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re: multichannel satellites?





Hi AMSATs,

Why multichannel FM transponders ???
A multi frequency FM uplink on a satellite will only increase the problems 
of blocking the satellite by more stations.
e.g what will happen when some amateur blocks one input with a high uplink 
power ??? You can have 10 other uplink channels, but the downlink will be 
blocked !!

The FM sats have another disadvantage. The only mode it can do is FM voice. 
Beginning amteurs can not simply test on a quiet frequency, or when some 
amateur transmits SSTV, or do packet via the satellite amateurs are 
complaining that the satellite is blocked.
In amateurs world is some kind of tradition that FM sats are just for 
DX-ing. To be honest, I have done many experiments via FM sats, like short 
RTTY test, short SSTV test, 1k2 FSK&BPSK and even 9k6 packet :-)
Unfortunatly not many amateurs were happy with my tests...

A better solution is a lineair transponder system.
This allows users to do whatever they want, without interfering each other. 
A transponder system can even be used to make FM contacts !!!!
I know many amateurs know that FM on an lineair transponder is not good for 
the power budget. This is true for most amateur satellites, but with enough 
power budget it must be no problem to do FM.

Maybe it is some idea for future satellites :-)

73 de PE1RAH
William
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