Question

What is the use of notch filters in Loran-C receivers?

(a) Reduce interference from other frequencies

(b) Reduce interference from other stations

(c) Reduce interference from sky waves

(d) Reduce atmospheric noise

This question was posed to me in final exam.

My question is based upon Hyperbolic Radio Systems topic in chapter Terrestrial Radio Navigation System of Avionics

Answer 1

Correct choice is (a) Reduce interference from other frequencies

To explain I would say: Loran-C signal reception can be impaired by interference from other signal broadcast on slightly different frequencies. To avoid degradation of S/N associated with these interfering sources, Loran -C sets are equipped with notch filters.