13 Like film, radio was invented in the late 19th century, but experienced its formative era of commercial expansion in the 1920s. On November 2, 1920, radio station KDKA in Pittsburgh, Pennsylvania, broadcast the presidential election returns. It was the first-ever live radio transmission for a popular audience, and although few Americans that evening had the necessary technology to hear the results, by 1922 more than 3 million households had acquired radio sets. Seven years later, more than 12 million households owned radios, fueling an industry that saw $852 million in annual sales. The Roaring '20s was the time of the Jazz Age. Many of the top jazz musicians were African-Americans, such as Duke Ellington, Louis Armstrong and Fats Waller. A central component of the Harlem Renaissance, jazz reached beyond Harlem in the 1920s. As Americans in the '20s became more progressive and rejected traditional forms of music, notions about morality, and what was deemed respectable, they accepted and enjoyed jazz in their households via radio.
