Vertical Antennas for DX: Why Size and Shape Matter Across the Bands

Vertical antennas remain a cornerstone for DX hunters, especially when horizontal space is limited. But not all verticals are created equal, and the optimal choice changes significantly depending on the band you're targeting. Here's a breakdown of what works best and why, from the higher HF bands down to 160 meters.

6m to 12m: The Sweet Spot for 5/8 Wave Verticals

On the higher HF bands (10m, 11m, and 12m), the 5/8 wavelength vertical consistently outperforms the simpler quarter wave.

Why? The 5/8 wave vertical offers a low radiation angle with a gain of around 3 dB over a quarter-wave. This makes it ideal for DX, especially when mounted with a decent radial field or ground plane.

While a 3/4 wave vertical might offer a slightly lower takeoff angle and marginally more gain, it comes at a cost: it is bulkier, harder to match, and begins to exhibit high-angle lobes. The performance advantage often isn't worth the complexity unless you're after every last decibel.

For most DXers, a well-tuned 5/8 wave offers the perfect balance of performance, simplicity, and manageable size for 6-12 meter bands.

15m to 20m: The Quarter Wave Reigns Supreme

In the middle HF bands like 15m, 17m, and 20m, the classic ¼ wave vertical remains the DX champion.

At these frequencies, the physical size of a ¼ wave radiator becomes practical (around 3.7 to 5 meters tall). A properly installed quarter-wave vertical with a good radial system delivers an excellent low-angle pattern with clean impedance characteristics, making it easy to match and very efficient.

Adding traps or trying to extend the vertical to a 5/8 or longer length often introduces high-angle radiation or complicates the design without a significant DX benefit. For simplicity and performance, ¼ wave is king here.

30m to 160m: The Inverted L with a Half-Wave Vertical Component

As we drop into the low bands (30, 40, 60, 80, and 160 meters), full-size verticals become physically massive. Here, the inverted L antenna with a vertical portion approaching half a wavelength becomes the go-to DX performer.

Why half-wave vertical portion? Because it maximizes current distribution in the lower section of the antenna where it's most effective. This helps lower the takeoff angle dramatically, especially when the vertical section is elevated at least 12 to 20 meters.

A classic inverted L for 160m with a 20m vertical and 30m horizontal portion, for example, provides good efficiency and a decent DX pattern. The same applies on 80 and 40 meters.

For traditional verticals, radials remain essential, but even 4 to 8 raised radials can be effective. However, in the case of our EFHW Inverted L using 68:1 or 70:1 transformers, radials are not needed. These configurations operate with high input impedance and are referenced to ground through a common-mode choke and optionally a short counterpoise, not through a classic radial network.

Unlike shortened verticals with base loading, which tend to be lossy and radiate less efficiently, a properly designed inverted L keeps most of the radiation low to the horizon—exactly what you want for DX.

Note on Local vs Short Skip vs DX

Verticals as described above excel in two domains:

  • Local contacts (LOS) on 6-20 meters due to their omnidirectional coverage and decent ground wave performance.
  • DX and NVIS on 30-160 meters when configured with long vertical portions (for low-angle DX) or moderate heights (for strong NVIS coverage).

However, for short skip (200-800 km) where a medium to high angle of radiation is needed, these verticals are not ideal. Horizontal dipoles, EFHW's, near-resonant EFOC's or doublets at appropriate heights perform far better in that zone.

Conclusion: Choose the Right Vertical for the Right Band

DX success with verticals isn't just about height—it's about choosing the best electrical length for the band.

  • 6-12m: Use a 5/8 wave for maximum low-angle gain.
  • 15-20m: Stick with a ¼ wave for clean, easy DX operation.
  • 30-160m: Go inverted L with a vertical portion as long as possible, ideally close to ½ wave. For EFHW variants with 68:1 or 70:1 transformers, no radials are required.

Matching your antenna type to the band improves your chances of making those long-haul contacts. Sometimes, a few degrees in takeoff angle make all the difference between hearing the DX and working it.

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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.