radio direction finder

noun

1. a navigational aid establishing a fix by means of the bearings of two known radio stations. : RDF

Word History and Origins

Origin of radio direction finder¹

First recorded in 1920–25

Example Sentences

Why would Earhart start out on such a hazardous journey without knowing how to operate her aircraft’s radio direction finder to the nth degree?

From Forbes

Crossing the Himalayas just south of the Tibetan plateau, working without beacons, without beams, usually with no more than a radio direction finder, C.N.A.C. pilots have done some of the most spectacular and useful transport flying of the war.

From Time Magazine Archive

Best known is his Learmatic Navigator, a combined automatic radio direction finder and directional gyro, for which he got the Frank Hawks Memorial Award last December.

From Time Magazine Archive

In the lagoon lies the 6,000-ton S. S. Northwind, with a radio direction finder and a 35-man airport staff which laid out a runway channel with green and red buoys.

From Time Magazine Archive