Radio Waves

Radio waves are made up of electric and magnetic fields and are therefore known as electro-magnetic waves. The electric and magnetic fields are always at right angles to each other, (90 degrees). The polarity of these fields is defined by the electric part of the wave. The radio wave shown below would be a vertical wave. For the most part in ham radio we are only concerned with the electric part of the wave. There are special instances where you need to know about the magnetic part of the wave, but for the majority of ham radio operation the focus is on just the electric field. Radio waves can take on many shapes such as vertical, horizontal, circular and random. No matter the polarity of the wave those fields are still at right angles to each other.

radio wave showing the electric and magnetic fields

Antennas and Radio Wave Polartization

In order to send and receive radio waves you must use an antenna. To efficiently send these radio signals the antenna must somewhat match the polarization of the radio waves. There are many different kinds of antennas for this reason.