FG> But being on the far side of the Moon will block *all* rf noise
 FG> from Earth, leaving only signals from lunar 
 FG> orbiting sats, and any
 FG> manned/unmanned probes in deep space, which 
 FG> could easily be allowed
 FG> for. 
 BM>  I see.  I assumed (I know - never ASSume) that 250k miles would be
 BM>  enough distance that low power rf would no longer 
 BM> be a problem but then
 BM>  again with a large array they still might be able 
 BM> to eavesdrop on some
 BM>  Conressman's cel call.  ;)
 
   Depending on the size of the dish, we might even pick up an alien 
civilization's `local' communications, too. (As opposed to signals  
intentionally transmitted for the purpose of contacting other civilizations.)
 
   There was an interesting article in the April 1977 Popular Electronics 
about how future hobbyists on the Moon could DX Earth radio. Seems, among 
other things, that a typical FM broadcast station would be easily recieved 
from there, with a modest directional antenna, and a normal reciever. The 
problem would be in recieving signals from multiple stations on the same 
frequency, that are well out of range of each other. And the mostly 
horizontal pattern of VHF and UHF broadcast stations mean that only those 
stations on Earth's limb (or, looking at it another way, those stations for 
whom the Moon is near the horizon, rising or setting) would be most easily 
recieved.
 
   Personally, if I had a chance to go on a shuttle mission, in addition to 
some ham contacts (KA2WQA), I'd bring a scanner to see what terrestrial 
reception at those altitudes is like....
 
   And still closer to Earth, in addition to RFI hazards to the plane's 
systems, those who try to use a cellphone at altitude complicate things on 
the ground because they can easily hit many cell sites at once.....
 
   Frank
 
--- Maximus 2.01wb
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