Check out Spectrum Lab for decoding the VHF/UHF telemetry signals.

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=9270

It might not give you the detail needed for serious monitoring, but it will allow you to 
decode and view the FM telemetry signals.  I listen to 163.605 and 218.3 Mhz at my 
location.

I took a look at the GeoTool program.  It seems to work ok but crashes on two of my 
systems, suspect they will have that fixed soon.  The program does a great job of 
decoding and displaying the signal.


Michael
Tuolumne CA





Date sent:      	Tue, 11 Jul 2006 13:44:17 +0100
From:           	Ian Smith 
To:             	psn-l@..............
Subject:        	Re: Help with telemetry equipment
Send reply to:  	psn-l@..............


Hi,

labview has some great demodulation software built into it as well as software to 
interface with sound cards. That's what I was thinking of when I wondered how the 
signal was encoded. Still wondering...

Cheers

Ian

James Hannon wrote:
I would expect that a sound card would be stable enough to 
decode the telemetry signals. All the cards I have seen use a 
crystal for the reference frequency. As long as the 
temperature of the card doesn't vary over a wide range you 
will be ok. The real question is: Is there software avaliable 
to do the demodulation?

As far as the radio stability is concerned: The signals are 
transmitted as FM so a slight mistuning of the radio will not 
affect the frequency of the tones. 

Jim Hannon


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