Icom IC-725 Instruction Manual page 17

15
4 PRE-OPERATION
SQUELCH CONTROL
Mutes the speaker. Signals and noises that are stronger
than the squelch threshold level open the squelch and
audio is emitted from the speaker.
RIT CONTROL
Used for fine tuning stations which call off frequency
or for compensating for frequency drift.
Shifts the receive frequency up to +1 kHz from the
displayed frequency without shifting the transmit
frequency.
AF GAIN CONTROL
Varies the audio output level
from the speaker. Clockwise
rotation increases the volume.
THROUGH
CW/N SWITCH
By installing an optional CW narrow filter. The transceiver
has better receive selectivity in CW mode.
AGC SWITCH
Out position: AGC slow
Normally used when operating in SSB or AM mode.
In position: AGC fast
Normally used when operating in CW mode.
Note that the AGC switch does not function in FM mode.
PREAMP SWITCH
Used when receiving weak signals. Push [PREAMP] to the
IN position to improve the S/N ratio and sensitivity.
Especially useful during DX operation.
ATTENUATOR SWITCH
Used when the received sound from the speaker is distorted
by very strong signals. Push [ATT] to the IN position to
activate the 20 dB attenuator.
NOISE BLANKER SWITCH
Reduces pulse-type noise such as that generated by auto-
mobile ignition systems.
Note that the noise blanker function does not function in
-AM and FM modes and may not work well when strong
signals are on nearby frequencies or when noise is con-
tinuous rather than pulse-type.