[amsat-bb] PSAT PSK31 experimental software

Robert Bruninga bruninga at usna.edu
Mon Aug 24 14:16:51 UTC 2015

PSAT seems to be returning to good health.  We will keep the digipeater off,
but will now announce it is safe to resume PSK31 experiments.

Remember, when we ran out of power, great progress had been made with Andy's
pre-compensating PSK31 uplink software (below).  Here also are the latest
elements for PSAT:

1 90720U          15234.36512451 +.00008395 +00000-0 +21488-3 0 0099
2 90720 054.9897 293.1329 0244566 052.6872 309.6216 15.1526532401420

When PSAT-1 is using the PSAT-1 callsign, that means the digipeater is off.
But as of now, PSK31 experimentation is authorized.  28.120 PSK31 uplink and
435.350 FM downlink.

Bob, WB4aPR

-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of
aflowers at frontiernet.net
Sent: Wednesday, July 15, 2015 6:41 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] PSAT PSK31 experimental software

I put together an experimental program called DopplerPSK to compensate for
the Doppler shift on the NO-84 (or NO-83) PSK31 uplink.  In essence, its a
PSK31 transmitter that is merged with an orbital propagator to cause your
transmitted signal to drift exactly opposite to uplink Doppler effect.  It
does this in a phase-continuous correction so that you don't get errors due
to discontinuous frequency adjustments from controlling a radio in discrete
In the case of PSAT and BricSat, it should cause your signal to stay at
constant frequency in the satellite's uplink receiver, and thus you should
get a stable frequency on the FM downlink as well.  In turn, this means you
should be able to use your favorite PSK31 demodulating software to copy the
downlink since the frequency drift should stay well within the AFC tolerance
of the software.
Anyway, if there are any adventurous people who are set up to give this a
go, I would be interested in seeing if it actually works.
You can find a rough quick-start guide (which contains an explanation of how
it works and what you need to get started) and the application package on
the rather minimalist page here:
It's an experiment, so be prepared for disappointment.  I am :-) Andy K0SM/2
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