ICOM IC-703 Manuale Utente

66

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.

qSet the desired frequency in an HF band.

• The AH-4 will not operate on frequencies outside of

ham bands.

wPush [TUNER] for 1 sec.

• The [TUNER] light flashes and “CW” appears while tun-

ing.

eThe [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.

rTo 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

For mobile operation

For outdoor operation

Long wire

Optional AH-2b
antenna element

DOptional AH-4 

RDANGER!: 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.