American Television Stations
Television started in the United States long before it became commonplace anywhere else. A lot of people were involved in developing various pieces of it. Vladimir Zworykin invented the picture tube; Philo Farnsworth started the Philco brand of radios, and later television.
Television stations in the United States were started as experimental stations operated by private companies. The first highly-publicised demonstration was NBC's "WNBT Channel 1" at the 1939 World Exhibition in NYC, but experiments largely stopped when World War II intervened. It's not just that strategic metals were in short supply and many of the men involved busy in foxholes and tanks trying to win the war; anyone both clever enough to build a television and tight-lipped enough not to tell the Germans what they were up to was busily experimenting with radar.
After the war ended, television in the United States more-or-less took off. About a hundred television stations were on the air on a dozen possible VHF TV channels by 1948. With the discovery that they could sell commercials - the first one was a film showing a Bulova watch during a sports game - there was a realization that money could be made in this way. (Well, not a lot of money at first; Bulova paid only $7 to run its ad, but it was a start.)
Originally, television stations operated on Channels 1 through 13 (VHF). A few VHF channels above 13 were lost to the military during the war; Motorola got the rarely-used Channel 1 reassigned to two-way land-mobile radio by 1948, leaving just twelve channels. By 1948, stations were interfering with each other and it was becoming harder to find free space for new channels. The Federal Communications Commission [FCC] issued a freeze on further licenses for television stations.
By late 1952, the FCC had opened the UHF television band, adding TV channels 14 through 83. They also set up an allocation system: Each community in the United States was assigned a series of channel allocations, generally designed to prevent stations from interfering with each other, usually with 150 miles distance between two co-channel stations (Chicago shares the same channels as Wausau, Wisconsin, for instance). To prevent interference with radio astronomy on 611 MHz, Channel 37 was reserved in the 1960s and remains unused today.
In analogue over-the-air television, a UHF frequency represented a massive disadvantage in the early years; UHF stations were routinely spaced at least six channels apart due to the poor quality of the early tuners, and stations which had the least-desirable spots at the top of the dial would often attempt to swap allocations with a broadcaster who'd gone broke or who hadn't built their facilities yet. For instance, a UHF 74 station on a Massachusetts mountaintop somewhere might swap with other broadcasters until they landed on the slightly more desirable UHF 19.
Assignments in the Channel 70-83 range were rare, except for tiny repeater stations ("translators") which merely rebroadcast some other station into an area where obstacles blocked the main signal. By the mid-1980s, the FCC dropped TV channels 70-83 to release the frequencies for mobile cellular telephones, so the highest channel that could be assigned was 69. With the creation in the late 1990s of digital television, and the 2008 conversion of analog broadcast television to digital, more high-UHF channels were reassigned and lost to mobile services, with the UHF TV band ending at Channel 51. Channel 55 was bought by Qualcomm for their Flo TV mobile television service nationwide, a service that flopped for multiple reasons (including equipment costs and a monotonous schedule); Channel 55 was then sold to AT&T to expand their 4G footprint. A subsequent repack in 2019-21 left pretty much nothing above UHF 36, although the original channel numbers do still appear in the individual station branding and the virtual subchannel numbering. WCBS-TV still has an eyeball and a large number '2' in the logo, even if (2.1 CBS-HD) is actually now on UHF.
During the analog TV era, the prevention of co-channel and adjacent-channel interference from other stations was one of the FCC's top priorities. On the VHF band, no two stations could be assigned next to each other, so there would never, for example, be a Channel 9 and Channel 10 in the same area. (The minimum separation distance was 60 miles.) There are some exceptions: Because of a 4 megahertz distance between their frequencies, a Channel 4 and Channel 5 can be in the same area (e.g., the Twin Cities). There was a huge gap between 6 and 7, and an even larger gap between 13 and 14. Also, Channel 6 is directly below the FM band, so almost any FM radio could pick up the audio of analogue Channel 6 on 87.75 MHz FM.
Generally speaking, in the UHF band at least six channels separated stations located within 20 miles of each other. There were rare exceptions to this rule. For instance, in Sacramento, Channel 31 had been on the air since 1974 with its transmitter located with the rest of the city's TV transmitters about halfway between Sacramento and Stockton to the south. In the late 1980s, the FCC assigned Channel 29 to Sacramento with the proviso that the new station's transmitter could only be located about 15 miles north of the city. However, with the advent of digital TV, which has fewer problems with co-channel and adjacent-channel interference, Channel 29 has since relocated its transmitter near the rest of the Sacramento transmitters.
UHF stations are also allowed to use much higher power output than VHF. In the analog era, this was 5000 kilowatts compared to 100 kilowatts for Channels 2-6 and 316 kilowatts for channels 7-13. However in the digital age, channels 2-6 are undesirable for transmissions due to the signal's fragility in the face of impulse noise from motors and appliances. They have been rarely assigned for digital television outside wide flat areas (such as the NBC affiliate in Las Vegas).
