Icom AH-740 HF Automatic Tuning Antenna

Introduction

Thank you for purchasing the AH-740 HF Automatic Tuning Antenna. This antenna is designed primarily for use with Icom HF transceivers. Please refer to your HF transceiver instruction manual for operation. Contact your dealer if you have any questions.

IMPORTANT: READ ALL INSTRUCTIONS carefully and completely before using the AH-740. SAVE THIS INSTRUCTION MANUAL as it contains important safety and installation instructions.

Features

• Compact and lightweight
• Fast tuning speed
• Covers 2.2 to 30 MHz range when using with the optional NVIS kit

About CE and DOC

Icom Inc. declares that the versions of AH-740 with the "CE" symbol comply with the essential requirements of the Radio Equipment Directive 2014/53/EU and the restriction of the use of certain hazardous substances in electrical and electronic equipment Directive 2011/65/EU. The full text of the EU declaration of conformity is available at: https://www.icomjapan.com/support/

Disposal

The crossed-out wheeled-bin symbol indicates that electrical and electronic products, batteries, and accumulators must be taken to designated collection locations at the end of their working life within the European Union. Dispose of them according to local laws.

UKCA Statement: United Kingdom Authorised Importer: Icom (UK) Ltd. Address: Blacksole House, Altira Park, Herne Bay, Kent, CT6 6GZ, U.K. For UKCA Declaration of Conformity, contact info@icomuk.co.uk or call +44(0) 1227741741.

Explicit Definitions

Precautions

• DANGER HIGH VOLTAGE! NEVER touch the antenna terminal, ground terminal, or antenna while transmitting.
• WARNING! NEVER transmit while installing the antenna, as this may cause electric shock.
• NEVER use without a ground connection. USE the ground terminal for ground connection.
• DO NOT operate your HF transceiver without running the vehicle's engine. When the transceiver's power is ON and the vehicle's engine is OFF, the vehicle's battery will soon become exhausted.
• DO NOT use the AH-740 in areas where the temperature is below -40°C (-40°F) or above +70°C (+158°F).

Icom and the Icom logo are registered trademarks of Icom Incorporated (Japan). All other products or brands are trademarks of their respective holders.

Supplied Accessories

The following accessories are supplied with the antenna:

1. Control cable (approx. 6 m, 19.7 ft)
2. Coaxial cable (approx. 6 m, 19.7 ft)
3. Whip antenna
4. Antenna spring
5. Bolts (M8) x 2
6. Nuts (M8) x 2
7. Spring washers (M8) x 2
8. Flat washers (M8) x 4
9. Spring washer (M16) x 1
10. Nut (M16) x 1
11. Flat washer (M16) x 1

Miscellaneous Items

The following items are additionally required for installation but are not supplied with the AH-740. Please purchase them locally:

• Mounting base
• Rubber vulcanizing tape
• Electrical tape

Icom is not responsible for the destruction, damage to, or performance of any Icom or non-Icom equipment if the malfunction is due to:

• Force majeure, including fires, earthquakes, storms, floods, lightning, other natural disasters, disturbances, riots, war, or radioactive contamination.
• The use of Icom products with any equipment that is not manufactured or approved by Icom.

System Installation

Ground Connection

It is essential that the antenna is connected to an effective and stable RF GROUND POINT, such as the vehicle chassis. It is recommended that body panels are also bonded to the vehicle chassis. Ensure all contact points are free of paint, ground to a shiny finish, and protected from rusting with conductive grease before bolting the mounting stud and ground strap terminals.

Cabling

A coaxial cable and a control cable are supplied. A ground strap is provided on the base of the tuning antenna for a reliable connection with the vehicle's metalwork. Connect the ground strap to the chassis frame or body metalwork whenever possible. Avoid routing antenna cables with engine ignition cabling. Use a One-Point (Star) Station Ground for the entire HF system where your transceiver is installed. Feed both (+ and -) thick wires from the vehicle battery to the transceiver location. Do not use the vehicle's metalwork as a replacement for the negative (-) wire. Use suitable noise filters for alternators. Consult your dealer for details.

Coaxial Cable

Insulate the lead-in cable of the AH-740 antenna terminal and antenna element from other metal objects. To prevent interference, keep cables as far as possible from other antennas and electronic equipment.

Mounting Base

A mounting base must be prepared locally for the AH-740 installation. Select or fabricate a strong metal bracket for the antenna plate, approximately 8-10 mm (0.31-0.39 inches) thick, and weld or bolt it firmly to the vehicle chassis or other strong structure. Consult your technical dealer or installer for suitable mounting base details.

Installations

Typical Installation Scenarios

SUV Installation: Recommended scenarios use a Universal Gibbet Mounting System (front) or the Spare Wheel Antenna Bracket (rear). Ensure the tuning antenna unit is kept clear of the vehicle's hood and other metal panels for best communications in all directions.

Pickup Truck Installation: Recommended options use a Universal Gibbet Mounting System (front) and a customer-provided bracket (middle). Both methods provide effective communications in all directions.

Sedan Installation: Recommended options use a Universal Gibbet Mounting System for both front and rear antenna locations. Ensure the tuning antenna unit is optimally raised above the trunk and hood of the vehicle.

