Icom AH-4 and AH-3 ( automatic antenna tuner )
connection to any radio
Both AH-3 and AH-4 are similar
is a redesign of connection digram of the ICOM
IC-AH3 and IC-AH4 by 5B4AEZ.
There is four wire control cable coming out
beside coax cable.
Control cable has
White: Start tuning
Green: Tuning in
RED: 12 V DC input
- Put about 10 watts of power into tuner. ( CW
- After about 0.5 second, press start switch
for a moment. ( use momentary contact switch
- LED start blinking , which indicate tuning
is in process.
- After about 3 seconds or so, LED shut off,
and tuning is completed,
If tuning is successful SWR should be less than
Some radio start to reduce the power when SWR
is high, this tuner takes at least 10 watts of
power for tuner to work properly. Most of the 100
watts radio should not have any problem, since
they still put out 10 watts or so, even with high
But, it does not work with some QRP radio ( 5
watts or less ).
Adjust power level, if necessary.
You may extend control cable to 100 feet , it
still work fine, you can put this tuner on top of
Let me know , how it worked