What will happen if uplink and downlink frequencies are same?

In satellite communication, the uplink frequency is higher than the downlink frequency because the attenuation level increase with an increase in frequency . The power at the ground station (Base Station) is more than compared to the power available at the satellite.

Explanation: The original signal being transmitted from the earth station to the satellite is called the uplink , and the re-transmitted signal from the satellite to the receiving stations is called the downlink. … As a result, most satellites contain multiple transponders, each operating at a different frequency.

The satellite transmitter generates a signal that would jam its own receiver ; if both uplink and downlink shared the same frequency.