What Height HF Vertical Antenna Should I Buy?

Antenna Physics · Answered

What Height HF Vertical Antenna Should I Buy?

Short answer: buy the tallest your lot, your HOA, and your wind allow — taller is more aperture on 40, 80, and 160 — then let your favorite band break the tie. Every height peaks on a different band, and the gain at that peak is real, modeled dBi.

Why taller helps on the low bands

On 80 meters a full quarter-wave is about 66 feet. Any residential vertical is shorter than that, so every added foot is more of the antenna the band wants. That is aperture: physics, not promise.

Where each height peaks

A Greyline is a vertical dipole. Its feedpoint sits about four feet above the ground, and the element above it sets the aperture. Near five-eighths of a wavelength, a vertical lays its signal toward the horizon — the ARRL Antenna Book puts it roughly 3 dB over a quarter-wave at low angles. Bob Zavrel, W7SX, modeled every Greyline height in NEC; here is where each one peaks:

20 feet Peaks on 10 meters · the best-seller
24 feet Peaks on 10–12 meters
Skyline 29 & 33 Peak on 17 meters · about +3.5 dBi
Skyline 37 Peaks on 17 meters at about +4.0 dBi, pushing toward 20 meters · the most low-band aperture without guying

See the modeled gain for any height and band in the VDA Optimizer.

The limits that decide it

Wind first: every Greyline is ASCE 7-10 rated — 12 feet to 155 mph down to 28 feet at 55 mph. Then the HOA and the neighbors: a flagpole at 20 feet reads as a flagpole. Then your bands: DXers who live on 40 and 80 buy height; operators who live on 10 through 17 can pick the height that peaks on their favorite band.

Reply to any Greyline email with your lot and favorite band, and I will tell you what I would put up. — Jon Kimball, KL2A · 435-200-4902