[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: Moon Relay

At 10:39 03/03/2004, you wrote:

>So, all teasing aside, do the signal link budget numbers consider the sun
>therminal noise reflected from the rest of the moon? We do of course know
>the moon reflects at microwave freqs: think EME.
>In fact, answering my own 1st question, this is something EME operators
>already have to deal with. How significant is the noise level of the moons
>reflections from the sun at "full moon"?
>Jim Towler
>New Zealand

Sun noise reflected from the moon is insignificant compared to the thermal 
emissions from the moon itself (moon noise).

Moon noise is only an issue where antenna beamwidths are very small.  On 
10GHz with a 3m dish for example, where the antenna beamwidth is about 0.5 
deg, I see approx  2dB of moon noise.  It varies slightly with the phase of 
the moon, and from memory is at a maximum some days after full moon (time 
delay with the surface of the moon heating up).

For UHF / low microwave link budget calculations with typical amateur sized 
antennas it is negligible compared to other factors eg ground noise and sky 


Charlie G3WDG 

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org