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multichannel satellites?



> I guess we should hold out hope for a multi-channel FM bird then!  :-)

Actually for our approved satellite project next year we get something in
LEO with a 100W power budget.  We thought about multichannel FM, but
although I like the single channel FM birds, just putting additional
adjacent single-signal-at-a-time FM Capturing channels on the same bird
didnt seem to have anything great going for it.

With analog three people can all say somthing at the same time on the SAME
frequency and it all adds and everyone still hears everyone.  Its just
like face to face.  You still hear the other guy's comment.  But on FM,
capture kills all but the winning power OR kills them all and noone hears
any of them.

Thus for chattting amongst a group, analog is better HANDS DOWN. But
adding multiple FM channels accomplishes nothing towards group discussion,
and only detracts from the excitement by splitting out still single
monolog or decimating transmissions onto more channels and diluting the
advantage of finding everyone in one place.

So we rejected the multichannel FM approach completely even though we had
the power budget for it.  We currently plan on 6 transponders:

  3 uplink and 2 downlink packet channels
  a dedicated SSTV FM channel
  a dedicated FM voice repeater
  a dedicated 3 KHz linear up/ FM down multiuser PSK31 full duplex xponder
  and 30 KHz or so of analog SSB transponder..

All downlinks on 2m for receipt on HT's with whip antennas.  And we
welcome anyone to build for us the 30 KHz 10m SSB uplink and 2m SSB
downlink transponder ready to go by mid 2004...

Bob


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