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POTA with a 20 Meter Vertical Delta Loop and the Elecraft KX2!

15 Comments

There’s a portable wire antenna design I’ve been wanting to put on the air for POTA and SOTA for what seems like ages: a 20 meter vertical loop.

I mentioned in a Ham Radio Workbench podcast episode a few months ago that I planned to build a field-portable delta loop antenna and that led to a mini discussion about configurations, feed points, height off the ground, etc. and how all of those factors can influence the characteristics and dynamics of the antenna.

Vertical loops are pretty fascinating and incredibly effective.

Delta loops are super easy to build (no more difficult than an EFHW) but this summer has been insanely busy for me and I simply hadn’t gotten around to it yet.

Then my good friend Joshua (N5FY) who runs tufteln.com sent me a prototype 20M delta loop in the mail. We’d been talking delta loops and he couldn’t help but build one. He asked that I take it to the field and put it on the air, then give him any feedback and notes I might have.

Joshua’s design incorporates a 4:1 transformer and was cut to be resonant on 20 meters. I’d actually planned to build one identical to this because the type of loops I’ve deployed at home have been fed with ladder/window line which isn’t as portable as something I could feed with RG-316.

Holmes Educational State Forest (K-4856)

On Friday, September 1, 2023, I grabbed the delta loop antenna and the KX2, then made my way to Holmes Educational State Forest.

I knew that Holmes wouldn’t be busy and that there were a number of options for spots to set up.

After a little scouting, I found a great site to set up the antenna.

I planned to set up this antenna as close as I could to an equilateral triangle with the apex up about 30 feet and the feedpoint in the middle of the base of the delta.

Deploying the antenna in this configuration meant that I only needed one line in a tree to hoist the apex of the delta and two lines to pull out the corners of the base.

I brought along some paracord with tent stakes to secure the base corners of the loop. In the end, though, I simply attached the paracord to trees instead of using the stakes.

I (somewhat reluctantly) made a video of the entire activation including the antenna deployment. I wanted to take my time deploying this antenna for the first time, so the antenna deployment section of the video is much longer than usual.

You absolutely cannot see the loop in this photo, but it’s there…I promise!

In the end though? It wasn’t as difficult as I thought it would be. The last vertical delta loop I deployed was a 40 meter loop which is roughly double the size–in my head I was expecting the aperture to be larger than it was.

My arborist line and 12 oz weight hanging to provide a gentle tension to hold the apex of the loop up.

The 20 meter loop is actually pretty compact and almost as easy as setting up as an inverted vee.

With my loop properly deployed, it was time to hit the air!

Gear:

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On The Air

I started calling CQ POTA and within 11 minutes, I worked my first ten stations thus validating the activation in very short order. Woo hoo!

I continued working stations on the 20 meter band until I logged all of the hunters who were calling. All in all, I worked 24 stations in 33 minutes on the 20 meter band.

Next–just for kicks–I moved up to the 17M band to see if the KX2 internal ATU could match the loop on 18 MHz. Sure enough it could.

Even though 17 meters was pretty dead, I did manage to work two stations.

I then discovered that the 20M loop could be tuned/matched from 17 meters to 12 meters via the KX2’s internal ATU.

But the biggest surprise? I moved up to the 10 meter band where I discovered that the loop was 1:1 resonant without needing an ATU! What!?!

I’ve always been under the impression that vertical loops are essentially mono band, so this was a very welcome surprise indeed!

Ten meters was completely dead that day, but it’s brilliant to know that it’s a proper option with this antenna!

QSO Map

Here’s what this five watt activation looked like when plotted out on a QSO Map:

Activation Video

Here’s my real-time, real-life video of the entire activation.  As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos.

Note that Patreon supporters can watch and even download this video 100% ad-free through Vimeo on my Patreon page:

Click here to view on YouTube.

Loving the loop!

So loops aren’t the quickest to deploy and they need a bit of clear space along the plane of their profile.

That said, I will be taking the time to deploy this antenna many more times this year. I’m especially interested in how it might perform on a summit!

Keep in mind that this antenna is truly a prototype, but I think it’s possible Joshua may build a few to sell via tufteln.com later in the year if there’s interest. You might drop him a line or comment here if you like that idea.

Of course, like I said earlier, building a loop antenna is as easy as building an end-fed half-wave or random wire antenna. Consider homebrewing one! The internet is chock-full of info about building and trimming them for resonance.

