The End-Fed Half-Wave Antenna

Find a Tree, Hang a Wire

One of the things I appreciate about amateur radio is that sometimes the simplest solutions are also the most effective.

You can put up towers, beams, and rotators, and many operators do. But some of the most satisfying contacts I have made came from something far less elaborate: a length of wire, a transformer, and a nearby tree that was kind enough to cooperate.

That is essentially the idea behind the end-fed half-wave antenna (EFHW).

Electrically, it is a half-wave radiator fed at the end rather than the center. Because the impedance is extremely high at that point, a 49:1 transformer brings things back into a range that ordinary coax and radios can live with.

Once that happens, it behaves very much like a dipole. The real advantage, however, is mechanical rather than electrical.

• A dipole wants three support points.
• An EFHW is content with one.

Which means if you can toss a line over a limb, you can usually get on the air.

Why Portable Operators Love the EFHW

Portable operators discovered this long ago. POTA activators, field operators, and travelers like antennas that go up quickly and disappear just as fast. A coil of wire and a small transformer can live quietly in a backpack until needed.

The transformer, incidentally, is the part that deserves the most care. When they are poorly wound, they heat up, waste power, and behave badly across bands. When they are built correctly, they simply do their job and stay out of the way.

That quiet reliability is exactly what you want in an antenna system.

Over time I started winding transformers for my own EFHW antennas. A few friends asked for them, then a few more, and eventually that turned into a small Etsy shop where I offer a couple of versions of the ones I use myself.

The transformers I build are nothing exotic, but they are wound carefully on quality ferrite cores, sealed in weather-resistant enclosures, and tested before they ever leave my bench. They are the same ones I use when I throw a wire into a tree and see what the bands are doing that day.

If you enjoy winding your own transformers, I encourage it. Half the fun of amateur radio is experimenting and learning what works.

But if you'd rather skip the ferrite dust and get straight to the operating part, you can take a look here:

My Etsy Store

Either way, the basic advice remains sound:  Find a tree...Hang a wire...See who answers!

- 73 Dave

New sticker design drops!

Let’s just get this out of the way up front.

If you’ve ever chased a POTA activator from the comfort of your shack, your truck, or your back porch…you’re welcome.

My new sticker (available here for $4, FREE shipping) is for the people who wake up early, check the propagation, throw questionable amounts of wire into a backpack, and voluntarily sit at a picnic table talking to strangers on the radio. In other words: activators.

Parks on the Air works because someone actually shows up to the park. Not the website. Not the spot. The park. That means planning, hauling gear, finding a tree that might cooperate, dealing with weather that didn’t read the forecast, and explaining to a curious passerby that no, you’re not “with the government.”

So yes — when the log fills up and the pileups roll in…I activate parks. You’re welcome.

Designed to look like it belongs outdoors

I didn’t want this to look like a typical ham radio sticker. The artwork pulls from vintage national park posters and mid-century travel illustrations — a grid of landscapes that feel like places you’d actually activate from: mountains, deserts, coastlines, forests, and big empty spaces with questionable cell service. It’s part celebration, part inside joke, and part quiet flex.

Field-tested attitude

This sticker is made to live where activators live:

• Water bottles that have seen things
• Pelican cases full of cables you swear you’ll organize later
• Radios, notebooks, go-kits, and shack gear
• Anywhere you want to silently remind hunters who did the heavy lifting

Durable. Weather-resistant. Zero apologies. 

Wear it responsibly!

This sticker is not meant to start arguments. (It might start conversations.) If someone asks what it means, congratulations — you now get to explain POTA again. If another activator laughs and nods knowingly, mission accomplished. And if a hunter rolls their eyes? That’s okay. They still logged you.

Available now

The “I Activate Parks. You’re Welcome.” sticker just dropped in my Etsy shop. If you activate, you earned it. If you hunt, you know it’s true. If you do both… you definitely get it.

See you in the log!

2026! A New Year on the Air

The start of a new year is a good time to pause, reflect, and look ahead. Amateur radio has a way of rewarding that kind of mindset. It is a hobby built on learning, experimentation, and connection, often with little more than a wire in a tree and a willingness to try.

This past year included time on the air, time at the bench, and time helping support the broader amateur radio community. I continued building and refining EFHW antennas and sharing them with operators through my Etsy shop, and it has been encouraging to hear how those antennas are being used in the field, at home stations, and in portable operations.

One of the more significant developments this year was our club stepping in to take on the W5 QSL bureau responsibilities. That work is largely behind the scenes, but it plays an important role in keeping international contacts flowing and preserving one of the long-standing traditions of amateur radio. I am grateful for the volunteers who make that possible and for the operators who continue to value the exchange of QSL cards.

Looking ahead, the goal is simple: spend meaningful time on the air, keep learning, and contribute where I can. Whether that is through building antennas, supporting the bureau, or making a quick contact when conditions allow, the focus remains on the people behind the call signs.

