Dick --

One thing that may not have been mentioned is to run the signal wires
inside *metal* conduit, grounded at both ends (as well as you can).  Also,
don't run the 110V power lines in the same conduit.  A nearby lightning
strike could put a large spike on the power lines, which could couple into
the signal lines.

I agree with the suggestion of zener diodes across the signal lines.
Zeners are very fast at turing on and good-sized ones will dissipate a very
large amount of power for a short time.  Put them at the amp input and keep
the leads short to improve high-frequency response.

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......


At 08:06 PM 8/19/1999 -0400, you wrote:
>Well, my third board in 5 years has just bit the dust in an electrical 
>storm and power outage.  I have Larry's amp board in a vault out back and 
>run wires, barely below the surface to my PC in the house.  I also run a 
>wire from the house to the vault for 110 volts. Both the incoming line and 
>a line from the WWV antenna go to Larry's AtD board.  That is the board 
>that blew.   The incoming line and the case I have the amp in are grounded 
>or so it seems to me.  Is there any way to protect the overall system or 
>should I consider board replacement an operating expense.


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)