When listening to AM shortwave broadcasts, switch the AVC (automatic volume control) switch to the ''SLOW'' position, so that the fading of the signal is not as noticeable.
Switch to the ''FAST'' position when listening to CW (morse code) and also when listening to SSB (single sideband) signals.
''AVC'' can also be displayed on your receiver as an ''AGC'' (automatic gain control) switch.