Question

Which of the following is false with respect to secondary radar?

(a) Requires more power than primary radar

(b) Needs a transponder device on the aircraft

(c) IFF

(d) Better range

The question was asked in an interview for job.

I want to ask this question from Primary and Secondary Radar in portion Surveillance Systems, Mapping and Multimode Radars of Avionics

Answer 1

Right choice is (a) Requires more power than primary radar

To explain: Secondary radar requires less power than primary radar for the same amount of coverage area. This is because in secondary radar the pulse is one way; it triggers a reply pulse in the transponder of the aircraft which replies with some of the important flight parameters of the aircraft.