A quarter-wave vertical is a single vertical element worked against a ground system of radials. It's omnidirectional with a low takeoff angle, which makes it a strong DX performer — but its efficiency comes almost entirely from the radial field, not its height.
The radiator and each radial are both about a quarter wavelength. Ground-mount it with many buried radials (16 to 32 is a good target) or elevate the base and use four tuned radials. The feed impedance is close to 50 ohms, so it needs only a 1:1 choke, no transformer.
| Band | Vertical radiator length | Each radial (use 4 or more) |
|---|---|---|
| 160m | 37.47 m / 122.9 ft | 37.47 m / 122.9 ft |
| 80m | 18.99 m / 62.3 ft | 18.99 m / 62.3 ft |
| 60m | 13.29 m / 43.6 ft | 13.29 m / 43.6 ft |
| 40m | 10.03 m / 32.9 ft | 10.03 m / 32.9 ft |
| 30m | 7.03 m / 23.1 ft | 7.03 m / 23.1 ft |
| 20m | 5.02 m / 16.5 ft | 5.02 m / 16.5 ft |
| 17m | 3.93 m / 12.9 ft | 3.93 m / 12.9 ft |
| 15m | 3.35 m / 11.0 ft | 3.35 m / 11.0 ft |
| 12m | 2.85 m / 9.4 ft | 2.85 m / 9.4 ft |
| 10m | 2.50 m / 8.2 ft | 2.50 m / 8.2 ft |
| 6m | 1.41 m / 4.6 ft | 1.41 m / 4.6 ft |
Model this antenna interactively → for gain, takeoff angle and azimuth/elevation patterns.
About 5.02 m (16.5 ft) for the radiator, with radials of the same length, cut for 14.175 MHz.
More is better. Four tuned elevated radials, or 16 to 32 on-ground radials, is a good target. Too few radials wastes power as ground loss.
A vertical gives a lower takeoff angle (better for DX) and is omnidirectional, but it needs a good radial field and is more affected by poor soil. A dipole up high is simpler and quieter on receive.
Just a 1:1 choke at the feedpoint. It's unbalanced and already near 50 ohms, so no impedance transformer is needed; the choke keeps the coax shield from acting as a radial.