A popular term for an automatic radio direction finder used for navigation purposes on ships and aircraft. It is not strictly a compass, because it indicates direction with respect to the radio station to which it is tuned, rather than to the north magnetic pole. The modern radio compass uses a nondirectional antenna in combination with a bidirectional loop antenna to provide a unidirectional bearing indication. The navigator thus knows at all times whether the craft is traveling toward or away from the radio station used as a reference. The antennas are used with a special radio receiver that provides a visual indication of direction on a meter or cathode-ray indicator.