80 m Quarter-Wave Vertical or 160/80 m EFHW Inverted-L?
80 m Quarter-Wave Vertical or 160/80 m EFHW Inverted-L?
A 20 m quarter-wave vertical can be an outstanding 80-metre DX antenna when its return system is effective. A long 160/80 m EFHW Inverted-L can be the stronger practical choice when that radial field cannot be built. The answer lives in the installed current, loss and pattern—not in the antenna label.
Many operators hear “quarter-wave vertical” and immediately think “low-angle DX.” That is a sound starting hypothesis, not a finished station. The vertical needs its other conductor—the radial and ground-return system. My practical choice changes when the available property cannot support that system honestly.
Joeri's practical position: if I can install and maintain a serious radial system, I give the 20 m vertical a fair 80-metre test. If I cannot, I usually investigate the long EFHW Inverted-L first. That is a response to the site constraint, not a claim that an end-fed wire defeats every well-built vertical.
Both Antennas Are Electrically Substantial on 80 Metres
A 20 m radiator is close to a quarter wavelength around the middle of the 80-metre band. Its feedpoint is near a current maximum, and the return conductors carry comparable RF current. With low return loss, useful conductor diameter and clear surroundings, the installed pattern can favour low elevations.
A wire that operates near a half-wave mode on 160 metres is roughly one wavelength long on 80 metres before end effects and environmental loading are considered. Bent into an Inverted-L, it supports several current regions whose fields combine in three dimensions. It is not simply a short vertical with a harmless top wire, and the horizontal section is not automatically an “NVIS element.”
The bend height, horizontal length and direction, wire height, return path, feedline exterior, terrain and nearby conductors influence the result. On 80 metres, the longer wire can develop useful lobes and deep nulls. Whether a particular DX path falls inside a lobe is an installed-pattern question.
The Vertical Includes Its Radials
A base-fed quarter-wave vertical is one side of an RF circuit. Radials, ground screen, bonds, soil coupling and every connected conductor form the other side. The current maximum near the feedpoint makes resistance in that region especially important.
Rudy Severns, N6LF, measured real vertical ground systems as conductor count and geometry changed. His 160-metre experiment followed a particular 125 ft radiator, 130 ft on-ground radials, local terrain and soil while progressing from four to sixty-four radials. It demonstrates both measurable improvement and diminishing returns in that installation. It does not turn one radial count into a universal law.
A few elevated radials can also be effective when their lengths, symmetry, height, current balance and access are controlled. Nearby railings, gutters, utility wiring and soil change the current division. Count, total copper, layout and environment therefore belong in the same record.
Useful first-order accounting: at one declared feedpoint, efficiency can be represented as η = Rradiation / (Rradiation + Rloss). Both resistance terms must belong to the same equivalent circuit and reference plane. A low SWR does not reveal how much accepted power is lost in soil, radials, conductors or a network.
The EFHW Inverted-L Moves the Engineering Burden
The long Inverted-L can avoid the large monopole-style radial field. It cannot avoid electromagnetic return current. Its return may involve an intentional conductor, local capacitance, a declared section of coax exterior, support metal or a measured combination. If that path is not designed, station wiring can become part of the antenna.
The high-impedance end feed also requires a transformer that works into the actual complex load. Its ratio is not a universal recipe. Magnetising impedance, leakage inductance, winding capacitance, copper and core loss, voltage distribution, flux and thermal equilibrium all change with frequency, load, power and duty cycle.
That is why a fixed transformer ratio, ferrite mix or counterpoise length cannot establish the winner. Measure the installed load and transformer behaviour. Use a separate common-mode choke where the intended return branch should end, placing it from band-by-band coax-exterior-current measurements rather than a copied wavelength fraction.
High Feedpoint Resistance Is Not Proof of High Efficiency
An EFHW is fed near a high-voltage, low-current point in its standing-wave distribution. The kilohm-scale resistance at that port is not automatically radiation resistance. Comparing it directly with the base resistance of a quarter-wave monopole mixes two different reference planes and two different current normalisations.
For the vertical, include radial and soil loss, conductor and connection loss, any matching-network loss, feedline loss and unintended exterior current. For the Inverted-L, include transformer loss, conductor and connection loss, its intentional and unintended return paths, choke loss and feedline loss. Only then compare accepted power with radiated field.
Pattern Can Matter More Than a Small Loss Difference
A vertical over an effective return system can concentrate a useful share of its field at lower elevations. The Inverted-L's vertical and horizontal currents combine, producing an elevation and azimuth pattern that can favour some paths and suppress others. Real ground and terrain modify both.
