PSN-L Email List Message

Subject: RE: No intrest in earthquakes ?
From: Brett Nordgren brett3nt@.............
Date: Mon, 22 Feb 2010 23:30:20 -0500


At 10:09 PM 2/22/2010, you wrote:
>Right now I have the cover off. As you remember, this is in the wine cellar,
>very stable temperature.

Just to provide some perspective: With a 100 second instrument using a
spring having a temperature coefficient (of elasticity) of -240 ppm/deg C,
you will see a 1um/sec output shift--perhaps two lines on your
helicorder plot, from a temperature change rate of 6 milli-degrees C 
per hour.

Insulation is good.

I think adding the 50 second high-pass will reduce that effect considerably,
though rapid, small, temperature changes will still look big at the output.

>  But I agree the response is wild. I have it
>disconnected (high gain) right now and will try it again a little later

Good luck,


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