What can you do if you are told your FM handheld or mobile transceiver is over-deviating?

In an FM (Frequency Modulation) transmitter, the volume of your voice directly controls how much the radio wave's frequency changes or 'deviates.' Over-deviation means your audio signal is causing the frequency to swing too widely, which can cause your signal to distort or spill into adjacent channels. The most common cause of over-deviation is simply having the audio input too loud. By moving the microphone farther away from your mouth, you naturally reduce the audio level entering the transmitter, instantly correcting the over-deviation. Changing the transmitter's RF power level or letting the radio cool off will have no effect on how your audio modulates the signal, making those choices incorrect.