Founded by Hartford N. Gunn Jr., PBS began operations on October 5, 1970, taking over many of the functions of its predecessor, National Educational Television (NET), which later merged with Newark, New Jersey station WNDT to form WNET. In 1973 it merged with Educational Television Stations.
Unlike the five major commercial broadcast television networks in the United States, ABC, CBS, NBC, Fox and The CW – which compensate their affiliate stations to carry their programs – PBS is not a network but a program distributor that provides television content and related services to its member stations. Each station is charged with the responsibility of programming local content (often news, interview, cultural and public affairs programs) for their individual market or state that supplements content provided by PBS and other public television distributors.
In a television network structure, affiliates give up portions of their local advertising airtime in exchange for carrying network programming, and the network pays its affiliates a share of the revenue it earns from advertising (although this structure has been reversed in recent years, with the network compensated by the stations). By contrast, PBS member stations pay fees for the shows acquired and distributed by the national organization. Under this relationship, PBS member stations have greater latitude in local scheduling than their commercial broadcasting counterparts. Scheduling of PBS-distributed series may vary greatly depending on the market. This can be a source of tension as stations seek to preserve their localism, and PBS strives to market a consistent national lineup. However, PBS has a policy of "common carriage," which requires most stations to clear the national prime time programs on a common programming schedule to market them nationally more effectively. Management at former Los Angeles member KCET cited unresolvable financial and programming disputes among its major reasons for leaving PBS after over 40 years in January 2011.
Although PBS has a set schedule of programming (particularly in regard to its prime time schedule, while many members carry a feed of night-time programming from the PBS Satellite Service), member stations reserve the right to schedule PBS-distributed programming in other time slots or not clear it all if they choose to do so; few of the service's members carry all its programming. Most PBS stations timeshift some distributed programs. Once PBS accepts a program offered for distribution, PBS, rather than the originating member station, retains exclusive rebroadcasting rights during an agreed period. Suppliers retain the right to sell the program in non-broadcast media such as DVDs, books, and sometimes PBS licensed merchandise (but sometimes grant such ancillary rights as well to PBS).
As of March 2015, PBS maintains current memberships with 354 television stations encompassing 50 states, the District of Columbia and four U.S. possessions; as such, it is the only television broadcaster in the United States – commercial or non-commercial – which has station partners licensed in every U.S. state (by comparison, none of the five major commercial broadcast networks has affiliates in certain states where PBS has members, most notably New Jersey). The service has an estimated national reach of 93.74% of all households in the United States (or 292,926,047 Americans with at least one television set).
PBS stations are commonly operated by non-profit organizations, state agencies, local authorities (such as municipal boards of education), or universities in their city of license; this is similar (albeit more centralized in states where a licensee owns multiple stations rebroadcasting the main PBS member) to the early model of commercial broadcasting in the U.S., in which network-affiliated stations were initially owned by companies that owned few to no other television stations elsewhere in the country. In some U.S. states, a group of PBS stations throughout the entire state may be organized into a single regional "subnetwork" (such as Alabama Public Television and the Arkansas Educational Television Network); in this model, PBS programming and other content is distributed by the originating station in the subnetwork to other full-power stations that serve as satellites as well as any low-power translators in other areas of the state. Some states may be served by such a regional network and simultaneously have PBS member stations in a certain city (such as the case with secondary member KBDI-TV in Denver, which is not related to Colorado member network Rocky Mountain PBS and its flagship station and primary Denver PBS member, KRMA-TV) that operate autonomously from the regional member network.
Since 53% to 60% of public television's revenues come from private membership donations and grants, most stations solicit individual donations by methods including fundraising, pledge drives or telethons, which disrupt regularly scheduled programming. This annoys some viewers, since regularly scheduled programming is often replaced with specials aimed at a wider audience (such as music specials aimed at the baby boomer generation, and financial, health and motivational programs) to solicit new members and donations; during fundraising events, these programs are often interrupted within the broadcast by long-form segments (of six to eight minutes in length) extolling viewers to donate to their PBS member. Underwriting spots are aired at the end of each program, which differ from traditional commercials in several ways. Each spot must be approved to meet several guidelines. The main guidelines state that underwriting spots cannot be qualitative in any way, nor can they have any call to action.
PBS provides an alternate path for WEA alerts to wireless carriers. The alerts are transmitted through the PBS satellite network on the AMC-21 satellite to PBS stations who broadcast the messages over their transmitters for reception by wireless carriers at their cell sites.
The network is funded by a grant through National Telecommunications and Information Administration (NTIA).