[amsat-bb] Re: ARISSAT-1 TLM Problem

Douglas Quagliana dquagliana at aol.com
Wed Aug 31 17:12:52 PDT 2011

   ARISSatTLM only uses the 48 kHz sampling rate on soundcards, so 
that's the only rate your card needs to be able to run at for ARISSatTLM.
Douglas KA2UPW/5

James McBride wrote:
> Randy,
> Make sure you have any audio or DSP filters switched off, IF shift to 
> centre etc. I found the 'tone' control on the FT736 affects the decode 
> (eventually, by accident).. Also I found that I had a dirty contact on 
> the soundcard input to my PC's motherboard! After I fixed some of 
> these things, the decode was okay, mind you I suspect shielded cable 
> would also be better - I'm using twin speaker lead.. :(  . Put the CW 
> at the marker (as close as possible and adjust for doppler) in USB 
> mode and you should get some good frames eventually. I've found 
> usually the high elevation passes are reliable, the low ones at 3-5 
> degrees just don't give me enough of a chance to get telemetry sometimes.
> The soundcard is usually part of the issue also. My old P-4 shuttle 
> mainboard AC97 codec style soundcard I think only samples at 48KHz or 
> something and uses software drivers to pretend the sampling is at 
> other rates - a proper PCI soundblaster style card or high quality SDR 
> style soundcard would probably work better. At some stage I might try 
> a better PC but for now it works some of the time straight from the 
> headphone socket to line-in on the soundcard.
> 73
> James VK6FJA

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