the required fee. The ZoneAlarm site reported over 1.5 million downloads of its software. As a verification, we went back to www.grc.com, to see how the security looked now. The security check was perfect, including a message congratulating us on having secured the NetBios, which (it claimed) was a major weakness of systems tested. This package would be most useful for persons or companies who have permanent connections on the Internet. (th) Don Stevens Clear Skies! xor@........ Visit an Observatory near you! Perkins Observatory, P.O. Box 449, Delaware, OH 43015 Phone: (740) 363-1257 Fax: (740) 363-1258 www.perkins-observatory.org perkins@.......... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: Doug Sutherland doug@............. Date: Thu, 9 Mar 2000 02:41:32 -0800 Larry wrote: > It looks like this file is or has a virus in it. Yikes. Silly me I clicked on it. However I am running linux so I am doubtful that it will do anything . When I clicked on it, the file just opened up in a text editor, then I closed it. I actually opened the file to send the garbola back to the sender. Does anyone know if this virus is a threat on linux? -- Doug __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: Larry Cochrane cochrane@.............. Date: Thu, 09 Mar 2000 17:14:16 -0800 Doug, If you opened the file with a simple text editor you should'nt have any problems. Text editors normally don't run any code inside a file like this, so it can't do any harm to your system. -Larry At 02:41 AM 3/9/00 -0800, you wrote: >Larry wrote: > >> It looks like this file is or has a virus in it. > >Yikes. Silly me I clicked on it. However I am running linux so >I am doubtful that it will do anything . When >I clicked on it, the file just opened up in a text editor, then >I closed it. I actually opened the file to send the garbola >back to the sender. Does anyone know if this virus is a threat >on linux? > > -- Doug __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: david@............. (David Josephson) Date: Thu, 9 Mar 2000 17:20:02 -0800 (PST) > >I closed it. I actually opened the file to send the garbola > >back to the sender. Does anyone know if this virus is a threat > >on linux? It is not, seems to be directed at Windows machines only. Note that the message came from Cal State Fresno. Larry, a quick call to their sysadmin with the IP addresses listed is in order. Try the whois server at www.networksolutions.com and call the number listed for the tech contact. -- David Josephson / Josephson Engineering / San Jose CA / david@............. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: peaches@............ (Donna Whitaker) Date: Thu, 9 Mar 2000 15:24:10 -1000 (HST) Larry. I recived the LINKS2.VBS download also. Without opening it, I sicked my Inoculate/IT PE virus scanner on it and it came up with this: \LINKS2.VBS was infected with WScript.Freelinks worm. Not a virus. Deleted It was automatically deleted. Tony >> >I closed it. I actually opened the file to send the garbola >> >back to the sender. Does anyone know if this virus is a threat >> >on linux? > >It is not, seems to be directed at Windows machines only. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: Tom Genereaux entropy@.............. Date: Thu, 9 Mar 2000 19:27:21 -0600 On Thu, 09 Mar 2000, you wrote: > Larry wrote: > > > It looks like this file is or has a virus in it. > > Yikes. Silly me I clicked on it. However I am running linux so > I am doubtful that it will do anything . When > I clicked on it, the file just opened up in a text editor, then > I closed it. I actually opened the file to send the garbola > back to the sender. Does anyone know if this virus is a threat > on linux? > > -- Doug Nope. We, thank Ghu or the Deity of your choice, don't have Outlook Visual Basic. However, it IS one of several VB e-mail virii that are floating about. One of the current modes of propagation is blind mailing via listserv's such as PSN. I've forwarded the example on to CERT - even though it's been seen in the wild before and most virus checkers will catch it, CERT needed to know it's attempting to go around again. Tom Genereaux __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on the file LINKS2.VBS... From: Steve Hammond Shammon1@............. Date: Fri, 10 Mar 2000 01:34:23 -0800 You sure do a good job at managing this list Larry-- Thanks. Regards, Steve Larry Cochrane wrote: > > All, > > It looks like this file is or has a virus in it. I received several email __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Viris From: "wesgee" wesgee@........... Date: Thu, 9 Mar 2000 18:24:38 -0800 A attachment was sent to me and I broke one of my own rules.. I opened it up.. . I came from the tech list here at the university so I thought it was ok.. but found out it wasn't.. it must have gotten attached to the address book and sent automatically to every address in it.. as this is the first Email I have sent today.. sorry.. I killed it here.. John Gee wesgee@........... http://hambone2.engr.csufresno.edu Subject: sensors needed From: "Mike" bootleg@............ Date: Thu, 9 Mar 2000 18:44:19 -0800 I'm hoping someone can help me locate some real cheap or surplus = geophones. I'm on the Coast in NW Oregon. Lots of interesting movement nearby, but in small bits almost = unnoticeable except to the natives here. Unexplained slides occur often. I'm not rich, but I'm = sure hoping to set up a small homemade detector if I can get some help locating a few geophones. A slide happened 2 years ago on the mountainside across the street. I = don't think thats the end of it=20 either and I wanted to monitor its unseen movements. Thanks Mike

I'm hoping someone can help me locate = some real=20 cheap or surplus geophones. I'm on the Coast in
NW Oregon. Lots of interesting movement = nearby, but=20 in small bits almost unnoticeable except to
the natives here. Unexplained slides = occur often.=20 I'm not rich, but I'm sure hoping to set up a small
homemade detector if I can get some = help locating a=20 few geophones.
 A slide happened 2 years ago on = the=20 mountainside across the street. I don't think thats the end of it =
either and I wanted to monitor its = unseen=20 movements.
Thanks
Mike
 
Subject: Impact readings From: Don Stevens xor@........ Date: Thu, 09 Mar 2000 22:16:26 -0500 Does anyone know where I can find a sisemograph simulation of the impact of a large object on the surface, and in the ocean? Please send any info to my personal e-mail address listed above. Thank you. Don Stevens Clear Skies! xor@........ Visit an Observatory near you! Perkins Observatory, P.O. Box 449, Delaware, OH 43015 Phone: (740) 363-1257 Fax: (740) 363-1258 www.perkins-observatory.org perkins@.......... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: sensors needed From: The Lahrs JohnJan@........ Date: Thu, 09 Mar 2000 20:30:09 -0700 If the slide is very near you, then a small exploration geophone may do. For this you could try All Electronics http://www.allelectronics.com/ Call and ask, as they may not show up in the catalog. 800 826 5432 John At 07:44 PM 3/9/00 , you wrote: >I'm hoping someone can help me locate some real cheap or surplus >geophones. I'm on the Coast in >NW Oregon. Lots of interesting movement nearby, but in small bits almost >unnoticeable except to >the natives here. Unexplained slides occur often. I'm not rich, but I'm >sure hoping to set up a small >homemade detector if I can get some help locating a few geophones. > A slide happened 2 years ago on the mountainside across the street. I > don't think thats the end of it >either and I wanted to monitor its unseen movements. >Thanks >Mike > John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Check this***VIRUS*** From: Edward Cranswick cranswick@........ Date: Thu, 09 Mar 2000 21:10:55 -0700 PSN- I downloaded the attached file to my NT system and my virus detection software said that it contained a virus. -Edward wesgee wrote: > Have fun with these links. > Bye. > > ------------------------------------------------------------------------ > Name: LINKS2.VBS > LINKS2.VBS Type: VBScript File (application/x-unknown-content-type-VBSFile) > Encoding: base64 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Viris From: Norman Davis WB6SHI wb6shi@........ Date: Thu, 09 Mar 2000 20:54:01 -0800 I killed it here before I opened it. At 06:24 PM 3/9/00 -0800, you wrote: >A attachment was sent to me and I broke one of my own rules.. I opened it >up.. . I came from the tech list here at the university so I thought it was >ok.. but found out it wasn't.. it must have gotten attached to the address >book and sent automatically to every address in it.. as this is the first >Email I have sent today.. sorry.. I killed it here.. > >John Gee >wesgee@........... >http://hambone2.engr.csufresno.edu > > >Attachment Converted: "c:\comm\eudora306\attach\winmail.dat" > Norman M. Davis WB6SHI Shingle springs, CA mailto:wb6shi@........ http://www.directcon.net/normd/index.htm ICQ: 7192318 How to Know God... http://www.harvest.org/knowgod/index.htm __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Check this From: Oguzhan Aydogmus-HRB oaydogmus@................ Date: Fri, 10 Mar 2000 08:15:25 +0200 > ---------- > From: wesgee[SMTP:wesgee@............ > Reply To: psn-l@.............. > Sent: 10 Mart 2000 Cuma 02:07 > To: wesgee@........... > Subject: Check this > > Have fun with these links. > Bye. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Check this *** VIRUS *** From: Mark Robinson other@............... Date: Fri, 10 Mar 2000 22:33:09 +1300 The attachment is a worm that affects the mIRC IRC client as far as I recall ... DO NOT OPEN. wesgee wrote: > > Have fun with these links. > Bye. > > ------------------------------------------------------------------------ > Name: LINKS2.VBS > LINKS2.VBS Type: MPEG Video (video/mpeg) > Encoding: quoted-printable __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Check this From: "Dim.Chatz." dhk@............ Date: Fri, 10 Mar 2000 17:49:55 +0200 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of wesgee Sent: Friday, March 10, 2000 2:07 AM To: wesgee@........... Subject: Check this Have fun with these links. Bye. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: UNSUBSCRIBE From: CARRJJ@....... Date: Fri, 10 Mar 2000 12:41:06 EST UNSUBSCRIBE __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Turns on the coil From: Paul Jebb pfjebb@.............. Date: Fri, 10 Mar 2000 16:20:07 -0500 Dear Members: I am pecking away at a Lehman seismometer. Presently I am winding #38 wire on a a spool that is about 4 inches in diameter, and 3/4 inch thick. I think I can fill the spool, but that's a lot of turns. Can anyone suggest an optimum number of turns or suggest some guidelines? Thank you in advance. Paul Jebb Newcomb Central School __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Turns on the coil From: ted@.......... Date: Fri, 10 Mar 2000 16:30:43 -0500 That's a great time-saving idea, a combination coil and mass. Wind it with Pb wire and you'll be all set. :-) But seriously, I wouldn't bother to wind wire in any area which was not going to be directly between the poles of my magnet. If you have a magnet with that large a face diameter you should switch to building a cyclotron! Build up the middle of the coil form with a piece of wood or MDF board and just wind your coil on the outermost 1/2 inch or so. (It's Friday...) Regards, Ted Paul Jebb @.............. on 03/10/2000 04:20:07 PM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: "PSN-L@.............." cc: Subject: Turns on the coil Dear Members: I am pecking away at a Lehman seismometer. Presently I am winding #38 wire on a a spool that is about 4 inches in diameter, and 3/4 inch thick. I think I can fill the spool, but that's a lot of turns. Can anyone suggest an optimum number of turns or suggest some guidelines? Thank you in advance. Paul Jebb Newcomb Central School __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hi all. From: "Eric D. Fehr" fehr@............ Date: Fri, 10 Mar 2000 19:55:38 -0700 I just joined the list on Sunday, and would like to briefly introduce myself, and ask for some input. I'm from Alberta, Canada, and will be moving to the Bay Area soon to work for SegaSoft (well, OK, I was supposed to move in November, but who ever said getting a work visa was easy.) This move has prompted me to take a more active interest in seismic activities. I now have an irresistible urge to build things seismic (to the disdain of my wife). I have enough of a history in electronics to build and circuitry, etc, to drive the hardware, but I am trying to decide what would be the best type of sensor equipment to use. I wanted to build a Lehman sensor, but my wife vetoed it, due to size. Currently I am looking at possibly a geophone configuration, or a force balance accelerometer (if price is not prohibitive). A SG seismometer is also a possibility (or a modified design that I have been working on in my head - I have a preference for non-RF electronics). Does anyone know an approximate price for a decent FBA sensor (1-3 sensor - I'm guessing mega $ here...)? I have already contacted geospace for a quote on the GS-11 geophone, so I know what price range I would be looking at for that. I could also try a few more local surplus stores, as seismic surveys are quite active throughout Alberta. However, I have had no luck at any of these stores yet. I also have not seen any discussion anywhere on using an integrator in combination with a geophone. I would think that a geophone -> preamp -> low pass filter -> high pass filter -> integrator -> amp arrangement could be fairly sensitive for low cost, but would like to know some opinions about if it would be worth trying? If the high pass filter cutoff frequency were at aprox. 