Ah 4 Control Cable

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  1. Shielded Control Cable
  2. Icom Ah-4 Control Cable
  3. Icom Ah-4 Control Cable Extension

OPC-589 Microphone adapter cable (8 pin to RJ-45) OPC-599 Cable adapter converts 13-pin to 7/8-pin connectors. OPC-1529R Data cable (RS232 to 3.5mm) OPC-2321 Control cable for AH-740 (6m) OPC-440 Mic Extension cable (16.4ft) OPC-647 Mic Extension cable (8.2ft) External Speakers. Build a control cable for the AH-4. Build a conversion cable that is connected to the AH-4 supplied cable. When you chose No.1: Purchase a 4-conductor shielded cable and build the control cable. One side is for the J2 connector in the AH-4, the other side is for the IC.

My current antenna is the B.A.L. -- a large, horizontal loop that's about 150 meters of wire about 15-20 meters up in the trees around the yard. I think it's a great all band antenna.
I buried a couple of coax runs from the shack wall to a spot about 15m away behind a large bush. The ladder line from the loop falls down to this spot so I do not have wires directly hanging off the house (which makes the YL happy). I was using a DX Engineering MAXI-CORE Balun and was happy with the results. (As an aside: I love hamfests! I picked up this used balun for a song.) I used this setup for a few years and have been pretty happy with the results. Cable

Shielded Control Cable

Since the loop is a non-resonant antenna, the SWR can be high. I've been using the tuners built into my transceivers (Elecraft K2 & K3) but have been concerned about loss in the coax. Since I only run 100 watts or less, I want every bit of power to get to the antenna and not be used to heat the coax. Placing a tuner at the end of the coax run is supposed to reduce the coax loss. I had always planned on adding a remote tuner when the budget allowed. When I buried the coax, I also threw in a couple of runs of CAT-5 cable that I had laying around for use for some sort of remote control.
Cable

If you are using this cable with the IC-718, be sure to set the tuner menu to “4”. The LDG tuner and interface cable emulates the Icom-AH-4 tuner. Price – $10.00 US. Short video showing what it takes to get the AH-4 tuner from the box to operational status. AH-4 Manual Link: http://www.icom.co.jp/world/support/download/ma. Solder the control lines to it before installing permanently as it is much easier to do while outside of the housing than when it is in place. I used Icom's sequence from top to bottom of their connector and soldered them to the connector as follows: BK-1, RD-2, WT-3, GN-4.

The remote connection at the end of the coax run
I recently acquired an Icom AH-4 remote antenna tuner. I am using one of the CAT-5 runs as the control cable for the AH-4; I simply used each twisted pair together for the power and control signals. I no longer use the balun.

Icom Ah-4 Control Cable

All connected and ready to go!
Since I am using this tuner with a non-Icom radio, I needed a way to tell the tuner to initiate the tune cycle. I whipped up the circuit described as the universal controller

Icom Ah-4 Control Cable Extension

and it seems to do the job. (Edit Jan 2019: The link to the universal controller diagram http://www.k2.dion.ne.jp/%7Esradio/AH-4En.htmCable no longer works! There is a discussion on eham with a diagram that I think is similar.) I do plan on building a better controller that will initiate the tune cycle and then key the radio automatically.
The 'controller' in the shack
Ah 4 Control CableI've been very happy with the tuner so far. It finds a decent match (less then 1.5:1) on all bands and I believe it has made a difference. I don't have empirical evidence to support that, though! At least I no longer worry about loss in the coax...Control