Ham Radio Portable Insights: Reasons to Consider an End-Fed Half-Wave Antenna

Plus, WG8X takes a look at a couple of great POTA antenna options— the Spooltenna Parks EFHW4010 and the new DX Engineering TWIG EFHW Feedpoint Kit.

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Hi everyone, this time let’s talk a little bit about end-fed half-wave antennas (EFHW). I’ve been using them for a few years, ever since a friend gifted one to me.

My plan for this article is not to deep dive into the physics behind it or turn you into electrical engineers. Rather, I want to share some info about them and maybe light a fire under you to perhaps try using or building one of your own.

The big advantage I’ve found using an EFHW in the field is you can pull up to a site and literally be on the air in moments with barely any tuning or fuss. You can tie off the impedance transformer to a handy post or tree a few feet above the ground and then toss the wire over a convenient limb. When camping, I use my fiberglass telescopic mast attached to the hitch mount on the truck or camper. The possibilities are absolutely endless.

An EFHW is a variation of the half-wave dipole. Both use a half-wave resonant length wire. The primary difference is the feedpoint. Where a standard dipole is fed at the center (low impedance), the EFHW is fed at the end (high impedance) using a 49:1 or 64:1 transformer.

The amount of wire attached is a ½ wave on the lowest band of interest. For instance, a 66-foot wire is a half wave at 40M, a full wave at 20M, three half waves at 15M, and a double full wave at 10M. The 40 to 10M seems to be a popular configuration for this antenna.

There is a lot of information on the web and in print about EFHWs. One source I recommend is this video by Peter Waters, G3OJV.

Peter has a commonsense approach to the EFHW. Some of the takeaways from his video are:

A counterpoise is not needed. If you believe that it is then feel free to try it for yourself.
Your EFHW doesn’t have to run in a straight line. You can route the antenna whichever way works best for your installation. Yes, it will change your radiation pattern somewhat, but it will still work and you will still make contacts.

As Peter seems to be fond of saying, “we are amateurs, not professionals.” Don’t be afraid of experimenting—you may be surprised at the results.

The EFHW which was gifted to me by a friend uses a double stacked core. The advantage to double (or triple) stacking cores is that it allows for higher power.

rf choke in an outdoor enclosure — Double stacking the ferrite cores for higher power capability. (Image/WG8X)

I’ve run this one at 100W CW for hours with no issues. I was told that they are a real pain to wind, but well worth the time. It uses #14 or #12 enameled wire. Lighter wire can be substituted if you are planning to run QRP or are trying to save weight. An afternoon at “YouTube university” will yield much more information about winding your own.

I spent some time looking at the EFHWs available from DX Engineering and bought a couple that interested me.

First was the Spooltenna Parks EFHW4010. I’m really impressed with this one. Its small size fits easily into a backpack, and the manufacturer says it can handle up to 100W SSB (50W CW). The field test sheet that’s included shows the measurements that were taken on that specific antenna.

spooltenna end fed antenna hub — The Spooltenna Parks EFHW4010 deployed at a campsite. (Image/WG8X)

I installed mine inverted-V style using a mast extended to around 25 feet. The far end of the antenna ran out to a convenient tree. Checking the SWR with my RigExpert antenna analyzer yielded results consistent with what I saw on the field test sheet.

It performs as you’d expect from an EFHW. It has turned into my go-to antenna for a recent camping trip and will find a place in my POTA Go-Box.

The next antenna I tried was the DX Engineering TWIG EFHW QRP Antenna Feedpoint Kit. It couldn’t be any simpler to set up:

Open the package
Attach your wire to it
Toss the wire over a convenient support
Hook the TWIG to your rig
Make contacts!

TWIG End-Fed Half-Wave Antenna Feedpoint Kit — TWIG EFHW QRP Antenna Feedpoint Kit (Image/DX Engineering)

For QRP operations, this antenna is absolutely the simplest and smallest I’ve seen so far.

The connector for the wire at the balun end is similar to the WAGO connectors that I’ve used in the past; simple! The power rating is only 25W SSB/10W CW/5W Digital, so let’s leave those amplifiers at home.

Lastly, let’s talk about your Go-Box. Part of the fun for a lot of people is experimenting with antennas while out in the field. For that you really need an antenna Go-Box. My box contains: