D Using The At-180 - Icom IC-718 Advanced Manual

3
OPTIONS
Connecting an external antenna tuner

D Using the AT-180

See also page 2-3 for the tuning operation�
Coaxial cable supplied
with the AT-180
To [ANT]
Setting the internal switches
The optional AT-180 has 3 operating settings�
Select the suitable setting for your antenna system�
1� Remove the top cover of the AT-180�
2� Set the tuner switches to the desired positions
according to the table below�
SW Position
A The tuner operating settings are set with
(default)
S2�
B THROUGH INHIBIT MODE
The tuner tunes the antenna even when the
antenna has poor SWR (up to VSWR 3:1
after tuning)�
S1
In this case, manual tuning is necessary
each time you change the frequency,
although the tuner automatically starts tuning
when the VSWR is higher than 3:1�
This setting is called "through inhibit�"
However, the tuner is set to "through" if the
VSWR is higher than 3:1 after tuning�
TUNER SENSITIVE MODE
C
The tuner tunes each time you transmit
(except in the SSB mode)� Therefore, the
lowest SWR is obtained at any given time�
In the SSB mode, the setting is the same as
S2
the "D" position�
D NORMAL MODE
(default) The tuner tunes when the SWR is higher
than 1�5:1� Therefore, the tuner activates
only when tuning is necessary�
ACC cable supplied with the AT-180
To [ACC]
IC-718
Operation
AT-180
GND
AT-180 inside the top cover
S2
D C
3-5
HF antenna
either of two
[ACC] connectors
S1
B A