EFHW Inverted-L or Ground Vertical? Compare the Complete Top-Band System
EFHW Inverted-L or Ground Vertical? Compare the Complete Top-Band System
On 160 and 80 metres, I often choose an EFHW inverted-L when a serious radial field is not practical. That is a site decision, not a law of antenna topology: the winner is the installation that turns more accepted power into useful field on the paths that matter.
A ground-mounted quarter-wave vertical and an end-fed half-wave do not lose power in the same places. The vertical can be dominated by its radial and soil return. The EFHW can avoid a large monopole-style radial field, but adds a high-ratio transformer, high RF voltage and an easily overlooked feedline-exterior return path. Compare every loss and every current at the same system boundary.
My practical position: when the choice is a compromised ground vertical or a well-controlled EFHW inverted-L, the inverted-L is often the better 160/80-metre station antenna. A ground vertical with an effective radial system can equal or beat it, especially where its installed pattern better serves the required path.
The Ground Vertical Pays for Its Return System
A quarter-wave monopole is driven at a high-current point. Its radial conductors, connections and nearby soil form the other side of the antenna. Power dissipated in that return system does not become useful radiation, even when the feedpoint impedance looks convenient and the SWR is low.
Rudy Severns, N6LF, measured real HF verticals while changing radial number, length and elevation. His 160-metre experiment compared four through sixty-four 130-foot on-ground radials; his wider series recorded feedpoint impedance, current division and transmission change. The important lesson is not one magic radial count. Performance depends on conductor geometry, soil, spacing, symmetry and the installed environment, and the improvement per extra wire eventually becomes a site-specific trade.
A base-fed inverted-L is still a monopole system when it is fed against radials. Bending the upper wire can change radiation resistance, current distribution and pattern, but it does not cancel the need for an effective return. If the radial field is the weak part of the station, changing only the shape above it cannot make the return loss disappear.
The EFHW Avoids the Radial Field, Not the Return Current
An EFHW is fed near a high-impedance region of the installed half-wave current distribution. Its feedpoint current is lower and its voltage is higher than at the base of a quarter-wave monopole. This makes it possible to build a useful low-band antenna without the large ground-level radial field used by a conventional vertical.
But the transformer still has two terminals, and current still closes through the complete electromagnetic structure. The return can include an intentional counterpoise or local reference, transformer and enclosure capacitance, a controlled length of coax exterior, support hardware and nearby conductors. If those paths are not declared, the shack, bonding network and cable route can become part of the antenna by accident.
That is why I say without a radial field, not without ground, without counterpoise or without return. The practical advantage is real when the return path is small and controlled. It is not permission to leave the system undefined.
High Feed Impedance Is Not an Efficiency Measurement
The familiar expression η = Rradiation /(Rradiation + Rloss) is useful only when all terms belong to the same equivalent circuit and reference plane. The kilohm input resistance of an end-fed half-wave is not automatically its radiation resistance, and a ground-loss resistance measured or assumed for a base-fed monopole cannot simply be placed in series with that end impedance.
Matching transformation changes the impedance and current seen at its input; it does not create radiation resistance or erase loss. In a real EFHW system, power can be lost in the transformer core and winding, conductor, dielectric, wet hardware, return path and feedline. Exterior-feedline current can also radiate and reshape the pattern, so a field increase is not automatically proof that the intended radiator became more efficient.
The honest system efficiency is:
ηsystem = Puseful radiated / Paccepted at the declared input plane
To explain the result, account separately for mismatch, feedline loss, transformer loss, conductor and junction loss, return-system loss and power carried by unintended common-mode paths.
A transmitter seeing 50 Ω does not prove any of those terms. Conversely, a difficult feedpoint impedance does not prove poor radiation if a low-loss matching network presents the transmitter with an acceptable load.
The Transformer and Choke Have Separate Jobs
The impedance transformer must handle the measured complex load at the installed feedpoint over the intended bands and duty cycle. Primary inductance, leakage, winding capacitance, ferrite properties, core volume, insulation, voltage clearance, enclosure environment and cooling all matter. A ratio printed on a box is not a loss or power rating.
The common-mode choke sets a boundary for current on the coax exterior. It does not perform the impedance transform, and the transformer does not guarantee that the feedline is isolated. Place the choke from a band-by-band exterior-current map and the return section you deliberately intend to keep. A copied fraction-of-a-wavelength rule can create another resonant conductor or move a current maximum rather than suppress it.
An UNUN plus a measured choke therefore gives two independent controls: impedance transformation and common-mode boundary. Verify both under the actual load; do not infer either from SWR alone.
Pattern Can Reverse the Ranking
A ground vertical can provide an excellent low-elevation pattern when its radiator, return system and surroundings are favourable. An inverted-L combines vertical and horizontal current components; the current-rich sections, height, bend, ground, return conductor, feedline and nearby structures set its azimuth and elevation pattern.
