Question

Which of the following is responsible for the reduced use of transmitter power in radar altimeter?

(a) Low range

(b) Interference with other bands

(c) Receiver low noise amplifier

(d) Radome

The question was asked in class test.

My question is taken from Radar Altimeter in section Celestial Navigation, Doppler and Altimeter Radars of Avionics

Answer 1

The correct option is (c) Receiver low noise amplifier

To elaborate: The transmitter power depends on the sensitivity of the receiver. The receiver low noise amplifier typically has a 2 to 3 dB noise figure, resulting in a sensitivity level that allows relatively low transmitter power.