Vertical Antenna

The vertical is a quarter-wave monopole worked against ground. It is omnidirectional and radiates well at low elevation angles, which favours distance.

Configuration

A single vertical radiator fed at the base. The element length defaults to 5.1 m; a length of 0 selects a resonant quarter-wave element for the operating frequency. The azimuth field is disabled because the pattern is the same in all directions.

Characteristics

• Typical gain around 1.8 dBi, evenly in all compass directions.
• Low typical takeoff angle around 18 degrees: good for long-distance ionospheric paths despite the modest gain figure.
• Vertical polarization, which is strongly favoured on short-range ground-hugging paths. For local and regional coverage below a few hundred kilometers on the lower bands, a vertical often outperforms much "bigger" horizontal antennas.
• Ground quality matters more than for horizontal antennas; poor ground raises losses.

Sizing

A resonant quarter-wave element in meters is approximately 71.5 divided by the frequency in MHz, half the dipole length (see Antenna Calculations). Example: about 10 m at 7.1 MHz.

When to use

Pick the vertical for omnidirectional low-angle coverage, groundwave range on the low bands, or when there is no room for long horizontal wires. Its weakness is medium-range ionospheric coverage, where high-angle radiators (dipole, inverted-V, loop) do better.