Icom AH-703 User Manual

INSTRUCTIONS

Top element

Short terminal A

Short element

Loading coil A

Short terminal B

Loading coil B

Short terminal C
Loading coil C

Short terminal D

Loading coil D

Short terminal E

Base element

Antenna connector
(PL-259 type)

Base
element

Top element Allen wrench

Grounding wires

Set screw

HF/50 MHz 5-BAND ANTENNA

Thank you for purchasing the AH-703

BAND ANTENNA

and 50 MHz bands, and is designed for portable
operation of the IC-703 when carried in the LC-156.

. This antenna covers 7, 14, 21, 28

HF

/50MHz5-

AH-703

■ IMPORTANT

READ ALL INSTRUCTIONS carefully and completely

before using the AH-703.

SAVE THIS INSTRUCTION SHEET!— This instruction
contains important safety and operating details for the
AH-703.

■ PRECAUTION

R WARNING: HIGH VOLTAGE!
NEVER touch the antenna element/wire while tuning

or transmitting. This may result electrical shock or burn.

R WARNING SUSPEND operation immediately or
NEVER put up the antenna when thunder occurs or

can be heard in the distance.

R WARNING NEVER assemble or disassemble the
antenna at any crowded area. A person may be in­jured.

Please read these instructions thoroughly before
using the AH-703.

■ Antenna description

USE the AH-703 for portable operation with the IC-703
ONLY. NEVER install the antenna to a vehicle for mo-

bile operation.

DISCONNECT the antenna when not using the an­tenna for long period of time.

DO NOT use chemical agents such as benzine or alco­hol when cleaning, as they can damage the AH-703.

READ THE IC-703 INSTRUCTION MANUAL FIRST
before attempting to operate the transceiver.

■ Supplied items

■ Antenna specifications

• Frequency coverage :

• Type of antenna : 1⁄4λ type whip antenna

• Antenna connector : PL-259 (50 Ω: nominal)

• Max. input power : 20 W

• Total antenna length : Approx. 1,390 mm; 4.6 ft

• Weight : Approx. 330 g; 11.6 oz

All stated specifications are subject to change without notice or
obligation.

7, 14, 21, 28 and 50 MHz bands

(at the longest element length)

(without grounding wires)

Icom, Icom Inc. and the logo are registered trademarks of
Icom Incorporated (Japan) in the United States, the United King­dom, Germany, France, Spain, Russia and/or other countries.

■ Assembling the antenna

Loosen

Adjustable

Tighten

IC-703

Separation cable

controller case

AH-703

Pass the grounding wire
through the cable hole and
keep in the side pocket.

Loosen

Set screw

Tighten

q Attach the top element to the base element, then

tighten the top element.

w Tighten the set screw.
e Attach the grounding wires to the [GND] terminal of

the IC-703 rear panel as illustrated below.

• Keep the grounding wires in the LC-156 side pockets via
the cable hole.

• Keep the separation cable on the outside of the LC-156.

e Push [TUNER] on the IC-703 controller, then mea-

sure the VSWR.

• See the IC-703 instruction manual for the VSWR mea­surement procedure.

r When the VSWR is not good enough (VSWR>1.5:1)

or not tuned, adjust the following.

• Top element length:

Loosen the nut of the top element, then adjust
the element length as illustrated below.

• To improve VSWR on a higher or lower frequency in
the selected frequency band, adjust the top element
by lengthening or shortening it, respectively.

• After the element length adjustment, tighten the nut.

• Grounding wires:

Adjust or change the wires angle, holding posi­tion, etc.

The above illustration is example only

When SWR cannot be reduced, abnormal function­ing of the transceiver may occur, etc., change the
cables

phone cables)

(grounding, separation, DC power and micro-

wiring, as described in the “■ Opera-

tion hints”.

■ Adjusting the antenna

q Set the desired operating frequency on the IC-703.
w Connect the short element between the short termi-

nals to suits the set operating frequency as follows.

Freq. Short element
Band connection

7 MHz Remove the element All loading coils (A–D)

14 MHz D–EA–C

21 MHz C–EA–B

28 MHz B–E A only

50 MHz A–E No loading coil

Using loading coil

t Repeat the steps e and r until the VSWR be-

comes better than 1.5:1.

■ Operation hints

K The IC-703 separation cable may work as the

grounding cable (counterpoise).
Changing the cable wiring may also provide better
VSWR.

K The quality of communication during portable oper-

ation depends on the operating frequency, field con­dition, etc.
When the operating condition is not good, changing
the place of operation may help improve operating
performance.

K When changing the operating frequency, manual

tuning is helpful for good operation. Even changing
the frequency 10 kHz, you should start with manual
tuning.

1-1-32 Kamiminami, Hirano-ku, Osaka 547-0003, Japan

A-6313H-1EX-q Printed in Japan

© 2003 Icom Inc.