Icom AH-4 RFI Hint

Hey Guys,

Just wanted to write a quick post that may be of help to other new Icom AH-4 Users.

While the more experienced OM out there will probably find this obvious, the trouble lies in the fact it is so obvious that Icom completely forget to mention it in their product manual!

To work properly, the Icom AH-4 needs ferrite cores placed on both the feedline and the control line – the manual does not cover this.  I used 12 large cores on each successfully, but more would be better!

It took me a lot of mucking about when I was just getting into the hobby to get this tuner to work without ‘irradiating’ the shack.  The manual states that it is designed for random wire use with a ground rod – so I thought it should just work, right? No. 

It wasn’t until I sunk my 4th grounding rod, salted the earth with drain cleaner (it makes for a very conductive electrolyte, and i didn’t like weeds in my concrete anyway), prayed to the gods of radio, and yet still had RFI levels that would crash my Icom IC-7000 on the higher bands, that I finally found the solution in ferrite cores.

Now, I love the AH-4 Tuner, and use it to tune up everything from verticals to dipoles!


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