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decoding telemetry with integrated sound "card"

Saturday morning I tried again to decode AO40 telemetry using AO40rcv.  It was around MA40 where the Doppler wasn't extremely fast, but the signal was very strong.  I increased the audio level until the vertical lines on the waterfall display turned yellow.  I set the center frequency to the middle of the audio passband, as shown on the AO40rcv waterfall display.  I tried AFC off and AFC on.  It tried it with and without auto Doppler tuning from the satellite tracking program.  AO40rcv seemed to stay in sync all the time, but I never once got a "CRC good" block.

I'm using a Dell computer with "integrated sound".  W6IHG told me that he was never able to successfully decode telemetry with his Dell integrated sound "card".  He added a true SoundBlaster compatible sound card and was then able to decode telemetry very reliably. 

The Dell integrated sound works fine with slower data modes such as PSK-31, MFSK-16, and RTTY.  But AO40rcv never gets a good checksum when decoding the AO40 400 baud BPSK telemetry.  Has anybody successfully decoded AO40 telemetry using a Dell integrated sound "card"?  

Wayne Estes W9AE
Mundelein, IL, USA

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