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Re: NASA's American Student Moon Orbiter...



 
In a message dated 04/07/2008 01:16:33 GMT Standard Time,  
domenico.i8cvs@tin.it writes:

Hi Ed, KL7UW

If we put AO40 at a distance of 400.000 km instead  of 60.000 km
from the earth the increase of isotropic attenuation at 2400  MHz is
about 16 dB etc etc etc.........


Hi  Ed / Dom
 
On the other hand, if you were to reduce path loss by using 70cm as the  
uplink band and 2m as the downlink the numbers begin to look quite  possible.
 
Also, if the satellite is orbiting the moon, then it's quite likely  that the 
attitude will be such that the experimental end of the satellite is  pointing 
at the moons surface. This probably also means that the communication  
antennas are not pointing at the earth, so high gain will not be possible.  Maybe 3 
or 4dB is the limit.
 
So how about 10W of 2m on the satellite and a passband that's say 5kHz  wide? 
 Not good for SSB, but passable for CW or reasonable speed  coherent BPSK
 
Regards
 
David









   
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