Signal Lab

Operator Spotlight · N3EQF · DX Flagpole 24 + 4 ft Extension

Eighty Meters After Twenty-One Years

Tom Dandrea, N3EQF, moved into an HOA community twenty-one years ago. In all that time, he never made a single contact on 80 meters from home.

Tom’s DX Flagpole at 24 feet, this summer — the before picture. Four more feet went on top in September.

He was already happy with his 24-foot Greyline DX Flagpole. It gave him the world on the higher bands, and it went down and back up on its tilt-over base in seconds — Tom has done it on video in fourteen. But 80 meters stayed silent. Then he added four feet.

Down on the tilt base, the top of the pole is at arm’s length. That is how four feet go on in an afternoon, by one person.

Franz Josef Land in the Russian Arctic on 15. Papua New Guinea on 17. And a band that had been closed to him for two decades, open the same week. He titled his review “Size Does Matter!” The physics agrees with him.

Why Four Feet Opened A Whole Band

On 80 meters, a wavelength is roughly 260 feet. A 24-foot antenna is a small fraction of that — electrically short — and a short antenna has a low radiation resistance: the part of its impedance that actually turns power into signal. Everything else in the circuit, every connection and every bit of conductor, competes with it for your watts.

For an antenna this short, radiation resistance rises with roughly the square of its length. That is John Kraus, W8JK, in Antennas. Going from 24 to 28 feet is about 17 percent more length, but (28 ÷ 24)² is about 1.36 — roughly a third more radiation resistance on 80. Efficiency is radiation resistance divided by radiation resistance plus losses, so a third more of the good number moves the needle exactly where the antenna was weakest. On 15 and 17, where 28 feet is already a healthy fraction of a wavelength, the same four feet buys aperture in a different way.

That is why the low bands reward height, and why the top of the pole is the most valuable real estate on it.

Tom Built The System Right

Tom’s station is worth copying, because each piece does one job well:

The choke keeps the coax from becoming part of the antenna. The short run of low-loss cable is what lets a tuner in the shack do its job well: loss in a mismatched line grows with its length and with how lossy the cable is to begin with, and forty feet of LMR-400 keeps that small. Walter Maxwell, W2DU, spent a whole book, Reflections, on that point. If you want to see the numbers for your own run, the Feedline Loss Calculator does it in seconds.

The Next Nine Feet

Tom already knows where the road leads. In his words, if he had room for the 9 ft whip on top, he would add it next — and probably gain 160 meters. He is right about the direction: the whip adds the most aperture where the antenna is electrically shortest, which is 160 and 80. A 28-footer plus the whip is the Skyline 37, the most aperture we build.

Plenty of owners run the whip as a weekend accessory. With a tilt base, it threads on by hand on a Friday evening and comes off Monday morning. CQ World Wide phone runs October 24 and 25 — a fine weekend to find out what 160 sounds like from your lot.

If you want to learn the low bands from the operators who wrote the book on them, the TopBand reflector archive holds decades of them trading real data, free. John Devoldere, ON4UN, wrote the book itself: ON4UN’s Low-Band DXing, published by the ARRL.

Watch the bands tonight — live cluster, RBN, and conditions run free on our DX Console, where Greyline owners like N3EQF glow gold.