Question

Why is there a huge spectrum space between the transmitted and received signal in satellite communication?

(a) Reduce interference

(b) Maximum efficiency

(c) Less attenuation

(d) To reduce space occupied by filters

I have been asked this question in an interview for internship.

My question is taken from Satellite Subsystems topic in chapter Satellite Communication of Avionics

Answer 1

Correct option is (a) Reduce interference

For explanation I would say: Because of the close proximity of the transmitter and the receiver in the satellite, the high transmitter output power for the downlink is picked up by that satellite receiver. Naturally, the uplink signal is totally obliterated. Furthermore, the transmitter output fed back into the receiver input causes oscillation. To avoid this problem, the receiver and transmitter in the satellite transponder are designed to operate at separate frequencies. In this way, they will not interfere with each other.