20M QRP Dipole

I’ve been building a collection of antennas dedicated to QRP. You can get away with so much less weight and space with low power equipment. To that end, I built a 20M dipole just for QRP.

The Balun

I had a Type 31 core 2631801802 in stock that is .870 (21.70mm) Outside Diameter. I also had some random enamel wire laying around. I made the 1:1 current balun with 12 continuous turns around the toroid and soldered it to a BNC connector. This little core had pretty good attenuation if memory serves, around -23dB I believe. Not quite as good as it’s bigger brothers but still not too shabby. I don’t know how much power this mini core can take. I don’t think I’d go much more than 10 or maybe 20w SSB at max. Probably 5 or 10w CW.

The Wire

I cut two lengths of 16AWG wire ~5M/16’6 and left them a little long. I then soldered the element wires to the enamel wires. I put a loop of 95 paracord through the toroid for a hanger. Then I used some glue lined heat shrink to hold the whole thing together. I squished the top wires and loop with pliers while the glue was hot for added adhesion. This is a dedicated monobander for 20M.

Deployment

I decided in advance that I was going to deploy this in an Inverted V configuration, using the DX Commander mast and two plastic electric fence stakes. This is a lower to the ground setup but I wanted this to be as easy to deploy as possible pretty much anywhere. The problem with dipoles is you need three supports for them and that can be a pain for mobile setups. You have to have trees the right distance apart and that can be tricky to find on the prairies. So I figured that an inverted V would work just fine, even with the steeper angle. There won’t be much DX with this antenna - but with QRP there generally isn’t anyways. It’s a pretty quick deployment that could also be used for EMCOMM if need be. I used 25’ of RG-316 coax with no additional 1:1 choke at the rig. There was no evidence of common mode current issues.

What I did notice right away was that my wires were actually a tad bit short. I thought I left them long enough but alas, I over shot the middle of the band. It’s still pretty good across the band and it might vary a bit in the next setup.

It was clear that I didn’t have enough wire to make a folded back loop to hang them. So when I got back to the QTH I made some more paracord loops and shrink wrapped them to the ends of the wires. The glue lined wrap bonded well to the paracord and they feel pretty secure. I hate soldering in extra wire for this kind of thing so I’m hopeful these loops will hold up well.

Field Operations

I brought along my CW Morse key and hunted some POTA stations. I made 4 contacts in total in about 25 minutes. Two from WA, 1 from SD and 1 from NM. A station in NY heard me but the band fell apart and we couldn’t comeplete the contact. So this setup offers coast to coast coverage. I didn’t bother running a WSPR test because it’s a dipole and everybody knows what they do. But all in all, I’m happy with this QRP dipole. It will have a permanent home in the QRP antenna collection.

73 de VE5REV