NON-RECOMMENDED Installation: Avoid using a Universal Gibbet Mounting System at the rear on minivans or 4WD vehicles where the Antenna Main Assembly and partially Whip Section are obstructed by vehicle metal panels, as this will affect communications.

For best communications, position the antenna as high as possible. The figure below shows preferred option selections. The figure also shows an antenna installation using the optional AH-5NV for best communications on short ranges (30–300 km) and medium ranges (up to 1500 km).

What is NVIS?

NVIS stands for Near Vertical Incidence Skywave. NVIS radio-wave propagation provides usable signals between groundwave and skywave distances (between 50 and 650 km). Radio waves travel upwards into the ionosphere and are refracted back down in a circular area. Signals can be received up to 650 km from the transmitting station. Refraction fails if the frequency is too high, and signal strength is reduced if the frequency is too low due to absorption.

Precautions when the optional AH-5NV is installed on a vehicle

WARNING! The NVIS antenna element can swing significantly while driving. It is strongly recommended to remove the NVIS antenna while driving to prevent it from swinging excessively and interfering with your driving.

Installation Outline

IMPORTANT! The antenna is a critical element in any communication system. Correct installation is vital for achieving optimal antenna system performance and transceiver operation. Icom recommends that installation of the AH-740 be carried out by qualified technicians only.

1. Attach a mounting base to a desired position on your vehicle. (Purchase the mounting base locally.)
2. Mount the AH-740 onto the mounting base. Refer to "Mounting" for details.
3. Connect the control and coaxial cables between the transceiver and the AH-740. Refer to page 5 "Cable connections" for details.
4. Connect the ground strap to the vehicle's chassis. Refer to page 5 "Cable connections" for details.
5. Attach the supplied antenna spring and whip onto the AH-740.

Mounting

WARNING! Mount the AH-740 securely with the supplied nuts and bolts. Otherwise, vibrations and shocks could loosen the antenna tuner, causing it to fall and potentially result in personal injury.

• For greatest radiation effectiveness, position the antenna as high as possible.
• For human safety, mount the antenna at the front and opposite side of the driver's position whenever possible. Refer to the pictorial installations and scenarios shown on pages 2 and 3.
• Ensure enough clearance around the antenna so that any antenna flexing will not damage the vehicle. The Main Assembly can flex as much as 16 cm (6.3 inches) without damage.
• Ensure the antenna is as far from the vehicle's vertical and horizontal metal panels as possible.
• Mount the antenna on a mounting base with a 17 mm (0.67 inches) hole for the M16×2 mm (M0.63×0.08 inches) threaded mounting stud.
• Rotate the Main Assembly until the ground strap is directed towards the vehicle body, and then firmly tighten the nut.
• Use only the original hardware and proper tools.

Cable Connections

1. Connect the coaxial cable and the control cable to the AH-740. Insert the control cable connector into the antenna body socket, then rotate the connector ring to lock it in place.
2. Wrap the antenna connector with rubber vulcanizing tape, and then wrap electrical tape* over the rubber vulcanizing tape to secure waterproofing. (*Rubber vulcanizing tape and electrical tape are not supplied. Purchase locally.)
3. Secure both the coaxial and control cables to protect the inside connections.
4. Connect the coaxial cable and the control cable to the transceiver. Connect the coaxial cable to an appropriate antenna connector. Connect the control cable to the D-sub 9 pin type antenna tuner control connector, or the 4 pin type connector when the optional OPC-2321 is used. Refer to your transceiver's instruction manual for details.
5. Ground the transceiver, AH-740, and shield cable of the control cable to the ground terminal.

Optional AH-5NV

When using the AH-740 with the optional AH-5NV, install the AH-5NV as follows:

1. Place the swivel magnet holder onto the vehicle and attach the NVIS antenna element to the antenna spring of the AH-740. Secure the antenna element by tightening the set screws.
2. Insert the antenna element into the swivel magnet holder as shown below.
3. Tighten the set screw.

Specifications and Options

Specifications

• Frequency coverage: 2.2–30 MHz (with NVIS kit), 2.5–30 MHz (with supplied whip)
• Power supply requirement: 13.8 V DC (supplied from the HF transceiver)
• Current drain: Maximum 0.6 A
• Operating temperature range: -40°C to +70°C (-40°F to +158°F)
• Antenna connector: SO-239
• Maximum Input power: 125 W (PEP)
• Automatic tuning time: Approximately 2 to 3 seconds (new frequency), 0.15 seconds (typical, retuning to a memorized frequency)
• Automatic tuning accuracy: SWR 1.5:1 or less (after tuning, except for multiples of 1/2λ)
• Dimensions: 238 (H) × 145 (W) × 160 (D) mm, 9.4 (H) × 5.7 (W) × 6.3 (D) inches, 3.5 kg, 7.7 lb (except whip and antenna spring)

Control Connector Information

Options

• AH-5NV NVIS KIT: Approximately 4.5 m (14.8 ft) long antenna, covers 2.2 MHz through 30 MHz. WARNING! At least two people are needed to unpack the optional AH-5NV NVIS KIT. Work in an open space as the element is tightly coiled and can spring open with a lot of force. This could cause serious injury or other damage.
• OPC-2321 CONTROL CABLE: Approximately 6 m (19.7 ft) long control cable for Icom's amateur transceivers that have a 4-pin type antenna tuner control connector.

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