What determines the optimum frequency range for the transmission of signals in a system that's transmitting electromagnetic signals between an antenna on the surface of the earth and an orbiting satellite antenna.
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Many factors, and since your question is so broad, a broad answer follows:
The signal bandwidth (amount of information per second) will determine a minimum carrier frequency. In practice, the modulated signal should have a bandwidth of not more than say 1% of the carrier frequency.
Then, at lower carrier frequencies, you need to consider antenna size (which can be too large for a satellite), and ionospheric effects (mostly in HF range).
Commercial satellites communicate in the microwave range (L band, all the way to the K bands and above).
At high carrier frequencies, atmospheric attenuation becomes a problem. Also clouds and rain provide attenuation in the K bands.
Small amateur radio satellites normally operate in UHF and VHF, but those frequencies allow for a very small bandwidth (1200 or 9600 bits per second).
Juancho
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