Vertical and horizontal (radio propagation)

Radio propagation, the process by which radio waves travel from a transmitter to a receiver, is heavily influenced by the polarization of the radio waves. Polarization refers to the orientation of the electric field component of the radio wave. The two primary types of polarization are vertical and horizontal.

Vertical Polarization: In vertical polarization, the electric field component of the radio wave is oriented vertically, perpendicular to the Earth's surface. Vertically polarized waves are often used for ground wave propagation, where the wave travels along the surface of the Earth. This is because the Earth's surface, being relatively conductive, provides a good path for vertically polarized waves to travel. Vertically polarized waves also tend to be less susceptible to signal degradation caused by obstacles like trees and buildings when operating at lower frequencies.

Horizontal Polarization: In horizontal polarization, the electric field component of the radio wave is oriented horizontally, parallel to the Earth's surface. Horizontally polarized waves are commonly used for skywave propagation, where the waves are reflected or refracted by the ionosphere back to Earth. At higher frequencies, horizontal polarization can often provide better signal strength and less interference in line-of-sight communications, especially over open terrain. However, they are more susceptible to signal blockage by vertical obstacles.

The choice between vertical and horizontal polarization depends on various factors, including the frequency of the radio wave, the type of propagation desired (ground wave, skywave, or line-of-sight), the terrain, and the presence of obstacles. Antenna design must match the desired polarization for optimal signal transmission and reception.