User:Stickguy/shared time

In broadcasting, shared time refers to a situation when several radio and television broadcasters share the same radio frequency or television channel. Each broadcaster is a distinct, although not necessarily independent, entity, however the distinction is not always necessarily apparent to viewers.

Radio
A shared frequency in radio is most common in the United States, with two or potentially more separate stations, each licensed by the Federal Communications Commission, often with separate studios and transmitters, operating on the same frequency at different times of day. This arrangement is extremely rare today.


 * In Chicago, three multilingual stations – WCRW, WEDC, and WSBC – operated at 1240 kHz from the 1920s to the late 1980s, when WSBC's owners bought out the other two stations.
 * In the Poughkeepsie, New York area, a campus radio station, WFNP, operates at 88.7 MHz only during the evening and overnight hours, and only during the school term. Classical station WRHV operates on that frequency the rest of the time.

Television
A shared channel on television may take several forms depending on the jurisdiction.

Restricted licence
When the first independent television (ITV) stations launched in the United Kingdom, operators in many larger regions were allocated rights to only weekday or weekend broadcasting. This restriction was eventually lifted everywhere except London, where Carlton Television and London Weekend Television remain nominally separate, however they are now owned by the same company and managed as a single "ITV London" unit.

In addition to this weekday/weekend split, a separate licence was issued for a national ITV breakfast television contractor, currently GMTV, which broadcasts nationwide from 6:00 to 9:25 a.m. daily.

A similar situation exists in France, where France 5's analog terrestrial broadcasts are restricted to the daytime hours; Arte broadcasts over the same facilities overnight. However, both channels are now available on a 24-hour basis through digital television.

Allocated time
In the Netherlands, several membership-based public broadcasting organizations jointly operate Netherlands Public Broadcasting (or NPO), which operates three television channels and seven radio networks. Although officially each channel is operated full-time by NPO, airtime is allocated among the member groups based on the number of members each group has.

North American cable television
From 1982 to 1985, the U.S. children's cable network Nickelodeon sold its satellite transponder rights during primetime hours (when children were unlikely to be watching TV) to an independently owned arts channel, known initially as ARTS and later as the Arts & Entertainment Network.

When A&E launched its own 24-hour service in 1985, Nickelodeon filled the evening hours with Nick at Nite, focusing on classic sitcoms. However, while likely perceived by most viewers as simply a programming block on Nickelodeon, Nick at Nite was officially a separate cable network, allowing it to appear separately in the Nielsen Ratings. This setup continues today, and has since been replicated by Cartoon Network and Adult Swim.

A version of this appeared in Canada for a time in the late 1990s, when The Movie Network launched several multiplex channels that operated only during the evening and overnight hours. Some cable companies were only able to fit these channels onto their lineups by combining them with other channels such as Treehouse TV and CNBC, which also operated during the evening hours but had limited viewership at those times. With the uptake of digital cable, this practice became redundant and was abandoned.

Other capacity issues
In areas using a multichannel digital terrestrial television system such as in the U.K., the number of channels available at any one time is often limited, and as a result many channels are only able to broadcast for a certain number of contracted hours per day (sometimes just one). However, each service appears on a separate virtual channel.

For example, a single DTT slot carries the CITV Channel (channel 75, 06:00 - 18:00), Tele G (channel 8 in Scotland only, 18:00 - 19:00), teleshopping channel Gems TV 1 (channel 44, 19:00 - 21:00), CNN (channel 84, 21:00 - 1:00), and premium service Top Up TV Anytime 2 (channel 39, 01:00 - 06:00).