<P> In 1904, well before commercially viable technology for mobile radio was in place, American inventor and self - described "Father of Radio" Lee de Forest did some demonstration around a car radio at the 1904 Louisiana Purchase Exposition in St. Louis . </P> <P> Around 1920, vacuum tube technology had matured to the point where the availability of radio receivers made radio broadcasting viable . A technical challenge was that the vacuum tubes in the radio receivers required 50 to 250 volt direct current but car batteries ran at 6V . Voltage was stepped up with a vibrator that provided a pulsating DC which could be converted to a higher voltage with a transformer, rectified, and filtered to create higher - voltage DC . </P> <P> In 1930, the American Galvin Manufacturing Corporation marketed a Motorola branded radio receiver for $130 . It was expensive: the contemporary Ford Model A cost $540 . A Plymouth sedan, "wired for Philco Transistone radio without extra cost," is advertised in Ladies' Home Journal in 1931 . In 1932 in Germany the Blaupunkt AS 5 medium wave and longwave radio was marketed for 465 Reichsmark, about one third of the price of a small car . Because it took nearly 10 litres of space, it could not be located near the driver, and was operated via a steering wheel remote control . In 1933 Crossley Motors offer a factory fitted car radio . By the late 1930s, push button AM radios were considered a standard feature . In 1946 there were an estimated 9 million AM car radios in use . </P> <P> An FM receiver was offered by Blaupunkt in 1952 . In 1953, Becker introduced the AM / FM Becker Mexico with a Variometer tuner, basically a station - search or scan function . </P>

When did they first put radios in cars