Radio is a form of wireless communication that uses electromagnetic waves of frequencies below visible light to transmit signals. Radio waves are produced by oscillating electric currents and can travel through space. Antennas are devices that convert the electric currents into radio waves for transmission and pick up radio waves for reception, allowing communication over long distances. In the late 1800s, Guglielmo Marconi began working on developing radio into a commercial wireless telegraph system and built some of the first radio transmission equipment, making discoveries about how antenna height impacts transmission range.