QRP POTA at Fort Dobbs: No antenna? No problem!

I’m a pretty organized field radio guy if I do say so myself.

In all of the hundreds of field activations I’ve attempted since the days of the National Parks On The Air (NPOTA) program, I’ve only arrived on site two or three times and discovered I was missing a key component of my field kit.  Out of those times, only once do I remember that the missing component prevented my activation (it was hard to power my radio without a battery and power cable). The other times, I was able to improvise.

As I mentioned in this two-parter series, I tend to build two different types of field kits:

  • one that’s fully self-contained (like the MTR-3B kit),
  • or one that’s modular, where component families (transceiver, antenna, power, etc) are in their own packs and can be moved from pack to pack.

I always prefer having dedicated field kits, but they’re pricey because they require a dedicated antenna, battery, radio, key/mic, earphones, pack, connectors, and sometimes even their own throw line.

I assemble modular kits around a particular radio and antenna system prior to leaving the QTH to go on an activation. I have a method for doing this which prevents me from leaving stuff behind.

Save this time…

On Thursday, April 7, 2022, before leaving the house for a quick overnight trip, I grabbed my SOTA pack and disconnected my Elecraft KX3 from the KXPA100 amp in the shack.

My pre-side rails KX3 in the shack.

My KX3 is used a lot in the shack–along with the Mission RGO One and Ten-Tec Argonaut V–it’s one of my staple rigs at the QTH. I didn’t think I would have time to complete an activation on this quick trip, but if I did, I wanted to use the KX3. I also grabbed one of my pouches that contained a 12V battery, distribution panel, and power cord.

Also inside the pack was my Elecraft KX2 kit. It was in there from a previous activation, so I just left it in the bag.

When a window of opportunity for a quick activation opened on Friday, April 8, 2022, I grabbed it. I didn’t have time to go far afield, so I chose to activate the closest park to where I was running errands that day.

Fort Dobbs State Historic Site (K-6839)

As I was driving to the site on I-40, it dawned on my that I might have forgotten to pack an antenna.

Not a good feeling, but I was only 10 minutes from the park, so there was no turning back.

You see, a couple days beforehand, I did a bit of an antenna inventory at the QTH–I took all of my antennas out of their packs, checked them over carefully for any damage or fault points and  made notes.

I normally keep a 20M EFHW antenna in my KX2 field kit, but I remembered that also I removed it during the inventory.

Once I arrived at Fort Dobbs, I opened my SOTA pack and confirmed that I had no antenna. Not a one.

I kept a clear head and realized that if I wanted to complete the activation, I needed to do one of two things:

  1. Search the car in case, somehow, I had a spare antenna floating around in there. Unlikely, but I’d feel like a fool if I aborted an activation with an antenna in the car.
  2. Go to a nearby hardware or dollar store and find some cheap wire.  The KX3 has a brilliant internal ATU to match pretty much any wire I connect to it.

So, I searched the car.

By some miracle I found the same spool of speaker wire I used to make my 28.5′ random wire antenna in 2021. I did not expect that spool to be in the car–what a pleasant surprise!

I didn’t intentionally put the speaker wire in the car. In fact, I think it was in a box of antenna-building supplies I took to share with a friend a couple weeks earlier. The box was pretty full, and I suppose it slipped out? I found it under our picnic blanket. It was like finding gold. No kidding.

This speaker wire saved me a trip to the hardware store.

Besides, I’d been thinking about making another speaker wire antenna for the field kit I’m building around the Xiegu X6100, but instead of using a 28.5′ radiator as I did with my first random wire, I thought about lengthening it to 31′ and shortening the counterpoise to 17′. These are proven lengths used by other field ops. I thought the longer 31′ radiator might afford matches on the 60 meter band.

No antenna, no problem!

I was actually kind of chuffed to do a bit of field improvisation!

I also realized I didn’t have a tape measure to cut the radiator and counterpoise to length.

What I did have, though, were standard North Carolina issue park picnic tables which I knew were eight feet in length!

I used the picnic table top to measure out 32 feet (thus four lengths of the table) and simply backed off a little less than one foot on the last pass to yield 31 feet. (A few extra inches provides length to make a loop at the end of the radiator.)

I then split the zip cord into two 31′ lengths.

Next, I took one of the 31′ lengths and measured 16 feet on the picnic table (two lengths of the table) and added one more (estimated) foot to give me 17 feet for the counterpoise.

Finally, I stripped the ends of the wires and inserted them into the BNC binding post adapter I keep in my KX2 kit.

What made all of this possible, of course, was the fact that the KX3 has a rather wide range internal ATU. With no way to otherwise match impedance, I would have needed to build a more complicated antenna.  That was not in the cards on a day when I had such a small activation window.

In addition, without the BNC binding post adapter, I would have struggled to connect the radiator and counterpoise to the KX3. I could have connected to the counterpoise to one of the KX3 ground lugs, but fitting the radiator conductor in the female BNC port and keeping it there on a windy day?  That would have been very challenging indeed. Not impossible, mind you, but certainly not an elegant solution.

Gear:

Even taking the time to film this activation and antenna build, I still was able to hop on the air in fairly short order.

Had I built this antenna in the field without documenting it on video, it might have taken me five additional minutes. Super easy.

On the air

I fired up the KX3 and hopped on the air.

Starting on 40 meters, I quickly found and worked my buddy Eric (WD8RIF) who was also activating a park in Ohio. Turns out this would be the first of three Park-To-Park (P2P) contacts.

Within 13 minutes, I worked eight stations on 40 meters.

I then decided to QSY to the 30 meter band.

