Transmission method in which a carrier wave is
modulated so that its frequency is proportional
to the amplitude of the audio signal.
With FM the receiver sensitivity is not as good as in
SSB, but the immunity to interferences is
greater, as well as the tolerance to quick signal strength variations.
Hams use Fm only on VHFbands and up, for local
QSO or when using
repeaters.
Audio signal quality is similar to AM,
because hams use a narrow bandwidth FM,
in order to reduce spectrum use.
