2.Radio and Television

From the 1920sto the end of World WarⅡ，radio was a popular source of news and political analysis in the US.According to Statistics compiled by the US Radio Advertising Bureau，98%of all US households had at least one radio.Of Americans over twelve，95.3%listen to radio for an average 3hours and 20minutes each workday.There were 11，974radio stations in the United States.In an effort to hold audiences many radio stations appeal to special interests.Some offer an all-news or all-music format；others broadcast professional sporting events.In large cities，some stations attract immigrants by presenting foreign language programs.

VOA（Voice of America）perhaps is the most famous radio station of the US for the expansion of propaganda to foreign countries.VOA radio station is in Washington D.C.It was launched in 1942，originally for war information，but now it has 16broadcasting stations，sending news to the whole globe in 41 languages day and night.

Few people today doubt the pervasiveness of television’s influence on people’s life.In the US，almost every home has a color television，and a great majority of American households have two or more televisions.Cable television was originally designed as a means of improving TV reception in some rural areas.But it has become very common in the country since 1975，when RCA（Radio Corporation of America）put its first communications satellite in operation.Although the number of cable channels increases year by year，and climbs toward the fabled 500-channel level，less than 13%of all cable systems carry more than 54channels.

There is no government-owned television network in the US.Nearly all TV networks are commercial，and programs are interrupted every quarter of an hour or so for advertisements.What television does best，however，is to provide live coverage of contemporary events.For this reason，television becomes a useful tool for politicians to influence the public for their political purposes.Democratic and Republican National Conventions were televised for the first time in 1952.Dwight Eisenhower ran the first political TV ads during his campaign.In many communities，local educational stations broadcast school board and city council proceedings.Congressional hearings and debates are available on C-SPAN，while Court TV covers major trials.