America's largest television network is not ABC, CBS or NBC but PBS
The commercial giants dominate talk of American television, but the largest network is the non-profit Public Broadcasting Service. Unlike its rivals, PBS has no single central schedule: each member station largely decides what to air. It is a reminder that a network can mean very different things.
In the technical sense, a television network is a central operation that feeds programmes to many stations or pay-TV distributors. Until the mid-1980s most countries' viewing was dominated by a handful of terrestrial networks, and many early ones, including the BBC, CBC and NBC, grew out of radio. Where every transmitter simply relays the same central feed, people use network, channel and station almost interchangeably, though professionals keep them distinct. In North America many cable and satellite services are called channels because they have no affiliate stations at all.
Networks do not have to make their own shows. Studios such as Warner Bros. Television or Sony Pictures Television sell programmes to rival networks at once, and schedules are padded with imports and archive material. Local stations may insert their own adverts, identifications and emergency alerts, or break away entirely for regional programming. A national feed might reach more than 200 affiliated stations or only a dozen. Modern control centres rely on automation synchronised to atomic time from GPS so that transitions look seamless.
In the United States the Big Three, ABC, CBS and NBC, long ruled the airwaves, supplying affiliates with news, daytime and prime-time programming. Fox, launched in October 1986, has since joined them as a fourth major network. Cable opened room for new channels, including programming for bicultural Latino audiences, and digital television added subchannel networks devoted to classic shows, music or sport. The media historian Tim Vos has argued that policymakers never deliberately set out to create a system dominated by commercial networks, and some legislators tried to limit their advantages.
Britain offers a contrasting model. The Crown-owned BBC funds its domestic services through a licence fee paid by residents, so they carry no advertising, while its commercial arm, BBC Studios, employs about 23,000 people worldwide. The technology behind it all goes back to 7 September 1927, when Philo Farnsworth demonstrated electronic television in San Francisco.
Source: Television broadcaster
