My End-Fed Half-Wave (EFHW)

The last few years have seen a resurgence of interest in the end fed half-wave wire EFHW antenna. A half-wave at the lowest band of interest will also work well on all harmonically-related bands which has become particularly attractive to those wanting a quick portable wire antenna.

It looked like an interesting antenna to try, as I was in need of a good 80m radiator and following several days of fine summer-like weather, I was able to get my new 80 / 40m wire vertical completed ... a half-wave on 80 and a full-wave on 40m. It’s built as an inverted-L, going up 80’ and the remaining 50’ being horizontal at the same height. It’s fed at the base through an impedance matching transformer and was pruned for the CW end of the band.

There's always a great sense of anticipation when first testing a new antenna and the experience only comes around once in a rare while ... it always brings back memories of my teenaged ham years, quickly scrambling off of my parent's steep three-story roof and tuning-up the DX-20 to see if the latest antenna was going to be something special. Yesterday was similar, except for the roof-top scrambling and the old DX-20.

By mid-afternoon everything was wired up ... but before waterproofing all the connections against the west coast rains, I went to the shack and warmed-up the FT-1000mp, setting it for exactly 10W out. Tuning across 40m, I immediately heard fellow NRR’r Howie, WB2AWQ down in Reno, calling CQ on 40m with one of his military transmitters. He came back immediately and we had a short chat, so at least I knew the new antenna worked!
 

 
Having  waterproofed all of the connections, I ventured to the shack once more, now just 45 minutes before sunset. I’ve always found that a quick way to gauge relative antenna performance is listening for my low-power signal via the vast KIWI online SDR network

With the power still set at 10W on 40m I listened on several east coast SDRs, from NH, PA, MD, NY, VA and immediately heard a surprisingly good signals on all of them. Even at 5 W, the signal was copyable. Several of them produced an audible copy when I reduced power to just 1W.

I then tried two SDRs in Brazil and immediately heard the 10W signal again! How about KH6 ... still late afternoon out there? Yes, easy copy in Hawaii as well. 

Dare I push my luck and try one more ... one of the SDRs in Iceland? 

I almost fell out of the chair when the 10W signal was good copy there as well ... still 15 minutes until sunset and with bright sky outside the shack window. 

One last thing to try was 80m although it was still very early here for 80 ... the SDR in MD returned a nice copy at 10W to complete my quick round of pre-sunset testing. 

From these early observations it would appear that the new antenna is working well but I had yet to do any A-B comparisons with my benchmark best performer, a 40m half-sloper which will be hard to beat. 

The 40m half-sloper has always outperformed any other antennas that I have tried. It's the same one that I completed my Tuna Tin 40m W.A.S. on, so its been well tested.

The following evening, I had a chance to A-B test the new antenna, listening on the Kiwi network once again with my power set at 10W.

N8DTT/6 (California)  EFW 1S unit better
NO2CW (Florida)   EFW slightly better
Jersey Shores, NJ    EFW slightly better
TF1VHF (Iceland)  EFW slightly better
ND7M (Nevada)     equal with slight edge to EFW
KA7EZO (Utah)      equal
RTM (Dominican Republic)   sloper ~ 1/2 S unit better
KP4CA (Puerto Rico)   equal
Paraguay   equal
PY2GN (Brazil)   EFW ~ 1/2 S unit better
AI6VN/KH6 (Hawaii)   equal
VE7HUN (BC)   equal  (groundwave)

Unlike 1/4 wave verticals that require a fairly robust counterpoise / radial system for effective operation, the counterpoise requirements for a half-wave are far less-demanding. Mine consists of about fifteen short turf-pinned radials and the first 50' of the coaxial feedline's shield. A common mode choke (CMC) is installed on the feeder at the 50' point, keeping any RF out of the shack and the rest of the feedline from radiating.

I was actually pretty surprised at these results but how they will relate to everyday operating is yet to be determined. My main goal was to get a good-performing 80m antenna and anything that works well on 40 would be a nice side benefit but not really required. Unfortunately I don't have another 80m antenna to run some A-B checks with but from what I can tell, performance on 80m seems to be good.

If you are on Facebook, there is a lot of good discussion and information available on the End Fed Half Wave Antennas group.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

7 Responses to “My End-Fed Half-Wave (EFHW)”

  • ZAL---VU2DK:

    Hi Steve–sounds like a pretty effective antenna you built up for the low bands–I hope you using a proper pi or pi L network for tuning it & not relying on the modern day ferrite transformer tuning—can assure you a proper coil condenser tuning works very well on these end fed antennas.

  • Steve VE7SL:

    Zal, the matching transformer is ferrite … three large #43 cores. No doubt there are some losses here but the pi system would not be lossless either. So far, things seems to work well. The feedline to the new antenna is about 100’ longer than the feeder to the sloper so there’s another 1/2db or so which doesn’t help yet it still gives my all time best antenna a good run for the money. If it was several dB poorer, I’d blame it on the transformer 🙈

  • Bob AK3Y:

    Great job, Steve. I have two EFHW’s (commercial units from myantennas.com) – one for 80 through 10 meters and the other (in a perpendicular orientation)for 160 through 40 meters. The EFHW16040 is an inverted L, while the EFHW8010 is a straight line up around 50 feet. Fantastic antennas! In my case, I have approximately 50 feet of RG-213 going to each, but no additional counterpoises. The EFHW16040 is grounded at the transformer (no change in SWR with or without ground), while the EFHW8010 is not (transformer box at 35 feet in the air). I needed to add an additional coil (approx 12.5 uH) about 30 feet from the feed point on the EFHW16040 to get 60 and 40 meters to resonate.

    In 54 years of hamming, these have been (by far) the best wire antennas that I have used. Have fun! Best 73, Bob AK3Y

  • BOB LECH AF2DX:

    Hi Steve,
    Thanks for the information on the EFHW wire antennas.
    Except for a mag loop indoors,I use nothing but the end fed antenna outdoors.
    73
    BOB AF2DX

  • Gary - KBØKDX:

    Steve, thanks for an informative and encouraging article concerning end fed antennas. HOA Stealth antennas are a must for me and the end fed wire antennas are my best bet it seems. I also found the link to Steve Dick’s (K1RF) “The End-Fed Half-Wave Antennas” guide to be the icing on the cake, answering ALL my lingering questions about End Fed antennas, right down to where I could purchase the 1 post stainless wire rope clips. I recently purchased a MyAntennas.com EFLW-1K, 53 ft. End-Fed Long Wire (160-6m/1kW-max) antenna and a MyAntennas CMC-130S-3K Common Mode Filter Choke. I plan to mount the long wire in an unusual stealth fashion on my roofs eve. I am very anxious to see what results I get compared to my attic mounted 37 ft. OCFD. I have so few options so, I am desperate. 73! Gary – KBØKDX

  • Gary - KBØKDX:

    Hi Bob AK3Y, thanks for sharing your info on your EFHW’s (commercial units from myantennas.com) antennas. I always appreciate hearing about other HAMS antenna configurations and the results. 73, Gary KBØKDX

  • Steve VE7SL:

    Thanks for your comments and good luck Gary with your new antenna system!

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