Robert UN7RX has proposed one of the user-friendliest and simplest solutions for the IC-706 series; it will also work with other Icom transceivers fitted with the 4-pin Molex socket for connection of the AH-3 or AH-4 automatic tuner.
The UN7RX circuit consists of one-half of a CD4013, one resistor, two capacitors and one diode. When tuning, it is not necessary to switch modes or reduce RF power output; this circuit does all that automatically.
For the IC-756Pro3, configure the radio per p. 89 of the User Manual (Optional external tuner operation).
First push of TUNER button - LED blinking, no TX.
Second push of TUNER button - carrier TX on, RF output 10W.
Third push of TUNER button - TX off, normal RX.
Copyright © 2005, UN7GM and UN7RX
Text edited and page created by A. Farson VA7OJ/AB4OJ
Last updated: 10/12/2005