Scheduled radio broadcasting begins

On November 2, 1920, the Westinghouse station KDKA in Pittsburgh went on air with the returns of the presidential election between Warren Harding and James Cox. The announcer was Harold Arlin, and the station grew out of experiments by the engineer Frank Conrad, whose amateur transmissions had drawn listeners. Westinghouse saw the commercial point: if people could hear programs at home, they would buy receiving sets. Radio had existed since Marconi in 1895 as a way to send messages, and Fessenden had sent voice and music in 1906. What changed in 1920 was the idea of a regular schedule aimed at a general audience.¹²

Technology and war made it possible. The vacuum tube amplifier, developed in the 1900s and 1910s, let stations send voice clearly and let receivers be small and cheap. Armed forces in World War I had trained thousands of radio operators and built factories for the equipment. Priority claims are contested: stations in the Netherlands, Argentina and Detroit were also airing programs in 1919 and 1920, and KDKA is best seen as an early licensed station in the United States, not as the unique first anywhere.¹³

The growth was explosive. Hundreds of stations opened across the United States within about two years, and the first paid on-air advertisement was sold by New York's WEAF in 1922. In Britain the British Broadcasting Company began daily service from London in November 1922, and became the publicly owned British Broadcasting Corporation under John Reith in 1927. By 1930 about 40 percent of American households owned a radio. Presidents and prime ministers could speak to millions at once, and listeners everywhere received the same news, music and sports at the same moment.²