Since before World War II ADF equipment has been used on aircraft as an aid to navigation. The function of an ADF system is to enable the pilot to determine the headings, or direction, of the radio stations being received. The ADF system operates on a frequency range of 90 to 1800 kHz, a range that makes it possible for the system to receive radio-range stations in the LF band and standard broadcast stations. By use of the ADF system, a pilot can determine the aircraft’s position, or the pilot can “home” on a radio broadcast station or a radio beacon station by flying directly toward that station using the indication of the radio compass or radio magnetic indicator. To find the aircraft’s position, the pilot or the navigator determines the headings of two different radio stations and then plots the headings on a navigation chart. The point at which the heading lines cross will be the location of the aircraft.