28' DX Flagpole Antenna — 160-6M, No Radials

HOA Stealth Flagpole Antenna | 160-6M | No Radials | Made in USA

The DXF28 - The Flagship. Maximum Aperture.

The DXF28 is the tallest flagpole antenna Greyline builds, and the choice for operators who want every bit of aperture the design can carry. At 28 feet the vertical dipole reaches 5/8-wave geometry on 15 meters, and every band benefits from the added length up to that geometric ceiling. Modeled gain figures for this height are stated on the aperture page with their reference and band. A property asset that flies a full-size flag and satisfies an HOA board.

Why a Flagpole Antenna?

Most HOA CC&Rs explicitly permit residential flagpoles. The DXF's RF function is entirely internal - no visible stubs, no loading coils, no radial wires. From the street it is a flagpole, and a handsome one. The approval you need is already written into the CC&Rs. It is called a flagpole permit.

Flag-Down Protocol

The flag is the wind load. At 28 feet the flag-up rating is 35 MPH and the flag-down rating is 55 MPH, both per ASCE 7-10. US federal flag protocol already calls for lowering the flag when weather approaches, which is why the flag-down figure is the structural number for a storm. This is standard practice for commercial flagpole installations at this height. If you want this much aperture in an exposed location, the DXV28 carries the 55 MPH rating with no flag to lower.

Field Report - Virginia

Independent review, published before purchase. First night: G4 on 160M, LZ on 80M, TZ4 on 20M, KP4, 9K, KH6, CE, and Europeans on 40M. Next morning: 31 QSOs in 15 minutes on 40M CW. MFJ shack tuner. Drake L7 amp. "It does work."

Rich, NN3W | 28' DXV, same VDA core | Verified Owner

Independent Assessment - Defense Antenna Executive

"I ran a defense antenna company for 7 years. I am very impressed with the look, quality, machining, and part fit. It is a professional-grade product." HOA approved in Colorado. Concrete foundation. FT8 DX confirmed to Hawaii, South America, Europe, and Africa.

Rob Freedman, WC0R | Retired Defense Antenna Executive | Amateur Extra | Colorado HOA

The Physics

Why No Radials, and Why It Works

A traditional quarter-wave vertical feeds at the current maximum at its base, which pushes maximum resistive loss directly through soil. Every ohm of ground resistance sits in series with radiation resistance, taking signal before it leaves the yard.

The Greyline VDA is a vertical dipole. It covers 160-6M from a single feedpoint with no radials. Return current flows through the lower element rather than a buried radial field, which reduces ground coupling and removes the dependency on soil conductivity. At 28 feet the geometry reaches 5/8-wave on 15 meters, and this is the largest low-band aperture in the DXF lineup.

The physics behind the no-radial vertical dipole is established, published work. The reference shelf is cited at the foot of this page, and a deeper explainer lives in the Signal Lab.

"I run 32 feet of DXV at my own station and work Africa and Asia regularly on 10 through 30 meters. This week I am adding the 9-foot whip to it, because there is still more to be had. Go as tall as your lot allows. The improvement across the bands is real, and it is the cheapest signal you will ever buy."

Jon Kimball, KL2A | Founder, Greyline Performance

Before You Install - Run a Noise Audit

The 2-inch pole footprint is the smallest ground signature of any full-HF antenna. A traditional radial field extends hundreds of feet at 160 meters, running toward every noise source on the property. The VDA goes where you choose. Take a battery-powered AM radio, tune off any broadcast station, walk the property, and find the quietest spot. That is where the pole goes.

In the Box

Everything You Need. Nothing You Don't.

Structural Engineering

Built for Real Weather

Every DXF is engineered to ASCE 7-10 structural standards. The flag is the dominant wind load, which is why the two columns differ. Federal practice is to lower the flag when weather threatens, so the flag-down figure is the engineering number.

Standard 2-inch series, per ASCE 7-10. Lower the flag during approaching weather per US federal flag protocol. Shorter poles carry substantially higher ratings, and a shorter pole with the 9' DX Whip on top will out-reach a taller bare one. Call and we will work out the right combination for your site.

Construction - 6061-T6 Aircraft Aluminum

Outside: 2-inch OD, full length. A uniform profile top to bottom, clean and invisible as an antenna. Inside: the wall graduates where the physics demands it, 0.125 inch through the lower 30 percent where base bending stress peaks, and 0.065 inch through the upper 70 percent where reducing mass at height lowers dynamic wind load. No plastic anywhere. All metal, stainless hardware throughout.

At 28 feet the pole presents 4.67 square feet of wind surface, and the moment arm is at its longest. Every additional square foot of projected area translates directly into greater base bending stress and greater fatigue loading on every gust cycle. The graduated wall is not a cost measure. It is the correct engineering response: maximum material where bending stress peaks, minimum mass where it only adds load.

A 4-inch OD pole at the same height would present roughly 9.3 square feet, which is twice the load at the height where load matters most. Outer diameter is the variable that reveals everything. A slim section sheds wind that a fat one fights.

Every Greyline wind rating is derived from ASCE 7-10 values using actual geometry and published methodology. A wind rating without a cited standard is a guess dressed as a spec. Ask any antenna maker which standard they used. If they cannot name one, you have your answer.

Take It Further

Upgrades That Move the Needle

160-6M, One Pole

The 28' DXF is the flagship of the line: maximum aperture, 160 meters through 6 meters, no radials. The largest electromagnetic capture area Greyline ships in a residential VDA, ASCE 7-10 rated to 55 MPH flag-down. Adding the 9' DX Whip extends the upper radiator on every band and moves the 5/8-wave point toward 17 and 20 meters. Modeled gain figures are stated with their reference antenna and ground conditions on the aperture page.

Aperture and Gain - the honest physics

HOA and XYL Approved

We've Done the Hard Part for You

Every DXF ships with an HOA Architectural Brief and a Property Integrity Letter, field-proven across more than a decade of installations and engineered to ASCE 7-10 from the ground up.

Feed System Note

The DXF is a balanced VDA. The tuner and RF choke must maintain a floating balanced feed. See the Tuner and Balun Configuration Guide.

Specs and Shipping

"Band conditions have been bad, but I'm still working Real DX from 160 through 10 meters, and it is outperforming the end-fed long wire I ran for years, which only ever reached the Pacific and rarely heard Europe."

Jerry, NC7U | Washington

Common Questions

Before You Order, Answered.

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.

The full shelf lives under The Signal Lab, The Shelf We Read From in the menu, open to everyone.

Ready?

The DXF28 Ships Free in the USA

Hand-built in Sun Valley, Idaho. Maximum aperture, 160 through 6 meters, no radials, HOA documents in the box.

Not sure this is the right height? Call 435-200-4902 and a real person will work it out with you.

Exposed site? The DXF24 with the 9' DX Whip stands taller than a bare 28 and holds a higher wind rating. No flag to lower? The DXV28.

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