Hi

> Have you posted two or three recordings of the spikes?

I am doing that just now. Thanks for the reminder.

Here is a recording of the spike that did happen last night. 

This is the larger type of spikes.

http://www.simnet.is/jonfr500/earthquake/winquake/spike.hvt1z.gif

Here is a recording of the smaller spikes that happen after I did
connect the cat-5 cable directly to the geophone.

http://www.simnet.is/jonfr500/earthquake/winquake/smaller.spikes.hvt1z.psn.gif

Timothy Carpenter wrote:

> Do you have the geophones connected single-ended or double-ended (full
> differential). If your board has the capability, I'd recommend that
> your
> connections be full differential.

I connect both wires.

John Popelish wrote:

> Could be, but I am suspecting a heater switching on and off, every
> few 
> seconds.  Printer fuser roll heater comes to mind.

I only own a ink printer.

Randy Kimball wrote:

> Do you have a cell phone.... now hang on...
> Cell phones check in with the tower systems every so often.  This is
> how
> they know if your phone is on line and to which tower to transmit to
> your
> cell phone. I'm no cell phone expert so my version of this is perhaps
> off
> just a little but I think this is the layman's version of what
> happens.  If
> your cell is on and in the area of .... well you get the rest... this
> is the
> daut daut daut..daut sound we hear in our car radios at times when the
> cell
> phone is near the radio receiver.  In my coach I hear it in my CB,
> too.
> 
> Could this be the mystery everyone is seeking?

I own a GSM phone (cell phone), I know that it can pickup noise from it
if I am close to the line or to the ampilfer board. But that is not all
the time, I can also see a diffrance from that type of noise and what I
am dealing with now. My gsm phone is usally on the board on my main
desktop computer, that is a good meter away from the amplifer board and
the wire that is connected to the geophone.

I know now that there is a noise in the MW radio band (Chris did ask me
to check on that). That noise comes from the computers that I own. I
can't change my setup becose I live in a limited space.

Regards.
-- 
Jón Frímann
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/

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