Antenna Challenge #2: K6ARK End-Fed Half-Wave paired with the Elecraft KX1

I mentioned in a previous post that my personal Activation Challenge for 2022 was “to build a new antenna each month and deploy it at least once that month during a field activation.”

In January, I built a doublet with a military fixture/winder.

For February, I decided to purchase and build a counterpoise-less end-fed half-wave kit from from Adam (K6ARK).  This kit is available on Amazon.com for a mere $19.95 (affiliate link).

The build itself is pretty straight-forward and not terribly complicated. With that said, you do need a fine soldering iron tip and a little dexterity to manipulate these super tiny components. Adam includes instructions for building an EFHW with a counterpoise, without a counterpoise, or a random wire antenna. The coil can be configured as a a 49:1 Unun, 9:1 Unun, or 1:1 Balun.

If you choose the EFHW route you will need to solder one surface-mount capacitor on the board. If you’ve never worked with surface mount components before, take your time and use a good magnifying glass.

Blue Ridge Parkway (K-3378 NC)

On Monday, February 21, 2022, on my way back from town, I hopped on the Blue Ridge Parkway and drove to one of my favorite roadside spots on a grassy hill surrounded by trees.

Since I configured the K6ARK kit as a counterpoise-less EFHW, I wasn’t entirely sure how stable the SWR would be in the field. For this reason, I was a wee bit nervous pairing it with my MTR-3B since that little radio lacks an SWR meter and really needs a good match.

I decided, instead, to pair the K6ARK antenna with my Elecraft KX1 which has a built-in ATU that can both monitor the SWR and find an impedance match if needed. Of course, I turned off the internal ATU for the activation, but if I needed it, I knew I could engage and use it.

KX1 Ultra-Compact Field Kit:

Other Gear:

Setup was very easy.

I launched the throw line in a tree, pulled the 40M EFHW over a branch, and connected the antenna’s BNC directly to my KX1.

This was truly a first for me: I’ve never used an end-fed antenna that had no counterpoise whatsoever. This is actually why I configured the antenna the way I did; purely to see how effectively it might work in the field. I understand that this is how Adam configures his for SOTA outings.

It is insanely compact.

I must assume that the antenna is less efficient without a counterpoise. I know, too, that when I touch the radio chassis it has a positive effect on SWR as a path to ground is found.

Of course, the only way to see just how effectively this antenna would work in the field was to give it a go! As I like to say: less theory, more practice!

On the air

I plugged in the antenna, turned on the KX1 and…wow…a fabulous match–the same as it was when I trimmed the antenna at the QTH: about 1.3:1. A very good sign!

The first station I worked was my good friend Eric (WD8RIF) on 40 meters. He was at a park in Ohio and I heard him on frequency after turning on the radio (we tend to use the same POTA frequencies) so I quickly worked him P2P! That QSO didn’t make it on the activation video because I hadn’t yet started recording.

I’d decided in advance I wanted to play on 20 meters, so I switched to 20, and started calling CQ POTA.

In 18 minutes, I worked an additional 13 stations.

Besides working a number of POTA friends, it was fantastic to finally put PEI in the books during an activation. I think I’ve logged most of the Canadian provinces along the US border and in the Maritimes, save PEI! Thanks, VY2DP!

Here are my logs:

QSO Map

Here’s what 3 watts into a counterpoise-less EFHW can do in about 20 minutes:

Activation video

Here’s my real-time real-life video of the entire activation. As always, it’s ad-free and the QSOs are unedited:

Click here to view on YouTube.

Thank you

Thanks for reading this field report! As always, I’d 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.

I must admit that I can see the antenna challenge becoming more and more interesting as the year progresses. I’m really looking forward to building and using a wide variety of antennas in 2022.

As I write this report on March 28, 2022, I’m not sure that my March antenna challenge will happen in this month. It might happen in April–thus two antennas in April. March turned out to be a crazy month for me and there was a period of over 3 weeks where I didn’t complete a single activation. Talk about POTA/SOTA withdrawal!

I was in isolation in early March after a run-in with Covid. Then my mom’s health took a temporary bad turn–fortunately, she’s on the mend. Radio had to take a sideline during all of this, but now I’m happy to report that I’m back in the saddle. In fact, I’ve had some pretty amazing activations recently.

I jokingly refer to my time in the field as “radio therapy.”

Perhaps it isn’t a joke, though. When I go outdoors and play radio, it feeds my soul in so many positive and meaningful ways. It’s a break from the ordinary and an opportunity to do something extraordinary. After each activation, I walk out with a spring in my step.

If you ask my buddy Jim (N4JAW)? He’ll tell you that playing radio in the field and home is an integral part of his cancer treatment. It keeps him energetic, positive, focused, and it actually fuels his fight with cancer that, I’ve no doubt, he will kick to the curb! Jim is a force to be reckoned with!

Thank you, friends, and here’s wishing you all a little radio therapy this week.

73/72,

Thomas (K4SWL)

24 thoughts on “Antenna Challenge #2: K6ARK End-Fed Half-Wave paired with the Elecraft KX1”

  1. Thanks Thomas.

    It looks like an easy to build kit until I factor in my older eyes and less than rock steady hands. Still the price is right so I may try it someday after I build the two other kits I have.

    Do you have a list of the antennas you will be building? Or are you winging it each month?

    Thanks for all you do. After starting my own site I realized how much work is involved. The writing is easy for me but all the picture taking and making sure things are just right as I get the site started and relearning WordPress takes a lot of time. I’m still working on the look and feel. And I’m not even close to doing YouTube videos yet.