This also made for some strange channel configurations. Channel 3 is used mostly in cities that live in the shadow of other larger cities—like Philadelphia to New York, or Sacramento to San Francisco—or in fairly remote areas. The nearest Channel 3 for Southern California is over 100 miles away in Santa Barbara. Los Angeles was allocated 2, 4, 5, 7, 9, 11 and 13. San Diego was allocated Channels 8 and 10, but as a sop to the Mexicans, Tijuana was allowed to have Channels 6 and 12. Away from the Mexican border? Spanish-language channels (like Univisión and its predecessor, the Spanish International Network) were usually UHF.
The addition of the UHF band allowed for the addition of something else: Educational Television. This originally began in the mid-1960s with the National Educational Television network, which was privately operated but had government grants to help with some of the operating costs. Also, educational stations are not permitted to run commercials, so most of them were started by local governments who used them to run programs to their local schools. In some of the larger cities (Los Angeles, New York City, Washington DC) educational television stations were licensed by private non-profit groups. Some stations are run by colleges.
Unlike the choices made by other nations, the U.S. government never got into the broadcast business for domestic consumption. All U.S. broadcast stations, radio and television, are privately owned. Some stations were operated by municipal governments for educational television services, but in general, in the United States, private for-profit companies operate television stations. This is the reason why most countries have fewer than 10 broadcast television stations, and the United States has over 7,000.
Same thing for broadcast networks. There are no federal networks; all broadcast networks, radio and television, are operated by private organizations. Even the educational networks are operated privately, although they do receive some public funding.
Until around the 1980s, the maximum number of television stations that could be owned by an organization was limited to seven, of which a maximum of five could be VHF stations. This rule was later changed to limit stations by amount of coverage of the country rather than absolute number. Also, during the 1970s a rule was created that prohibited a major newspaper from owning a television station in its home market. (Many television stations were owned by the local newspaper, one example being WTMJ Channel 4, the NBC affiliate in Milwaukee, was, and still is, owned by the Milwaukee Journal-Sentinel.) Many newspapers solved this problem by making trades with other newspapers in other cities to own a station outside their home area.
There is, however, an exception to the seven-station rule for educational television networks which are operating on a state-wide basis, they can run as many stations in the state as they can find the funding for. Yes, I did say "find funding". With the exception of a small amount of money from the federally funded Corporation for Public Broadcasting, educational stations have to find ways to raise money on their own; they generally do not get public subsidies. Since educational stations can't show commercials, most educational television stations have "pledge weeks" where, instead of running commercial breaks, they have people come on and beg viewers to call in and subscribe to the station, usually asking for about $10 a year or so, with the amount rising with inflation, and as of 2010, the usual request is for about $30. Many stations offer premium gifts such as boxed sets of various programs, book tie ins, and other special offers in exchange for larger donations of $150 to $365 a year, along with the omnipresent (and often mocked) tote bag.
The above seven-station rule (for commercial stations) meant that even the networks could only own seven stations around the country. Typically they owned the three major markets (LA, Chicago and New York), but beyond that the locations differed. Currently, the four major networks own stations in the following markets:
- ABC: New York (WABC), Los Angeles (KABC), Chicago (WLS), Philadelphia (WPVI), San Francisco (KGO), Houston (KTRK), Durham-Raleigh (WTVD), Fresno (KFSN);
- CBS: New York (WCBS), Los Angeles (KCBS), Chicago (WBBM), Philadelphia (KYW), Fort Worth-Dallas (KTVT), San Francisco (KPIX), Boston (WBZ), Detroit (WWJ), Minneapolis-St. Paul (WCCO/KCCO/KCCW), Miami-Fort Lauderdale (WFOR), Denver (KCNC), Sacramento (KOVR), Pittsburgh (KDKA), Baltimore (WJZ);
- FOX: New York (WNYW), Los Angeles (KTTV), Chicago (WFLD), Philadelphia (WTXF), Dallas-Fort Worth (KDFW), Boston (WFXT), Atlanta (WAGA), Washington DC (WTTG), Houston (KRIV), Detroit (WJBK), Phoenix (KSAZ), Tampa-St. Petersburg (WTVT), Minneapolis-St. Paul (KMSP), Orlando (WOFL), Memphis (WHBQ), Austin (KTBC), Ocala-Gainesville (WOGX);
- NBC: New York (WNBC), Los Angeles (KNBC), Chicago (WMAQ), Philadelphia (WCAU), Fort Worth-Dallas (KXAS), San Jose-San Francisco (KNTV), Washington (WRC), Miami-Fort Lauderdale (WTVJ), San Diego (KNSD), New Britain-Hartford-New Haven (WVIT).
