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Re: FM satellites (Millennium Project)



Mike,

No a bad idea actually.

ka7hbb@janel.navicom.com wrote:
> 
> What we need is quit building single channel FM birds and either put
> in a couple of channels or make use of a linear transponder in FM
> mode and somehow break it into multiple channels. Its not like AO-10
> never had FM bounced thru it before...or RS10 etc...Although I still
> like the multi channel FM idea better as a beginners bird.

The reason SSB birds like FO20/29 are so efficient is SSB.  The
transponders are linear, in that whatever they receive on the uplink,
they retransmit on the downlink.  SSB is efficient because it
concentrates energy into a narrow slice of spectrum.  FM on the other
hand uses a very large slice of spectrum to carry any intelligence.  The
larger the slice, the more power it takes.

A dual channel bird as I've proposed could sustain itself with solar
panels and an onboard storage battery.  If you start adding FM voice
channels, the power budget goes up, the size of the solar panels must be
increased, the size of the satellite increases, launch possibilities
become harder to muster ...

The whole idea behind a constellation of birds, is that one will always
be overhead for YOUR use if we plan the system properly.  With 20 or 30
such birds, you could change tones and access a different bird as the
previous one nears the horizon.

I love that there is dialogue regarding what could possibly be the next
great amateur radio space project.  Kindle the spark, and get on the
bus; the Millennium Bus.

73, Mike in Fort Myers, FL 


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