Bout The Antenna Tuner; U Sing The Antenna Tuner Operation - Icom IC-7851 Instruction Manual

■ About the Antenna tuner
The internal automatic antenna tuner automatically
matches the transceiver to the connected antenna.
After the tuner matches an antenna, the variable ca-
pacitor angles are memorized as a preset point for
each frequency range (100 kHz steps). Therefore,
when you change the frequency range, the variable
capacitors are automatically preset to the memorized
point.
CAUTION: NEVER transmit with the tuner ON when
no antenna is connected. This will damage the
transceiver. Be careful of the antenna selection.
■ Using the Antenna tuner operation
➥ Push [TUNER] to turn on the internal antenna tuner.
The antenna is automatically tuned when the an-
tenna SWR is higher than 1.5:1.
• When the tuner is ON, the [TUNER] switch indicator
lights white.
• While tuning, the [TUNER] switch indicator blinks red.
NOTE:
• NEVER transmit without an antenna properly
connected to the selected antenna port.
• When 2 or more antennas are connected, select
the antenna to be used with [ANT].
• If the SWR is higher than about 1.5:1 when tun-
ing above 100 kHz on an antenna's preset point,
hold down [TUNER] for 1 second to start manual
tuning.
• The internal tuner may not be able to tune in the
AM mode. In such cases, hold down [TUNER] for
1 second to manually tune.
• MANUAL TUNING
During SSB operation at low voice levels, the internal
tuner may not tune correctly. In such cases, manual
tune the antenna.
➥ Hold down [TUNER] for 1 second, to start manual
tuning.
• A side tone is heard and the [TUNER] switch indicator
blinks red while tuning.
• If the tuner cannot reduce the SWR to less than 1.5:1
after 20 seconds of tuning, the [TUNER] switch indicator
goes out.
• AUTOMATIC TUNER START (HF bands only)
If you want to deactivate the tuner under conditions
of VSWR 1.5:1 or less, use the auto tuner start func-
tion and turn the tuner OFF. This function activates the
tuner automatically when the SWR exceeds 1.5:1.
This function is turned ON in the set mode.
[TUNER]
(p. 15-14).
13-7
ANTENNA TUNER OPERATION
[TUNER] indicator
13