Until now, my HF antennas have mostly been off the shelf. I’ve gone out with an AlexLoop (hmm, alexloop.com seems to be down. I don’t know if that’s permanent), and the Elecraft AX1. They’ve both been fine, but have some drawbacks. The AX1 is a bit finicky about getting its radial(s) good enough, and the AlexLoop is a bit tricky to set up in a temporary but stable way.

I have not had a good experience with the half wave G5RV, yet, for some reason.

So since all HF antennas are compromises, why not try an inverted V dipole? I had the UniBalun recommended to me, so I went with that. There are some minor things to think about, which is what this blog post is about.

To become an antenna, I also needed antenna wire, and a way to put the middle of the dipole high up, with the antenna wire extending straight diagonally down. For a 20m (14MHz) antenna, I cut two 5.2m pieces, expecting to need to either cut or fold them back a bit, for the right resonance.

On the UniBalun side I could just crimp an M4 ring to attach the antenna wire, but on the other end of the wire I needed to be more creative. It needed to be able to attach to paracord, and also be fairly easily adjustable in how much should fold back. Even if I were to cut it, I’d probably still want it folded back a bit, to adjust for anything from exact band location to moisture in the ground.

I ended up using a butt splice crimp, without crimping it, as a kind of zipper to create the attachment loop. I then used a ziptie to make sure the fold is along the main wire as much as possible.

The antenna coiled up

The antenna wire fold

I think an improvement here would be to use a second butt splice crimp instead of the ziptie, and glue the folded tip to it. That way it can move and be adjustable, and also straight.

If wind starts moving it, there’s always gaffa tape.

I had an extendable window washing pole, so that sorted height. I added a guying collar to secure it with paracord, though a hitch knot appeared to be stable enough too, and is more flexible about how high up you want the guying wire. The guying collar is the same diameter as the pole. Which means while I got it on, it ain’t never coming off. I probably should have bought a slightly bigger guying collar, and secured it with a shelf of tape below it. But it works.

My bike’s wheel held the base in place.

Tuning

My antenna analyzer has bluetooth. I thought I’d check that out, to prevent me going back and forth too much. But the Android app is not compatible with the current Android release. And the Linux app didn’t seem to work either.

So I told AI to build one:

I think I have connected to a rigexpert AA-650 Zoom via bluetooth. The mac
address is 04:91:62:xx:xx:xx. Write a crate and TUI for remotely working the
rigexpert. If you need me to do something from a user with more access then
tell me what commands to run. Use the crate ratatui for the TUI, and for
command line parsing use clap with derive.

After a few more minor user improvement prompts, I ended up with something pretty usable. Here’s two example sweeps from my testing today:

TUI antenna analyzer

It saves everything from the session, so I can inspect the return loss and other graphs after the fact, too.

I’m treating this tool as any official tool I find online; I didn’t look at the code at all. I would not have spent the time to actually build this manually. I would have given up and only used the rigexpert directly. Well, I did use it directly, too.

Rigexpert photo

So how did it go?

It went well. The UniBalun is rated for 5W in data modes, so that’s what I ran.

PSKReporter showing propagation

Not bad at all. Unreasonably effective, in fact.

I also dialled in to my BBS over the mercury HF modem.

Does it look professional, too?

Nope!

Whole setup

Antenna components

Radio picnic checklist

This is my checklist for going out and playing radio. I don’t bring everything, only what I’ll need on the day. But I do go through the list every time because it’s easy to forget something.

  • USB hub (my Elecraft requires two USB ports to get audio and CAT), and one of my two USB-A ports has a yubikey nano in it.
  • HF radio
  • HF radio CAT cable
  • Food
  • External battery
  • Baofeng + AIOC (convenient modem)
  • Other HT
  • Laptop
  • Coffee thermos
  • Picnic blanket
  • Water
  • Set home station frequency & power (if dialing in back home)
  • Sunscreen
  • Headphone cable
  • Arrow antenna
  • AX1 antenna
  • AlexLoop
  • Antenna stand (for AX1 or AlexLoop)
  • Dipole
  • Dipole pole
  • Paracord
  • BNC cable
  • Camping stakes
  • Gaffa tape
  • Zipties
  • Alcogel
  • Paper towels
  • RigExpert
  • Scissors
  • Lighter (for sealing paracord after cutting)