On November 2, 1920, station KDKA in Pittsburgh went on the air with election returns, and it is usually named as the first commercial radio station in the United States. The broadcast was heard by a small number of people who had built their own sets with crystals and coils, or who listened in clubs and shops, and the returns came in by telephone and telegraph and were read out through the night. The audience was tiny. Radio had been a hobby for a few thousand people, and the station showed that it could be something else.
The station was run by the Westinghouse company, which made electrical equipment and wanted to sell sets. It put out a regular service of news and music and talk, and within two years there were hundreds of stations in the country. The change was quick. The sets sold. New York and Chicago and other cities had their own, and the first networks linked them by telephone lines in the middle of the decade, and the receiver became a piece of furniture in the front room.
The new medium changed politics and business and daily life. Candidates spoke to millions at once, advertising paid for the programmes, and families gathered in the evening to listen to music and comedy and drama and the news, and a common set of songs and phrases spread across a country of great distances. It also brought organised propaganda, for governments learned in the 1930s how well a voice could carry a message. The power was plain.
KDKA is still on the air, and the anniversary is kept in Pittsburgh, and the station is remembered as the point where broadcasting became an industry rather than a hobby. Television took over much of the audience later in the century, and radio found new roles in music and in news and in the car. The pattern of a single voice reaching a whole city at once began on an evening in November 1920.