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RE: SUNSAT PAROT Mode thought...



Bob,

The parrot mode pass I heard last night was pure bedlam!  I don't have any packet equipment (yet) but I suspect that you are right about how it would better utilize parrot mode than FM voice.

I'll just be glad to see the sat return to normal voice passes and hopefully on mode B as that doesn't seem to be as susceptible to interference from repeater inputs, outputs, and whover those Spanish speaking guys are.

73,
Dave W8IJ
Camp Hill, PA

>Date: Wed, 4 Oct 2000 21:07:13 -0400 (EDT)
>From: Bob Bruninga <bruninga@nadn.navy.mil>
>To: TAPR APRS Special Interest Group <aprssig@tapr.org>
>cc: amsat-bb@AMSAT.Org
>Subject: [amsat-bb] 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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