50-80% of the resonant frequency of the geophone, I would think that you could pull up low-end performance without inducing too much noise (from looking that the performance specs for the units). Well anyway, I seem to have rambled on enough for now, so till later, Eric __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hi all. From: john c cole johnccole@........ Date: Fri, 10 Mar 2000 22:33:14 -0600 Eric My name is John C Cole. I live in Houston Texas. Do not discard the idea of building a Leaman detector. It does not have to be big and conspicuous. I have built a mini Leaman and a mimi/mini Leaman . They are in operation now and they work well.The mini/mini Leaman is about 14" long , 8" high and 8"wide. It can be concealed anywhere. The geophones are for local events but , even a mini/mini will pick up events from around the world. A good detector that works well can be built for $65 to $85 . If you want more information on the construction of a good Leaman , check these locations. http://www.freeweb.pdq.net/fxc/four.htm or at http://freeweb.pdq.net/fxc/ ps- Plenty of pictures and information about our equipment and information on where to find more. good luck john cole ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hi all. From: meredith lamb mlamb1@.......... Date: Fri, 10 Mar 2000 22:09:38 -0800 "Eric D. Fehr" wrote: > I just joined the list on Sunday, and would like to briefly introduce > myself, and ask for some input. > > I - I have a preference for non-RF electronics). > Eric, Well...I've had fair luck with using a Hall sensor over time. If you're vaguely interested its at this web site: http://www.geocities.com/ResearchTriangle/Facility/1739/Index.html The Hall seismo displayed there is relatively big (really a monster), compared to other capacitive S-G's; but it doesn't have to be big. I think a homebrew rig may bag more quakes than a geophone and be more interesting and satisfying. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hi all. From: meredith lamb mlamb1@.......... Date: Fri, 10 Mar 2000 22:14:32 -0800 john c cole wrote: > Eric > My name is John C Cole. I live in Houston Texas. Do not discard the idea > of building a Leaman detector. It does not have to be big and > conspicuous. I have built a mini Leaman and a mimi/mini Leaman . They are > in operation now and they work well.The mini/mini Leaman is about 14" > long , 8" high and 8"wide. It can be concealed anywhere. The geophones > are for local events but , even a mini/mini will pick up events from > around the world. A good detector that works well can be built for $65 to > $85 . > If you want more information on the construction of a good Leaman , > check these locations. http://www.freeweb.pdq.net/fxc/four.htm or at > http://freeweb.pdq.net/fxc/ > ps- Plenty of pictures and information about our equipment and > information on where to find more. > good luck john cole > Hi John, Nice web site/s with all the photos. Your coil winder is a real nice item to have on hand....whats its sizes, manufacturer, date, capacity? Does it evenly space the wire over a form, or does it have that capacity? The only coil winder I ever saw surplus were huge monsters, that weighted like 100-200 plus pounds, and appeared to be meant for large gauge wire. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Hi all. From: "Giovanni Rotta" rottag@.......... Date: Sat, 11 Mar 2000 07:05:14 +0100 Hi, Eric ! A warm welcome from the PSN Italian networks ! Giovanni Rotta Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.368 N Long. 13.299 E rottag@.......... http://www.fesn.org ----- Original Message ----- From: Eric D. Fehr To: Sent: Saturday, March 11, 2000 3:55 AM Subject: Hi all. > I just joined the list on Sunday, and would like to briefly introduce > myself, and ask for some input. > > I'm from Alberta, Canada, and will be moving to the Bay Area soon to work > for SegaSoft (well, OK, I was supposed to move in November, but who ever > said getting a work visa was easy.) This move has prompted me to take a > more active interest in seismic activities. I now have an irresistible > urge to build things seismic (to the disdain of my wife). > > I have enough of a history in electronics to build and circuitry, etc, to > drive the hardware, but I am trying to decide what would be the best type > of sensor equipment to use. I wanted to build a Lehman sensor, but my wife > vetoed it, due to size. > > Currently I am looking at possibly a geophone configuration, or a force > balance accelerometer (if price is not prohibitive). A SG seismometer is > also a possibility (or a modified design that I have been working on in my > head - I have a preference for non-RF electronics). > > Does anyone know an approximate price for a decent FBA sensor (1-3 sensor - > I'm guessing mega $ here...)? I have already contacted geospace for a > quote on the GS-11 geophone, so I know what price range I would be looking > at for that. I could also try a few more local surplus stores, as seismic > surveys are quite active throughout Alberta. However, I have had no luck > at any of these stores yet. > > I also have not seen any discussion anywhere on using an integrator in > combination with a geophone. I would think that a geophone -> preamp -> > low pass filter -> high pass filter -> integrator -> amp arrangement could > be fairly sensitive for low cost, but would like to know some opinions > about if it would be worth trying? If the high pass filter cutoff > frequency were at aprox. 50-80% of the resonant frequency of the geophone, > I would think that you could pull up low-end performance without inducing > too much noise (from looking that the performance specs for the units). > > Well anyway, I seem to have rambled on enough for now, so till later, > Eric > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Hi all. From: "Giovanni Rotta" rottag@.......... Date: Sat, 11 Mar 2000 07:05:14 +0100 Hi, Eric ! A warm welcome from the PSN Italian networks ! Giovanni Rotta Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.368 N Long. 13.299 E rottag@.......... http://www.fesn.org ----- Original Message ----- From: Eric D. Fehr To: Sent: Saturday, March 11, 2000 3:55 AM Subject: Hi all. > I just joined the list on Sunday, and would like to briefly introduce > myself, and ask for some input. > > I'm from Alberta, Canada, and will be moving to the Bay Area soon to work > for SegaSoft (well, OK, I was supposed to move in November, but who ever > said getting a work visa was easy.) This move has prompted me to take a > more active interest in seismic activities. I now have an irresistible > urge to build things seismic (to the disdain of my wife). > > I have enough of a history in electronics to build and circuitry, etc, to > drive the hardware, but I am trying to decide what would be the best type > of sensor equipment to use. I wanted to build a Lehman sensor, but my wife > vetoed it, due to size. > > Currently I am looking at possibly a geophone configuration, or a force > balance accelerometer (if price is not prohibitive). A SG seismometer is > also a possibility (or a modified design that I have been working on in my > head - I have a preference for non-RF electronics). > > Does anyone know an approximate price for a decent FBA sensor (1-3 sensor - > I'm guessing mega $ here...)? I have already contacted geospace for a > quote on the GS-11 geophone, so I know what price range I would be looking > at for that. I could also try a few more local surplus stores, as seismic > surveys are quite active throughout Alberta. However, I have had no luck > at any of these stores yet. > > I also have not seen any discussion anywhere on using an integrator in > combination with a geophone. I would think that a geophone -> preamp -> > low pass filter -> high pass filter -> integrator -> amp arrangement could > be fairly sensitive for low cost, but would like to know some opinions > about if it would be worth trying? If the high pass filter cutoff > frequency were at aprox. 50-80% of the resonant frequency of the geophone, > I would think that you could pull up low-end performance without inducing > too much noise (from looking that the performance specs for the units). > > Well anyway, I seem to have rambled on enough for now, so till later, > Eric > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Wondermagnet web site additions From: meredith lamb mlamb1@.......... Date: Fri, 10 Mar 2000 23:32:41 -0800 Hi all, Forcefield/Wondermagnet has added some more magnets to their product list, which could be of interest. See: http://www.wondermagnet.com For those with a diamagnetic interest (levitation), their item #16 is especially noteworthy. Its a 1/4" diameter rod thats 1" long with a thin gold plating and has a R45 or 45 category; which means it is magnetically enhanced over a typical R30 or R35 neodymium magnet which are much more common. Frankly; it the best magnet I've ever seen in this type of experimental application, as I've levitated it in a bored hole piece of graphite and a more normal "discs" of graphite. There is one gamble with this magnet in levitation and that is that when it was originally gaussed, the uniformity can vary over the length of the magnet; and it can assume a "tilt" or slope from a horizontal plane of afew degrees (normal) and on up to some ~ 20 or more degrees. If you're interested it maybe prudent to obtain afew and go from there. This magnet is also more brittle than a standard magnet, and it should be handled with care to prevent unintended collision with other metallic objects. The magnetization is 1/2 the diameter lengthwise, or, in other words it floats horizontally in a levitation stand. (The poles are not per a normal magnet, with the N on one end and S on the other). This magnet would NOT be good for normal seismographic coil induction, as the field mostly cancels out because of its pole arrangement. This magnets magnetic enhancement significantly aids diamagnetic levitation and much better stability than a normal production neodymium magnet. This message is simply a information referral to the item/s on hand, and I do not share a commercial interest therein. Common magnet propertys and application interests....yes. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: Quake Hits Cental Italy From: Seisguy@....... Date: Sat, 11 Mar 2000 15:16:43 EST Quake Hits Cental Italy ..c The Associated Press ROME (AP) - A mild earthquake shook central Italy on Saturday, cracking medieval churches and crumbling rock walls, roofs and houses in towns and villages around Rome. No injuries were immediately reported. The earthquake hit at 11:35 a.m. with a preliminary magnitude of 4.1, Italy's National Geophysics Institute said. It put the ep icenter at Monti Tiburtini, about 30 miles southeast of Rome. The quake rocked buildings in the capital but there were no immediate reports of damage there. Near the epicenter, in the town of Cervara, the quake opened cracks in the foundation and front of a 15th-century church, promp ting the mayor to order it closed. To the north, the shaking cracked the vault of the recently restored church of St. Mary of the Assumption in the town of Gerano and collapsed the roof of a four-story building there. Other damage across central Italy included an abandoned house made of rock that collapsed, and the attic apartments of four bui ldings. AP-NY-03-11-00 0856EST Copyright 2000 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewri tten or otherwise distributed without prior written authority of The Associated Press. Announcement: America Online has added Reuters newswires to News Profiles. To add Reuters articles to your daily news delivery, go to KW: News Profiles and click on "Modify Your News Profiles." Then click "Edit" and add Reute rs from the list on the left. To edit your profile, go to keyword NewsProfiles. For all of today's news, go to keyword News. Subject: extending geophone period From: S-T Morrissey sean@........... Date: Sat, 11 Mar 2000 21:34:43 -0600 (CST) Regarding extending the operating period of a geophone: See "A Versatile Equalization Circuit for Increasing Seismometer Velocity response Below the Natural Frequency", by Peter M. Roberts; BSSA, (Bulletin of the Seismological Society of America), Vol 79, pp 1607-1697, October 1989. The paper describes extending the period of a 1-hz seismometer (L4-C) to 10 seconds. The major problem is that the equalization requires a total amplifier gain of 488, so amplifier noise is a the limiting problem. Noise power spectra are not presented. An instrument company makes a three-component 1-hz replacement for the L4-C using a variation of the circuit and 4.5hz geophones installed in a solid cylinder about the size of a single L4-C. It is a good medium gain instrument for network studies in active areas, but like the 1-hz seismometer, only senses the 6-second microseisms if they are abnormally large. The major problem with period extension schemes using small geophones (equalization, VBB feedback, NIC circuits, etc.) is that the force of the moving mass (20 - 30 grams) on the suspension is quite small compared with the constants of the leaf springs, such that mechanical self noise contributes a significant amount of noise. This makes them excellent for being rugged devices, but not particularly sensitive compared with the noise models. Examples of geophone noise levels are given in the paper by Riedesel. At 1 hz, there is a factor of about 100 times more nose from a 4.5hz geophone compared with an L4-C with a 1000 gram mass. "Limits of Sensitivity of Inertial Seismometers with Velocity Transducers and Electronic Amplifiers"; by Mark A Riedesel, R.D.Moore, and J.A.Orcutt; Bulletin of the Seismological Society of America, Vol. 80, No. 6, December 1990. