The End-Fed Half-Wave Myth: Why Most EFHWs Are Doing It Wrong
At RF.Guru, we design our EFHW antennas differently. You won't find random multi-band gimmicks in our EFHW catalog—only carefully engineered dual-band and monoband designs. We do offer multiband antennas in other categories like our EFOC line, which are more efficient (yet still compromise antennas), but perform far better than any 8010 or 4010 EFHW. Still, they’re not DX beasts either—just smart, practical solutions.
Why Only Half- and Full-Wave Dual Band Configurations?
Because physics matters.
An EFHW only performs efficiently when each radiating segment is either a half or a full wavelength on the band of operation. Trying to make a wire behave like something it’s not—like in a so-called “multi-resonant” EFHW (hello?!, 8010)—leads to:
- unpredictable impedance curves
- poor pattern control
- high magnetic strain on the ferrite core, which increases losses and reduces long-term reliability
- excessive common-mode currents
The 8010 EFHW is perhaps the most misunderstood antenna in ham radio history. It’s a mess of high impedance feedpoints, lossy current distribution, and junky patterns. Unless you’re feeding it with a prayer and 30 dB of tuner loss, you’re likely creating more RF noise than signal. Don’t believe the hype—believe the measurements.
Our EFHW Design Philosophy
We only build EFHWs in:
- Monoband Half-Wave, or
-
Dual-Band Full/Half-Wave Combinations, such as:
- 160m/80m
- 80m/40m
- 60m/30m (special)
- 40m/20m
- 20m/10m
We match impedance carefully with optimized transformer ratios. That’s why we offer 49:1, 56:1, 68:1 and 70:1 variants—depending on band, height, and layout. (inverted-L, Sloper, Vertical, HalfSquare etc ...)
Why Not Use a 49:1 on Everything?
Because one size doesn’t fit all.
A horizontal EFHW above 10 m works well with a 49:1. But try that on an inverted-L or vertical EFHW, and the feedpoint impedance can rise to 4000–6000 Ω or more—far beyond the 2450 Ω sweet spot of a 49:1. In that case, the transformer under-matches the antenna, leading to:
- higher SWR
- poor pattern efficiency
- and often capacitive reactance at the input
Tip: If you’re unsure, it’s safer to choose a higher ratio rather than a lower one. Over-transforming is less harmful than under-transforming. A slightly too-high ratio gives a higher (but inductive) impedance at the radio—usually easier to tune. But a too-low ratio results in excessive capacitive reactance, which is harder to match and risks instability or tuner stress.
EFHW Antennas in Our Catalog
All are designed as low-angle DX antennas, rated between 2 and 4 kW ICAS. The 30 m and 60 m monoband variants are derived from our EFHW6030 platform.
| Configuration (Bands) | Transformer Ratio | Mounting Height | Suitable Layout |
|---|---|---|---|
| 30m Monoband (Sloper) | 56:1 | >12 m | Sloper |
| 30m Monoband (Vertical) | 70:1 | 4–6 m feedpoint | Vertical |
| 60m Monoband | 70:1 | 4–6 m feedpoint | Inverted-L |
| 40m/20m Dual | 49:1 | >10 m | Horizontal or Sloper |
| 20m/10m Dual | 49:1 | >10 m | Horizontal or Sloper |
| 60m/30m Dual | 70:1 | 3–6 m feedpoint | Inverted-L |
| 80m/40m Dual | 70:1 | 3–5 m feedpoint | Inverted-L |
| 160m/80m Dual | 68:1 | 1–3 m feedpoint | Inverted-L |
Typical Radiation Behavior
| Configuration | Radiation Angle Type |
|---|---|
| 30m Monoband (Sloper) | Low-angle DX |
| 30m Monoband (Vertical) | Low-angle DX |
| 60m Monoband | Low-angle DX |
| 40m/20m Dual | Low-angle DX |
| 20m/10m Dual | Low-angle DX |
| 60m/30m Dual | Low-angle DX |
| 80m/40m Dual | Low-angle DX |
| 160m/80m Dual | Low-angle DX |
Deploy with knowledge. Radiate with purpose.
At RF.Guru, every EFHW is engineered—not guessed. No gimmicks, just performance.
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Written by Joeri Van Dooren, ON6URE – RF, electronics and software engineer, complex platform and antenna designer. Founder of RF.Guru. An expert in active and passive antennas, high-power RF transformers, and custom RF solutions, he has also engineered telecom and broadcast hardware, including set-top boxes, transcoders, and E1/T1 switchboards. His expertise spans high-power RF, embedded systems, digital signal processing, and complex software platforms, driving innovation in both amateur and professional communications industries.