Description:

 
This telemetry demodulator card is used to receive analog telemetry from 
remote seismometer sensors used by the USGS and other agencies. This 
board converts any one of 8 tones into an analog signal (+- 5 volts for a  
+- 125 hz deviation).The tones are spaced  340 hz apart and start at 680 hz.  
The tone to decode is selected buy a dip switch. To use this board you must be  
able to receive one of the USGS sensors using a radio scanner. The audio  
out of the scanner connects to the input of the board and the output can go  
to a analog to digital converter or a chart recorder.  

Board Dimensions:
5 3/4 x 7 3/4 inches or 14.5 x 19.7 cm.

Additional Information Earthquakes - After the Shock This article by Ken Navarre describes how the USGS uses telemetry to record earthquakes. In the article you will find a list of frequencies to look for telemetry signals.