Icom AH-4 User Manual

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INSTRUCTIONS

HF + 50 MHz AUTOMATIC ANTENNA TUNER

AH-4

Thank you for purchasing the AH-4 AUTOMATIC ANTENNA TUNER. The AH-4 matches your transceiver to an antenna more than 7 m/23 ft long (3.5 MHz and above).

Please read these instructions thoroughly before installing and operating the AH-4.

DANGERµ

Ground terminal

Mounting plate

RNEVER use this tuner when it is ungrounded. Always ground the tuner through the ground terminal before operating. DO NOT use the mounting plates for grounding.

NEVER transmit or tune without an antenna. 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.

FEATURES

WIDE TUNING RANGE

The AH-4 provides reliable matching of frequencies 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 ANTENNA ELEMENT.

AUTOMATIC DIGITAL CONTROL TUNING

The built-in 8-bit microprocessor chooses the lowest SWR condition from more than 1,040,000 different LC (coil/capacitor) combinations.

45 FREQUENCY MEMORIES FOR FAST TUNING

The LC combinations of 45 previously-used frequencies are automatically memorized in the AH-4. Once a frequency is memorized, the AH-4 tunes on that frequency in less than 1 sec. Note that the AH-4 does not memorize a frequency which is normally tuned within 2.5 sec. 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: 50 MHz tuning is possible with the IC-729*, IC-706MKII, IC-746 and IC-756; the IC-706 and IC736 can only be tuned 3.5–30 MHz.

*Connect a 50 MHz antenna connector for 50 MHz operation.

SUPPLIED ACCESSORIES

 

 

u

q

 

 

w

 

 

 

 

i

e

 

 

r

 

 

t

 

 

y

o

!0

q U-bolts ..................................................................

2

w U-bolt plates .........................................................

2

e Flat washers (M6 large) ........................................

8

r Flat washers (M6 small) .......................................

4

t Spring washers (M6) ............................................

8

y Nuts (M6) ..............................................................

8

u Hex head bolts (M6 × 50) .....................................

4

i Self-tapping screws (A0 6 × 30) ...........................

4

o PL-259 connectors ...............................................

2

!0Weatherproof cap .................................................

1

!1Control cable (OPC-136; 5 m)...............................

1

!2Coaxial cable (5D-2V × 5 m) .................................

1

Icom AH-4 User Manual

INSTALLATION

NOTE: After inserting the coaxial cable into the AH- 4 top cover, solder the PL-259 connector to the coaxial cable.

Remove the top cover (Fig. 1).

Install the control cable and coaxial cable (Fig. 1).

Connect and solder the PL-259 connector to the coaxial cable (Fig. 4).

Connect the control cable to the AH-4 (Fig. 2).Connect the GND cable to the AH-4 (Fig. 3).Replace the top cover.

Mount the AH-4 in the desired location; on an antenna pole, in your vehicle’s trunk, etc. (Fig. 5).

Connect an antenna to the AH-4 (Fig. 6).

Connect the control cable and the coaxial cable to the transceiver.

Fig. 1 COVER REMOVAL AND CABLE

INSTALLATION

Strain relief insert

Coaxial cable

Control

cable

Cable clamp

Remove 8 screws from the top cover and remove the cover.

Loosen the screws on both cable clamps. If desired, install a strain relief insert (supplied) corresponding to the diameter of the cable.

Install the coaxial cable through the top cover cable clamp.

Install the control cable through the bottom cover cable clamp.

After connecting the coaxial cable and control cables, tighten the cable clamp screws.

Fig. 2 CABLE CONNECTIONS

Antenna element AH-2b (optional)

Coaxial cable

IC-706MKII rear panel

GND

NOTE: For the IC-756 and IC-746, connect to ANT 1.

 

black (GND)

PL-259

red (DC13V)

white (START)

connector

green (KEY)

 

 

J2

 

 

 

J8

Top cover

 

 

 

GND

Bottom cover

 

 

Control cable

 

 

Fig. 3 GROUND CONNECTIONS

The transceiver and antenna tuner must have an ade-

• Ground example

 

 

 

 

 

quate ground connection. Otherwise, the overall ef-

 

 

 

 

 

 

 

 

 

 

 

 

fency of the transceiver and antenna tuner installation

 

 

 

 

 

 

 

To AH-4 GND terminal

will be reduced. Interference, RF feed back and elec-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

trical shocks from other equipment could also occur.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For best results, use the heaviest gauge wire or strap

 

 

 

 

 

 

 

 

 

 

 

yyyy;;;;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

available and make the connection as short as possi-

 

 

 

 

 

 

 

 

 

 

 

yyyy;;;;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ble. (see right)

 

 

 

Copper pipe

Metal object

Copper screen

A long wire connected to the GND terminal as a counterpoise is also acceptable.

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