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18
4
OPERATION
The AT-120, AT-130 or AH-4 matches the IC-78 to a
long wire antenna more than 7 m
(23 ft)
long (3.5 MHz
and above).
• See p. 11 for connection.
• See the connected antenna tuner’s instruction man-
ual for installation and antenna connection details.
• Setting example:
NEVER operate the AT-120, AT-130 or AH-4 without
an antenna wire. The tuner and transceiver will be
damaged.
NEVER operate the AT-120, AT-130 or AH-4 when it
is ungrounded.
Transmitting before tuning may damage the trans-
ceiver. Note that the AT-120, AT-130 or AH-4 cannot
tune when using a
1
⁄
2
λ
long wire or multiple of the op-
erating frequency.
TUNER OPERATION
• Tuner type setting (p. 32)
q
Push [PWR] for 1 sec. to turn power OFF.
w
Enter
initial set mode.
• Turn power ON while pushing and holding [SET].
e
Push [UP
Y
] or [
Z
DN] to select [TUNER].
r
Selects connected antenna tuner type by rotating
the channel selector.
• no : no antenna tuner is selected.
• 4
: AH-4 is selected.
• 12 : AT-120 is selected.
• 13 : AT-130 is selected.
y
Push [PWR] for 1 sec. to turn power OFF.
u
Push [PWR] to turn power ON again.
• MANUAL TUNING
q
Set the desired channel.
w
Push [TUNER] to start tuning.
• “
” blinks and “CW” appears while tuning.
e
“
”
lights constantly when tuning is completed.
(except when AT-120 is connected; the indicator
goes out)
• When the connected wire cannot be tuned, the “
”
goes out, the antenna tuner is bypassed and the an-
tenna wire is connected to the antenna connector on
the transceiver directly.
r
To bypass the antenna tuner manually, push
[TUNER]. (AH-4 only; starts tuning again when AT-
120 or AT-130 is connected)
For mobile operation
For outdoor operation
Long wire
Optional AH-2b
antenna element
MIC
I
C-
718
PHONES
SQL
AF
SHIFT
RIT
LOCK
MODE FILTER
TS
PWR
TUNER
∫
∫
COMP
P.AMP
UP
NB
ATT
SET
CH
DN
ENT
F-INP
V/M
1
MW
4
A=B
2
M=CL
5
SCN
8
ANF
0
NR
.
A/B
3
VOX
9
7
SPL
M V
6
▲
AT-120
AT-130
AH-4
R
R
WARNING: HIGH VOLTAGE!
NEVER touch the antenna element while tuning or
transmitting.
Tuning is required for each frequency. Be sure to
re-tune the antenna before transmitting when you
change the frequency— even slightly.
[TUNER] switch
ï
Optional AT-120/AT-130/AH-4 operation
Tuning indicator;
Blinks: While tuning
Appears: Tune is completed
Disappears: Tune is not completed
(When AT-120 is connected, the
indicator disappears even when
tuned completely.)