A remote receiver reporting a stronger signal does not by itself prove higher total radiation efficiency. The antenna may simply place more accepted power toward that receiver's bearing and arrival angle. That is still a valuable result; it just needs the correct name: realised gain for that path.
| Decision | Evidence that answers it |
|---|---|
| Which system loses less power? | Loss measurements for the radial or return network, transformer or matching network, conductors, joints and feedline at declared reference planes. |
| Which is stronger on a DX path? | Equal accepted power and calibrated simultaneous or rapid A/B/B/A field measurements at the relevant bearing and elevation. |
| Which gives broader useful coverage? | Three-dimensional installed patterns across the band, not one favourable contact or one azimuth cut. |
| Which stays repeatable? | Complex impedance, radial and exterior-feedline current, temperature and restored-baseline checks across weather and band changes. |
| Which fits the property? | Support locations, radial access, wire clearance, maintenance, storm loading, touch boundaries and exposure assessment. |
SWR and Noise Reports Need Context
A low SWR confirms only that the impedance presented at that measurement plane is close to the reference impedance. Loss can broaden or flatten an SWR curve. A transformer or tuner can create a good station-side match while dissipating power, and a lossy radial system can also make a vertical look easier to match.
Likewise, a quieter receiver does not automatically identify the more efficient antenna. The pattern may reject a local noise direction, common-mode current may have changed, the receiver may see a different level or propagation may have moved. Compare wanted-signal SNR with fixed receiver settings and a restored baseline.
Choose the Site Constraint Before the Antenna Name
I investigate the 20 m quarter-wave vertical when the site can support a substantial, maintainable return system and low-elevation coverage is the priority. It is a clean 80-metre concept, and it deserves to be tested as the complete radiator-plus-radial antenna.
I investigate the long 160/80 m EFHW Inverted-L when one high support and a long wire route are practical but a large radial field is not. It trades ground-system copper for more wire aloft, a high-voltage feed, a demanding transformer and a return path that must still be controlled.
Neither choice is free. The good engineering question is not “which topology wins?” It is “which complete installed system produces the field I need without hiding unacceptable loss, stress, common mode or maintenance?”
Run a Comparison That Can Survive Propagation
- Freeze the installations: document every radiator segment, bend, radial, return conductor, feedline route, bond, support, terrain feature and nearby conductor.
- Calibrate the planes: sweep complex impedance at the antenna terminals and station input across the intended part of 80 metres.
- Measure network loss and stress: test the transformer or matching network with representative complex loads, operating power and duty cycle; record voltage, current and equilibrium temperature.
- Map current: record radial-current division and coax-exterior current at repeatable positions before and after choking changes.
- Model the whole geometry: include the Inverted-L bend and return structure, or the vertical and radial field, with defensible ground parameters.
- Compare the field: use equal accepted power, simultaneous receivers or rapid A/B/B/A switching, fixed receiver settings and a restored baseline.
RF safety: an EFHW end and its transformer can carry high RF voltage. The vertical base, elevated radials and matching components can also develop hazardous voltage or current. Keep people outside assessed exposure and touch boundaries, maintain electrical and mechanical clearance, de-energise before adjustment and verify component temperature at the intended power and duty cycle.
Bottom line: a 20 m quarter-wave vertical with an effective radial field is a serious 80-metre DX antenna. Where the property forces that return system into a lossy compromise, a long 160/80 m EFHW Inverted-L is often my better starting point. Measure both complete systems before turning that practical preference into a universal claim.
Primary technical references
- Rudy Severns, N6LF — Ground-System Performance, Part 1: Test Setup and Instrumentation
- Rudy Severns, N6LF — 160-Metre Vertical Ground-System Experiment
- IEEE Std 145-2025 — Standard for Definitions of Terms for Antennas
- Recommendation ITU-R BS.705-2 — HF Transmitting and Receiving Antenna Characteristics and Diagrams
- Lawrence Livermore National Laboratory — Numerical Electromagnetics Code
- NIST — A Two-Port Model for Antennas in an Arbitrary Environment
- Recommendation ITU-T K.52 — Guidance on Complying with RF-EMF Exposure Limits
Mini-FAQ
- Is a 20 m vertical a full-size antenna on 80 metres? It is close to a quarter-wave starting length near the middle of the band. The installed electrical length and feedpoint impedance still depend on conductor diameter, the return system, ground and surroundings.
- Does an EFHW Inverted-L need no radials at all? It may avoid a large monopole-style radial field, but it still needs electromagnetic return current through an intentional conductor, capacitance, a declared coax-exterior section or a controlled combination.
- Is high EFHW feedpoint resistance proof of high efficiency? No. It is a port impedance near a low-current, high-voltage point. Radiation and every loss term must be compared at consistent reference planes.
- Does the horizontal leg guarantee NVIS while the vertical part gives DX? No. Every current region contributes to one combined three-dimensional pattern. Height, routing, ground and frequency determine the useful elevation and azimuth response.
- Can SWR reveal which antenna radiates better? No. SWR describes the match at one plane. It does not separately reveal transformer, matching-network, radial, soil, conductor, feedline or common-mode loss.
- How should I compare the two systems? Hold accepted power and receiver conditions constant, measure their losses and return currents, and use simultaneous or rapid A/B/B/A field comparisons across the bearings and elevations that matter.