IC-7100 | IC PAC Cable

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To make use of the Tuner button on my IC-7100 I needed a cable to connect between the rig and my LDG Z-100 Plus Autotuner. A quick Google revealed several sources of such a cable, however at over £20 I thought it was a bit expensive, so I decided to make one myself.

I had in the shack some suitable cable, some heat shrink and some cable sleeving, I just needed a DC power plug, a 3.5mm stereo jack and a 4 pin Molex connector. All three items were purchased via eBay for just £6 including delivery.

Once all the parts had arrived in the post, I measured out a suitable length of cable, then cut three more, ending up with red and black for power and white and green for the key and start functions needed in order to operate the ATU.

A simple pin out diagram for the cable is available on the LDG website here and I used this to wire up all of the connections, I opted for soldering the Molex connector as I didn’t have a suitable crimping tool to hand, although I guess a pair of long nose pliers would have made a good enough bodge! After that I slid over the cable sleeving, previously purchased via eBay, then two lengths of heat shrink, one for each end of the cable. At the other end of the cable I soldered the DC power plug next, then finally the stereo jack.

At this point I switched my IC-7100 and the Z-100 Plus off, and connected up the cable to test it. Once connected, and the rig powered back up again, a TUNE icon appeared on the IC-7100 display indicating it had detected my ATU, and a press of the TUNER button set off the Z-100 Plus tuning up my antenna.

After the quick test, I powered everything down, then got the heat gun out to shrink the heat shrink tubing completing my little cable assembly.

Now it is all connected back up, all I have to do to tune my antenna is to press the TUNER button on the IC-7100 and wait a couple of seconds for a match to be made. How simple is that?!


After using the IC PAC cable for about 6 months now, I can defiantly say that making one to use with my Icom IC-7100 was a great idea and it has made operating just that little bit easier. I’ve now re organised the shack and I’ve been able to locate the ATU on a shelf out of the way above my operating bench.