[amsat-bb] PSAT PSK31 Great! and nopw Posit Reporting

Robert Bruninga bruninga at usna.edu
Wed Jul 1 23:56:26 UTC 2015

PSAT is working very well.  Plenty of energy.  The PSK31 transponder is on
all the time in AUTO mode as long as there are users in the 10m uplink
passband.  Doppler is a challenge for some stations depending on geometry
to the pass.

Question? Have we had any success in PSK31 authors to include Doppler
correction in their software?

KO6TZ provided a table summary of various PSK programs and their
capabilities on the PSAT web page.  Ideal satellite mode operations include
operating full duplex and Doppler correction.


If anyone has direct influence on any PSK31 authors, you might mention our
needs for a Satellite mode that includes these features.  PSAT has an
estimated life of over 3 years.

Although PSK31 operation is primary, we have plenty of power, so the APRS
digipeater (only 300 mW) is also on full time.  In addition, we have
activated PSAT’s own APRS position reporting, and with its position
knowledge, it also has unique Bulletins for each Continent.

Take the positions with a grain-of-salt, however, since we have quirks in
the onboard clock and have to frequently re-sync the clock to the real
orbit.  But we have ground stations in Maryland and Europe assisting in

Your best PSK31 Uplink opportunity with least Doppler change (so everyone
else can decode  you)  is the highest elevation pass while coming towards
you and then away from you.

You can see these stations in the waterfall with practically no Doppler
change.  Those uplink stations off to either side will have more and more
changing Doppler during the pass.

Its fun to watch the waterfall ad visualize what is going on.


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