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Advanced electronic design From: ted@.......... Date: Sun, 12 Mar 2000 15:28:14 -0500 Now that I have your attention, here's my humble request. Some of you may know I sing in a Barbershop Quartet. Our training tapes come with my part on the left channel and the other three guys on the right. This is great in the car - I can study my part by swinging the balance over to the left, then fill out the harmony by swinging it over to the right. Until now I haven't been able to do this on my portable player, since it's just a mono unit. Today I got a great deal ($20) on a stereo walkman-type casette player. It plays left track in the left earphone and right track in the right - but there's no L/R balance. Aha you are probably thinking, Ted could throw together a few variable resistors and come up with a little balance box to put between the player and the earphones. You would be right if Ted knew anything about electronics beyond E=IR and P=IE. I can solder and wire, but only by following the most exquisitely detailed instructions. Imagine Dave Barry trying to play baseball and you'll get the general idea. If anyone is willing to put together such a design for me I would be forever grateful, and would reward this kind soul with a cassette tape of our quartet singing numerous Barbershop favorites once we learn some. Actually we are going to be singing in our first competition on April 1 (bad timing, I know) so we will either know at least two songs by then or look pretty silly. Thanks! Regards, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Distant seismogram coming in... From: meredith lamb mlamb1@.......... Date: Sun, 12 Mar 2000 14:59:07 -0800 Am seeing a teleseism coming in now. Guess as to origin time of UTC 22:30 or thereabouts. Not large amplitude. Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MEXICO From: "Francesco" franuc@...... Date: Mon, 13 Mar 2000 00:50:28 +0100 Hello Meredith, the event is this: 22:21:27.7 14.8N 92.6W 33G Mb5.7 A NEIA NEAR COAST OF CHIAPAS, = MEXICO =20 Francesco Italy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hello -- From: "SMITH ROBERT L." bobsmith5@........ Date: Mon, 13 Mar 2000 09:05:12 -0500 Hello to the list. I have a long-standing, latent interest in amateur seismology which was recently awakened by and exchange with a gentleman seeking information on communicating by microcontrollers with a remote seismograph. What follows is an extracted description of the history of my interest that was taken from a recent exchange with a fellow microcontroller designer. ***************************************** Hi xxxxx -- Seismometry is a subject that has been dear to my heart for many years. I would be very interested in learning about your unit. Is it described in available literature anywhere? Especially on the Web?. Background -- My mothers sister married late in life to a very interesting gentleman by the name of Mr. Elmer Rexin. He was the plant engineer at the Nunn-Bush shoe company in Milwaukee, Wisconsin for most of his adult life. Somewhere back in the '50's or thereabouts, the USGS was conducting water table surveys of deep wells in the area and placed a float and drum recorder in one of the deep wells in the Nunn-Bush factory. During the period of recording Uncle Elmer noticed that certain anomalous squiggles on their recordings corresponded to major seismic events that had made the news at the time. After the USGS packed up their equipment and left, my Uncle built an improved, much more sensitive recorder and, with the blessing of Nunn-Bush, proceeded to monitor the disturbances. The correlation with seismic activity was immediately evident and the instrument proved to exhibit exceptional sensitivity. This phenomenal well has been investigated by various scientists and a theory of operation was formed. It was hypothesized that the deep well had tapped into a large underground cavern of water and the well casing behaved as the tube of a very large inverted syringe - thus amplifying the slightest disturbance in bed rock formations. The work has been written up in various journals, unfortunately I cannot remember any of the references. Somewhere at my family home in Illinois there are dozens of rolls of paper with pen squiggles on them marking various events over the years. They were salvaged by my family after my Aunt and Uncle passed away in the '80's. ***************************************************** I am making this posting in hopes that someone here on this public network may know of this work and can point me to any of the reports that were published in the past. Many thanks and good squiggles to all, Bob Smith -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hello -- From: Ed Thelen ethelen@........ Date: Mon, 13 Mar 2000 08:27:11 -0800 There were two articles in Amateur Scientist column of the "Scientific American" that mention Elmer Rixon and his water-well seismograph. June, 1953 - page 117 - has about a page of text text and a large diagram May, 1961 - page 182 - almost two pages starting discussing Elmer Rixon's work, and continuing mentioning Gerald I. Shea's work, with more diagrams and recordings If you are interested, and cannot get microfilm type images from your local library, I can scan and send the articles to you. Reference to the above articles is in the web site for Society for Amateur Scientists at http://web2.thesphere.com/SAS/WebX.cgi?13@................ under "Seisograph". The Society for Amateur Scientists has obtained rights to make a CD of all Amateur Scientist columns of the "Scientific American". You can check for the progress at http://web2.thesphere.com/SAS/WebX.cgi?13@................... Elmer Rixon and Gerald Shea were early founders of the World Amateur Seismological Society (WASS) that published a quarterly newsletter/journal during the 1960's to 1975. Ed Thelen - "SMITH ROBERT L." wrote: > Background -- > > My mothers sister married late in life to a very interesting > gentleman by the name of Mr. Elmer Rexin. He was the plant > engineer at the Nunn-Bush shoe company in Milwaukee, > Wisconsin for most of his adult life. Somewhere back in the > '50's > or thereabouts, the USGS was conducting water table surveys > of deep wells in the area and placed a float and drum > recorder in one of the deep wells in the Nunn-Bush factory. > During the period of recording Uncle Elmer noticed that > certain anomalous squiggles on their recordings corresponded > to major seismic events that had made the news at the time. > After the USGS packed up their equipment and left, > The work has been written up in various journals, > unfortunately I cannot remember any of the references. > Somewhere at my family home in Illinois there are dozens of > rolls of paper with pen squiggles on them marking various > events over the years. They were salvaged by my family > after my Aunt and Uncle passed away in the '80's. > > ***************************************************** > > I am making this posting in hopes that someone here on this > public network may > know of this work and can point me to any of the reports > that were published in > the past. > > Many thanks and good squiggles to all, Bob Smith > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Turns on the coil From: Paul Jebb pfjebb@.............. Date: Mon, 13 Mar 2000 15:29:04 -0500 Hi Ted, Thanks for responding. I can do 1/2 inch easily. What are some problems that may arise if there are too many turns of wire? Paul ted@.......... wrote: > That's a great time-saving idea, a combination coil and mass. Wind it with > Pb wire and you'll be all set. :-) > > But seriously, I wouldn't bother to wind wire in any area which was not > going to be directly between the poles of my magnet. If you have a magnet > with that large a face diameter you should switch to building a cyclotron! > Build up the middle of the coil form with a piece of wood or MDF board and > just wind your coil on the outermost 1/2 inch or so. > > (It's Friday...) > > Regards, Ted > > Paul Jebb @.............. on 03/10/2000 04:20:07 PM > > Please respond to psn-l@.............. > > Sent by: psn-l-request@.............. > > To: "PSN-L@.............." > cc: > Subject: Turns on the coil > > Dear Members: > I am pecking away at a Lehman seismometer. Presently I am winding #38 > wire on a a spool that is about 4 inches in diameter, and 3/4 inch > thick. I think I can fill the spool, but that's a lot of turns. Can > anyone suggest an optimum number of turns or suggest some guidelines? > > Thank you in advance. > Paul Jebb > Newcomb Central School > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hello -- From: George Harris gjharris@............. Date: Mon, 13 Mar 2000 12:55:03 -0500 > , the USGS was conducting water table surveys > > of deep wells in the area and placed a float and drum > > recorder in one of the deep wells in the Nunn-Bush factory. > > During the period of recording Uncle Elmer noticed that > > certain anomalous squiggles on their recordings corresponded > > to major seismic events that had made the news at the time. About 5 years ago, I made contact with a person in the Santa Barbara area who had been running a similar recorder for some time. It was written up in the local paper, and a couple of us went to see the unit. It was a float with a weight on the bottom, and a very small rod on the top. It floated in a pool of water in a hole in his yard. A magnet on the top generated a signal in a coil. As I remember it was held in the center by threads to the sides. The output was to a drum recorder which he had constructed. The unit seemed to have good sensitivity to both local (he was not too far from a railroad track), and distant events. George Harris __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Turns on the coil From: ted@.......... Date: Mon, 13 Mar 2000 16:18:19 -0500 That was covered recently by Sean-Thomas...is there any way to recent request archives of the list? It has to do with finding a balance between enough turns to give a good output voltage and not so many turns that the damping would become extreme... I think. Resistance of the coil then gets very high...which is also good in some ways and bad in others... Boy, this is just like my performance work - the answer is always "it depends..." :-) Regards, Ted Paul Jebb @.............. on 03/13/2000 03:29:04 PM Please respond to psn-l@.............. Sent by: psn-l-request@.............. To: psn-l@.............. cc: Subject: Re: Turns on the coil Hi Ted, Thanks for responding. I can do 1/2 inch easily. What are some problems that may arise if there are too many turns of wire? Paul ted@.......... wrote: > That's a great time-saving idea, a combination coil and mass. Wind it with > Pb wire and you'll be all set. :-) > > But seriously, I wouldn't bother to wind wire in any area which was not > going to be directly between the poles of my magnet. If you have a magnet > with that large a face diameter you should switch to building a cyclotron! > Build up the middle of the coil form with a piece of wood or MDF board and > just wind your coil on the outermost 1/2 inch or so. > > (It's Friday...) > > Regards, Ted > > Paul Jebb @.............. on 03/10/2000 04:20:07 PM > > Please respond to psn-l@.............. > > Sent by: psn-l-request@.............. > > To: "PSN-L@.............." > cc: > Subject: Turns on the coil > > Dear Members: > I am pecking away at a Lehman seismometer. Presently I am winding #38 > wire on a a spool that is about 4 inches in diameter, and 3/4 inch > thick. I think I can fill the spool, but that's a lot of turns. Can > anyone suggest an optimum number of turns or suggest some guidelines? > > Thank you in advance. > Paul Jebb > Newcomb Central School > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hello -- From: wizard@......... (Rick Jerome) Date: Mon, 13 Mar 2000 16:25:55 -0800 , the USGS was conducting water table surveys > of deep wells . If you are interested in well monitoring in general you might want to contact Eddie Quilty at the USGS in Menlo Park. He has been doing some research on wells in Southern California. His report is "Water Level and Strain Changes Preceeding and Following the August 4, 1986 Kettleman Hills, California Earthquake". The last e-mail address I have for him is eddie@.................... . Hope that you find this interesting. Michael D Tuolumne, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: Re: Fwd: Re: Computer Interfacing From: The Lahrs JohnJan@........ Date: Mon, 13 Mar 2000 18:35:23 -0700 In case anyone is interested in developing their own software for the Dataq DI151-RS AD unit, here are some related messages. John >X-Sender: dataq@............ >X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.0.58 >Date: Mon, 13 Mar 2000 11:47:41 -0500 >To: The Lahrs >From: X Chen >Subject: Re: Fwd: Re: Computer Interfacing > >Ken passed me your email. > >To write program for DI-151 (or DI-190/150/194), you can: > >If you are using Windows 95/98/NT, please use ActiveX control and >C, Visual BASIC 5 or higher, or Labview. The ActiveX control and its VB >or Labview samples can be downloaded from >http://www.dataq.com/upgrade/all/activex.exe > >If you are using Windows 3.1 or DOS, you have to write your own device >driver. All the information about DI-151 can be found at >http://www.dataq.com/spec100.htm, and a test program we used in the early >stage of testing DI-150, which is a cousin of DI-151, can be found at: >http://www.dataq.com/support/di150qb.zip It doesn't support all the >commands for DI-150, but it can be used as a starting point and reference. > >Regards, > >Xun Chen > >At 06:08 PM 3/11/00 -0700, you wrote: >>Hi Ken, >> >>This question came back from a science email list that I belong to. If >>you want >>to respond, I'll pass your comments to the group. >> >>John >>>Resent-Date: Sat, 11 Mar 2000 15:34:02 -0800 >>>Date: Sat, 11 Mar 2000 15:33:35 -0800 >>>From: Ed Phillips >>>Subject: Re: Computer Interfacing >>>To: sciclub-list@.......... >>> >>>The Lahrs wrote: >>> > >>> > At 06:30 AM 3/11/00 Dave in Ohio wrote: >>> > >Learned Group: >>> > > >>> > >I have acquired a group of oddball 8086,286,386 computers ... [and] >>> would >>> > >like to >>> > >build simulation models using the game port, RS-232, Serial, Parallel, >>> > >whatever! >>> > >>> > Dave, >>> > Take a look at the RS151 AD unit and software from Dataq. >>> > http://www.dataq.com/di150.htm >>> > You can't beat the price of $100 for an AD that connects to the >>> serial port >>> > of a PC and free display software. I believe they have some Basic >>> software >>> > that you can start with to generate your own program. >>> > John >>> >>> I've been using one of the RS150's for a year. Great unit! The >>>display and analysis program alone is worth more than the hundred >>>bucks. Would like more detail about connecting to it with Basic. >>>That's not in the documentation I have. >>> >>>Ed John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Turns on the coil From: Larry Cochrane cochrane@.............. Date: Mon, 13 Mar 2000 19:25:19 -0800 At 04:18 PM 3/13/00 -0500, you wrote: > > >That was covered recently by Sean-Thomas...is there any way to recent >request archives of the list? Links to archives of this list can be found here: http://www.seismicnet.com/maillist.html. -Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: STAINLESS STEEL SHIM STOCK From: RADIOTEL@....... Date: Wed, 15 Mar 2000 00:25:30 EST While visiting one of my favorite surplus haunts this morning I discovered that they had just received a case of stainless steel shim stock which may be of use to some of you making a STM-8 or SG seismo. The shim stock is .005 gage and in a roll 6 inches by 50 inches. They have approximately ten rolls for a price of $12.50 per roll. The store is C and H Sales Company, 2176 E. Colorado Blvd., Pasadena, CA 91107. Toll Free Phone # 1-800 323-9465. I would imagine that these rolls will be sold fast if one is interested. BTW, I have no affiliattion with this store which has been in business for over 50 years. Jim Allen Cerritos, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: CNSS Update] From: Edward Cranswick cranswick@........ Date: Wed, 15 Mar 2000 12:16:13 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Tom- I think that Dave Wald is the single most important person for the useful development of ANSS because he is the one working to develop an active feedback relationship with the ultimate users of the groundmotion recorded where people live -- the people themselves. I see that Dave Wald has not been included as a participant in the ANSS planning and that is a serious oversight if you are seriously planning to make this project relevant to the Internet citizens of seismogenic regions who are already more connected with each other and with what is shaking than we are. -Edward "Heaton, Thomas" wrote: > Dear CNSS members, > > The following is an update on CNSS issues. Please note that we > will have a meeting of the CNSS at 7:00 PM on 11 April 2000 at > the SSA meeting in San Diego. The update will also be available at > http://www.cnss.org/. > > Tom Heaton > > CNSS Update > 3/13/2000 > Tom Heaton > heaton_t@........... > > This is to update you on recent developments that are relevant to the > Council on the > National Seismic System (CNSS). This is an important time for US > seismographic > networks; there are two major proposals that are in the planning stages > (ANSS and > USArray) and one new consortium to further strong-motion recording has been > started > (COSMOS). These proposals present operators of regional networks with > challenging > new opportunities, and if they are successful, seismographic systems will be > very > different 10 years from now. Strong-motion and regional seismic networks > will be an > integrated 4,000-station system (ANSS); an 800-station, low-noise, > very-broad-band > network will slowly roll across the nation (USArray); and the US National > Seismographic > Network (USNSN) will be expanded from its present 40 stations to 75 > stations. These > bold visions of the future raise many critical questions. What will be the > relative roles of > the USGS, IRIS, individual universities, and state agencies? ANSS and > USArray both > propose extensive regional broad-band networks; how will they be > coordinated? Will > ANSS and USArray operate independent data management systems? These and > many > other questions must be answered in the coming months. > > Annual Meeting > > The CNSS annual meeting will be held from 7:00 pm to 10:00 on Tuesday 11 > April 2000 > in the Pacific/Surf/Tropic Room of Hanalei Hotel during the Seismological > Society of > America meeting in San Diego. I anticipate that the new ANSS and USArray > initiatives > will be the main topics of discussion at this meeting. In particular, we > will discuss the > proposed management structure of the ANSS that was developed at the first > meeting of > the Interim Steering Committee. We will also discuss recent efforts to form > a software > standards committee for seismic networks. If you have other items that you > would like to > put on the agenda, please mail them to me. We will post updated information > on this > meeting at the CNSS web site (http://www.cnss.org/). > > ANSS Interim Steering Committee > > The USGS hosted the first meeting of the ANSS Interim Steering Committee > that was > held in Albuquerque on 29 Feb. 2000. Thanks are extended to John Filson, > Harley Benz, > Jill McCarthy and Joyce Costello, who organized this historic meeting. The > purpose of > the meeting was to begin development of an implementation plan for the ANSS > and to > develop a proposed management structure. The overall goals of the ANSS have > been > widely discussed at previous meetings and are described in "Requirements for > an > Advanced National Seismic Sysytem" (USGS Circular 1188). > > Participants in this meeting were chosen by the key agencies that represent > a wide variety > of groups with a stake in ANSS. These include the SSA, EERI, IRIS, CNSS, > COSMOS, > USGS, TriNet, PEER, MAEC, MCEER, and WSSPC. Tom Heaton(CIT), Walter > Arabasz (U of Utah), and Lind Gee (UCB) represented the CNSS at the meeting. > Also > attending the meeting were Jonathan Bray (PEER/UCB), Jim Davis (State of > CA), Goran > Ekstrom (IRIS/Harvard), Arch Johnston (MAEC/U of Memphis), Lucy Jones > (TriNet/USGS), Steve Malone (SSA/UW), David Oppenheimer (USGS), Kaye > Shedlock > (USGS), David Simpson (IRIS), Paul Somerville (EERI/Woodward-Clyde), and > Carl > Steppe (COSMOS). > > Development of a proposed management structure was a key issue at this > meeting. The > relative importance of regional centers and the role of national management > was a hot > topic. There was a strong consensus that the number of regional centers > should be a > relatively small number. This will require significant changes from our > current structure > of many independent networks. In anticipation of this change, several > California > networks are planning to join together in the California Integrated Seismic > Network > (CISN), which is described below. > > It is important that other regions begin to explore workable management > structures that > can meet the needs of their region. There was consensus that individual > regions must > have a strong management structure, but this does not necessarily imply that > all activities > reside in one physical location. The formulation of implementation plans > for individual > regions is difficult and critical. If individuals have some strong opinion > about the > management of seismic instrumentation in their part of the US, then they > should begin > talking with others in their region about what a workable regional center > may look like. > > Support for ANSS > > There are four separate steps that are necessary for funding to be allocated > to the ANSS; > both the House and the Senate must authorize it, and both the House and the > Senate must > appropriate it. While it is not necessary, it is also extremely helpful if > the President's > proposed budget also contains ANSS funding. The President's proposed FY2001 > budget > requests $4.2M for ANSS. While this is far too little to allow serious > implementation of > ANSS, it is viewed by some as an important step to full funding of ANSS. > That is, the > issue of ANSS has been formally introduced into the appropriations process. > Congress > could still pass an appropriation bill with the full funding. Now is the > time to contact > appropriations committee members in both the House and Senate. The > following is > a summary of the status of ANSS legislation. > > 1. House authorization. ANSS has already been authorized by the House > at level of > $38 M per year for FY2000 through FY2004 (see http://thomas.loc.gov/ and > search on HR1184). This authorization has been referred to the Senate. > 2. Senate authorization. A similar bill (see http://thomas.loc.gov/ > and search on > S1639) authorizing ANSS was introduced in the Senate and is pending before > the > Senate Commerce Committee, which is chaired by Senator John McCain (AZ). > Undisclosed sources indicate that Senate authorization is likely, although > Senator > McCain has been occupied with his recent presidential campaign. > 3. House Appropriation. This is the probably the most critical action > item. > Support for ANSS can be sent to > > The Honorable Ralph Regula > Chairman, Subcommittee on Interior > Committee on Appropriations > U.S. House of Representatives > B-308 Rayburn House Office Building > Washington, DC 20515-6023 > > with a cc to > > Joel Kaplan, Staff > Subcommittee on Interior > Committee on Appropriations > U.S. House of Representatives > B-308 Rayburn House Office Building > Washington, DC 20515-6023 > [Tel: 202-225-2081] > > The following congressmen are also on this critical committee. > > Norman Dicks, Wash. > Jim Kolbe, Ariz. > John P. Murtha, Penn. > Joe Skeen, N.M. > James P. Moran, Va. > Charles H. Taylor, N.C. > Robert E. (Bud) Cramer, Jr., Ala. > George R. Nethercutt, Jr., Wash. > Maurice D. Hinchey, N.Y. > Zach Wamp, Tenn. > Jack Kingston, Ga. > John E. Peterson, Penn. > > 4. Senate appropriation. This is also a very important committee, > since House and > Senate bills must go to conference. Letter of support should be sent to > > Senator Slade Gorton, > Chairman, Subcommittee on Interior > Committee on Appropriations > United States Senate > SD-131 Dirksen Senate Office Building > Washington, DC 20510-6033 > > with a cc to > > Ginny James, Staff > Subcommittee on Interior > Committee on Appropriations > United States Senate > SD-131 Dirksen Senate Office Building > Washington, DC 20510-6033 > [Tel: 202-224-7233] > > Other members are in order of rank, > > Republicans: (8) > Slade Gorton (WA), Chair > Ted Stevens (AK) > Thad Cochran (MS) > Pete Domenici (NM) > Conrad Burns (MT) > Robert Bennett (UT) > Judd Gregg (NH) > Ben Nighthorse Campbell (CO) > > Democrats: (7) > > Robert Byrd (WV), Rnk. Mem. > Patrick Leahy (VT) > Ernest Hollings (SC) > Harry Reid (NV) > Byron Dorgan (ND) > Herbert Kohl (WI) > Dianne Feinstein (CA) > > CISN > > Planning for a California Integrated Seismic Network has occurred over the > past 12 > months. This planning effort has included the Southern California > Seismographic > Network (USGS/Pasadena and CIT), the Northern California Seismographic > Network > (USGS/Menlo Park and UCB), the California Strong Motion Instrumentation > Program > (Calif. Div. Mines and Geology), and the US National Strong Motion Program > (USGS). > This planning effort is a natural follow-up to the TriNet Project > (http://www.trinet.org/), > which has been operating for more than 3 years. A FEMA earthquake > mitigation grant > provided 5 years of funding to develop and operate the TriNet system in > southern > California. FEMA funding for this project will terminate at the end of > 2001. The current > managers of TriNet (CIT,USGS, and CDMG) have stated their intentions to > replace the > TriNet structure with a new statewide structure that also includes UCB and > USGS/Menlo > Park. The goals of CISN are virtually identical to those of ANSS, and it is > viewed that > CISN is a likely candidate of an ANSS regional center. CISN has also been > actively > pursuing financial support from the State of California. > > USArray http://www.iris.iris.edu/USArray.html > > USArray has been included as a proposed Major Research Equipment (MRE) > initiative > by NSF (see page 19 of > http://www.geo.nsf.gov/geo/adgeo/fac_lrp/facilities_plan.pdf). > Support for USArray appears to be strong and there will be extensive > discussion of this > project at both the SSA Annual Meeting (April 10-12) in San Diego > (http://www.ssay2k.ucsd.edu/), and at the IRIS Annual Workshop in Rockport, > Me. (May > 7-10, http://www.iris.edu/workshop00_info.html). > > Coordination between ANSS and USArray is a key issue. In particular, if > both initiatives > are funded, then it must be decided how data are managed when USArray > stations are > interspersed among ANSS stations. Should separate data management > facilities be > developed for ANSS and USArray? If USArray is funded and ANSS is not > funded, then > strategies must be developed to cope with the policy problems raised by > having a high- > quality broad-band network for basic research (USArray), while being stuck > with an > antiquated seismic monitoring system. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Subject: shim stock From: S-T Morrissey sean@........... Date: Wed, 15 Mar 2000 13:45:02 -0600 (CST) Regarding shim stock for hinges or flexures: In the event that C&H sells out of the shim stock that Jim has posted info on, it can be obtained from McMaster Carr Supply (630 833 0300): (MC, VISA, by UPS) In rolls of 0.005" x 6" x 50": stock number 9502K14 alloy 302 Stainless Steel $13.64 " " 9504K18 half-hard temper brass 5.63 " " 9020K41 spring temper phosphor bronze 10.95 Other materials are available in thicknesses from 0.001". I use the 0.002" brass for the box flexure for the new seismometer. Difficulties with the stainless are that it is almost unsolderable; if you epoxy the hinges, rough up the stainless with 600 grit emory. I use the office paper cutter to cut it into narrow strips. