Heavy-Duty Base · 160-6M · No Radials · Made in USA
The 28' HD: The Greyline Built for Wind, and Built to Grow.
The same Greyline design, every band 160 through 6 from a single feedpoint with no radials, built on an oversized heavy-duty base. For exposed sites, northern winters, open ground, and operators who want the full 28 feet with real margin under it, and the room to go taller later.
Two Reasons People Choose HD
Wind today. About 94 mph (preliminary engineering estimate; PE-certified rating to follow), against 55 for the standard 28-foot. The first one went to Iceland to face the winter winds.
Height tomorrow. The heavy-duty base is a platform. Add the 9' whip and it is a Skyline 37 HD. Add a section and it is a 32' HD, then a Skyline 41 HD, the tallest Greyline. Add below the feedpoint, 4 feet, 8 feet and more, and you raise the feedpoint and lift the image, the other half of a vertical's RF picture, with a longer ladder line to match. Buy the base once; grow the antenna for years.
Want it to fly a flag? The HD also comes as a real flagpole, flag kit included: 28' HD DX Flagpole →
Want it taller now? The HD finishes in the same top sections as every Greyline, so the 9' DX Whip seats right on it: 37 feet of HF vertical on a heavy-duty base, about 86 mph (preliminary), with the whip's added length paying most on 40, 80 and 160. Taller still: the whole HD Series →
Why a Heavy-Duty Base
A wind rating comes from the whole pole, not the diameter alone. A fatter pole catches more wind, so it only wins when the structure is engineered for it. The HD is: an oversized heavy-duty base where the bending load lives, every joint bolted in stainless, engineered to ASCE 7-10. For reference, the standard 2-inch 28-footer is rated 55 MPH; the HD runs about 94.
Which 28-Footer? Same Antenna, Two Builds
| 28' (2-inch) | 28' HD (heavy-duty base) | |
| Signal | Identical: every band 160-6M, same feedpoint, same performance | |
| Wind | 55 MPH (ASCE 7-10) | About 94 MPH (preliminary; PE-certified to follow) |
| With the 9' whip | Skyline 37, about 55 MPH | Skyline 37 HD, about 86 MPH |
| Built for | Most yards and HOA lots; tilt it down ahead of a big storm | Open ground, ridgelines, coastline, high plains, northern winters; and owners who plan to grow the pole, above and below the feedpoint |
| Price | $1,250 DX Vertical · $1,325 DX Flagpole | $2,195 DX Vertical · $2,270 DX Flagpole |
| Ships | Within days | In 1-2 weeks |
| Tilt | Tilt-Up Base | 3" HD Tilt-Up Base |
Why No Radials, and Why It Works
A traditional quarter-wave vertical feeds at its base, so every ohm of ground resistance sits in series with the antenna and steals signal before it leaves your yard. The Greyline VDA is a vertical dipole: return current flows through the lower element, not a buried radial field, so the antenna stops depending on your soil. Frozen ground, rock and sand included. One feedpoint, every band.
Pair It With the 3" HD Tilt-Up Base
A heavier pole deserves its own tilt. The 3" HD Tilt-Up Base is built alongside the antenna, with the same one-direction pivot that stops dead at vertical, so the HD comes down for maintenance, for every height change, or ahead of a storm, one person, no ladder. It ships in the same window, and it's 10% off with the HD in the cart.
Watch: Two Minutes
One person walks a 24' Greyline down on the standard Tilt-Up Base, retracts the whip, and walks it back up. The HD tilt uses the same pivot, scaled for the heavier pole. Bart, N1BRL, start to finish →
Specs
| Height | 28 feet; 37 feet with the 9' DX Whip; grows with sections above or below the feedpoint |
| Pole | Oversized heavy-duty base, 6061-T6 aluminum, stainless hardware |
| Bands | Every band, 160-6M |
| Design | VDA, Vertical Dipole Antenna, off-center fed |
| Radials | None |
| Wind | About 94 MPH; about 86 with the 9' whip. Preliminary engineering estimates; PE-certified ratings to follow |
| Foundation | About 12 cubic feet of 3,000 psi concrete over gravel, set plumb; PE-designed foundation for exposed or critical sites; drawing on the Assembly Documents page |
| Ships | In 1-2 weeks; free to the USA and Canada; worldwide at carrier cost |
| Home | Designed and built in the Mountain West · KL2A and HQ in Sun Valley, Idaho |
| Warranty | 7 years. We improve the design whenever we learn a better way; this page is the current reference. |
Photo: a standard Greyline 28-footer. HD build photos from the bench are coming.
Ham Radio is fun again! Pass it on… 73, Jon KL2A · Greyline Performance · 435-200-4902