Icom AH-4 User Manual

Inside the Icom AH-4 Tuner!
This paper describes the Icom AH-4 wide range antenna tuner. It attempts to compensate for a rather
sparse instruction manual by providing information on how to interface the AH-4 with any HF radio. In
addition, it also provides recommendations regarding antennas for fixed locations. An overview and
description is presented as well. Those who are interested in antenna tuners (the AH-4 in particular)
and those who just plain like to look into the guts of hardware and see how things work will want to
read on.!
Chris, K9EQ!
Table of Contents
Table of Contents" 1!
1. Overview" 2!
2. AH-4 Design" 3!
3. Inside the AH-4" 4!
4. AH-4 Radio Interface Operation" 6!
5. Electrical Interface" 8!
6. Revision History" 8
AH-4 Operation
K9EQ
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Icom AH-4 Specifications

Frequency and Impedance

frequency range with antenna longer than 7 m	3.5–54 MHz
frequency range with AH-2b	7–54 MHz
input impedance	50 Ω

Power

maximum input power	120 W
tuning power required	10 W (5–15 W)
rated voltage	13.8 V DC ±15% (current drain less than 1 A)

Operating Environment

usable temperature range	–10°C to +60°C (+14°F to +140°F)
VSWR	2.0 : 1 or less
dimensions	172(W) × 69.5(H) × 230(D) mm; 6[25]⁄32(W) × 6[3]⁄4(H) × 9[1]⁄16(D) in

Weight and Dimensions

weight	1.2 kg (2.65 lb)
dimensions	172(W) × 69.5(H) × 230(D) mm; 6[25]⁄32(W) × 6[3]⁄4(H) × 9[1]⁄16(D) in