Thank you to everyone who made contact, offered feedback, or supported these efforts over the past year. I look forward to what the new year brings and hope to hear you on the bands.

73, Dave

Thanks for sharing!!

From K2MAS.net

I've had a number of folks share my antenna and Etsy store recently and I want to give a huge shout out thank everyone for do it! Recently, Mark (KA5TXN) shared a great CW activation at Hagerman National Wildlife Refuge in a video using my new clamp-style EFHW antenna. You can watch his videos here and read up on his blog with all his content at: DitWit Portable Radio.

Also, last week, Matthew (K2MAS) shared a shot of one of his GoBoxes which includes the same antenna. I think Matthew also shared a link on a Ham Radio Beginner's page on Facebook, but I can't find the link anymore. Anyway, check out Matthew's website which include a really cool equipment list with links to lots of great gear! 

Of course, I will always appreciate the mention by Thomas (K4SWL) back in August, 2025, when he used my antenna for a POTA activation in Québec! Thomas has an amazing page with hundreds of great videos and dozens of contributors. Thanks, again, Thomas!

Let me know if you see my antenna's pop up other places! I'd love to give a nod and hearty, "thanks!" to everyone who's using them.  -73 Dave

Lake Life Radio: FT8

We spent a few days at a friend’s lake house on Cedar Creek Lake during our school’s fall break, and I couldn’t resist packing a little radio gear along for the trip. The view was too good not to play a bit of radio—with a deck overlooking the water, light breeze, and a perfect spot to string up an antenna.

I set up my go-box running the QDX on 20 meters, powered entirely by the internal 6Ah battery. The noise floor was impressively low out there—almost silent compared to home—and everything just worked. My collapsible fiberglass fishing rod made a perfect temporary mast for the EFHW I built, and I ran about 8 watts for roughly three hours without any issues.

I logged several good FT8 contacts across the country and even had a nice JS8Call chat with an OM in Iowa right before the battery gave out. The little transformer handled it all beautifully.

Sometimes it’s fun to strip things down to the basics—radio, nature, and a little time to relax. It’s also a good reminder that you don’t need a big station to make great contacts.

(And yes, that EFHW transformer was one of my own builds—the same kind I make by hand for my Etsy store.)

High-Power EFHW is HERE!

You asked for it, and here it is. Our newest release is a higher-power version of the End-Fed Half-Wave (EFHW) antenna. Same small size, same simple setup, just with a little more muscle. Get it now on our RadioPrep Etsy store.

This one is rated for 80 watts SSB or 40 watts CW/Digital, which means you can push a bit more power through it whether you’re chasing DX from the park or checking in on your favorite net. It’s only slightly bigger than our QRP model, but don’t let the size fool you—this little box is ready to play.

The Lever-Lock Difference

Here’s the part I’m most excited about: with so much positive feedback, we went with a lever-lock system for this one. Just strip the insulation off your wire, drop it in, close the lever, and you’re done. That’s it. No soldering, no banana plugs, no “where did I put that adapter?” moments.

If you grab one of our pre-cut wires, be sure to choose the BARE option. (The 2mm banana won’t fit the lever-lock, and you’ll miss out on how easy this is!)

Why You’ll Like It

• Quick setup – connect almost any size bare wire in seconds.

• Works the bands – from 80 through 10 meters, just choose the wire length that fits your style.

• Strong on the lows – built with 43 material, it really shines on the lower bands.

• Packs small – toss it in your bag, it’s weather-resistant and field ready.

• Built by hand in Texas – every unit is assembled and tested right here.

The Details

• BNC female coax connector

• Weather-resistant semi-rigid cover

• Comes with an S-carabiner (color will vary—surprise!)

This antenna is all about keeping things simple without giving up performance. If you liked the original QRP version, you’ll love this one. More power, same small package, still easy to carry anywhere.

Wire Length Cheat Sheet

Want multi-band? Go long. Want a single band? Go short. Here’s what works:

Length	Band(s)
134 ft	80m–20m–15m–10m
67 ft	20m–15m–10m
43 ft	30m
33 ft	20m
22 ft	15m
16 ft	10m

(As always, trim for lowest SWR.)

Thanks to Thomas at QRPer!

A big thanks to Thomas over at QRPer.com for taking the time to put my little EFHW through its paces!

There’s nothing quite like sending an antenna out into the wild and then getting to see it tested in real-world POTA conditions. I can tinker, test, and trim all day in the backyard, but watching someone else deploy it, work stations, and share their honest impressions is priceless.

I really appreciate Thomas not just for the thoughtful review, but for the work he puts into documenting his adventures. If you’re not already following QRPer, you’re missing out on one of the best blends of radio, gear, and field fun out there.

Thomas, thanks again for giving the RadioPrep EFHW some airtime. Operators like you make this hobby so much more fun and inspiring.

Now back to the workbench, because there are always more wires to cut, trim, and tangle. 😅