Vertical, with radials that match.

A quarter-wave vertical needs something to work against — a set of radials that act as the other half of the antenna.

How to use it

• Pick the band / frequency (voice or digital), and your element material.

What you get

• The radiator length (one quarter wavelength) and the radial length.
• Radials are set 5% longer than the radiator — the correct figure, not the 12% some references repeat.

Tips

• Four radials is the minimum; more is better. Elevated radials can droop to raise feedpoint impedance toward 50 ohms.
• Ground-mounted verticals want many short radials on or in the soil.

Good to know

Ground quality strongly affects a vertical’s real-world efficiency — this sizes the metal correctly, but the dirt under it does a lot of the work.