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Re: Repeater on the Moon



> 1. Thanks fellows, there are actually lots of good ideas coming out of 
> this
> and the basic homework needs to be done anyway. What is possible now 
> was
> probably not really feasible when the U.S. went to the moon, or I am 
> certain
> that somebody would have tried to hitch a lift via NASA.

Back in the Apollo days, I don't think any third-party payload concepts 
would have been taken seriously.  NASA really didn't start considering 
that until the STS program, which was designed to carry standardized 
payloads, and back in 1969-1972 NASA wasn't sending up anything but 
their own payloads, and even that list was mighty short .. at least now 
most of the space agencies realize that hitchhiking is a fact of life 
for some of the smaller customers ..

> 3. I have received claims on here that you can do E-M-E with 20 watts 
> and a
> couple of 5 element yagis with good signal processing. I assume these 
> guys
> are not sitting on their laurels and the high power stations are 
> working out
> how to do E-Mars-E  before the DL satellite is launched and we have a
> repeater there.

E-Mars-E, passive reflection only?  Can't see that doing much of 
anything .. you'd need the equivalent of an Arecibo dish (with the 
Gregorian corrector *and* a liquid He cooled LNA) on both ends to even 
work CW on that path .. if you could even do it with that.  Even with a 
transponder that's going to be more of a "because it was there" 
accomplishment than an experiment of much practical use.

>  Incidentally, if we used the same techniques for AO40, could we use
> microwatts and a rubber duck antenna? All we need then is someone to 
> come up
> with a compressed working speech channel of a few hundred Hz..........
> It will all happen someday, usually devised by someone who does not 
> know
> it's impossible,

Well .. the narrower your bandwidth at the receiver, the less 
background noise gets in through the filter.  EME on average backyard 
sized antennas works because a CW filter is extremely narrow and lets 
in very little noise, plus modern LNB's are much higher performance 
than what was out there in the 60's and 70's -- you can routinely get 
single-digit noise figure LNB's for C and Ku-band TVRO systems these 
days.  I doubt you'll be able to compress voice into that small a 
bandwidth, but I'd be loath to say it's impossible .. I've seen too 
many things I didn't think were possible done successfully ..

Heard from a flight instructor:
"The only dumb question is the one you DID NOT ask, resulting in my 
going out and having to identify your bits and pieces in the midst of 
torn and twisted metal."

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