In the broadcasting industry (especially in North America), a network affiliate (or affiliated station) is a local broadcaster which carries some or all of the television program or radio program line-up of a television or radio network, but is owned by a company other than the owner of the network. This distinguishes such a television station or radio station from an owned-and-operated station (O&O), which is owned by its parent network.
Notwithstanding this distinction, it is common in informal speech (even for networks or O&Os themselves) to refer to any station, O&O or otherwise, that carries a particular network's programming as an affiliate, or to refer to the status of carrying such programming in a given market as "affiliation".
 Network owned-and-operated stations
In the United States and Japan, respectively, Federal Communications Commission (FCC) and Ministry of Internal Affairs regulations limit the number of network-owned stations as a percentage of total market size. As such, networks tend to have O&Os only in the largest media markets (e.g. New York City and Los Angeles), and rely on affiliates to carry their programming in other markets. However, even the largest markets may have network affiliates in lieu of O&Os. For instance, Tribune Broadcasting's WPIX serves as the New York City affiliate for the CW Television Network, which does not have an O&O in that market. On the other hand, several other TV stations in the same market — WABC (ABC), WCBS (CBS), WNBC (NBC), WNJU (Telemundo), WNYW (Fox), WWOR-TV (MyNetworkTV), WPXN (ION), WXTV (Univision) and WFUT (TeleFutura) — are O&Os.
In Canada, the Canadian Radio-Television and Telecommunications Commission (CRTC) has significantly more lenient rules regarding media ownership. As such, most television stations, regardless of market size, are now O&Os of their respective networks, with only a few true affiliates remaining. The Canadian Broadcasting Corporation originally relied on a large number of privately owned affiliates to disseminate its radio and television programming. However, since the 1960s, most of the CBC Television affiliates have been replaced by network owned and operated stations or retransmitters. CBC Radio stations are now entirely O&O.
While network-owned stations will normally carry the full broadcast programming schedule of the originating network, an affiliate is independently owned and typically under no obligation to do so. Affiliated stations often buy supplementary programming from another source, such as a broadcast syndication service or another television network which does not have coverage in the station's broadcast area. Some affiliates may air such programs instead of those from their primary network affiliation; a common example of this was the popular Star Trek: The Next Generation (1987-1994).:124
 Member stations
A handful of networks, such as the US-based Public Broadcasting Service (PBS) public television and National Public Radio (NPR), have been founded on a principle which effectively reverses the commercial broadcasting owned-and-operated station model and is called a state network. Instead of television networks owning stations, the stations collectively own the network and brand themselves as "PBS member stations" instead of as affiliates or O&O's.
Individual stations such as WPBS and KPBS are not owned by the Public Broadcasting Service; most belong to local community non-profit groups, universities or local and state educators. The national PBS system is owned collectively by WPBS-DT, KPBS and hundreds of other similar broadcasters in communities nationwide. Individual member stations are free to carry large amounts of syndicated programming and many produce their own educational television content for distribution to other PBS member stations through services like American Public Television or NETA; likewise, most content on PBS's core National Programming Service is produced by various individual member stations such as WGBH, WNET and WETA.
These are not affiliate stations in that the ownership of the main network is not independent of ownership of the individual local stations.
The "member station" model had historically been used in Canada in the early days of privately owned networks CTV and TVA, but the original "one station, one vote" model has largely faltered as increasing numbers of stations are acquired by the same owners. In CTV's case, the owners of Toronto's CFTO-TV's systematic pattern of acquisition of CTV member stations ultimately allowed control over the network as a whole, turning former member stations into CTV O&O's.
 Dual affiliations
In some smaller markets in the United States, a station may even be simultaneously listed as an affiliate of two networks. A station which has a dual affiliation is typically expected to air all or most of both networks' core prime time schedules — although programming from a station's secondary affiliation normally airs outside of its usual network time slot, and some less popular programs may simply be left off a station's schedule. Dual affiliations are most commonly associated with the smaller American television networks, such as MyNetworkTV and The CW, which air fewer hours of prime time programming than the "Big Four" networks and can thus be more easily combined into a single schedule, although historically the "Big Four" have had some dual-affiliate stations in small markets as well.
