[amsat-bb] PSK retransmission on PSAT-2 (now SSTV?)

[Robert Bruninga]

Using translate.google.com it appears that Roland captured his PSK31 two-way
PSK31 via the HF to UHF transponder (just what PSAT2 is designed to do via
the Brno transponder)..

What I'd like to see is another station transmitting SSTV at the same time
to see if we can do a 2-way SSTV via the transponder.

My previous emails on the topic were hampered by the need to make sure there
was a PSK31 carrier also in the passband at the same time.  Which is hard to
do from one PC and existing software..

BUT!!! The easiest way is for two stations to make a SKED and one transmit
PSK31 and the other transmit SSTV at the same time.  That will keep the
transponder up.  Then they SWAP after the first successfully SSTV relay and
the other person sends the PSK31 while receiving the SSTV.

Since PSAT2 is full duplex HF up and UHF down,  both stations can TX and RX
at the same time and it is easy!  No special hardware or software required!

A sked would go like this.  The first person simply brings up PSK31 software
and sends CQ SSTV, CQ SSTV continuously  asking for an SSTV contact.
Another station, hearing the transponder come up, then Transmits his SSTV
image on the same 10m uplink and both stations can see and hear in real time
both signals.

When the SSTV receiving station (who is TXing the CQ SSTV message) gets an
image, then he changes his MSG to QSL and then he waits for the other
station to drop his SSTV tones and come up on PSK31.  This will now hold up
the transponder for the original station to now drop his PSK31 and switch to
transmit his SSTV!

With 40 seconds per image, this will need a good 1.5 minute mutual pass...
for a 2-way SSTV exchange

Bob, WB4APR


-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Roland Zurmely via
AMSAT-BB
Sent: Thursday, May 21, 2020 1:45 PM
To: AMSAT <amsat-bb at amsat.org>
Subject: [amsat-bb] PSK retransmission on PSAT-2

< https://www.qsl.net/py4zbz/psat2.htm#b >
73 de Roland PY4ZBZ