In a satellite communication why the up-link and down-link frequency are different

I have 3 questions:

In a satellite communication why the up-link and down-link frequency are different


Why rain fade occurs at higher frequencies not at lower frequencies

Is frequency and power directly proportional

Thanks for the reply..

well, lets say your uplink to the satellite was at 10.000 Ghz at 10 watts, and your downlink from the satellite was at 10.000 GHz and -120 dBm at the receiver. And the tranmitter and receiver used the same antenna. Do you forsee any potential problem with that?

Because *** make the rain fade depends on freq, so people tested it and found so.

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Why can't write ***=Jesus?

Biff44 gave you something to ponder there ... work out his Q back to you and you will have your answer
Basically, without getting into the physics, the higher into microwave freq's you go, the higher the attenuation due to rain or even just significant humidity
In field tests I have had 60% humidity on a clear sky day totally killing a 100km 24GHz path. as soon as the humidity dropped below 40% the signals were quite strong

no, no relationship at all .... you can have any power level at any frequency or conversly any fixed power level could be at any frequency
the only thing limiting a given power level at a given freq is technology. ie ... its more difficult to produce very hi power levels as you increase in frequency

cheers
Dave