Not long after the first commercial radio station went on the air in 1920 (KDKA in Pittsburgh). By 1924, articles in Popular Mechanics were giving instructions on installing radios in cars. In 1929, Galvan Manufacturing developed the first car radio...with a wire mesh antenna that went between the car's roof upholstery and roof. This Motorola (a portmanteau of 'motor and 'Victrola') radio sold for $110, when a new car could be had for under $800.

Giles Slade, Big Disconnect: The Story of Technology and Loneliness