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Re: Amateur radio module on commercial Geo Sat?



on 12/19/00 6:36 PM, Tony Langdon at tlangdon@atctraining.com.au wrote:

> Just one wee little question.  How would TDMA work, when there's stations
> spread across a wide area (with vastly different, and generally large
> propagation delays), without being either horrendously slow, or stations
> accidentally falling out of their timeslots, due to propagation delays?
> 
> That's one of the limitations of GSM mobile phones in rural areas here,
> incidentally.
> 
> Just curious how you'd tackle these issues.

One more thing Tony: Doppler shift varies between different stations and
their position to the satellite.  For a geosynchronous bird doppler isn't a
problem since the relative motion of the bird to the earth is zero or
thereabouts. However, with any other kind of orbit, doppler is going to
affect things one way or another.  So not only do you have to stay on
frequency with TDMA, you'd also have to stay in your time slot.  That is
interesting how that would work!

There's probably an answer!

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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