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RE: Oscar 0



> I think it is very intriguing to put an amateur transponder 
> on the moon,
> but before we
> get started let's do the link margin calculations. The moon 
> is very very
> far away and
> most hams will not be able to work a lunar transponder with 
> an HT and an
> arrow
> antenna. Only those "elite" hams with big antenna arrays in their
> non-covenant
> restricted backyards will be able to work a repeater on the moon, and
> once it is
> deployed there we will no doubt see postings on amsat-bb about how
> "Amsat builds satellites for the elite minority and not for 
> the average
> ham."  So lets make sure that
> everybody understands this up front.

I'd done some rough sums in my head and came to this conclusion.  Has anyone
done a reasonably accurate link calculation for a lunar transponder?  And
what sort of antennas would we use?  That would no doubt depend on how
accurately we can point the things.  Even on the lunar surface, thich
"nominally" faces the Earth, there is enough libration to limit the antenna
gain that can be used before a tracking antenna is necessary to keep Earth
within the beam.

> radio operators, and only to an elite group of hams at that. But it
> can't hurt to ask.

Never hurts to ask. :)
> 
> With the passing of Werner Haas, Amsat has lost more than half of its
> linear
> transponder design knowledge. Werner designed and built most of the
> communications payload for AO-10, AO-13 and Phase 3D. I frankly don't
> know
> who is going to step forward to fill those shoes. I don't 
> know of anyone

Maybe there's an object lesson here about putting one's eggs in the same
basket (or brain, in this case).  Unless technologies used by AMSAT are
documented and kept in a safe (but accessible) place, this will happen
again, with the associated cost of re-learning the art.

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