INSTRUCTIONS
HF + 50 MHz AUTOMATIC ANTENNA TUNER
1-1-32 Kamiminami, Hirano-ku, Osaka 547-0003, Japan
Dec. 2020
A8295W-1EX-3 Printed in Japan
© 1997–2020 Icom Inc. –1 –
–4 –
AH-4
Thank you for purchasing the AH-4 HF + 50 MHz
AUTOMATIC ANTENNA TUNER. The AH-4 matches
your transceiver to an antenna more than 7 m/23 ft long
(3.5–54 MHz), or the optional AH-2b (7–54 MHz).
Please read these instructions thoroughly before
installing and operating the AH-4.
qU-bolts ………………………………………………………2
wU-bolt brackets ……………………………………………2
eFlat washers (M6 large) ……………………………………8
rFlat washers (M6 small)……………………………………4
tSpring washers (M6) ………………………………………8
yNuts (M6) ……………………………………………………8
uHex head bolts (M6 ×50) …………………………………4
iSelf-tapping screws (A0 6 ×30) …………………………4
oPL-259 connectors …………………………………………2
!0 Weatherproof cap …………………………………………1
!1 Rubber vulcanizing tape …………………………………1
Control cable* (5 m; 16.4 ft) …………………………………1
Coaxial cable* (5D-2V: 5 m; 16.4 ft)…………………………1
*Not shown in the illustration to the left.
RNEVER operate this tuner without a solid ground. Always
connect the ground wire to the ground terminal. DO NOT
use the mounting plate as a ground terminal.
NEVER transmit or tune without an antenna connected.
Failure to use an antenna will damage the tuner.
RHIGH VOLTAGE! NEVER touch the antenna while
transmitting or tuning. Place the antenna in a position where
you are sure it will not be touched.
DANGER!
❍WIDE TUNING RANGE
The AH-4 provides reliable matching from 3.5 MHz to 54 MHz
when using at least a 7 m (23 ft) antenna; or 7 MHz to 54 MHz
when using the AH-2b .
❍AUTOMATIC DIGITAL CONTROL TUNING
The built-in 8-bit microprocessor chooses the lowest SWR using
❍45 FREQUENCY MEMORIES FOR FAST TUNING
The LC combinations of 45 previously-used frequencies are
automatically memorized. Once a frequency is memorized, the
AH-4 tunes on that frequency in less than 1 second. Note that
the AH-4 does not memorize a frequency which is normally
tuned within 2.5 seconds. Memories are retained only when the
power is on.
❍WEATHERPROOF DESIGN
The AH-4’s tightly sealed plastic case allows convenient
mounting virtually anywhere. The AH-4 can be mounted
outdoors under your antenna.
❍0.3 W RADIATED POWER
Radiated power during tuning is less than 0.3 W, minimizing
interference to other stations.
✍NOTE:
The AH-4 can be used with most of Icom HF transceiver,
which covers HF through 50 MHz bands.
However, the IC-706 and IC-736 can only be tuned in the
3.5–30 MHz range.
FEATURES
SUPPLIED ACCESSORIES
Ground terminal
Mounting plate
q
w
e
r
t
y
u
i
0
!1
Tuning is required for each frequency. Be sure to retune
the antenna before transmitting when you change the
frequency— even slightly.
(eg. IC-7300)
qTurn ON the transceiver.
• Each time you push
, “TUNE” is displayed or goes
out, and the AH-4 is turned ON or OFF (bypassed).
wHold down
for 1 second to start manual tuning.
• The tuner reduces the SWR to less than 2:1 after 2~3 seconds
of tuning.
LWhile tuning, “TUNE” blinks red.
LIf the tuner cannot reduce the SWR to less than 2:1 after 15
seconds of tuning, “TUNE” goes out.
Hold down [TUNER] for 1 second.
eAfter tuning, “TUNE” is displayed.
LWhen the long wire antenna cannot be tuned, “TUNE” goes
out. In that case, the AH-4 is bypassed and the wire is directly
connected.
NOTE:
length and connection. Note that the AH-4 cannot tune a
OPERATION
DSpecications
• Frequency range : 3.5–54 MHz (with an antenna longer
than 7 m; 23 ft)
7–54 MHz (with the AH-2b)
• Maximum input power : 120 W
• Tuning power required : 5 to15 watts
• Rated voltage : 13.8 V DC ±15%
(current less than 1 A)
• Usable temperature range : –10°C to +60°C (+14°F to +140°F)
• VSWR : 2.0 : 1 or less (except antennas a
one half wave or multiple of a one
half wave in length)
• Weight (approximately) : 1.2 kg (2.65 lb)
• Dimensions : 172(W) × 69.5(H) × 230(D) mm
(projections not included) ; 6.8(W) × 2.7(H) × 9.1(D) inches
Allspecicationsaresubjecttochangewithoutnoticeorobligation.
DOptions
•OPC-420
Shielded control cable helps protect the transceiver from RF
feedback and extends separation between tuner and transceiver
up to 10 m. (cable length 10 m; 32.8 ft)
•AH-2b
A 2.5 m long antenna element for mobile operation with AH-4.
Frequency coverage: 7–54 MHz with the AH-4.
SPECIFICATIONS AND OPTIONS
Fig.5MOUNTINGEXAMPLES
RDANGER! HIGH VOLTAGE! NEVER touch the antenna while transmitting or tuning. Place the antenna in a position
where you are sure it will not be touched.
AH-2b + long wire
AH-2b
(optional)
Long wire
Long wire
