[amsat-bb] PSAT2 status (GREAT NEWS!)

[Robert Bruninga]

PSAT2 is doing great!



PSK31 and SSTV transponder  have been on since launch.

SSTV downlinks are looking good.

See Gallery:  http://www.urel.feec.vutbr.cz/esl/psat2/sstv/

Still waiting for first report of user PSK31 contacts.



But I have not said much about the VHF modes… because we have had
difficulty commanding.  This is because the PSAT2 VHF uplink uses an
inexpensive narrowband XCVR module which is intolerant of overdeviated
signals, exactly what you get with +/- 3 kHz of Doppler.



ANYWAY, we can now consistently command if we set the Kenwood to narrowband
NFM and do it right in the middle of the pass.  Plus, we can extend that a
bit  (1.25 KHz after center) by then changing the radio step size to 6.25
Khz where the channel raster ups the channel by 1.25 KHz).



So, we now have command again!  You may have seen that we have turned on
Sun vector S#... telemetry and can easily see by plotting the 1 minute xyz
xyz xyz vector triplets that it is smoothly tumbling at about 1.3 RPM for
nice battery charging and good thermal management.



The downlink is live on FINDU:

http://www.findu.com/cgi-bin/raw.cgi?call=psat2-1&time=1

Background:

This last 6 days of crisis was complicated by the fact that I am operating
in a temporary dungeon while the building is being renovated and all my  27
years of lab stuff is in 200 boxes surrounding me.  I installed a temporary
ground station on the top floor and modest antennas and a TV rotator and
the contractor let me drill a hole through the wall that they can seal up
later.  But the big problem is the 8 flights of stairs from my PC and
internet connectivity  in the dungeon up to the radio 6 times a day for
passes with only a few hours sleep and all kinds of what-if-dead-ends.  And
with passes from 10 PM to 2 AM.



But we are back in the saddle again!



And this good news reprieve is only an hour old, so it will take a while to
decide what we want to do next.  In any case, the Brno University PSK31 and
SSTV transponder has all the power for now, so enjoy.

Uplink USB on 29.4815 and downlink on 435.350 +/- Doppler.  The transponder
only comes up if there is a user in the uplink with PSK31.



Bob, WB4APR