9' DX Whip — Adjustable 5/8λ Tuning for Greyline VDA

DX Performance Parts · Greyline VDA Compatible

The 9’ DX Whip — More Aperture. Real Gain. Drop-In Fit.

The 9’ DX Whip extension adds 9 feet of radiating aperture to any Greyline DXF or DXV antenna. It installs in minutes, adds no visual bulk worth mentioning, and shifts your antenna’s 5/8λ sweet spot up by the equivalent of a full model size. The 20-foot becomes a 15M full-size performer. The 24-foot hits 5/8λ on 17M. These are real, measurable improvements — not approximations.

Direct Fit

Compatible with all DXF and DXV models — 12, 16, 20, 24, and 28 foot. No tools beyond hand-tight. No modification to the antenna required.

The Physics

Why 9 More Feet Matters

For a vertical antenna, the 5/8λ point is peak gain — up to 3.5 dBi over isotropic at the optimum DX radiation angle. Below 5/8λ, gain is building. Above it, the pattern begins to rise in angle and the gain advantage diminishes. Adding 9 feet shifts your entire operating point up the gain curve toward — or to — the 5/8λ sweet spot on a higher band.

The effect is most pronounced on the bands where your combined height is closest to 5/8λ. On bands where the antenna is already well past 5/8λ, the whip has less effect — which is why the 28ft model sees diminishing returns from the whip on 15M (already at sweet spot) but meaningful improvement on 20 and 30 meters.

Physics foundation: Zavrel W7SX · Antenna Physics: An Introduction (ARRL, 2020) · gain figures at optimum angle over average ground.

W7SX Gain Data

What the Whip Does to Your Antenna — By Height

dBi gain at optimum angle over average ground. Source: W7SX · Antenna Physics: An Introduction (ARRL, 2020). EDZ = Extended Double Zepp region — pattern lobing rises above DX-favorable angles. Gold = band sweet spot for that combined height.

Best Upgrade in the Lineup

The 20ft + whip (29ft total) achieves 5/8λ on 15 meters — matching the 28ft bare antenna. If you own a 20ft and want flagship 15M performance without replacing the antenna, this is the answer.

The 24ft + whip (33ft total) hits 5/8λ on 17M while simultaneously at 1/2λ on 20M. That’s the Founder’s home station configuration — the closest you can get to a 32ft antenna in a standard Greyline setup.

From the Founder

“I run a 32-foot at home and work Africa and Asia regularly on 10 through 30 meters. Real gain across every one of those bands. Go as tall as your lot allows — the multiband improvement is real.”

— Jon Kimball KL2A · Founder, Greyline Performance

Installation

Two Minutes. No Tools.

Specs

Every Greyline design decision traces back to named, published antenna physics — Zavrel W7SX, Kraus W8JK, Severns N6LF on ground systems, Maxwell W2DU on transmission lines, Lewallen W7EL on modeling. Not opinions. Cited works.

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Ham Radio is fun again! Pass it on... 73, The Greyline Performance Team · Sun Valley, Idaho · 435-200-4902