 In the 1950s, television superseded radio as the most popular broadcast medium, and commercial radio programming shifted to narrower formats of news, talk, sports and music.Religious broadcasters, listener-supported public radio and college stations provide their own distinctive formats.During the first 3 decades of radio, from 1887 to about 1920, the technology of transmitting sound was undeveloped; the information-carrying ability of radio waves was the same as a telegraph; the radio signal could be either on or off.