Geoff:

For wire resistance, see:  http://bnordgren.org/seismo/WireTempco.pdf

I assume that copper still acts the way it did in 1961 when the table 
was printed.

Their formula apparently is RT2 = RT1*(1+(T1-T2)*0.00393)) which 
should be a fairly decent approximation.

Regards.
Brett


At 05:03 PM 11/16/2012, you wrote:

>Thanks to all who have responded,
>I have decided to go with a negative input
>Preamp with about x600 DC gain and an N=1 LPF
>about 3 Hz right at the preamp.
>I will place on my web site at some future
>date an updated schematic.
>I have chosen this over heavy hardware filtering
>because with heavy filtering the
>waveform seems horribly distorted in phase
>and shape. The geophone is HS10-1 1Hz and the
>resistance vary greatly over the year.
>In winter it can be near 400Ohms and in
>summer about 440 or 450. Maybe someone
>can point me to a formula for copper wire
>which converts temp to resistance.
>I have been playing around since 1994 with
>various circuits watching the noise level
>increase as the area becomes populated.
>I know where all the oil gas and coal is going,
>back into the ground as energy.
>The single best way to get a proper response
>is with a 5 second geophone with like 3V/(in/sec)
>or better generator constant and vertical and small
>enough to bury in the ground. Hopefully, no greater
>than 500 OHMS resistance at STP.
>I have seen nothing better than Larry's hardware
>to keep great time keeping and show everything. I think
>he might one day be a standard for Amateurs.
>just need that 5 second geophone at a reasonable cost.
>I have seen no better geophone than the SPZ HS10-1.
>But it is horribly expensive as a new device.
>Possibly you will not find one today.
>I was lucky to find the used one from Larry.
>
>Prosit, Cheers, AufWiedersehen;
>geoff [GVA]


__________________________________________________________

Public Seismic Network Mailing List (PSNLIST)

To leave this list email PSNLIST-REQUEST@.............. with 
the body of the message (first line only): unsubscribe
See http://www.seismicnet.com/maillist.html for more information.