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.