Method and apparatus for loop direction finding with no ambiguity

A method and apparatus is provided for deriving the direction of a received signal from a signal source using first and second orthogonally-mounted loop (12, 14) antennas and an omnidirectional antenna (16). In operation, output signals from each of the antennas are generated and repeatedly supplied to signal processing circuitry in a cyclical fashion as the receiver is rotated to locate the transmitter. The amplitudes of the output signals from the first and second loop antennas are then compared (94) to determine whether the signal source is located in a null of the first loop antenna. If so, a null indication signal is generated. The phases of the output signals from the second loop antenna and the omnidirectional antenna are compared to determine whether the received signal is being received in a predetermined region of the second loop antenna. If so, an ambiguity indication signal is generated. The null indication signal and the ambiguity indication signal are then logically combined to generate a visual output (122) representing the direction of the signal source.