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SUNSAT PAROT Mode thought...



The SUNSAT Parot mode is perhaps the most powerful and sensitive Amateur
Satellite mode to date for HT-to-HT operations.  Being on 2m it has a 9 dB
path-loss advantage both ways to OMNI antennas and has minimal doppler.
It could be very workable from an HT with whip antenna.

The problem is that with only a 10 second RECORD-PLAYBACK-in-the-blind 
cycle, it is almost useless for voice which takes about  5 seconds for
each transmission.  With 100's of stations trying, no amount of
arguing over operators and procedures will change this.

However, if each station could limit their transmission to only a single
0.3 second burst each cycle, then as many as 30 stations could be
successful per cycle.  This is easy to do with a UI packet at 9600 baud.
Anyone with a 9600 baud TNC could participate and anyone with THD7(g) HT 
or TMD700 mobile rig can do it from the front panel.

Many will argue that PAROT mode is not for packet.  I agree.  But I dont
see any way that VOICE can work except out in the middle of the atlantic
or Pacific or Antarctica, or of course for those that run 1000 watts.

It might be nice to see some experimentation at somethign new, something
that is better suited to the mode at hand than just a repeat of the same
experiences on the FM sats.  For those that are totally opposed to this
experiment, consider that for each person that tries ONE 9600 baud packet
per cycle, that is one less person that you are competing with for the
other 9.5 seconds.  Therefore it coiuld be considered in your best
interest also...

Just a thought...
de WB4APR, Bob

P.S.   HOW TO DO IT:

1) Set to 9600 baud, TNC to Band A, 145.825.
2) Set path to NONE!  (this makes packet 7 bytes shorter)
3) Set TXD to 200 ms!

At a random time after the RECORD begins, send your packet.
During playback, anyone that got in will be repeated AND they will
hear themselves to CONFIRM that they got through.  Thus NO OTHER
transmissions are needed from that station.  Theoretically, during a 10
minute pass, over 300 stations could be successful.  But statistically in
such an ALOHA situation, the actual number would be closer to 60.  But
much better than the 12 voice calls I pulled out tonight.

Actually 1200 baud would work even 7 dB better, though the packet will be
about 0.5 second instead of 0.3.   But the sound of a 1200 baud BRAAAP
would certainly not go over well! <grin>


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