Mark, Jim and Others... With the input shorted at the A/D board there should only be +- 4 or 5 counts of noise. Either Mark has a ground loop problem or his Amp is oscillating. -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: "Jim Hannon"
To: Sent: Saturday, December 23, 2000 6:05 AM Subject: Re: Amplifier noise? > Mark, > I think that what you are seeing is about the noise level of Larry,s 16 > bit A/D card. You can check this by operating the A/D card with it's input > shorted. Check the noise level and see how it compares to the noise when > your amplifier is connected. > > At 08:53 PM 12/22/00 -0600, you wrote: > > > >Hello Everyone, > > > > > >Recently I finished construction on my first seismometer. I used > >schematics off of Larry Cochrane's web site to wire wrap the amplifier: > >http://psn.quake.net/sgsumamp.gif and http://psn.quake.net/sgproc.gif > > > >I housed the amplifier in a steel box, grounded to analog ground on the > >amplifier board. > > > >I have the output of the amplifier connected to Larry's 16 bit A to D board > >with about 16 feet of shielded wire. The shield, around the wire, is > >grounded to the case of my computer. When viewing the output with SDR I am > >getting about 80 to 100 counts of continuous noise. I don't know what the > >frequency of the noise is but the period is too short to see on SDR. > > > >Is this noise level abnormally high and does anyone have any suggestions on > >how to reduce the noise. > > > >Thanks for your time! > > > >Mark > > > > > > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL > > __________________________________________________________ > > 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)
Larry Cochrane <cochrane@..............>