    W4MKH
    https://qrpguy.net/

    1. Ha ha! As I said in the video, I’m a “Gross Motor Skills” kit builder, so the tiny parts were a bit of a challenge. Magnifying glasses helped, though. And good tweezers. 🙂

      I have a running list of antennas in my head for the next four months with some vague ideas to take me through September. Folks are sending me great suggestions, too!

      Running a website takes passion and patience for sure. For a quite a while, we write articles for a very, *very* small audience. That’s why you have to be into this for something beyond audience numbers. It sounds like you’re well on your way, OM. My advice? Just enjoy the journey!

      Cheers & 73,
      Thomas

      1. Being retired funds are limited to SS at the moment as I haven’t touched my retirement funds and probably won’t until next year. Still, I’m not in it for the money or the numbers though being gifted with stuff to try and do a review on from time to time would be nice.

        Would you be interested in tis antenna for one of your projects? https://www.qrpkits.com/dualbanddipole.html

        If so I will bring you one when we come up in May. If you like it then keep it or if you don’t like it for POTA/SOTA then you can gift it to a new ham or send it back to me.

        W4MKH
        https://qrpguy.net/

        1. Hi, Marshall,

          Man–that looks like a great kit! I just ordered the 20/40 trapped dipole! 🙂

          Hope to see you in May, OM!

          Cheers,
          Thomas

  2. I enjoy reading all your reports Thomas. I am envious of the climate in your area though. My field activations here in Ontario are limited to the warmer months.

    I am surprised at the notebooks you use. I prefer paper logging and recently switched to Rite in the Rain brand after having water splashes on too many logs!

    John VA3KOT

    1. Hi, John,

      We are pretty lucky to have a long activation season. 🙂

      So I actually do carry Rite in the Rain notebooks as well. I only pull them out when I think water is an issue, though, because they’re pricier per page than my other notebooks.

      I look forward to working you P2P this summer!

      Cheers,
      Thomas
      K4SWL

    2. Good to see you, John. I have the K6ARK antenna built as an EFHW as in the article. Perhaps I can work you again sometime when you come out of hibernation – maybe for a RaDAR event.
      73
      Pat
      N0SHU

  3. Thanks Thomas for this review. I’ve considered getting one though small things and I don’t do gud when it comes to soldering which is evident by my not having started the Cricket 20, I bought. Time though, we’ll see.

    I also started my ham blog as something I always wanted to do, though I do have my PadreRichard blog which I post to more often.

    Guess slow is still good.

    73
    Fr Richard
    Wb8yxf

      1. Thanks Thomas, nice article, and yes it looks ‘easy’ if my iron will work and my hands steady……. and the mag lens, do magnify……
        However, I will get it built sooner or later!!

        73
        Fr Richard
        WB8YXF

  4. Fun to have my first POTA CW contact recorded. Forgot to send my state, as I had mentioned in the email I sent to you after, looks like HAMRS wanted me in RI instead of IA. . My sending didn’t sound quite as bad as I thought after listening. I did definitely send C0 instead of K0 on the first try. 🙂

    1. You sounded great, Andrew! I’m so honored to have been at the other end of the ether for your first CW POTA contact–especially glad you have it now recorded.

      There have been days–as an activator–I struggle to send my own call correctly! It’s all a part of being a CW op. Ha ha!

      Cheers & 73,
      Thomas
      K4SWL

  5. Can’t wait to check out the video Thomas. I wait until I’m totally relaxed so I can enjoy it. Your therapy is contagious 72 W4zxt

  6. Last week I received the KM4ACK EFW (End Fed Wire) antenna and assembled it. Had to wind the 49:1 balun and assemble the parts onto the supplied Wire Winder. Came with 65 ft of wire and BNC connector (optional as to what connector you order).

    Took it and my IC705 to local park and I was impressed with the antenna’s performance. Threw throw line over 40 ft tree, pulled up one of of the antenna, secured the other with wire winder and balun on the other about 4ft off the ground and connected 50 ft RG58 coax.

    It had low SWR, less than 1.5:1 on 10m 15, 20 and 40m so did not use my T1 tuner, connected directly to the IC705.

    I think I will use this for my POTAs in the future. But must have a tree to get it up.

    73, ron, n9ee/r

  7. I have a similar antenna, the “Spark Plug”. It works surprisingly well. Made a believer out of me.

    1. I have that antenna too. I have tuned it but I haven’t actually tried it on the air yet. Hoping to do some hunting with it this week or next. I still have to tune the 80 & 10 meter hamsticks and check out the end fed random wire. Been using them on the large WRC tripod and I want to try them out on a stake mount.

      W4MKH
      https://qrpguy.net/

  8. Nice stuff, Thomas. although I’m the kind of choke and counterpoise kind of folk. when it comes to endfed antennas (be those resonant or not), yet you demonstrated that, when it comes to a “temporary” antenna, one may jump the gun and go for whatever the menu offers 🙂

    That being said… are you going to try my idea (email) about using your speaker wire doublet as a “Marconi T antenna” (with a ground stake or counterpoise) or as an “inverted L” ?

    Just curious by the way

  9. After watching Adam’s first videos on building that antenna, I ordered parts and started making my own K6ARK inspired EFHW antennas. It’s a standard 49:1 unun just in a compact setup. They have worked so well that I’ve made several for friends. Most of my builds have been 40m, but I’ve made them resonant on 20m and 17m.

    It is my go to antenna with my KX2 – EFHW resonant on 40m easily tunes with the internal tuner on just about everything except 80m. I’ve had 20+ successful POTA activations with that setup with most contacts on 40m, but also include 20m and 17m. I also use it with my QDX and a Raspberry Pi when I want to do digital.

  10. Thanks for post !, Just assembled the 49:1 for eflw .. what awg wire did you use ? .. going to use with my 818nd

    73
    Joe
    Ka3gmz

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