There is no fixed division in which the vertical wire produces DX and the horizontal wire produces local coverage. On 160 and 80 metres, the useful elevation range also changes with distance, ionospheric state, terrain and operating objective. A few decibels at an irrelevant angle do not win the contact.
ITU-R BS.705-2 treats antenna pattern, imperfect ground, topography and surrounding structures as separate practical influences. A NEC model can calculate current and field for a declared wire structure and ground model, but the result is evidence only when the model contains the conductors that actually carry current and respects the limitations of its ground treatment.
When I Prefer Each System
| Site condition | Useful starting choice | What still needs proof |
|---|---|---|
| Little room for a radial field, but one tall support and a long upper span are available | EFHW inverted-L with a deliberate local return and measured choke boundary | Transformer loss and temperature, exterior-coax current, voltage clearance and installed pattern |
| Space and access allow a substantial, maintainable on-ground radial system | Quarter-wave vertical or base-fed inverted-L | Radial-current distribution, soil loss, accepted power and pattern over the real terrain |
| Elevated radials are practical and can remain symmetrical and inaccessible | Elevated-radial vertical | Radial current balance, detuning by nearby conductors, touch voltage and feedline isolation |
| The station needs harmonic multiband operation from one wire | EFHW inverted-L can be operationally attractive | Every band's transformer load, loss, common-mode current, pattern and tuner stress |
| One narrow low-angle path is the priority | Choose from installed pattern evidence, not topology name | Calibrated field by bearing/elevation or a validated full-geometry model |
Browse the current RF.Guru EFHW Inverted-L collection as implementation options, not as a substitute for commissioning. Exact matching, rating and installation limits belong to the current product record for the selected model.
Run a Comparison That Can Answer Why
- Declare both geometries. Record wire lengths and heights, radial or return conductors, feedline routing, supports, nearby structures, soil condition and terrain.
- Use one input reference plane. Measure forward and reflected power where both complete antenna systems begin, and account for feedline and switch loss.
- Map current. Record individual radial currents and coax-exterior current at repeatable positions on every operating band.
- Measure the transformer. Use the installed complex load, intended power and duty cycle; record loss, temperature and voltage margin separately from SWR.
- Compare fields, not anecdotes alone. Use calibrated local probes, simultaneous remote receivers or rapid A/B/B/A switching by bearing, with a restored baseline.
- Model the actual installation. Include the horizontal leg, return conductor, intended coax section, mast and important nearby conductors; publish ground assumptions and model limits.
- Repeat under useful paths. Separate total efficiency from pattern and propagation, and keep receiver bandwidth, AGC and reporting method fixed.
RF-voltage boundary: the EFHW feed hardware and wire ends can carry high RF voltage. Keep them inaccessible to people and animals, maintain clearance from gutters, branches and flammable material, provide strain relief and weather sealing, and check transformer and choke temperature at the intended power and duty cycle. Elevated radials can also carry hazardous RF voltage and must remain out of reach.
Joeri's bottom line: if I cannot build the ground system that a 160/80-metre vertical deserves, I would rather put the copper into a long EFHW inverted-L and control its transformer, return path and choke. If the site can support an excellent radial system, I let measured loss and installed pattern decide.
Measurement foundations
- Rudy Severns, N6LF — Ground-System Performance, Part 1: Test Setup and Instrumentation
- Rudy Severns, N6LF — Ground Surface and Elevated Radial Comparisons
- Rudy Severns, N6LF — 160-Metre Vertical Ground-System Experiment
- ITU-R BS.705-2 — HF Transmitting and Receiving Antenna Characteristics and Diagrams
- Numerical Electromagnetics Code (NEC-2) User's Guide
Mini-FAQ
- Does an EFHW inverted-L need a radial field? It can work without a large monopole-style radial field, but it still needs a controlled RF return through an intentional conductor, local capacitance, a defined coax section or a measured combination.
- Does high feedpoint resistance make the EFHW nearly lossless? No. High input resistance is not automatically radiation resistance. Transformer, conductor, dielectric, return-path and feedline losses must be referred to the same complete system.
- Can a ground vertical beat it? Yes. A vertical with an effective radial system and a pattern suited to the required path can equal or outperform a particular EFHW inverted-L installation.
- Where should the choke go? Place it from a band-by-band exterior-current map and the return boundary you intend to keep. No fixed coax length is universal.
- Does low SWR reveal the more efficient antenna? No. SWR reports mismatch at one reference plane; it does not separate radiation, transformer loss, ground loss, feedline loss or common-mode current.
- How should I compare the two? Use the same accepted-power reference, document both current paths, measure loss and exterior current, and make rapid A/B/B/A or simultaneous field comparisons with a restored baseline.