16
ANTENNA TUNER OPERATION
16-7
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Setting the AT-180 internal switches
The optional AT-180 has 3 operating confi gurations for
HF band operation. Select a suitable confi gurations for
your antenna system.
q Remove the top cover of the AT-180.
w Set the tuner switches to the desired positions ac-
cording to the table below.
Automatic tuner start D (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 function.
PTT tune function D
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 fi rst transmis-
sion on the new frequency. (p. 10-11)
Turn this function ON in the Set mode.
SW Position Operation
S1
A
(default)
The tuner operating mode is set by S2
described below.
B THROUGH INHIBIT
The tuner tunes the antenna even when
the antenna has poor SWR (up to VSWR
3:1 after tuning). In this case, manual tun-
ing is necessary each time you change
the frequency although the tuner auto-
matically 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.
S2
C TUNER SENSITIVE SETTING
The tuner tunes each time you transmit
(except SSB mode). Therefore, the low-
est SWR is obtained at any given time.
For SSB mode, the same SETTING as
the “D” position.
D
(default)
NORMAL
The tuner tunes when the SWR is higher
than 1.5:1. Therefore, the tuner activates
only when tuning is necessary.
• AT-180 inside top cover
S2 S1
DC BA
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