Frequency Modulation (FM)

A method of encoding information in a carrier wave by varying its frequency, commonly used in marine radio communications.

Frequency modulation (FM) is a technique used to transmit information over radio waves by varying the frequency of the carrier signal in proportion to the amplitude of the input signal, which typically contains voice or data. In marine environments, FM is widely employed for short-range VHF (Very High Frequency) radio communications, such as those used between vessels or between a vessel and a shore station. FM provides clearer audio quality and better resistance to signal degradation from electrical interference and atmospheric conditions compared to amplitude modulation (AM). This makes it particularly suitable for the often noisy and dynamic conditions at sea. Marine VHF radios operating on FM are essential for coordinating navigation, reporting positions, requesting assistance, and maintaining safety at sea. FM also allows for the use of squelch controls, which suppress background noise when no transmission is being received, further improving communication clarity.