9-2
9
ANTENNA TUNER OPERATION
■
About the optional AT-180
automatic
antenna
tuner
The AT-180 automatic antenna tuner automatically
matches the IC-7200 to your antenna. Once the tuner
matches the antenna, the variable capacitor settings
are memorized as a preset point for each frequency
range (100 kHz steps). Therefore, when you change
the frequency range, the variable capacitors are auto-
matically preset to the memorized point.
NOTE:
• The AT-180 can match both the HF and 50 MHz
bands. However, operation is different for the
bands.
• When connecting the AT-180, the IC-7200’s out-
put power should be more than 10 W. Otherwise,
the AT-180 may not tune correctly. The AT-180’s
minimum operating input power is 8 W.
CAUTION: NEVER transmit with the tuner ON if no
antenna is connected. This will damage both the
transceiver and antenna tuner.
TUNER
D
Automatic tuning
• For the HF band:
Push
TUNER
to turn ON the tuner. The antenna is au-
tomatically tuned during transmit if the antenna SWR
is higher than 1.5:1.
• When the tuner is ON, “
” appears.
• For the 50 MHz band:
Hold down
TUNER
for 1 second to tune the antenna.
If
“
”
blinks slowly while transmitting, hold down
TUNER
for 1 second again to retune the antenna.
D
Manual tuning
During SSB operation on the HF bands at low voice
levels, the AT-180 may not tune correctly. In such cas-
es, manual tuning is helpful.
Hold down
TUNER
for 1 second to start manual tun-
ing.
• When the CW mode is selected, a side tone is emitted, and
“
” blinks; then, the previous mode is selected.
If the tuner cannot reduce the SWR to less than 1.5:1
after 20 seconds of tuning,
“
”
disappears. In this
case, check the following:
• the antenna connection and feedline
• the antenna SWR (p. 3-13; meter function, p. 6-11; Mea-
suring SWR)
Through inhibit (HF bands only)
The AT-180 has a through inhibit setting. When select-
ing this setting, the tuner can be used at poor SWR’s.
In this case, automatic tuning in the HF bands ac-
tivates only when the SWR exceeds 3:1. Therefore,
manual tuning is necessary each time you change
the frequency. Although termed “through inhibit,” the
tuner will be set to the “through” configuration if the
SWR is higher than 3:1 after tuning.
CONVENIENT
• Tuner sensitive setting (HF bands only)
If you require critical tuning at any time during trans-
mission, select the tuner sensitive setting.
See page 9-3 for selection details.
• Automatic tuner start (HF bands only)
If you want to turn OFF the tuner when the VSWR is
1.5:1 or less, use “automatic tuner on” and turn OFF
the tuner. See page 10-11 for automatic tuner func-
tion.
• PTT tune function
The AT-180 tunes when [PTT] is pushed after the
frequency is changed (more than 1%) if the AT-180
is turned ON. This function removes the “hold down
TUNER
” operation and activates with the first trans-
mission on the new frequency. (p. 10-11)
Turn this function ON in the Set mode.
Previous view
