U.S. public television stations are independent and serve community needs. All public television organizations are linked nationally, however, through three national organizations: the Corporation for Public Broadcasting (CPB), created by Congress in 1967 to channel federal government funding to stations and independent producers; the Public Broadcasting Service (PBS), formed in 1969 and which today distributes programming and operates the satellite system linking all public TV stations; and the Association of Public Television Stations (APTS), which helps member public TV stations with research and planning. In addition to these public TV stations, there are a growing number of noncommercial stations run by Christian evangelistic ministries, which are, for the most part, supported by donations from viewers and member churches.
Radio
The beginning of regular commercially licensed sound broadcasting in the United States in 1920 ended the print monopoly over the media and opened the doors to the more immediate and pervasive electronic media. By 1928, the United States had three national radio networks - two owned by NBC (the National Broadcasting Company), and one by CBS (the Columbia Broadcasting System).
In 1998, the number of U.S. commercial radio stations had grown to 4,793 AM stations and 5,662FM stations. In addition, there are 1,460 public radio stations in the United States. Most of these stations are run by universities and public authorities for educational purposes and are financed by public and/or private funds, subscriptions and some underwriting. NPR (National Public Radio) was incorporated in February 1970 under the 1967 Public Broadcasting Act. NPR was created to provide leadership in national newsgathering and production and to act as a permanent nationwide interconnection of noncommercial stations.