Intermodulation interference in mobile multiple-transmission communication systems operating at high frequencies (3¿30 MHz)

Nonlinear responses in the transmitters, antennas and surroundings of a mobile multiple-transmission communication system give rise to intermodulation interference to the desired weaker signals at the receiver. The major sources of nonlinearity, for various transmitter configurations such as narrowband and wideband, have been identified. Laboratory-based experiments supporting the field trial work have investigated the nonlinear behaviour of ferromagnetic materials from the standpoint of surface preparation and chemical composition. Emphasis has been given to the shipborne environment.