End Fed OCF and EFHW

Plain-English verdict: Choose an EFHW when its bands and layout fit your plan. Consider an End Fed OCF when multiband flexibility matters and you are willing to make the coax-and-choke geometry part of the design, not an afterthought.

First, a tiny naming trap

“End Fed OCF” here means the one-end architecture. It is different from the familiar conventional off-center-fed dipole with two physical wire legs. In this one-end version, the long wire is one branch and a selected length of the outside of the coax shield is the other branch. A choke marks where that intentional coax branch stops. In other words: the coax is wearing an antenna hat for part of its trip.

Side by side

“Often” is intentional. Feedpoint impedance, SWR, pattern, and loss are properties of the whole installed system, not just a label on a product box.

Feature	EFHW / End Fed Half Wave	End Fed OCF / One-end Off-center-fed
Core idea	A wire operated near a half-wave on the lowest target band; higher bands use higher-order modes.	Two unequal current branches at an accessible end: the long wire plus a deliberate outside-coax branch to a choke.
Feedpoint mood	Near a current minimum: high impedance and high RF voltage are expected.	Moved away from the extreme current minimum: often a more moderate, installation-dependent impedance.
Typical matching discussion	Often a high-ratio transformer such as 49:1 is used to bring an approximately kilohm-level end impedance toward 50 ohms.	A moderate-ratio UNUN, often 4:1 as a starting point, plus a separate choke. Measurements decide the final answer.
Bands	Best fit for intended half-wave and harmonic modes. “Multiband” does not mean the pattern or stress stays the same on every band.	Can be arranged for broad multiband use, but coverage and SWR depend on the chosen wire length, coax-exterior branch, choke position, and installation.
What the coax does	Ideally, the feed line stays out of the antenna system. A counterpoise provides the return path, and a properly selected choke near the feed point helps keep the shield from acting as an uncontrolled radiator.	Part of the antenna system on purpose up to the choke. The choke is a boundary, not decorative jewelry.
Pattern behavior	Higher-order modes create extra lobes and deeper nulls; height and nearby objects still matter.	Pattern depends on both the wire and the intentional coax branch, plus their real-world geometry.

The EFHW scorecard

Why it is lovable	Where it asks for attention
Simple physical idea: one half-wave wire with an accessible feed end. A very good match for selected bands that follow the intended half-wave and higher-order modes. Popular for portable use because the wire can be straightforward to deploy. Can be low-loss when the matching network and installation are designed for the actual load.	The feedpoint is a high-voltage neighborhood. Insulation, transformer design, power, mismatch, and duty cycle deserve real attention. A high-ratio transformer is not a magic wand; its stress and loss change with frequency and load. Needs a deliberate return path and common-mode control. Non-harmonically related bands may need a tuner and may not be a happy match for the transformer.

The End Fed OCF scorecard

Why it is lovable

Where it asks for attention

Moves the feed away from the EFHW’s extreme end-current minimum, so a moderate transformation may be practical. Can be a strong multiband candidate when the site supports a defined wire-plus-coax branch geometry. Some suppliers use a shorter wire than an EFHW while covering many higher frequency bands. Lower feedpoint voltage than an EFHW is a plausible design benefit in this architecture, but still verify the actual installation.

The coax exterior deliberately radiates up to the choke. Route it carelessly and the antenna’s behavior can change with it. The choke location is part of the antenna geometry; a cookbook distance cannot be universal. Some bands may still need a tuner. The system is less “hang wire, forget wire” than it first appears: measure exterior common-mode current and confirm the choke is doing its job.

A decision guide

If your station says this	Start by considering this
“I want a simple wire for a planned group of harmonically related bands.”	EFHW. Its half-wave operating modes may fit neatly. Still budget for a suitable transformer, insulation, return path, and feedline choke.
“I want more high-HF bands from one accessible end, and I can control the coax route and choke position.”	End Fed OCF. Treat the exterior coax section as intentional antenna hardware, then validate it with measurements.
“I want to run whatever length happens to fit and never think about matching.”	Neither gets a free pass. Geometry, the return path, and an antenna tuner or matching network will still have opinions.
“I see a great SWR curve.”	Excellent start, not the finish line. Check common-mode current, transformer temperature, RFI, received noise, and on-air results.

Three practical checks before calling either one finished

• Draw the whole antenna system. Include the radiator, the counterpoise or intentional coax-exterior branch, coax route, mast, choke positions, and nearby conductors.
• Measure more than SWR. Record resistance and reactance across the bands you intend to use, and note exactly where the measurement reference plane is.
• Map the complete coax at several positions. Then move one thing at a time and see what actually changes.