The Vertical End-Fed Halfwave vs. an Inverted V

The end-fed wire is especially attractive for backpackers who would rather carry a small tuner than a roll of coax.

But does the end-fed wire work as well as a traditional dipole? There were plenty of reports like "I worked W1ABC in Vermont" or "I got a 589 in Utah" or "It really seems to get out" or "It tuned up really well," but I didn't see any one-on-one comparisons.
So, with the Flight of the Bumblebees looming on my calendar, I decided to run some experiments myself.

In these tests, I compared antenna configurations that I thought I and other QRPers might use in the field. Basically, I looked at ground-mounted end-fed vertical half-wave wires versus inverted Vs at different heights.

In Experiment No. 1, I compared a 40-meter inverted V to an end-fed "vertical" half-wave. The inverted V was fed with about 70 feet of RG8x to the apex at 52 feet with the ends at about 30 feet.

That's pretty typical of what I can put up while hiking. The end-fed wire antenna was 66 feet long, attached directly to a tuner at nearly ground level, and the top was at 50 feet.
The wire was pulled away from the tower in the middle, so it wasn't vertical . . . again, I think this is typical of what I might do on the trail (I don't often find trees higher than 50 feet around here, so I use inverted Ls or bent verticals).

The tuner was connected to the radio through a very short piece of RG8x. Consistent with the recent discussion on QRP-L, I added a couple of 33-foot radials at the tuner, but I found that they had very little effect on the SWR or the tuning. The tuner was able to get the SWR down to about 1.2.

Using an antenna switch so I could make very quick changes, I made comparisons with dozens of stations in Europe, Asia, South America, and all over North America, daytime and nightime, receiving and transmitting.

The antennas were always very close in performance, but the end-fed wire was never better than the inverted V.

Instead, the V was often about 3 dB (half an S unit) better - never more than a full S-unit (and even that was rare). So I'd say that an end-fed half-wave vertical is roughly comparable to an inverted V with the apex at the same height as the top of the vertical.

Experiment No. 2 was on 20 meters, and allowed me to compare an end-fed half wave wire "vertical" to an inverted V that was much higher than the vertical.
The end-fed wire was 33 feet long, attached to the tower at about 25 feet and pulled away in the middle to make a crooked vertical (as before, it was fed directly by a tuner at ground level which was connected to the radio by a short piece of coax, and two quarter-wave counterpoises were laid on the ground).

The inverted V apex was at 52 feet, with the ends about 40 feet above ground. So, unlike in the 40-meter tests, the V was on average a lot higher than the end-fed wire.
This time, the high inverted V was always better than the half-wave end-fed bent vertical, by an average of nearly two S units. Sometimes the difference was as much as 3 or 4!

Taking this one step further, Experiment No. 3 compared the same 20 meter vertical half-wave to a dipole at about 20 feet.

The result, as expected: The vertical half-wave outperformed the low dipole by about an S unit everywhere except sometimes for the close-in stuff (stations within 1,000 miles or so).

IN SUMMARY

The best: High dipole (higher than the top of an end-fed half-wave wire).

About equal: End-fed half wave vertical and a dipole at the same maximum height.

The worst: Low dipole.

My final conclusion: If you can get a dipole or inverted V up in the air at least as high as the top of an end-fed half-wave wire you're thinking of using, and you don't mind carrying the extra coax, do it. The dipole will be better . . . sometimes by a lot.

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Bruce Draper, AA5B, is a prolific writer, QRP operator and outdoorsman who is a frequent contributor to The ARS Sojourner. A former editor of the ARRL's National Contest Journal, Bruce lives in Albuquerque, NM.