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9
ANTENNA TUNER OPERATION
The AH-4 matches the IC-703 to a long wire antenna
more than 7 m/23 ft long (3.5 MHz and above).
• See p. 16 for connection.
• See the AH-4 instruction manual for AH-4 installation and
antenna connection details.
NEVER
operate the AH-4 without an antenna wire.
The tuner and transceiver will be damaged.
NEVER
operate the AH-4 when it is ungrounded.
Transmitting before tuning may damage the trans-
ceiver. Note that the AH-4 cannot tune when using a
1
⁄
2
λ
long wire or multiple of the operating frequency.
AH-4 operation
q
Set the desired frequency in an HF band.
• The AH-4 will not operate on frequencies outside of
ham bands.
w
Push [TUNER] for 1 sec.
• The [TUNER] light flashes and “CW” appears while tun-
ing.
e
The [TUNER] light lights constantly when tuning is
complete.
• When the connected wire cannot be tuned, the
[TUNER] light goes out, the AH-4 is bypassed and the
antenna wire is connected to the antenna connector on
the transceiver directly.
r
To bypass the AH-4 manually, push [TUNER].
• PTT tune function
The AH-4 is always tuned when the PTT is pushed
after the frequency is changed (more than 1%). This
function removes the “push and hold [TUNER]” oper-
ation and activates first transmission on the new fre-
quency. This function is turned ON in initial set mode,
item 34 (p. 81).
CW
[TUNER]
Push [TUNER] for 1 sec.
USB
AH-4 setting example:
For mobile operation
For outdoor operation
Long wire
Optional AH-2b
antenna element
D
Optional AH-4
AUTOMATIC ANTENNA TUNER
operation
R
DANGER!: 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.
CONVENIENT
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