Our Logic Behind DX Monoband Antennas

At RF.Guru, we don’t just throw wire in the air and call it an antenna. Every design choice is deliberate—based on propagation physics, mechanical stability, and real-world DX performance.

Yes, we do build compromise multiband antennas like the EFOC, DeltaRex, IronWave, or even the VertX206—they're excellent solutions when you're space-constrained or need band agility.

But when it comes to monoband antennas for serious DX, compromise takes a back seat to efficiency, radiation angle, and build quality.

Here’s why we choose specific antenna types for each band:

For 4m, 6m, 10m, and 12m: The 5/8λ Vertical with Fixed Radials

Why a 5/8λ?
Because it delivers the lowest radiation angle possible at a practical height—without requiring a tower. Especially for 10 m and 12 m, a 5/8λ radiator:

  • Is still mechanically manageable (about 6.5 m for 10 m band)
  • Shifts the current maximum higher on the element, lowering the takeoff angle
  • Offers ~3 dB more gain at low angles compared to a 1/4λ

This makes it ideal for long-haul DX, where shallow angles matter most.

Why not a 1/4λ here?
At typical mounting heights, a 1/4λ radiates with a higher takeoff angle—less effective for DX. You simply don’t get the same horizon-focused punch unless you elevate the whole system well above ground.

Radials?
We use four fixed rigid radials at 45° angle on all our verticals. They form a durable, repeatable ground plane that doesn’t sag or detune—ensuring consistent, symmetric radiation patterns.

For 15m, 17m, and 20m: The Raised 1/4λ Vertical with Rigid Radials

Why not 5/8λ here?
Because a 5/8λ radiator for 20 m would be ~12.5 m long—mechanically unwieldy at portable or fixed height.
And if you're mounting it at a low elevation, the benefits of 5/8λ are lost anyway.

That’s why we prefer a 1/4λ vertical with elevated, rigid radials:

  • Keeps height between 3.5 and 5.2 m, practical for field and fixed use
  • Matches easily to 50 Ω
  • Offers clean low-angle radiation, with reduced ground loss due to raised radials
  • Is mechanically simple, rugged, and replicable

Again, we use 4 rigid radials set at 45° angles—no wire, no tuning guesswork. It’s all predictable.

(5/8st we will release in 2026)

For 20m, 30m, and 40m: The End-Fed Half Square (Monoband Only)

Why?
When a rotatable Yagi isn’t an option, but you still want gain and front-to-back, the End-Fed Half Square is ideal:

  • +3 to +5 dB forward gain at low angles
  • Strong rear nulls to reduce QRM
  • Two support poles, no rotor needed
  • Horizontally polarized with low-angle focus—especially effective over ground or seawater

It’s monoband and it’s big—but it performs like a stealthy two-element beam.

For 40m, 80m, and 160m: The Inverted L EFHW

Why?
The Inverted L End-Fed Half-Wave gives you both:

  • Vertical low-angle radiation for DX
  • Horizontal NVIS coverage for regional traffic
  • Full resonance, no tuner required
  • High radiation resistance → low loss and low noise
  • Simpler and more efficient than short verticals with lossy coils

This makes it ideal for low-band DXers who also want to cover the local net.

Final Word: Built for DX, Not Just "Making It Work"

We don’t deny that shortened, loaded, or multiband antennas can work. They do—and we build those too, when the situation calls for it.

But this monoband lineup is different. These are:

  • Physically resonant
  • Mechanically sound
  • Electrically efficient
  • Low-angle beasts

If you want to put more signal into the horizon—and hear more weak ones coming back—this is the system you build.

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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.