Re: [amsat-bb] AO-16 digipeat

["laura halliday" <marsgal42@xxxxxxxxxxx>]

Bob Bruninga <bruninga@usna.edu>

 wrote:

>And in the 12 years since launch, we now have SOUND cards that can decode
>the PSK data and so NO SPECIAL HARDWARE is required.  Just plug UHF
>allmode receiver into sound card, and we now will have another COMM
>satellite for anyone to use...  Look at the popularity of PSK-31 and
>AO40RCV software.
>
>If someone would just write the PSK software, then everyone could use
>these AO-16, LO-19 and IO-26 digipeaters as easy as PSK-31...

I did some brainstorming on this once. The problem
is Doppler correction, so I considered a solution
that didn't need any: direct conversion to I/Q base-
band, then a stereo input sound card (which they all
are anyway). For a couple of spot frequencies crystal
control would be easy to get right. Think of it as
one of S53MV's zero-IF radios, done in software.

The maximum Doppler is well within the audio frequency
range of a sound card. The only issue then is the
hole in the pass either side of zero-beat, when
the output frequency is too low. This is not an
insurmountable problem...

Laura Halliday VE7LDH     "Que les nuages soient notre
Grid: CN89lg                    pied a terre..."
ICBM: 49 16.57 N 123 0.24 W        - Hospital/Shafte

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