The “End-Fed” That’s Never Really End-Fed

If an antenna were truly fed at the very end of a conductor, with no other metal connected, its feedpoint impedance would soar toward infinity. Current goes to zero at the end of a half-wave wire; voltage rises sharply; the impedance becomes enormous. That’s basic antenna physics.

Real half-wave whips fed at the end already show several hundred to over a thousand ohms — and that’s with thickness, ground interaction, and the rest of the world influencing the wire. If the marketing claim were literally true (“no counterpoise needed, feed at the end”), you would need a transformer approaching infinity:1 to match 50 Ω to that point. Such a transformer does not exist.

And that’s the clue: the popular HF “end-fed” antenna is not truly end-fed. It always recruits a second conductor — coax shield, station ground, mast, rain gutter, your rig, or your body — to complete the RF current loop like every other antenna.

What “End-Fed” Would Mean in Textbooks

Take a perfectly isolated half-wave wire in free space:

• Feed at the center → current maximum, impedance ≈ 60–75 Ω.
• Feed at the very end → current minimum, voltage maximum, impedance enormous.

Thin that wire further, remove ground, remove nearby metal, and the impedance climbs even higher.

So if you were truly feeding the end, a 49:1 transformer would never be enough. The fact that it works at all is proof the EFHW is not operating as a single-wire system.

What Real EFHW Antennas Actually Are

In practice, the EFHW is:

• A long wire (½ λ or a multiple),
• Fed at one physical end,
• Matched through a step-up transformer (49:1, 64:1, etc.),
• Completed by a hidden return path.

That return path is essential. It is usually:

• The outside of your coax shield,
• A short counterpoise wire,
• Your mast, tower, or building structure,
• Your rig and station wiring,
• Your body.

RF current must return somewhere. If you don’t deliberately provide that path, the system will improvise one — and usually not in a predictable way.

The Transformer Isn’t Magic

The 49:1 or 64:1 autotransformer simply matches:

• 50 Ω at the rig → ~2–3 kΩ at the wire (on its design band).

What it does not do:

• Create the missing return conductor,
• Eliminate common-mode current,
• Guarantee stable performance on every harmonic band,
• Force the antenna to behave like the resistor used on the bench.

The Biggest Myth: “No Counterpoise Needed”

This is the most persistent misunderstanding. Every RF system needs a return path. If you don’t provide one, the coax becomes the missing half of the antenna.

Consequences:

• Feedline radiates — unpredictable pattern.
• RF in the shack — hot mic, tingles, distortion.
• Modeling becomes fiction unless the coax is included.

The EFHW works because there is a counterpoise — but it’s uncontrolled unless you make it deliberate.

“If SWR Is Good, It Must Be Efficient”

SWR only tells you that the rig is matched. It tells you nothing about:

• Core heating and losses,
• Common-mode current dumping energy into the dirt,
• Distorted radiation patterns,
• Losses on non-resonant bands.

The Back-to-Back Transformer Myth

Back-to-back tests show transformer quality into a perfect resistor. They do not represent real EFHW operating conditions, because real antennas are reactive, have common-mode paths, heat ferrite, and are not isolated test loads.

Back-to-back is useful to check your windings, but it is not a proxy for antenna efficiency.

“49:1 Is the Magic Ratio”

No single ratio is universal. Real feedpoint impedance varies with:

• Height,
• Orientation,
• Nearby structures,
• Wire length and harmonics,
• Ground conditions.

Some EFHWs want 64:1, 81:1, or different matching entirely. “49:1 for everything” is oversimplified marketing. 

We use ratios such as 68:1, 70:1, 49:1, and 20:1 for different types of EFHW antennas.

So What Is the EFHW Really?

Electrically, it is:

A highly off-center-fed dipole where the second leg is the feedline and station ground.

One wire is obvious. The other is sneaky.

Doing It Right

• Add a deliberate counterpoise. Even a few meters helps.
• Use a common-mode choke 0.05–0.1 λ down the line.
• Don’t expect perfection on every harmonic band. (We stick to dual and mono band)
• Monitor ferrite heating when running power.
• Account for the real RF return path.

The EFHW is not “magic,” just misunderstood. Once you accept that it is never truly end-fed, only end-connected, the design becomes far easier to optimize.

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