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: CNSS Update From: Edward Cranswick cranswick@........ Date: Wed, 15 Mar 2000 12:59:40 -0700 Tom- Are you aware of the San Jose Array that Art Frankel has been spear-heading for the last couple of years? It is unprecedented in the view that it provides of the actual propagation of ground motions -- and Art has done a brilliant job of giving us this vision . However it lacks any significant contact with the people in whose homes we have installed the Web sensors of ground motion (K2's) -- I don't believe they have even been informed of the websites above. These people represent the tip of the iceberg of a constituency of concerned and committed citizens and residents who would actively support NEHRP goals and funding programs. They provide the USGS with a direct contact to the people who are most connected with the data we are recording -- it is essential to involve them as partners in the our earthquake monitoring programs. -Edward "Heaton, Thomas" wrote: > Ed, > > Thanks for the comment. Dave is indeed an important person to ANSS. > Dave is a very active participant in the TriNet project and his > work has been important to forming the goals of ANSS. I'll discuss > with Lucy Jones (his supervisor) the issue of whether or not to > try to get Dave more involved in the management of ANSS. > > Tom Heaton > > -----Original Message----- > From: Edward Cranswick [mailto:cranswick@......... > Sent: Wednesday, March 15, 2000 11:11 AM > To: Heaton, Thomas > Cc: 'cnss-list@......... David Wald; geo_haz_team@................... > wehz@......................... Art Frankel > Subject: Re: CNSS Update > > Tom- > I think that Dave Wald is the single most important person for the > useful > development of ANSS because he is the one working to develop an active > feedback > relationship with the > ultimate users of the groundmotion recorded where people live -- the people > themselves. > I see that Dave Wald has not been included as a participant in the ANSS > planning and that is a serious oversight if you are seriously planning to > make > this project relevant to the Internet citizens of seismogenic regions who > are > already more connected with each other and with what is shaking than we are. > -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: CNSS Update (San Jose Array) From: Edward Cranswick cranswick@........ Date: Wed, 15 Mar 2000 13:11:28 -0700 All- The correct link to Art Frankel's website, "Description of Animation of Seismic Waves Observed Across the San Jose Array", is: -Edward Edward Cranswick wrote: > Tom- > Are you aware of the San Jose Array that Art Frankel has been spear-heading > for the last couple of years? It is unprecedented in the view that it provides > of the actual propagation of ground motions -- and Art has done a brilliant job > of giving us this vision . > However it lacks any significant contact with the people in whose homes > we have installed the Web sensors of > ground motion (K2's) -- I don't believe they have even been informed of the > websites above. These people represent the tip of the iceberg of a constituency > of concerned and committed citizens and residents who would actively support > NEHRP goals and funding programs. They provide the USGS with a direct contact to > the people who are most connected with the data we are recording -- it is > essential to involve them as partners in the our earthquake monitoring programs. > > -Edward > > "Heaton, Thomas" wrote: > > > Ed, > > > > Thanks for the comment. Dave is indeed an important person to ANSS. > > Dave is a very active participant in the TriNet project and his > > work has been important to forming the goals of ANSS. I'll discuss > > with Lucy Jones (his supervisor) the issue of whether or not to > > try to get Dave more involved in the management of ANSS. > > > > Tom Heaton > > > > -----Original Message----- > > From: Edward Cranswick [mailto:cranswick@......... > > Sent: Wednesday, March 15, 2000 11:11 AM > > To: Heaton, Thomas > > Cc: 'cnss-list@......... David Wald; geo_haz_team@................... > > wehz@......................... Art Frankel > > Subject: Re: CNSS Update > > > > Tom- > > I think that Dave Wald is the single most important person for the > > useful > > development of ANSS because he is the one working to develop an active > > feedback > > relationship with the > > ultimate users of the groundmotion recorded where people live -- the people > > themselves. > > I see that Dave Wald has not been included as a participant in the ANSS > > planning and that is a serious oversight if you are seriously planning to > > make > > this project relevant to the Internet citizens of seismogenic regions who > > are > > already more connected with each other and with what is shaking than we are. > > -Edward > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: shim stock From: ChrisAtUpw@....... Date: Wed, 15 Mar 2000 18:44:40 EST In a message dated 15/03/00 19:46:19 GMT Standard Time, sean@........... writes: > Difficulties with the stainless are that it is almost unsolderable; > if you epoxy the hinges, rough up the stainless with 600 grit emory. > I use the office paper cutter to cut it into narrow strips. Sean, If you use the proper stainless steel flux, EN58 austenitic stainless steel soft solders quite easily. The flux must be washed off thoroughly immediatly afterwards, as it is very corrosive. Regards Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: shim stock hinges From: George Harris gjharris@............. Date: Thu, 16 Mar 2000 12:52:26 -0500 S-T Morrissey wrote: > Regarding shim stock for hinges or flexures: > > In the event that C&H sells out of the shim stock that Jim has > posted info on, it can be obtained from McMaster Carr Supply > (630 833 0300): (MC, VISA, by UPS) Recently, I have located sources for thin beryllium copper which I consider the ideal material for hinges. The sample which I have is .002 thick, and has a strength of 70,000 psi. By heat treating at 600 deg. F for a couple hours, the strength is 150,000 psi. Due to the fact that the modulus of elasticity is about 60 % of steel, the hinges are more flexible. It is also fully solderable after removal of the thin oxide. By having a simple fixture, the part can be formed in the soft condition, and it will retain any shape after hardening. As an example, the parts which are 1/4 inch wide by .002 thick have an "S" shape to fit around a 1/2 in. rod and have an elastic limit of 75 pounds each. In order to heat treat it, I have constructed a tiny oven of firebrick which is placed on a gas range with a thermocouple sensor. I would consder making hinge springs for others at minimal cost if we can agree on a configuration which would be generally useful. The present springs are designed to fit around two 1/2 inch cylinders placed .7 inches apart, and be fastened by 4-40 screws on the far sides of the cylinders. The mounting holes are 1.67 inches apart, so that a pair cross at 90 degrees when mounted in opposite directions. Tabs of approximately 3/8 inch on each end can be used to conduct currents of any reasonable magnitude. George Harris - Benicia, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: shim stock hinges From: ChrisAtUpw@....... Date: Thu, 16 Mar 2000 20:37:15 EST In a message dated 16/03/00 20:55:44 GMT Standard Time, gjharris@............. writes: > Recently, I have located sources for thin beryllium copper which I > consider the ideal material for hinges. > The sample which I have is .002 thick, and has a strength of 70,000 > psi. By heat treating at 600 deg. F > for a couple hours, the strength is 150,000 psi. > ....... > In order to heat treat it, I have constructed a tiny oven of firebrick > which is placed on a gas range with a thermocouple sensor. Please do remember that Beryllium is EXTREMELY TOXIC. Regards Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: N.Calif event From: barry lotz gbl@....... Date: Thu, 16 Mar 2000 19:44:19 -0800 Hi I've uploaded a new event file for a small vertical "strong motion" accelerometer. I'm not to familiar with acceleration recording accept that I realize the frequency content is a higher. I increased my sample rate for the Lehman and this sensor to 50 hz. I was surprised to get little long period content in this recording. Is this common for accelerations? I am using a Vrdt at the end of a ~ 6" long beam with a phosphor bronze hinge at the support( natural freq is about 25 hz). I have a 4" speaker coil/magnet feedback to provide some damping. Is it possible the feedback is too strong ie damping to high and therefore my long period waves are truncated? The "official tap" test shows about a two cycle response before stopping so the damping appears to be reasonable.Though I highpassed the signal @ 0.5 hz there wasn't much below. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: N.Calif event From: Edward Cranswick cranswick@........ Date: Thu, 16 Mar 2000 22:57:54 -0700 Barry- I was intrigued by your question so I used it as an excuse to get my WinQuake act together and install the most recent version, v 2.6. A M5.8 earthquake is going to have an S-wave corner frequency near 1 Hz, and it can also generate alot of Raleigh waves on the vertical that are peaked at even lower frequencies. The S-wave corner frequency is controlled by the fault dimension, and to first order, it is equal to the reciprocal of the S-wave travel time along the fault, i.e., the fault length divided by the S-wave velocity. I looked at the spectra of your record and noted that it was flat from about 10 Hz (where you must have your low-pass, anti-aliasing-filter corner frequency) down to 0.5 Hz where your high-pass is. It would be interesting to see the record before you high-passed it: it should start rolling off at lower frequencies somewhere just below 1 Hz. In the absence of instrument response, in theory, the acceleration spectrum should be flat in the band that extends from the S-wave corner-frequency up to f_max -- the high-frequency limit caused by the low-pass filter characteristics of the Earth. -Edward barry lotz wrote: > Hi > I've uploaded a new event file for a small vertical "strong motion" > accelerometer. I'm not to familiar with acceleration recording accept > that I realize the frequency content is a higher. I increased my sample > rate for the Lehman and this sensor to 50 hz. I was surprised to get > little long period content in this recording. Is this common for > accelerations? -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: CNSS Update From: John Hernlund hernlund@....... Date: Fri, 17 Mar 2000 18:26:59 -0700 (MST) Edward, I have been using the CNSS catalog for some time now, but there has been some recent work done on relocating events in a global catalog and invariably producing much better data. Is there any efforts by the USGS to catalog and distribute any of this data, or if not do you know any good places to find this kind of data? John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: N.Calif event From: barry lotz gbl@....... Date: Fri, 17 Mar 2000 19:27:06 -0800 Ed Thanks for the assistance. As soon as I can get some photos together I would like to share my wanderings with others. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: CNSS Update (San Jose Array)] From: Edward Cranswick cranswick@........ Date: Mon, 20 Mar 2000 20:44:19 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Jim- As far as I know and from what Art Frankel says in his page of explanation on the website , the waveforms are acceleration recorded by the internal K2 FBAs and then band-passed at 0.125 - 0.25 Hz (4.0-8.0 s period) -- they have not been integrated. Only at these long wavelengths is the wave propagation coherent across the array, given the inter-element spacing of 1.0 km (which is large or small alternately, depending upon whether one is researching high-frequency seismology or paying for the hardware and installation). Though this seems quite a low frequency band, we coincidently saw a strong site response in Avcilar, Turkey at these frequencies that seems to be responsible for significant damage to 4-6-story reinforced concrete apartment buildings . With respect to your abstract (part of which I quote below), "DOE technical reports in the early 1970’s, were the first to describe the anomalous high shaking that occurs in parts of the Las Vegas Valley from seismic waves, generated from underground nuclear tests. A more recent publication (1998), by UNR Seismological Laboratory seismologists, determined the anomalous site amplification (anomalous shaking) for the Las Vegas Basin is even higher than previously reported. They analyzed DOE seismic strong motion data recorded in Las Vegas from the 1992, Little Skull Mountain earthquake, M5.6." though I participated in our aftershock investigation of the Little Skull Mountain Earthquake at NTS, I am not familiar with the work done in Las Vegas. I am sure that virtually anywhere one monitors a basin with sufficient density of seismic stations, one will finf "anomalous shaking". -Edward Jim ODonnell wrote: > Hi Ed- I just finished downloading the SJ Array movie, it took 50min's as > it is almost 8Mb, but it was really outstanding!!! Could you tell us > what seismometer is being used, as the K2, I gather, is only a digital > recorder from Kinemetrics. The data looks like it is in velocity, so I > am assuming you used a strong motion accelerometer and then integrated > but please fill us in on that. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Subject: Re: N.Calif event From: Edward Cranswick cranswick@........ Date: Mon, 20 Mar 2000 22:24:15 -0700 Barry- Check out these files: ftp://groundmotion.cr.usgs.gov/PSN/20000316/PLOT0018.GIF Acceleration. N.Calif event recorded by Larry's accelerometer in Redwood City. (error in annotation indicates velocity: CM/S) ftp://groundmotion.cr.usgs.gov/PSN/20000316/PLOT0019.GIF Velocity. Same as above, integrated to velocity (error in annotation indicates displacement: CM) ftp://groundmotion.cr.usgs.gov/PSN/20000316/PLOT0020.GIF Velocity. Same as above, integrated to velocity, and high-passed at 0.01 Hz (error in annotation indicates displacement: CM) -Edward barry lotz wrote: > Hi > I've uploaded a new event file for a small vertical "strong motion" > accelerometer. I'm not to familiar with acceleration recording accept > that I realize the frequency content is a higher. I increased my sample > rate for the Lehman and this sensor to 50 hz. I was surprised to get > little long period content in this recording. Is this common for > accelerations? . . . -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: HS 10-1 1 hz Geophone refurbishing From: Larry Cochrane cochrane@.............. Date: Tue, 21 Mar 2000 21:25:27 -0800 Greetings, If you have one of the GeoSpace HS 10 -1 geophones from the PSN group buy last year, or you happen to have one, I have the following info for you. A couple of days ago I contacted GeoSpace to see how much it would cost to refurbish one of the units I have. They could not give me a quite without seeing it, so I sent one (I have two from the group buy) too them. They called today and gave me a quote of $150.00 + shipping to overhaul the unit and to test and re calibrate the unit. Not bad... New units go for ~$2600. They do have a cheaper GS-1 model at ~$1000. If your interested, heres the person to contact: Tim Allmendinger at tima@................ and heres their address: GeoSpace Corp 7334 N. Gessner Houston, Tx 77040 attn: Tim Allmendinger Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: STS-1 docs From: Brett Nordgren bnordgren@.............. Date: Wed, 22 Mar 2000 13:52:20 -0500 To the hardware folks, Does anyone have any mechanical specs, dimensions or operation/service manuals for the Streckeisen STS-1 vertical? I recently finished up the preliminary analysis work on the fixed-end leaf spring like it uses, and would like to try out some calculations with data that's a little better than my guesses of its dimensions, etc. Also what I'd like to find out are things like how they attach their LVDT and forcing coils to the boom. With flexures? Rigid connection? And what are the effective mass, spring dimensions and thickness, etc. Info on their adjustment procedures would also help figure out some of the details. I'd be happy to pay for copies and postage for whatever anyone has. The side-plate boom design with a fixed-end spring looks like an interesting approach that might not be too hard to build if the spring analysis proves to work out OK. Best regards, Brett __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: STS-1 leaf spring From: S-T Morrissey sean@........... Date: Wed, 22 Mar 2000 13:55:51 -0600 (CST) Brett, The only published dimensional info on the STS-1 seems to be in the paper: Wielandt, E. and G. Streckeisen, "The Leaf-Spring Seismometer: Design and Performance", Bull. Seism. Soc. Am., 72, 2349-2367, December 1982 which has a sketch with some dimensions of the elliptic spring configuration. The spring, by the way, is firmly clamped at BOTH ends (to the frame and to the outside end of the boom) with the boom inside end pivot under the center of the ellipse. Both ends of the two-metal spring have to flex where they are massively clamped under head-touching-head rows of screws. Rumor has it that adjusting these screws is a dark art of the assembly process that can take weeks, and that there is a high rejection percentage (hence the high cost). The transducers are mounted above the spring and above the pivot with clear plexiglass fixtures. THey use a proprietary LVDT that accommodates the rotation about the flexures, which are ~ 6mm Bendix cylinders. The LVDT coils and the feedback/calibration magnets are mounted to the frame; fine pigtails connect to the moving coils. The STS manual gives no dimensions other than overall specs, but does have some useful photos. I have some installation photos of the sensor with all the shields removed, but not of any focused details. When I first explored making a VBB vertical in '97, I tried to emulate a 2x version of the elliptic spring. I quickly realized that the flexure of the ends of the spring was innately involved, and decided to mount the spring with isolating flexures instead, and use it strictly for one-dimensional lift of the boom rather than a bending movement. I can send you excerpts from the manual; most of it is taken up with schematics. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: STS-1 leaf spring From: Brett Nordgren bnordgren@.............. Date: Wed, 22 Mar 2000 17:10:36 -0500 Sean-Thomas, Thanks for the quick reply. At 01:55 PM 3/22/2000 -0600, you wrote: >Brett, > >The only published dimensional info on the STS-1 seems to be in the paper: >Wielandt, E. and G. Streckeisen, "The Leaf-Spring Seismometer: Design and >Performance", Bull. Seism. Soc. Am., 72, 2349-2367, December 1982 Yes, thanks, I'd gotten that one from Bob Barns. Those were the dimensions I was starting out with. Just guessed at the mass (0.41 Kg), and spring width (73mm), and don't yet know what to assume for the side-plate mass. >which has a sketch with some dimensions of the elliptic spring >configuration. The spring, by the way, is firmly clamped at BOTH ends >(to the frame and to the outside end of the boom) with the boom >inside end pivot under the center of the ellipse. Both ends of the >two-metal spring have to flex where they are massively clamped under >head-touching-head rows of screws. Rumor has it that adjusting these >screws is a dark art of the assembly process that can take weeks, >and that there is a high rejection percentage (hence the high cost). I'd suspected that there might have been two springs, possibly one Elinvar or such and one spring steel. Since both are clamped, they could be arranged to be spaced a small distance apart, far enough not to touch. I'm hoping that the tempco won't be too bad with a single steel spring as I have no idea where to get tempered Elinvar or Ni-Span-C . It might turn out that they are adjusting the net tempco toward zero by slightly tuning the spring geometry, which I think would indeed qualify as a dark art. >The transducers are mounted above the spring and above the pivot with >clear plexiglass fixtures. THey use a proprietary LVDT that accommodates >the rotation about the flexures, which are ~ 6mm Bendix cylinders. >The LVDT coils and the feedback/calibration magnets are mounted to >the frame; fine pigtails connect to the moving coils. With such a short radius, I'd been wondering how they avoided nonlinearities, or even worse, jamming in the bores. >When I first explored making a VBB vertical in '97, I tried to emulate >a 2x version of the elliptic spring. I quickly realized that the >flexure of the ends of the spring was innately involved, and decided >to mount the spring with isolating flexures instead, and use it strictly >for one-dimensional lift of the boom rather than a bending movement. I agree, the fixed-end spring is a hard gadget to analyze. Think I may have found an approach to solve it that's crude but fairly accurate, using Excel. Broke the spring into 600 pieces, assumed an end force and bending moment and calculated the bending of each piece as they get stacked end-to-end, sort of a poor-man's FEM approach. After stacking up all 600, that gave a trial location for the end of the spring and also its end-slope. Then used the Excel "Solver" function to try different values and directions for the force and different end moments until (after about 15 sec.) it would come up with set that had the spring arriving at the desired point at the desired angle. Messy, but the results are looking quite reasonable. >I can send you excerpts from the manual; most of it is taken up >with schematics. Anything you have the time to copy would be greatly appreciated. Happy to cover any costs. Thanks and best regards, Brett __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: STS-1 docs From: Karl Cunningham karlc@....... Date: Wed, 22 Mar 2000 16:38:09 -0800 Hi Brett -- Nice to hear from you again. I have constructed a 1:1 model of the STS-1 leaf spring, based on the sketch in the paper referenced by Sean-Thomas. By the way, I can send electronic copies of the article to anyone that wants them. I have done testing with several variations in dimensions and don't see any significant "zero length" effect (which, incidentally, I think might be more properly termed infinite length). I did see the many spring attachment screws in the photo in the paper, but I don't know how that works. Sean-Thomas, do you think they adjust the moment imparted to the spring at the attachment point? I was rather disappointed that the spring showed no zero-length effects, and have gone in the direction of investigating period-lengthening over-center auxillary springs. This seems promising, but kludgey. I am very interested in any changes I might try on the prototype that could improve its performance. I'd be happy to do any tests. Karl At 01:52 PM 3/22/2000 -0500, you wrote: >To the hardware folks, > >Does anyone have any mechanical specs, dimensions or operation/service >manuals for the Streckeisen STS-1 vertical? I recently finished up the >preliminary analysis work on the fixed-end leaf spring like it uses, and >would like to try out some calculations with data that's a little better >than my guesses of its dimensions, etc. > >Also what I'd like to find out are things like how they attach their LVDT >and forcing coils to the boom. With flexures? Rigid connection? And what >are the effective mass, spring dimensions and thickness, etc. Info on >their adjustment procedures would also help figure out some of the details. > >I'd be happy to pay for copies and postage for whatever anyone has. > >The side-plate boom design with a fixed-end spring looks like an >interesting approach that might not be too hard to build if the spring >analysis proves to work out OK. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: STS-1 docs From: Brett Nordgren bnordgren@.............. Date: Wed, 22 Mar 2000 21:38:51 -0500 At 04:38 PM 3/22/2000 -0800, you wrote: >Hi Brett -- > >Nice to hear from you again. You too, Karl, it's been a while. >I have constructed a 1:1 model of the STS-1 leaf spring, based on the >sketch in the paper referenced by Sean-Thomas. By the way, I can send >electronic copies of the article to anyone that wants them. I have done >testing with several variations in dimensions and don't see any significant >"zero length" effect (which, incidentally, I think might be more properly >termed infinite length). In looking at the first results of the numbers, it became apparent what they were doing. The major spring effect was from the bending effect at the ends, not the end forces. It's working more like the mainspring of a clock than like a coil spring. Imagine a leaf spring with each of its ends attached to the side of a round stick, so that by twisting the two sticks, you could make the spring form into a curve. If you only twist and don't push or pull on the ends, the curve will be an arc of a circle. Now, by just twisting, formin the spring into a half circle. Then start pulling to the sides to make the ends of the spring separate more. To keep the ends vertical (parallel), you will have to twist harder. Pull apart more, twist more. That's what seems to be happening to the spring in the STS-1. The end *force* exerted by the spring is actually trying to make the boom rotate downward. However the twist (the end moment) is a substantially greater effect, and is working in the direction to lift the mass. In that configuration, as the beam tips up and down, the end moment changes very little. With everything balanced, beam tilt has very little effect on the spring moment which equals very little change on the force supporting the mass which means long period. If you look at pictures of the STS-1, you can see the flattened curve the spring takes when the end forces applied to the spring are directed outwards, rather than inwards, as you might expect to have. To get that in your prototype, you need to be sure the spring is the length given in the article, so that it has to flatten out somewhat. Also, it appears that the STS-1 must be using fairly thin spring material. With something like 0.008" for a single spring, the model started looking fairly reasonable. 0.018" material bent that sharply would take a very permanent set. Over a +/- 5 degree boom motion, the lifting force looked to be changing by less than 0.6% Don't know what that implies for natural period, but pretty long for a first try. Maybe too good; I need to go over the numbers more closely to be sure they are all making sense. Still need much more playing to understand what's happening, particularly to find a configuration where the beam will sit stable at zero without help. As you can tell, this is still all real preliminary. Regards, Brett __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: [Fwd: CNSS Update]] From: Edward Cranswick cranswick@........ Date: Thu, 23 Mar 2000 17:57:43 -0700 John- In answer to your question below about relocating events in the CNSS catalog, I am forwarding a response from Bruce Presgrave of the NEIC. -Edward > Edward, > I have been using the CNSS catalog for some time now, but there has been > some recent work done on relocating events in a global catalog and invariably > producing much better data. Is there any efforts by the USGS to catalog and > distribute any of this data, or if not do you know any good places to find > this kind of data? > > John Hernlund > -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Subject: Quake coming in... From: meredith lamb mlamb1@.......... Date: Thu, 23 Mar 2000 21:34:51 -0800 Hi all, This one seems to have a significant vertical component signal. Probably north-south or central America. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Interesting Science Article From: John Hernlund hernlund@....... Date: Fri, 24 Mar 2000 14:57:12 -0700 (MST) Hello All, Just ran across an interesting article in today's Science about noise and how it is coupled to the atmosphere. The abstract follows: Resonant Oscillations Between the Solid Earth and the Atmosphere Kiwamu Nishida, 1 Naoki Kobayashi, 2 Yoshio Fukao 1 Continuously excited free oscillations of the whole Earth have been found in the ground noise in a frequency band of long-period surface waves. Here we report evidence of an annual variation of this phenomenon, indicating that the excitation source is not within the solid Earth. There is evidence that these seismic free oscillations resonate with acoustic free oscillations of the atmosphere. The observed amplitudes suggest that the excitation source is at or just above Earth's surface. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: STS-1 info From: S-T Morrissey sean@........... Date: Sun, 26 Mar 2000 21:30:15 -0600 (CST) Brett and Karl, Interesting work on the STS-1 leaf spring. The complexity of it reassures my own decision to avoid it and use a simple linear spring configuration. Unfortunately, I have not had the opportunity to dismantle a STS-1 to examine the hidden details. (but there is an interesting thought: just what major new insight into seismometer design will make those pricey pups so obsolete that they show up on ebay for $100 ? !!). I have heard (a rumor?) that they will not be made anymore because of the cost, and since the STS-2 is suitable for most applications. The advertised mass of the STS-1 is 0.6 kg. The mechanical period of the vertical used in calculating the response is 6 seconds. But note that the mechanical period only affects the damping in a VBB fedback system. The closed loop period is controlled by Cp, RI, and TI. As the sensor is tilted over backwards toward the hinge, the period will become infinite as the restoring force approaches zero. It seems that the micro-manipulative factory adjustments of the spring are made to achieve this, along with modifications of the thermal contributions of the two different spring materials. However, with the feedback turned on, long term changes in the mechanical period result in only very small changes in the damping and closed loop period. When the seismometers are installed, both the vertical and the horizontal are physically adjusted by tilting the base so that barely sustained constant amplitude self oscillations are achieved at a Tn of 20 seconds by the closed loop with the feedback resistor Rp disconnected. This way a specific mechanical period is achieved so that the factory calibration is replicated in the field. As for the clamping bars, I can only guess. An old technique used for clamping leaf springs involves a raised rounded ridge (or even a small hardened rod installed in a groove) on one side of the clamps' fixed half towards the spring body. The screwed clamp was outside this, and tighting the screws pivoted the spring over the ridge, changing the exit angle from the clamp and therefore the torque applied to the end of the spring. If this is the case for the STS-1, tightening the screws would change the ellipticity of the springs. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Huge Tele Comming In From: peaches@............ (Donna Whitaker) Date: Tue, 28 Mar 2000 01:25:10 -1000 (HST) very large here in hawaii __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Huge Tele Comming In From: n0cwr@......... Date: Tue, 28 Mar 2000 12:32:37 +0000 00/03/28 11:00:20 UTC 22.41N 143.59E Depth: 116.2 km 7.7Mw VOLCANO ISLANDS, JAPAN REGION At 01:25 AM 3/28/00 -1000, you wrote: >very large here in hawaii > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New channels online From: Larry Cochrane cochrane@.............. Date: Wed, 29 Mar 2000 01:24:19 -0800 Greetings, Recently I add a few more channels to my system. The new event files ending with LCZ, LCN and LCE are from the Kinematics FBA-23A I have on loan from the USGS. This sensors is a +- 2g max 3 component strong motion accelerometer. The new channels have a gain of 200 before the A/D converter. The LC4, LC5 and LC7 files on my system are from the same sensor, but with no gain between it and the A/D converter. I have been running these channels since 6/97. All channels go through low and high pass filtering before the A/D converter. See http://www.seismicnet.com/rwcstation.html for more information. By creating the new channels with the gain of 200 I have been able to record some nice seismograms. I was even able to record the 7.7Mw Volcano Islands event today! At first glance the raw files (their on my archive system) appear not to have recorded this event. But if you integrate the record, this converts acceleration to velocity, and then do a .02 hz 3 pole high pass filter to clean up the data, you will see a very nice recording of the event. The best file too look at is 000328a.lce. After integration and filtering It clearly shows the P, S and long period surface waves well above the background noise. I placed a gif image of the processed event file here ftp://www.seismicnet.com/000328a.lce.gif. Not bad for a strong motion sensor. Now that I have the new high gain channels I don't have to wait for large local events to get useful data out of the sensor. I would have done this sooner but I didn't think it had the dynamic range to add more gain between it and the A/D board. Since this sensor has a know output, it was calibrated and refurbished at Kinematics (for free!) last year, I can use it as a "standard" to compare it to other sensor I have on my system. Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Accelerometer update From: barry lotz gbl@....... Date: Wed, 29 Mar 2000 06:17:51 -0800 Hi All Well it's nice to occasionally have the math work out. I have been running a small vertical accelerometer for a few weeks now and I recently got a response from the 7.7 Volcano Isl. event. Using the equation Sean Thomas posted 11/99: A=T*10^[Ms-1.66*log(dist)+0.18] and multiplying by 2*pi*f twice to get acceleration I came up with an event P-P acceleration of 0.0000106g @ 20 sec. My sensor has a sensitivity of about 4.6E-8g/cnt. Using this I come up with a P-P response of about 250 cnts. The record corresponds. I'll post it and the SMT8 style vertical response, which was just at the clip level. Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New channels online From: Jim ODonnell jimo17@........ Date: Wed, 29 Mar 2000 06:48:35 -0800 Larry- Your work with the SM sensors is OUTSTANDING! Thanks.. Jim __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New channels online From: Larry Cochrane cochrane@.............. Date: Wed, 29 Mar 2000 14:48:48 -0800 Sorry, the correct URL for the gif image of the 7.7 event yesterday is http://www.seismicnet.com/000328a.lce.gif. -Larry >Date: Wed, 29 Mar 2000 01:24:19 -0800 >To: psn-l@.............. >From: Larry Cochrane >Subject: New channels online > >Greetings, > >Recently I add a few more channels to my system. The new event files ending with LCZ, LCN and LCE are from the Kinematics FBA-23A I have on loan from the USGS. This sensors is a +- 2g max 3 component strong motion accelerometer. The new channels have a gain of 200 before the A/D converter. The LC4, LC5 and LC7 files on my system are from the same sensor, but with no gain between it and the A/D converter. I have been running these channels since 6/97. All channels go through low and high pass filtering before the A/D converter. See http://www.seismicnet.com/rwcstation.html for more information. > >By creating the new channels with the gain of 200 I have been able to record some nice seismograms. I was even able to record the 7.7Mw Volcano Islands event today! At first glance the raw files (their on my archive system) appear not to have recorded this event. But if you integrate the record, this converts acceleration to velocity, and then do a .02 hz 3 pole high pass filter to clean up the data, you will see a very nice recording of the event. The best file too look at is 000328a.lce. After integration and filtering It clearly shows the P, S and long period surface waves well above the background noise. I placed a gif image of the processed event file here ftp://www.seismicnet.com/000328a.lce.gif. Not bad for a strong motion sensor. > >Now that I have the new high gain channels I don't have to wait for large local events to get useful data out of the sensor. I would have done this sooner but I didn't think it had the dynamic range to add more gain between it and the A/D board. Since this sensor has a know output, it was calibrated and refurbished at Kinematics (for free!) last year, I can use it as a "standard" to compare it to other sensor I have on my system. > >Regards, >Larry Cochrane >Redwood City, PSN > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New channels online From: Edward Cranswick cranswick@........ Date: Wed, 29 Mar 2000 17:16:25 -0700 Larry- I haven't looked at your record yet -- other than your picture of it below -- but that looks great, and you should send your earlier email about it (with the URL corrected) to Kinemetrics -- I am sure they would appreciate knowing what you have done with the FBA they repaired. -Edward Larry Cochrane wrote: > Sorry, the correct URL for the gif image of the 7.7 event yesterday is > http://www.seismicnet.com/000328a.lce.gif. > > -Larry -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Japan Mount Usu may erupt soon From: meredith lamb mlamb1@.......... Date: Wed, 29 Mar 2000 21:06:45 -0800 Hi all, All those Hokkaido earthquakes listed on the NEIC web sites, are but the larger of some 2,996+ smaller tremors over the last 3 days. Mount Usu seems to be giving signs of a near term eruption. See: http://www.discovery.com/news/earthalert/000327/volcanojapan.html The above is rather dated, but for the present the update seems to be hard to see there (they are probably undating their computer). Check: http://www.discovery.com Meredith lamb P.S. There are now 34 extrasolar planets discovered, with 2 more today. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Japan Mount Usu may erupt soon From: Canie canie@........... Date: Wed, 29 Mar 2000 20:12:52 -0800 Here's a recent update I got from USGS: *************************** Usu Volcano, Japan crisis *************************** From: Setsuya Nakada The present state of seismicity at Usu Volcano is the highest in level. Volcanic Alert was issued by JMA on the 29 March morning. This issue is the first time since the Unzen eruption (1990-95). Number of volcanic earthquakes on 29 March was 1,629 (16 and 599 on 27 and 28 March), including low-frequency earthquakes whose number increases with time. Felt quakes that took place on this day over 600 times. The quake of M4.2 occurred at 17:22 (JST), 29 March. According to JMA, the hypocenter of volcanic earthquakes locates on the northwestern slope. The focal mechanism analysis indicates a fault with nearly vertical slip plane. The GPS network of Geographical Survey Institute, Japan, which surrounds the volcano has caught the inflation of the volcano. Neither volcanic tremor event nor visible change in fumarolic gas has been observed yet. Committee including volcanologists, chaired by Prof. Tad Ui, Univ. of Hokkaido, gave the possibilities of an eruption on the northwestern slope, the summit eruption after migration of hypocenter, and phreatic or phreatomagmatic eruption following larger earthquakes. Flank failure and pyroclastic flows are also probable. People living in a city and two towns around volcano were required to evacuate from their houses by the local governments on the 29 March afternoon. Totally more than 9,000 people and all rourists in the hot spring resorts on the northern foot of this volcano had evacuated by the night. ************************************ Setsuya Nakada, Volcano Research Center, ERI, Univ. Tokyo TEL 03-5841-5695/FAX 03-3812-6979 At 09:06 PM 3/29/00 -0800, you wrote: >Hi all, > >All those Hokkaido earthquakes listed on the NEIC web >sites, are but the larger of some 2,996+ smaller tremors over >the last 3 days. Mount Usu seems to be giving signs of a near >term eruption. See: > >http://www.discovery.com/news/earthalert/000327/volcanojapan.html > >The above is rather dated, but for the present the update seems >to be hard to see there (they are probably undating their computer). > >Check: http://www.discovery.com > >Meredith lamb > >P.S. There are now 34 extrasolar planets discovered, with >2 more today. > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Japan Mount Usu may erupt soon From: Canie canie@........... Date: Wed, 29 Mar 2000 20:26:02 -0800 There's lots of updated info from Reuters and Associated Press: http://dailynews.yahoo.com/h/ap/20000329/wl/japan_volcano_8.html http://dailynews.yahoo.com/h/nm/20000329/wl/japan_volcano_6.html Canie At 09:06 PM 3/29/00 -0800, you wrote: >Hi all, > >All those Hokkaido earthquakes listed on the NEIC web >sites, are but the larger of some 2,996+ smaller tremors over >the last 3 days. Mount Usu seems to be giving signs of a near >term eruption. See: > >http://www.discovery.com/news/earthalert/000327/volcanojapan.html > >The above is rather dated, but for the present the update seems >to be hard to see there (they are probably undating their computer). > >Check: http://www.discovery.com > >Meredith lamb > >P.S. There are now 34 extrasolar planets discovered, with >2 more today. