GUEST POST – Dale N6JSX on adding a 17m mod to his 18AVT Vertical Antenna

Dale N6JSX/8 sent along a write up of another of his projects.

Enjoy & 73


Hi Steve K9ZW

Well since I have time to do some HAM stuff I’ve wanted to do for a long time…. this task was to remount my HF Hygain 18AVT 5-band Vertical.

Recently we installed on the property a dog-proof fence. I figured I’d experiment and see if the fence could be multi-functional.

My 18AVT was last setup in CA (1985-1992), so I had to do some refurbishment and use Penatrox to make good.

My experiment was to use the fence as a counterpoise since the 5′ chain-link is buried 1′ making it 4′ high with fence poles driven 3′ deep.

This time I added an Ugly Balun (4″ PVC with 26 turns of RG-8x). Used my MFJ-269 to tune up all bands – 10/15/20/40/80m. I have a 3KW MFJ-989c Tuner to move the 1:1.2 @ 3825 up and down the band – works well.

I was amazed how well it initially worked talking to EU/JA/Med the first day, with ease on 10/20/40m.

I was really surprised, didn’t expect it to work so well.The only issue was the high winds this week that required I add guy ropes for improved stability.

My favorite band is 17m and the 18AVT does not work it at all. This week I came across an article of how to add elements to a vertical.

My 18AVT now sports 17m (12.5′ quarter wave). I used the MFJ-269 to tweaked in the wire length to be flat across the 17m SSB band. See attached pics.

From the article’s descriptionl I designed my own element brackets, I installed/tested it by late afternoon —-> WOW it works slick.

It is very easy to build & attach to the vertical. (I intend to replace the 17m wire later – installing a small SS spring to the PVC attachment and get rid of the rope.)

I now have a 6-band vertical.

They say Vertical polarization has some advantages for DX and Digital, well I will see, but so far so good.

So if you pick up a clunker 4-5BTV, using these pics it should be easy for you to install additional bands, like 17/12m elements.

My next antenna project is making a 17m mono-yagi, it will be a 2 or 3-element beam using 17m HamSticks. When I get my tower up I’ll place it above my A4S tri-band.


Dale N6JSX/8

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