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PCSAT2 PSK-31 test Saturday Morning! (USA)



PSK-31 Saturday morning over USA...

OK, lets do it.  Wife is out of town so I can come
to work and turn on the PSK-31 over the East coast
of USA for a few passes.  It wont be on but about
5 minutes max in the middle of each pass.  I see
these at about...

   1225z,  1405z,  1540z and 1715z

PSK-31 stations should Spread out between 29.401
and 29.4025.  Remember that Doppler will start
your signal about 600 Hz higher and move your
signal down the passband to end 600 Hz lower from
beginning to end...

 Transmit the entire pass.  Listen on 435.275 FM 
donwlink +/- 9 KHz doppler.  The more signals the better.
(You probably have to run two PSK-31 programs
so you can RX on UHF FM while tansmitting on HF
uplink)...

There are two means of control of PSK xponder.
The one we are using during checkout is the 
backup method which is ON/OFF by direct sysop 
command.   The u ltimate one will be by a user 
packet connecton to the "PC2PSK" callsign.

The ON/OFF one is really a backup and so it also
has a backup fail-safe timer that at least turns
it off after 20 minutes.  So even if I miss the 
turn off command, it will cycle on and off 
every 20 minutes or so until I next get a shot
at it...

Turns out, that if it is the one orbit that goes
from USA, over Europe, then africa and then
AUS NZ, this 20 minute cycle will keep it on
to about the central of Europe then off 
over central africa then on over southern
AUS and NZ, then off, and then back on
for the west coast... maybe.  But we dont
know the exact timing of the 20 min timer...

Lots to test the next several days.

When we activate the USER access method, then any
station that wants to command on the PSK-31
can just connect to the callsign of PC2PSK.  His
packets from then on do nothing and are NOT
welcome, but simply the CONNECT LED
is the circuit that turns on the transponder.
His TNC and the PCSAT2 TNC will occassionaly
exchange CHECK packets to verify he is still
connected.  Once the user station is lost, the
TNC connection will timeout 7 minutes later
and the CONNECT LED will go out, and this
will drop the PSK-31 transponder.

We chose that so that it will timeout when the
satellite goes out of view of that station.  Such 
a station will have to have his TNC set for
FULL DUPLEX, because once the PSK-31
xpoonder comes on, this will open his squelch
and his TNC will not complete the connection,
because it will hear the channel busy...

With full duplex on, his TNC will ignore the
PSK noise and will let his TNC transmit to
complete the connection.  Unfortunately,
you cannot use a D700 for this purpose 
since it does not have a way to turn off
the channel busy on its internal TNC.

But the D7(g) does.  Use the DCD menu.

Remember, this satellite has no command
processor other than a pair of simple KPC-9612
dual port TNC's, so we  had to be a little
creative to find ways to command things...

Bob, Wb4APR
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