This guide details the operation, design, and electrical interface of the Icom AH-4 wide-range antenna tuner, including radio interfacing and antenna…
The Icom AH-4 is a wide-range antenna tuner designed to match a 50 ohm feed line to antenna feed impedances ranging from 10 to 5,000 ohms. It is capable of operating with up to 120 watts of power and utilizes a microprocessor control system with 22 relays to switch combinations of inductance and capacitance for tuning. The unit features a weatherproof housing suitable for permanent outdoor installation and interfaces with HF radios via a coaxial feed line and a 4-conductor control cable. Key design advantages include a power divider network that keeps the radio's SWR low during tuning and relays that are never switched under power to ensure longevity.
| Impedance Matching Range | 10 to 5,000 ohms |
|---|---|
| Maximum Power | 120 watts |
| Tuning Time | 1 to 3 seconds |
| Number of Relays | 22 |
| Operating Voltage | 12 volt |
| Peak Current Demand | Less than one amp |
The tuner matches a 50 ohm feed line to an antenna feed impedance in the range of 10 to 5,000 ohms.
The tuning process typically takes between 1 to 3 seconds.
Yes, it is enclosed in a weatherproof housing and is capable of being permanently installed outdoors.
The tuner requires 12 volts of power, typically supplied via a 4-conductor control cable.