Radio stationA radio station is a site configured for broadcasting sound. Traditionally, radio stations have broadcast through the air via radio waves, a form of electromagnetic radiation, but today many stations broadcast via cable, local wire networks, or the Internet as well or instead of atmospheric broadcasting. Often stations are linked in radio networks.
KDKA of Pittsburgh, Pennsylvania (owned by Westinghouse) started broadcasting as the first commercial radio station on November 2, 1920. The first broadcast was the results of the U.S. presidential election, 1920.
Radio stations are of a number of types. The best known are the AM and FM stations, both commercial and "public", or nonprofit.
AM stations occurred first. AM refers to amplitude modulation, a mode of broadcasting radio waves, and occurs on commercial US airwaves in the frequency range of 530 to 1600 kiloHertz (thousand cycles per second). FM refers to frequency modulation, and occurs on commercial US airwaves in the frequency range of 88 to 108 megaHertz (million cycles per second).
Many other types of radio stations exist. These include:
- base stations for police, fire and ambulance networks
- military base stations
- dispatch base stations for taxis, trucks, and couriers
- emergency broadcast systems