The broadcast type of radio network is a network system which distributes
radio programming to multiple
stations simultaneously, or slightly delayed, for the purpose of extending total coverage beyond the limits of a single broadcast signal. The resulting expanded audience for radio programming or information essentially applies the benefits of
mass-production to the
broadcasting enterprise. A radio network has two sales departments, one to package and sell programs to radio stations, and one to sell the audience of those programs to advertisers. Most radio networks also produce much of their programming. Originally, radio networks owned some or all of the stations that broadcast the network's
radio format programming. Presently however, there are many networks that do not own any stations and only produce and/or distribute programming. Similarly station ownership does not always indicate network affiliation. A company might own stations in several different markets and purchase programming from a variety of networks. Radio networks rose rapidly with the growth of regular broadcasting of radio to home listeners in the 1920s. This growth took various paths in different places. In
Britain the
BBC was developed with
public funding, in the form of a
broadcast receiver license, and a broadcasting
monopoly in its early decades. In contrast, in the
United States various competing
commercial broadcasting networks arose funded by
advertising revenue. In that instance, the same corporation that owned or operated the network often manufactured and marketed the listener's radio. Major technical challenges to be overcome when distributing programs over long distances are maintaining signal quality and managing the number of switching/relay points in the
signal chain. Early on, programs were sent to remote stations (either owned or affiliated) by various methods, including leased
telephone lines, pre-recorded
gramophone records and audio tape. The world's first all-radio, non-wireline network was claimed to be the
Rural Radio Network, a group of six
upstate New York FM stations that began operation in June 1948. Terrestrial
microwave relay, a technology later introduced to link stations, has been largely supplanted by
coaxial cable,
fiber, and
satellite, which usually offer superior cost-benefit ratios. Many early radio networks evolved into
television networks. ==See also==