Historically, the sole commercial station in a market would commonly take affiliations or secondary affiliations from most or all major national networks. As a local monopoly, a station could become a primary affiliate of one of the stronger networks, carrying most of that network's programming while remaining free to "cherry-pick" popular programming from any or all of the rival networks.
As US-marketed television receivers have been required to include factory-installed UHF tuners since 1964, the rapid expansion of broadcast television onto UHF channels in the 1970s and 1980s (along with increased deployment of cable and satellite television systems) has reduced the number of one-station markets, providing networks with a larger selection of stations as potential primary affiliates. A new station which could clear one network's full programming line-up better serves the network's interests than the former pattern of partial access afforded by mixing various secondary affiliations on the schedule of a single local analogue channel.
In 2009, after many years of decline, the era of secondary affiliations to multiple major networks (once common in communities where fewer stations existed than networks seeking carriage) finally came to an end at the smallest-market US station, KXGN-TV Glendive, Montana (CBS/NBC). The digital conversion allowed KXGN to carry CBS and NBC programming side-by-side, essentially becoming a primary affiliate of both networks.
In larger markets, multiple full-service channels may be operated by the same broadcaster using broadcast automation, either openly as twinstick operations or through the use of local marketing agreements and shared services agreements to operate a second station nominally owned by some other broadcaster. These may be supplemented by LPTV or repeater stations to allow more channels to be added without encountering federally imposed limits on concentration of media ownership. Often, the multiple commonly controlled stations will use the same news and local advertising sales but carry different network feeds.
Further, with the ability of digital television stations to offer a distinct programming stream on a digital subchannel, traditional dual affiliation arrangements in which programming from two networks is combined into a single schedule are becoming more rare. KEYC-TV is one such example, carrying CBS programming on its 12.1 subchannel and FOX on 12.2. KEYC's Watertown sister station WWNY-TV follows this same pattern (WWNY-DT 7: 7.1 CBS-HD, 7.2 Fox) but supplements this with a 15kW low-power HDTV station on the same transmitter tower under the control of the same owners using the same studios to provide a second HDTV channel for the Fox affiliate.
One notable exception to the survival of secondary affiliations are stations owned by West Virginia Media Holdings. WTRF-DT2 in Wheeling, West Virginia and WVNS-DT2 in Beckley, West Virginia both have Fox as their primary affiliation and MyNetworkTV as a secondary affiliation. Both are on the second digital subchannel of WTRF-TV and WVNS-TV, respectively, both of which are CBS affiliates on their main signal. In addition, WTRF has an ABC affiliate on WTRF-DT3, giving the station four different network affiliations between three subchannels.
In Canada, affiliated stations may acquire broadcast rights to programs from a network other than their primary affiliation, but as such an agreement pertains only to a few specific programs, chosen individually, they are not normally considered to be affiliated with the second network. Newfoundland's NTV (CJON 6 St. John's), nominally an independent, uses this model to acquire programming from the CTV and Global Television Network. CJNT-DT in Montreal is serving dual affiliation in both City and OMNI to satisfy its ethnic programming requirements due to its sale to Rogers Media in 2012. This model will be ceased as Rogers' has requested by the CRTC in late 2012 to change the station from a multicultural station to a conventional English-language station as they will produce 15.5 hours of local programming a week for CJNT (including a morning news program), and will contribute funding and programming to a new independent multicultural station in Montreal.
This was also done by MyNetworkTV in the 2009-10 season in the Des Moines and Memphis markets after those markets lost their individual stations to other networks as it offered the last broadcast season of WWE Friday Night Smackdown to the CW affiliates of both cities without forcing them to carry the remainder of the network's schedule.
 See also
- Harmetz, Aljean (1987-10-04). "Syndicated 'Star Trek' Puts Dent in Networks". The New York Times. Retrieved May 9, 2011.
- Pearson, Roberta (2011). "Cult Television as Digital Television's Cutting Edge". In Bennett, James; Strange, Niki. Television as Digital Media. Duke University Press. pp. 105–131. ISBN 0-8223-4910-8.
- About PBS - pbs.org
- Broadcasting-History.ca on CTV's historical (1966-1994) co-operative structure, with control by individually owned member stations
- Canadian Radio-television and Telecommunications Commission (2012-09-05). "Broadcasting Notice of Consultation CRTC 2012-475". Retrieved 2012-09-10.
- CRTC increases the diversity of voices in the Montreal market CRTC 2012-12-20