The 9' DX Whip — More Aperture. Real Gain. Drop-In Fit.
Every Band Benefits
Nine Feet of Adjustable Upper Radiator.
The 9' DX Whip extends the upper radiator on any Greyline VDA. Your antenna still works every band, 160 through 6 — now with more aperture. Length pays most on 40, 80, and 160, where every backyard vertical is electrically short, and it moves the bonus gain down the dial, toward 17 and 20 meters.
The whip is adjustable from 3' to 11.5'. In NEC modeling over average ground, the whip on a 28-footer (the Skyline 37) reaches about +4 dBi on 17 meters at the optimum DX angle — but that bonus is one detail in a broader story. The whip's real job is to give every band on the antenna a longer radiator.
How height and aperture pay →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.
Aperture Added
9 Feet
More signal down low; the bonus moves down the bands.
Modeled Bonus
Up to ~4 dBi
17M on the Skyline 37, NEC modeling over average ground.
Installation
Minutes
Install whip into top cap. Hand-tight. Done.
The Physics
Why 9 More Feet Matters
Height is aperture. On 40 and 80, where every Greyline is electrically short, the whip adds radiator exactly where it counts most. Higher up the dial, gain builds as the combined length grows toward the band's best geometry, and past it the pattern begins to break into lobes — so the whip moves the antenna's strongest band down the dial, from 10 meters toward 17.
That is the trade: the taller combinations gain strength on 17, 20, 30, and below, and enter a multi-lobe (EDZ) pattern on the top bands — which still work, with the energy spread across angles.
Gain figures: NEC modeling of total height, feedpoint section included, at the optimum angle over average ground. Further reading on the Bookshelf.
NEC Gain Data (Over Average Ground)
What the Whip Does to Your Antenna — By Height
| Base + Whip | Total | 40M | 20M | 17M | 15M | 12M | 10M | Strongest |
|---|---|---|---|---|---|---|---|---|
| 12 + 9 | 21 ft* | -1.63 | 0.64 | 1.35 | 1.88 | 2.66 | 3.24 | 10M |
| 16 + 9 | 25 ft* | -1.14 | 1.04 | 1.86 | 2.54 | 3.42 | EDZ | 12M |
| 20 + 9 | 29 ft | -0.47 | 2.27 | 3.54 | 2.50 | EDZ | EDZ | 17M · Skyline 29 |
| 24 + 9 | 33 ft | -0.02 | 2.27 | 3.54 | EDZ | EDZ | EDZ | 17M · Skyline 33 |
| 28 + 9 | 37 ft | 0.38 | 2.89 | 3.96 | EDZ | EDZ | EDZ | 17M, pushing toward 20M · Skyline 37 |
dBi gain at optimum angle over average ground, NEC modeling of total height, feedpoint section included. *The NEC runs were made at 12, 16, 20, 24, 29, 33, and 37 ft total; the 21 ft and 25 ft rows use the nearest runs (20 ft and 24 ft). EDZ = extended double Zepp region — the pattern turns multi-lobe, and plenty of that energy still lands where DX and regional contacts live. Gold = the strongest band for that combined height.
How to read the numbers: 0 dBi is an ideal quarter-wave standing on a full field of buried radials — the antenna almost no small lot can hold. The small minus figures on 40 meters mean within a decibel or two of that ideal, with no radials in your yard; about 1 dB is barely audible, and 3 dB doubles your power. Nothing here to fear. How to read antenna gain →
Want your exact numbers, including 30 meters? Run your base height plus the whip through the VDA Optimizer →
Best Upgrade in the Lineup
Put the whip on a 20-footer and it becomes a Skyline 29, strongest on 17 meters at about +3.5 dBi. On a 24-footer, a Skyline 33 — the same 17-meter bonus at the classic 40-meter quarter-wave height. On a 28-footer, the Skyline 37 carries the most gain of all: about +4.0 dBi on 17, pushing toward 20. Every one of them still works every band.
The founder runs a whip at home too: 9 to 11.5 feet on top of a 32-foot pole.
The Other End of the Same System
The whip goes on top and buys aperture. The Tilt-Up Base goes at the bottom and is how one person reaches the top — and lowers it again when weather comes. Two ends of one system. With any Skyline, the Tilt-Up Base is $50 off automatically.
Worth knowing before you order: installing a whip on a standing pole means a ladder and usually a second person. On a pole you can walk down, it takes two minutes with both feet on the ground — and so does every future change you will want to make up there.
From the Founder
Jon KL2A runs a 32-foot Greyline at home with a 9-to-11.5-foot whip on top, and works Africa and Asia regularly on 10 through 30 meters. When 10 meters opens, he likes the 24-foot. His advice to every buyer is the same: go as tall as your lot allows — the multiband improvement is real.
— Jon KL2A · Founder, Greyline Performance
Installation
Two Minutes. No Tools.
Install
Remove the existing top cap from your antenna. Thread the whip into it. Hand-tight. An automatic tuner will re-tune on first use — it detects the new configuration and updates its memory.
After Installation
If using a remote autotuner such as the LDG: reset the tuner memory on each band for the first tune. The new aperture means new impedance profiles — the tuner needs one pass per band to learn the configuration. Desk tuners: expect new settings on each band.
Specs
| Spec | Detail |
|---|---|
| Length | 9 ft nominal — adjustable 3 ft to 11.5 ft |
| Compatibility | All DXF and DXV models — 12, 16, 20, 24, 28 ft |
| Material | Aluminum — lightweight, corrosion resistant |
| Installation | Uses existing top cap — no modification required |
| Modeled Bonus | Up to about 4 dBi at optimum angle over average ground (height dependent — see gain table) |
| Shipping | Free to the USA and Canada |
| Assembled | By hand in the Mountain West |
Every Greyline design decision traces back to published antenna physics — the ARRL Antenna Book, Kraus on antennas, Severns on ground systems, Maxwell on transmission lines, Lewallen on modeling. Not opinions. Cited works.
Ham Radio is fun again! Pass it on… 73, Jon KL2A · Greyline Performance · 435-200-4902