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Re: AO40 telemetry tutorial?



Hi Wayne,

At MA30, it should be working fine with S5 signal over noise.  AO40rcv can 
deal with VERY rapid doppler changes...

One thought...did you turn the volume UP enough?  On my former sound card 
(SB 16), I had to turn the volume up until the program complained about 
being too loud, then back it down just below that.  I got the best decoding 
that way.  With my SB Audigy, the level is less fussy.

What center frequency are you using?  Mine does better at about 1200-1300 Hz...

Another thought--do you have any strange equalizer/sound effects software 
running?

Sorry, don't know of any tutorials...(the provided Help file in the program 
is very good.)

Mark

At 11:26 AM 2/12/2002 -0600, you wrote:
>This morning I tried to decode AO40 telemetry for the first time using 
>AO40rcv.  I never got any "CRC good" blocks out of 25 blocks 
>monitored.  This was around MA30.  AO40rcv appeared to stay "synced" 
>during each "read block" cycle.  I had the AO40rcv AFC on, and the Doppler 
>seemed to be changing about 6 Hz per second.  Is that within the AFC 
>tuning capability of AO40rcv?
>
>I'm sure the signal was strong enough.  The beacon was 5+ S-units above my 
>noise level.  The bottom part of the signal waveform was 2 lines (20 dB I 
>think) above the noise level.  I'm extracting the audio from my FT-847 
>data jack, and the audio interface works fine for PSK-31.  It does have 
>isolation transformers.  The spectrum and waterfall display looked similar 
>to the screen shot on AE4JY's web page.
>
>I did go to this site, but didn't find anything that solves my problem:
>
>http://ao40.homestead.com/TelemFAQ.html 
><http://ao40.homestead.com/TelemFAQ.html>
>
>Is there a tutorial that describes how to decode AO40 telemetry?  Things like:
>         Configuration of AO40rcv
>         Tuning requirements (maximum rate of change in Doppler shift)
>         Interpreting the waterfall display
>Interpreting the data
>
>Thanks in advance.
>
>Wayne Estes W9AE
>Mundelein, IL, USA
>
>
>
>----
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Mark L. Hammond  [N8MH]

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