Another major change in the 1990s and beyond is that the FCC now allows duopolies, where one company can own two stations in the same market. Originally, this was allowed only if the second station was at risk of failing, but in recent years, it's become pretty easy to get an FCC waiver under just about any circumstances except for ownership of two full-power affiliates which both carry one of the top-four networks in the same market. FOX owns MyNetworkTV O&Os in many of its major markets, and CBS owns five CW stations in markets  where it also owns its station; the other three CW O&Os  are not paired up with CBS stations. A number of other companies, including Sinclair and Raycom, own legal duopolies, and semi-legal ones (where they own a holding company that owns the second station in the market). Cunningham Broadcasting, for instance, is a de-facto Sock Puppet as its holdings consist pretty much entirely of stations which Sinclair cannot own directly; Cunningham pays Sinclair to run these stations, circumventing the ownership limits. Both Sinclair and Cunningham are controlled by members of the same family. Low power TV stations also have long been exempt from the ownership caps, largely because of their historic use as repeaters or rebroadcasters to fill geographic gaps in the main station's signal. The restrictions can also be circumvented by using digital compression to carry two network feeds on different subchannels of the same station; for instance, KXGN-DT 5 holds a stranglehold monopoly on Glendive, Montana – the 210th largest metropolis in America (out of 210) – and carries both CBS and NBC (channel 5.1 and 5.2 respectively, as subchannels on the same station). A claim of "economic hardship" can sometimes be used to justify multiple full-power stations with the same content in the same wide, rural market (so KVRR in Fargo, North Dakota is duplicated on KJRR Jamestown, KNRR Pembina and KBRR Thief River Falls, Minnesota; all at full-power). Educational stations are prone to use these full-power "satellite stations" as they were on UHF in an era when analogue TV could cover "up to" 100 miles VHF, 60 miles UHF if received on huge rooftop antennas. The smaller coverage area required more stations to do the same job.
Until the 1970s, most stations only operated from about 5 a.m. until about midnight or 1 a.m. While television stations were always licensed to operate 24/7, most did not. See ANSI Standard Broadcast TV Schedule for more details. This changed when the FCC changed the rules on commercials.
Until the 1980s, a television station was restricted to 21 minutes of commercials per hour. In fact, they were required to list every time that they exceeded 21 minutes at any time. However, when this rule was in place, it typically was a technical error; e.g., a station at one time might have accidentally run 21:10 of advertising.
This rule limiting advertising to 21 minutes in any hour was eliminated in the 1980s. This then allowed the stations to sell time during what would normally be off-air time to producers of infomercials. So stations that don't have enough material to fill the late-night time can sell the otherwise off-air time to infomercial producers.
At the very least, they do have to provide three hours of Edutainment Shows a week to serve their younger viewing audience with educational and informational content as a condition of their license. Most stations take this as a chore however (since nobody wants to advertise on them anymore because parents think that Lunchables will kill our children) and instead of actual enlightening programming, air either three hours of animal shows deep on Sundays when nobody is watching, quiz shows that think their audience has the intelligence of tree moss or, for the stations that really don't care but the FCC thinks they do, Saved by the Bell. Networks have sold their children's blocks off to other companies which actually produced true educational programming or somehow are able pass off that Hannah Montana has lessons about friendship and the music industry.
Which brings up another thing: any person can visit a television (or radio) station by asking to see the documents called its "public inspection file". Since television stations are privately licensed, the licensee is supposed to show that his license to operate a station is in "the public interest, convenience and necessity". So they keep files of all the comments they get, public and negative, as well as information about what good stuff they do, in hopes that their license will be renewed. In reality, a station is about as likely to have its license renewed as a single candidate in a dictatorship is likely to be re-elected. It basically takes either serious corruption by the licensee (like RKO General's various practices through the 1960s and 1970s), incredible technical incompetence (the CW affiliate in Evansville, Indiana lost their license for taking forever to build their digital transmitter and for their owners being in a deep financial mess with syndicators to the point where their spotlight program is the long-canceled Judge Hatchett; they still broadcast over a network of low-power translators), taking too long to file paperwork (this is the most common reason for license denials, though it's mainly among rural stations or a station where the owner treats it more like a fun hobby than Serious Business), or some other misconduct (in the case of a station in Mississippi during the Civil Rights Movement, complete denial of any airtime to African-Americans both locally and through NBC-transmitted programming) before it would not be re-licensed.
- The fact they could not was a plot point in the 80s-era film UHF
- Philadelphia, San Francisco, Detroit, Sacramento and Pittsburgh
- in Atlanta, Seattle and St. Petersburg/Tampa
- The story of Lamar Broadcasting and WLBT 3 Jackson, Mississippi as the only station to permanently lose an FCC-issued licence under the Fairness Doctrine could fill a broadcast textbook or two; The Other Wiki has a brief overview. Censoring NBC network news with repeated We Are Experiencing Technical Difficulties at the slightest mention of the Civil Rights Movement was likely the last straw.