Brad O'Dell

A quick note on random wire antennas.
If making your “Random” wire length is a-kin to throwing a dart at a dartboard and picking a length, then you are likely to have moderate to satisfactory results. Just keep in mind that random lengths can and do have lengths to avoid and lengths that are best suited for your application. Start with the length that works best for your area and see what it is with a section folded back on itself and the end supported with rope. If you find you are having issues, make the rope longer and the antenna length shorter or vice versa to find a good spot. This is the “hunt and peck” version of using a random wire antenna and works when you have an odd location to put an antenna. Once you are happy, secure your ends.
However, if you run into issues with your length selection, a silent key, John H. “Jack” Clarke VE3EED took the time to find out many of these lengths up to 450 feet and list many good options like 29  35.5  41  58  71  84  107  119  148  203  347  407  423 feet. So, move from hunting and pecking and try a few lengths Jack suggests and move closely around them with your adjustments. You can find Jack’s research information easily on the internet and dwell way down the rabbit hole on this. Just remember with antennas, that the one that gets you out on the air with no issues is a good one.

Credit for image.

I wanted to share an antenna build I found in a military book about ship antennas.

It is basically a 50′ wire and a 4:1 UNUN with a short ground wire.

For the radiating wire, I chose a 50′ section of #10 THHN.

To build the UNUN, I bought a FT240-43 Torroid and a waterproof Box from Amazon.

You will need one SO-239 connector which can be can be found here.

I drilled and mounted my hardware into the box as pictured below.

I like to use copper strap to tie the ground and SO-239 together. (Instead of the coax in the diagram)

It can be bought here for $4 per 10′.

Winding the torroid is 15 simple bifilar turns. I like to use this silicone wire.

If you follow the diagram, the wound torroid  should turn out like this…

It mounts in the box like this…

Chris and I used the air cannon to hang the 50′ vertical in a tree. A folding knife was used as a ground rod.

N4CPW making 40m contacts.

Video of 80m in early morning…




It was impressive how effortlessly the LDG auto-tuner matched 80/40/20/17/15/10. Looking back, I should have tried to tune 30m and 60m, but was taken into the distraction of chasing easy contacts on 80/40/20. I also should have tried the IC-7300’s internal tuner, but again, blame the aforementioned good time for not doing so. I should have run WSPR too. Darn.

N4CPW took the “UNTENNA” with him for further testing.

Maybe we can get the answers to those questions from him in a future update.



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