Thank you

Thank you for joining me on this activation!

I hope you enjoyed the process of testing this cool little antenna as much as I did.

Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support.

As I mentioned before, the Patreon platform connected to Vimeo make it possible for me to share videos that are not only 100% ad-free, but also downloadable for offline viewing. The Vimeo account also serves as a third backup for my video files.

Thanks for spending part of your day with me.

Have an amazing week ahead!

Cheers & 72,

Thomas (K4SWL)

15 thoughts on “POTA with a 20 Meter Vertical Delta Loop and the Elecraft KX2!”

  1. Thanks Thomas,

    Now I have another of Joshua’s creations to buy. I’m sure it will make him happy but it will get me in trouble with the XYL again.

    I really like the small form factor of his antennas. It allows for packing more options into your bag as they breakdown so small and lite.

    Have you tried using ham sticks on your activations? I’m starting to play around with a 40m ham stick dipole. And your post gave me an idea for a homemade loop as I already have a 4:1 from LDG.

    P.S. I need to email you concerning your policy on guest posts.

    W4MKH

    Reply

  2. Hi Tom-

    That’s a great result with that Delta loop! The single support line is a big plus for portable outings.

    // The mushroom pic is an Amanita. Pretty- but many of that family are lethal. Victims report they’re good eating- before liver and kidney failure occur.

    73- Dave, K1SWL

    Reply

  3. Hi Thomas,

    For some months now, I have been contemplating the idea of creating my portable delta loop antenna for 20m. Up to this point, I have successfully made homemade delta loop antennas for 6m and 10m, albeit with the apex facing downward. By configuring the delta loop with the apex down and an apex angle of about 37 degrees, it becomes possible to feed it at the bottom and achieve a 50 Ohm impedance without the requirement of a balun. In any case, it will be interesting to see if I can complete my plans for constructing a 20m delta loop before Tufteln offers one and I cannot resist buying it 🙂

    Anyway, as far as I know the antenna in your configuration is horizontally polarised. But I am not sure if “vertical” was meant that way.

    Cheers
    Thomas, DM1TBE

    Reply

    1. Hi Thomas-

      You bring up a good point! My favorite- a inverted-Y- can be adjusted for best match by changing the radial down-angles. A delta loop should act the same way.

      This looks like a good candidate for modeling. Thanks for the idea! 73- Dave, K1SWL

      Reply

    1. I think that’s his old url–he needs to update that. Seems like tufteln.net now forwards to Tufteln.com, so I’ve changed the urls to reflect that.
      Thanks!
      Thomas

      Reply

  7. Been there, done that. It may tune on other bands, but performance will be crap, *cough* severly reduced. From experience I’d recommend setting up the base first (above the head height) then raise the apex, saves on snags, tangling and wire twisting.

    4:1 almost forces you to use it favouring a moderately high radiaton angle. I’d ask for a 2:1 and will try feeding from the corner.

    Reply

  8. I wish I could get into your log from Colorado. I listen often but have only heard you once here in western part of the state and I could not get between the crowd with 25 watts and an attic dipole.

    Reply

    1. For some reason, it seems the path to CO is tough. That said, I do work the occasional friend in CO when in the field. I’m sure we’ll put each other in the logs someday!
      Cheers,
      Thomas

      Reply

  9. Delta Loop is one of my favorite antennas outside the city. Perhaps because I make it from a wire 80 or 40 meters long, and there is always enough space for it in the forest. I tried making the triangle upside down, but didn’t notice much difference with the apex up placement. I make the base of the triangle at a height above the head so that no one accidentally gets caught on it at night. I usually connect one of the bottom corners directly to the tuner, from which the cable goes to the transceiver.
    https://www.us7ign.com/?p=1821
    It allows you to get all the bands with tuner. In your case, you tuned not the delta loop itself, but the cable with the delta loop. Next time, try using just a 20 meter long piece of wire in the shape of a triangle, connecting its lower corner directly into the transceiver without a cable.
    I don’t like doing complex things where they can be done simply.

    Reply

    2. Let me make sure I understand you.

      Youo are talking bout a continous loop of w ire with one end connected to the tip and the other to the shield at the radio? That should present about 200 ohms to the radio’s auto tuner so the tuner should be able to handle it.

      How high do you have the apex and how high is the base leg off the ground?

      W4MKH

      Reply

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