On this day in 1915 the first transcontinental radio-telephone message was sent.

On this day in 1920 the Joseph Horne Company in Pittsburgh began selling radios for $10 apiece.

On this day in 1930 Lowell Thomas made his debut on the CBS Radio Network replacing Floyd Gibbons.

On this day in 1930 New York City College offered its first course in radio advertising.

On this day in 1936 Radio was first used for a presidential campaign.

On this day in 1940 the radio quiz show "Double or Nothing," was first heard on the Mutual Radio Network.

On this day in 1946 the "Adventures of Sam Spade" debuted on the CBS Radio Network.