[amsat-bb] Re: All Satellites (Alan P. Biddle)

Robert Bruninga bruninga at usna.edu
Sun Sep 27 07:42:48 PDT 2009

>> And wouldn?t it be a hoot if [these cubesats]
>> could put their RX/TX into a bent-pipe packet 
>> mode, and then we would have amateur radio 
>> global hand-held text messaging satellite system...
>> Using some of the 2-way very small micro APRS 
>> packet systems, a 2 to 5 Watt transponder will 
>> easily fit... in a small cubesat.  
>> See  www.aprs.org/cubesat-comms.html
> If you could have maybe five or six cubesats 
> with an FM transponder... [with] a good 15-minute pass 
> every hour... would work wonders for getting people 
> interested in satellites again.  ... [with a]
> dual-band HT and a homebrew Arrow clone

The beauty of the APRS packet text-messaging relay cubesat is
that it can have a 10 times higher power transmitter compared to
an FM voice transponder for the same average power budget.  This
makes it workable on an HT with just a whip antenna, instead of
needing a handheld beam.  Plus, each message takes one second
instead of 15 for each QSO. 

So that is why I prefer handheld packet text messaging as a
cubesat mission.  Ten times the downlink power budget and 15
times the number of contacts per pass.

AO51 downlink could be 10 times as strong if the transmitter
would just drop when not in use...


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