PCSAT2 PSK-31 TRANSPONDER OPERATIONS PLAN              7 AUG 2005
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FREQUENCY:  Downlink on 435.275+/-9 KHz Doppler FM
            Uplink 29.401 to 29.403 MHz PSK-31

The power budget of PCSAT2 cannot support continuous operations
of an FM downlink.  Thus the transponder has to be commanded on
and off on a foot-print-by-footprint basis to conserve power.

ARISS COMPATIBILITY:  Although PSK-31 operations will not 
interfere with ARISS operations, the on/off activation commands 
on a pass-by-pass basis do have the potential to interfere with 
ARISS voice operations on 2 meters.  Thus activation will be 
under the control of specificly authorized PC2PSK control stations 
with these resposibilities:

1) Be knowledgible and current on ARISS school contact schedules
2) Monitor 145.800 throughout pass
3) Do no commanding of PSK31 mode if voice ops are in progress.

PSK-31 OPERATIONS VIA PCSAT2:

Users will all operate full duplex transmitting throughtout the
pass on the HF uplink and monitoring all signals on the downlink.  
Move your signal so it is not on top of someone else and operate.  
There are two Doppler shifts you must account for:

1) Tuning your FM downlink from a starting 435.285 down to 
   435.265 in 5 KHz increments to keep the FM in your receiver

2) Setting your uplink so that the total +600 to -600 Hz uplink
   Doppler shift will not carry you out of the passband.

Notice that although the total doppler from AOS to LOS is about
the same, that the rate of change is variable depending on how
high your pass is to directly overhead.  A low horizon pass will
have a medium but almost constant rate of change.  A direct over-
head pass will have +600 Hz but very low rate for most of the 
first half the pass and then a very rapid change to a nearly
constant -600 Hz or so for most of the end of the pass.  

Many existing PSK-31 decoding programs may not be able to keep
up with these doppler rates, but should be able to use their
AFC for the beginning and ends of a directly overhead pass.  We 
have much to learn and develop here.  Notice that Doppler always
moves downward.

Dedicated, Trusted PSK-PASS control stations are needed.  If you
think you will be a frequent user of this mode and can fulfill
the responsibilities of a PSK-PASS control op, then contact
XXXXX who will manage these operators.  We also need a volunteer 
XXXXX to coordinate these control ops.

de WB4APR
Bob Bruninga
USNA Satellite Lab