Turns out, 30 meters was much more active than 40 that day.  I worked a total of 14 stations in thirteen minutes! Not bad at all!

Then I ran out of time.

I would have liked to hit 20 meters, but I needed to move on as I also had a 1.5 hour drive back to the QTH that afternoon.

QSO Map

These super simple random wire antennas that rely on your ATU to find an impedance match aren’t the most efficient out there, but as you can see they do work quite well even with only 5 watts of power:

Activation video

Here’s my real-time, real-life activation video which includes most of the antenna construction:

Click here to view on YouTube.

Thank you

Thank you for coming along with me on this interesting little activation. Looking back at it, I think what made the activation so fun was having to improvise a bit.

I was lucky to have the speaker wire in the car.  I was prepared to drive five minutes to a hardware store and grab pretty much any cheap wire I could find to complete this activation, but in truth I barely had the time to do that since my activation window was so short.

I was so pleased it all worked out and now I even have a dedicated antenna for the X6100 field kit! Woo hoo!

As I mention in the video, I’m going to consider this the March entry for my 2022 antenna challenge where I hope–by end of year–I’ll have build 12 antennas (roughly one per month). It’s been a super busy year and I’ve extended travels this summer, so I’ll likely build the majority of the antennas in the fall. Actually super excited about this challenge.

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 which allows me to open up my work life to write more field reports and film more activation videos. Simple as they are, it takes hours of dedicated time to publish each one.

If you’ve never built an antenna, consider doing so sometime this year! With a good ATU, antennas can be as simple as the one I made in this activation. Without an ATU, you might need to wind a coil and attach some connection points, but it’s not difficult. If you’re not into homebrewing, consider one of the amazing and affordable end-fed half-wave kits on the market. Or build a simple or linked dipole.  It’s quite rewarding hopping on the air with a homemade antenna!

Hey! Let’s go play radio!

Cheers & 72,

Thomas (K4SWL)

Bonus photos!

Look at this! You made it to the bottom of my field report! Congratulations!

As a reward (or punishment–?) here are a few extra photos I took at Fort Dobbs that day. Click images to enlarge:

14 thoughts on “QRP POTA at Fort Dobbs: No antenna? No problem!”

  1. Real Hams forget antennas for POTA and Real Hams shop at the Dollar Store for antennas

    I have been thru this on business trips and parks and have used Cat5 cable and even coat hangars so adapt and think it out

    Wire is wire
    John VE3IPS

  2. Great blog post for today, thanks much.
    Interesting, last month I was just through that area, and with a radio, though I didn’t take the time to stop as I was heading north…..

    73
    Fr Richard

  3. Note to self: That old spool of unused speaker wire the GF keeps saying to” just throw it out”? Stash it in the car! (Maybe in the spare wheel well … you know, because, “I thought you were throwing that out!?”)
    – Bill
    W4LTC

    1. This isn’t a random wire antenna that you built. You basically cut a 1/4 wave vertical with a single .125 wavelength radial. No wonder you had good results.

  4. Nice article! I have a KX2 I use for ultralight portable QRP on our travels.

    So personally how would you compare the KX2 to the X6100?
    I was thinking of getting one.

    Thanks,
    ve3bwp

    1. Honestly? The X6100–in terms of receiver–is a pretty big downgrade from the KX2. It has a lot of cool features and some future possibilities, but the audio and RX can’t compare with the KX2. It’s a fun radio in many respects, but quite a different animal than the KX2.

      Cheers,
      Thomas

      1. I pulled the trigger on the 6100 finally.

        Neat feature set and a true Shack In A Box but yes the receiver is definitely a rougher experience than the KX2.

        I’m enjoying it a lot but it’s my go bag /travel radio. If stolen or damaged I’ll cry. . . But not as loudly or as long as if something happened to my KX2!

  5. A longwire antenna — consisting of an actual long wire with a pop-bottle insulator soldered to one end — and a ZM 2, kept behind the truck seat, will always get you on the air in minutes. (And work about as well as any other antenna. Ssssh! Don’t say that out loud around other hams.)

    Good post! Thanks!

    Rob
    KB7PWJ

  6. Great article and video as usual. In case, there are some that want to build the same antenna, what were the exact dimensions of the radiator wire and counterpoise. You mentioned that the longer length might make a better match for the 60 meter band. Did you find that to be the case? In my experimentation, I didn’t find the 31’ radiator to be a better match than the proven 28.5’ antenna.

    Also, I have tested using a 28.5’ counterpoise by shortening the length. I shortened it down to 15’ before it became harder to match.

    So in your opinion, is one antenna better than the other?

  7. Interesting article Thomas and well done on the improvisation and activation! Nice to see the KX3 out too 🙂 Just goes to show you don’t need a perfect system to have fun, which you have alluded to in previous posts.

    Thanks for the history too, one of my other interests is the colonial period in North America. I looked up Captain Hugh Waddell and he was an Ulster Protestant from Lisburn so am guessing his lineage goes back to Scotland at some point as his ancestors would be plantationers in Ulster.

    I also note they said the “colonial possessions of England and France”, in 1707 the act of union between England and Scotland occurred so they were really the possessions of Great Britain (tsk tsk!!). Pedantic I am but us Scots were always in the thick of it!

    Kind regards,
    Gav
    GM0WDD

  8. A few months ago I forgot the coaxial cable at home. I was in a SOTA activation.
    I ended up attaching the efhw radiator directly on the PL connector of the radio (a Xiegu G90), using a banana plug.
    The internal tuner was able to find a match, and I successfully completed the activation.

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