[amsat-bb] Re: Turn off AGC when receiving BPSK-1000 (aiming your satellite)

[JoAnne Maenpaa]

> fact that none of these piggyback payloads have ever come
> to fruition,

Yeah, it brings us back to the original question about "why don't you guys propose a satellite that hooks on a bigger satellite?" ... we can't say we haven't tried ... Synchronous Amateur Radio Transponder (SYNCART) was an AMSAT rideshare was proposed in 1971: 
http://www.amsat-dl.org/images/stories/satellites/syncart/sync.pdf

> suggests that we need our own attitude determination 
> and control system if at all possible.

This topic came up a couple of times at the 2009 Baltimore Symposium. Tom Clark, K3IO gave a talk about the physics we need to know about if we put a motor on our satellite to raise the orbit ourselves. Dan Schultz, N8FGV presented on electric thrust for small satellites. In both cases attitude determination and control was needed because we had to point the right direction before turning on the thrust. The bonus would be we would know where antenna(s) were pointing.

> It wouldn't be terribly hard to network the ground stations 
> so that a conversation could be maintained as the ISS moves 
> from one to the next.

It could be like a handover during a cellular call? I proposed the ground stations could be tied together with a GEO-Eagle class bird, while the ISS was the "mobile":
http://home.comcast.net/~k9jkm/Education_AMSAT_Eagle.pdf
Lacking an Eagle we could substitute less glamorous but nicely functional terrestrial networks ;-)

> To simplify the implementation, provide good voice quality 
> and a backup data capability, the system would have to be
> completely digital.

Tim, AB0DO wrote a paper on this very topic:
http://www.saloits.com/papers/AMSAT2008.pdf

Heck, with all these papers written about it ... now we just gotta build one!

--
73 de JoAnne K9JKM
k9jkm at amsat.org