| a receiver with a loop antenna rotating on a vertical axis, used to ascertain the direction of incoming radio waves. |
| direction finder n. Abbr. DF A device for determining the source of a transmitted signal, consisting mainly of a radio receiver and a coiled rotating antenna. |
direction finder
radio receiver and antenna system for determining the direction of the source of a radio signal. A direction finder (DF) can be used by an aircraft or ship as a navigational aid. This is accomplished by measuring the direction (bearing) of at least two transmitters whose locations are already known. When the measured directions from each transmitter are plotted on a map, the intersection of the two plotted lines gives the location of the aircraft or ship carrying the DF. This technique, using the directions to two or more transmitters of known location, is called triangulation.
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