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Re: FCAL packet recovery



mcguire@stensat.org wrote:
> Any
> suggestions for post-processing the audio with the intent of pulling AX.25
> packets out of the muck?
> 
> Jim3 KB3MPL

Get an audio processing program like CoolEdit, Audition, or
Audacity and FIR filter the audio to remove as much of the
"noise" as you can. You probably want to start by filtering
out everything below about 1000 Hertz or above about 2500
Hertz. The exact cutoff numbers you choose depend on the
characteristics of the particular DSP filter you are using
and its rolloff, but the idea is to throw away as much of
the noise as you can and just leave the packet tones.

Sometimes this is all you need...

Of course, if one or more bits in the packet really ARE
corrupted with in-band noise, then the packet still won't
decode.

If you want, email me a copy of the recording and I'll
take a look too.

Douglas KA2UPW/5

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