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: UPDATE 1-Cracks seen on Japan volcano, may signal eruption From: Seisguy@....... Date: Thu, 30 Mar 2000 00:25:14 EST UPDATE 1-Cracks seen on Japan volcano, may signal eruption By Kazunori Takada TOKYO, March 30 (Reuters) - A military helicopter spotted cracks opening up on Thursday on the slopes of a rumbling volcano on Japan's northern island of Hokkaido, a sign the snow-capped mountain may be about to blow its top, officials said. Dozens of earthquakes and tremors were shaking the volcano and surrounding villages every hour and officials have told residents to move further away after nearly 10,000 people were evacuated on Wednesday amid warnings of an eruption. Cracks up to 100 metres (330 ft) long on the slopes of the 732-metre (2,402 ft) Mount Usu were spotted by a military helicopter patrol, the Meteorological Agency said in an emergency bulletin. The Geographical Survey Institute had found the volcanic activity had stretched the area around the mountain by one cm (0.4 inches), the Kyodo news service said. Train services in the area had been disrupted, it said. Some 60 troops had been sent to snow-covered villages around Mount Usu to evacuate the elderly and disabled, said an official of the Ground Self Defence Force, Japan's army. More than 3,000 earthquakes and tremors, including five measuring close to five on the Japanese scale of seven, have shaken the area around the volcano since it started to rumble on Sunday, a Meteorological Agency spokesman said. ``The volcanic activity at this time is greater when compared with previous pre-eruption activity,'' Naoya Mikami, deputy director of the Volcanological Division at the Meteorological Agency, told Reuters. However, he said he was unable to say whether such activity heralded a larger eruption than in 1978 when Mount Usu last blew its top, belching rocks and steam after a series of earthquakes. Mud slides triggered by the eruption killed three people. Local officials said they have extended the evacuation area and police patrolling towns near the foot of the volcano have been told to withdraw after ensuring all residents had left. Two quakes of magnitude 4.2 shook the area within minutes of each other late on Wednesday and officials said some tremors appeared to be growing more prolonged, perhaps signalling the movement of magma beneath the earth's surface. Officials warned of possible mud slides because the snow blanketing the slopes of the cone-shaped mountain could melt rapidly in the event of an eruption. Some 10,000 people were housed in schools and public halls after officials ordered residents of three nearby towns to move. ``I was so scared, I couldn't sleep,'' Suki Matsuyama, a 73 year-old woman, was quoted by the Mainichi Shimbun as saying. ``I didn't think earthquakes could be so frightening,'' she said. Some 3,300 military personnel are on standby, preparing food, water and blankets in case a full evacuation of the area becomes necessary and 40 others were sent on reconnaissance missions, the Defence Force official said. A Hokkaido government official said 55,000 people living in five towns around the foot of the mountain, including the hot spring resort town of Toya, could be affected by an eruption. Scientists have said there is a strong chance of an eruption, since history shows the mountain's volcanic eruptions are often preceded by one to several days of heightened seismic activity. Mount Usu normally logs 20 to 30 tremors a month, the agency said. Officials have warned there is a chance that an eruption at Mount Usu could mimic the deadly flow of superheated gas and ash from Mount Fugen in southern Japan in 1991, which killed 43 people. 00:22 03-30-00 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: extending Benioff response From: S-T Morrissey sean@........... Date: Thu, 30 Mar 2000 12:43:45 -0600 (CST) Here is some email I forgot to post regarding some specific questions that I haven't answered yet. Bob L. has asked about extending the effective period of a "baby" Benioff seismometer using either the equalization technique of Roberts or a VBB feedback method. An advantage of the "baby" Benioff 1 second seis is that it has a 14.402kg (for Z) mass. A disadvantage is that it is a variable reluctance transducer, so the inductance of the coils is a major problem. The seis has 8 coils of 125 ohms each, so it can be set up with the proper series/parallel combination to match almost anything, including the 80 ohm, 0.75 second galvanometers of the WWNSS system. For this a net DC resistance of 65 ohms is realized, which has an inductance of 5 henries. This puts the inductive pole (Rs+Rd)/L*2*pi at 4.5hz, or within the passband of the data. This inductance presents a major phase delay problem for a fedback system using the coils. For electronic recording the coils are connected all in series for 1000 ohms and overdamped with 1200 ohms in parallel. The inductance of this configuration is measured at 8 henries (mutual inductance of the individual coils makes the various combinations incalculatable). This moves the inductive pole to about 44 hz. For a feedback system, this is still a serious inductance, and the high coil resistance makes the transfer function unstable at higher frequencies. For this reason, I have not attempted to install a displacement transducer on one of my Benioffs so as to try a VBB feedback. But I see no reason why an equalization circuit wouldn't work to improve the long period response to 10 seconds or longer. To really make an effective improvement for teleseismic recording, 20 seconds or longer would be needed, which would really push the amplifier noise requirements, particularly the 1/f noise. _________________ On a previous topic regarding brass and stainless steel shim stock: Chris has suggested a readily solderable stainless steel alloy, EN58. There is possibly the rub, as it were. McMaster's shim stock is a 303 alloy, which McMaster says meets the specifications of AMS 5515, SAE 30302, Fed. Spec. QQS-766, and ASTM A177. It makes no mention of EN58 (which may actually be included in one of the given specifications.) The major difficulty of soldering thin/fragile assemblies and using a very corrosive flux is that one needs to use an electronic solder pencil to control the heat so as not to greatly modify the temper (as a micro torch would do), and I don't want to contaminate the tips I use for electronics with a corrosive flux, so they have to be carefully separated and cleaned. McMaster sells a variety of fluxes that I have tried, (and may try again, since I have managed to break a number of the box flexures that I made with 0.002" brass.) Also: George H. has suggested using a heat-treatable beryllium-copper alloy that can be heat treated to restore a hard temper after forming in a soft condition. This would make it a spring, which of course is needed in a vertical sensor, and I believe that some of the diaphram-style spring/flexures, such as in the L4-C, are made this way. But for an application as strictly a flexure in a fedback system, the ideal flexure will have NO restoring force, only positional stabiltiy, such as a pivot (which unfortunately have large micro-positional noise so they are not used). Heat treating might allow a thinner material to be used for the same strength as a thicker soft material with a minimum restoring force, so some calculations are needed. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Followup on Mt Usu in Japan From: meredith lamb mlamb1@.......... Date: Thu, 30 Mar 2000 13:56:49 -0800 Hi all, Apparently there is a remote controlled LiveCam of the Usu, Yotei, Orofure and Toyako Lake area in Japan. It may not be used at night there? Whether its operational at all is unknown at the moment? See: http://sv2.camera.mesh.ne.jp/abuta-e/ibs.htm The above is one of many volcano cams sites listed at: http://educeth.ethz.ch/stromboli/livecams/index-e.html Afew photos of Usu can be seen at: http://www.gsj.go.jp/jdehn/vphoto/vfjapn1.htm Latest reports state an eruption could occur at any time. As per the latest NEIC quake list, the number of ~mag 4 earthquakes has increased significantly. Mount Usu has been mentioned as one of the more dangerious volcanoes in Japan from its history. Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Followup on Mt Usu in Japan From: Canie Brooks canie@........... Date: Thu, 30 Mar 2000 13:07:13 -0800 Here's another live cam: http://www.stv.ne.jp/test1/usu.html Canie At 01:56 PM 3/30/00 -0800, you wrote: >Hi all, > >Apparently there is a remote controlled LiveCam of the Usu, >Yotei, Orofure and Toyako Lake area in Japan. It may not be >used at night there? Whether its operational at all is unknown >at the moment? See: > >http://sv2.camera.mesh.ne.jp/abuta-e/ibs.htm > >The above is one of many volcano cams sites listed at: > >http://educeth.ethz.ch/stromboli/livecams/index-e.html > >Afew photos of Usu can be seen at: > >http://www.gsj.go.jp/jdehn/vphoto/vfjapn1.htm > >Latest reports state an eruption could occur at any time. As >per the latest NEIC quake list, the number of ~mag 4 earthquakes >has increased significantly. Mount Usu has been mentioned as >one of the more dangerious volcanoes in Japan from its history. > >Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Followup on Mt Usu in Japan From: meredith lamb mlamb1@.......... Date: Thu, 30 Mar 2000 14:40:41 -0800 Canie Brooks wrote: > Here's another live cam: > http://www.stv.ne.jp/test1/usu.html > > Canie > Canie, Thanks alot for the reference to another cam of Usu. Interesting cam. Looks like early morning there now with the sun somewhat blinding the picture. Later on it will likely be clearer. Not sure but the picture may change every few minutes....but it could be every 15 minutes or more.... Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: extending Geotech 210 or 220 to a BB Sensor? From: Jim ODonnell jimo17@........ Date: Thu, 30 Mar 2000 21:08:31 -0800 Sean- I enjoyed your comments on the 'baby' Benioff... Geotech 210 and 220: I have 3 complete sets of the Geotech 210 & 220 seismometers, T is adjustable maybe 5-20s. A set being 2H's(220?) and a Z (210, I think). I just installed a set, at UNLV (using Larry's filt/amp and 16 bit A/D) all set about T=15s. I hope to set up 6 individual components in 6 high schools in the next 6 months. Would it be practical or even possible to convert one to a BB sensor? Any comment on this seismometer would be appreciated.... Jim __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Followup on Mt Usu in Japan From: "SMITH ROBERT L." bobsmith5@........ Date: Fri, 31 Mar 2000 11:02:45 -0500 I understand from the morning news that she blew. The last reload I could get off of the live camera was 07:48:34, was it a victum?? Bob Smith meredith lamb wrote: > > Canie Brooks wrote: > > > Here's another live cam: > > http://www.stv.ne.jp/test1/usu.html > > > > Canie > > > > Canie, > > Thanks alot for the reference to another cam of Usu. > Interesting cam. Looks like early morning there now with the > sun somewhat blinding the picture. Later on it will likely be > clearer. Not sure but the picture may change every few > minutes....but it could be every 15 minutes or more.... > > Meredith Lamb > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. -- --------- Avoid computer viruses -- Practice safe hex ------------- * * Specializing in small, cost effective embedded control systems * * Robert L. (Bob) Smith Smith Machine Works, Inc. internet bobsmith5@.............. Lumlay Road landline 804/745-1065 Richmond, Virginia 23236+1004 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Followup on Mt Usu in Japan From: Canie Brooks canie@........... Date: Fri, 31 Mar 2000 09:37:16 -0800 At 11:02 AM 3/31/00 -0500, you wrote:
I understand from the morning news that she blew.

The last reload I could get off of the live camera was
07:48:34, was it a victum??

No - the live cam is still operational - I managed to get a few shots of it - Maybe I'll try to put them out on a web page tonight (they are on my home system) - The camera location seems to move around - the shots I've gotten are from a few different angles.

Its nighttime over there now..so no pics and no lava is flowing.

Canie
Subject: VBB conversion of Geotech LPs From: S-T Morrissey sean@........... Date: Fri, 31 Mar 2000 13:18:56 -0600 (CST) Jim, What a lucky man; its too bad that all your Geotech LP seises are not verticals. The vertical data is much more interesting, since the horizontal generally shows very little of the P-wave. Also, the pier/site tilt problem is much greater for a horizontal, which will affect where you put them. The LP seises are good candidates for converting to a VBB instrument if the coil resistance is low enough. I don't know the parameters of the Geotech units, but a coil resistance of more than a few hundred ohms, when used as the feedback coil, will be unstable. You may have to wind new coils, or find a way to tap the existing winding. One of the first LP sensors that I converted to a VBB is the old Sprengnether 5100 of the WWNSS design: 15 seconds To, 500 ohm coils, and generator constant Gn of 83 N/A. The high coil Rf works in the transfer function because Gn is high as well as the mass is relatively large at 11.2 kg. I use an integrator at 400 seconds with the other parameters of RI = 402k, Cf = 12.29uf , Rp = 2.1 megohm, for a Tn of 280 seconds; Rf is actually 469 ohms, and r is 612900 volts/meter from the LVDT. This gives a velocity output of 11000 Volts/meter/second. I couple the output through a 3000 second high-pass filter to the display recorder in the lobby of our building. It has been operating this way since 1996. The very long period response readily shows 30 to 60 second barometric noise, especially when tornado weather is in the area. If you are going to convert a number of units to a VBB system, we need to make some headway on getting the circuit boards available. I have laid out new boards (voltage regulator, oscillator, VRDT amp/demodulator, and the quad amp board) for the new instrument, but I have not had any actually produced yet. When that happens, I can make a set available at cost, and then maybe Larry can assemble them into a working system. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L)