Process
Stations could choose to keep their initial digital TV channel allocation, do a flash-cut to their former analog TV channel, or attempt to select another channel, often an analog channel or pre-transition digital channel from another station that had been orphaned. Stations on channels 52 to 69 did not have the first option, as the FCC and then the U.S. Congress revoked them from the bandplan.
Many stations have chosen to keep their new channels permanently, after being forced to buy all new transmitters and television antennas. In some cases where the station's current analog tower could not handle the stress of the new digital antenna's weight and wind load, station owners had to construct entirely new broadcast towers in order to comply with the FCC's DTV mandate.
Most broadcasters were bitter at having to purchase digital equipment and broadcast a digital signal when very few homeowners had digital television sets. The FCC allowed broadcasters the opportunity to petition the Federal Communications Commission (FCC) for special temporary authority (STA) to operate their digital facilities at low power, thereby allowing broadcasters additional time in which to purchase their full-power digital facilities. However, the FCC gave a stern July 2006 deadline for all full-power television stations to at least replicate 80% of their current analog coverage area, or run the risk of losing protection from encroachment by other stations.
Most stations made an election in the first round, and most of those received their requested channels. Applicant conflicts with neighboring stations had to request a different channel in the second round. The third and final round occurred in May 2006.
Some stations requested that the FCC assign the best available channel.
Considerations
Aside from the practical considerations above, there are also technical considerations which are based on the physics of the radio spectrum. These affect the radio propagation of DTV just as with other signals.
The low VHF channels from 2 to 6, while requiring the lowest power (up to 100 kW analog video or 20 kW digital), are prone to electromagnetic interference. The ATSC digital TV system has severe problems with susceptibility to impulse noise, bursts of interference which briefly render the entire channel unusable, due to its inability to instantaneously determine where in a video frame to resume display when the signal returns. The result is macroblocking and pixelation of the entire signal whenever impulse noise sources (such as motors, appliances or electrical storms) are active. They also are the lowest in frequency and therefore the longest in wavelength, requiring the largest antennas both to transmit and receive. They are also prone to atmospheric ducting, especially at night when the ground (and the air near it) cools rapidly. Because of the antenna size (a properly-sized VHF TV 2 dipole spans approximately eight feet (2.7 meters)) and the fact that there are only five channels in this band, most set-top antennas are designed to receive the higher TV bands.
Furthermore, channel 6 abuts the FM broadcast band at 88 MHz, possibly causing and receiving interference from adjacent channels. (The FCC refused to remove this band from the bandplan, because taking the high UHF channels instead would bring in more money at auction. This also contradicts what has been done in every other country that has forced a DTV transition, all giving up the VHF bands.) A completely unaddressed issue is the use of HD Radio on 88.1 FM, where the lower sideband overlaps the far upper sideband of digital TV channel 6.
The upper VHF (band III), including channels 7 to 13, is better about the above problems, but still not as good as the UHF band. By keeping these for TV, it also prevents the use of the band for Digital Audio Broadcasting, as is done with local radio stations in Europe.
The UHF band contains 55 channels from 14 to 69, which excludes channel 37 in the U.S. Channels 52 to 69 are unavailable for digital TV, on a permanent basis, leaving only 37 channels. Stations generally try to choose a lower frequency, which causes some crowding and therefore election conflicts on the lowest channels. Still, the UHF band has great advantages over VHF, in large part because of its propagation characteristics and lack of impulse noise. The shorter wavelength also means that smaller antennas are needed, an advantage for both the broadcaster and the viewer. Another advantage is that the great majority of stations use this band, requiring only one type of antenna (and sometimes amplifier) to receive all of those stations. Key disadvantages of UHF operation include the need for greater transmitter power and the reduced coverage area; the edge diffraction of signals around terrestrial obstacles degrades rapidly as frequency is increased.
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).
8VSB is the modulation method used for broadcast in the ATSC digital television standard. ATSC and 8VSB modulation is used primarily in North America; in contrast, the DVB-T standard uses COFDM.
Terrestrial television is a type of television broadcasting in which the television signal is transmitted by radio waves from the terrestrial (Earth-based) transmitter of a television station to a TV receiver having an antenna. The term terrestrial is more common in Europe and Latin America, while in Canada and the United States it is called broadcast or over-the-air television (OTA). The term "terrestrial" is used to distinguish this type from the newer technologies of satellite television, in which the television signal is transmitted to the receiver from an overhead satellite; cable television, in which the signal is carried to the receiver through a cable; and Internet Protocol television, in which the signal is received over an Internet stream or on a network utilizing the Internet Protocol. Terrestrial television stations broadcast on television channels with frequencies between about 52 and 600 MHz in the VHF and UHF bands. Since radio waves in these bands travel by line of sight, reception is generally limited by the visual horizon to distances of 64–97 kilometres (40–60 mi), although under better conditions and with tropospheric ducting, signals can sometimes be received hundreds of kilometers distant.
Broadcast television systems are the encoding or formatting standards for the transmission and reception of terrestrial television signals.
Amateur television (ATV) is the transmission of broadcast quality video and audio over the wide range of frequencies of radio waves allocated for radio amateur (Ham) use. ATV is used for non-commercial experimentation, pleasure, and public service events. Ham TV stations were on the air in many cities before commercial television stations came on the air. Various transmission standards are used, these include the broadcast transmission standards of NTSC in North America and Japan, and PAL or SECAM elsewhere, utilizing the full refresh rates of those standards. ATV includes the study of building of such transmitters and receivers, and the study of radio propagation of signals travelling between transmitting and receiving stations.
The All-Channel Receiver Act of 1962 (ACRA), commonly known as the All-Channels Act, was passed by the United States Congress in 1961, to allow the Federal Communications Commission to require that all television set manufacturers must include UHF tuners, so that new UHF-band TV stations could be received by the public. This was a problem at the time since most affiliated stations of the Big Three television networks were well-established on VHF, while many local-only stations on UHF were struggling for survival.
WMVS, virtual channel 10, is a Public Broadcasting Service (PBS) member television station licensed to Milwaukee, Wisconsin, United States. Owned by Milwaukee Area Technical College, it is a sister station to fellow PBS member WMVT. Collectively branded as Milwaukee PBS, the two stations share studios at the Continuing Education Center on the MATC campus on North 8th Street in downtown Milwaukee, and transmitter facilities on North Humboldt Boulevard in Milwaukee's Estabrook Park neighborhood.
A television antenna is an antenna specifically designed for use with a television receiver (TV) to receive over-the-air broadcast television signals from a television station. Television reception is dependent upon the antenna as well as the transmitter. Terrestrial television is broadcast on frequencies from about 47 to 250 MHz in the very high frequency (VHF) band, and 470 to 960 MHz in the ultra high frequency (UHF) band in different countries. Television antennas are manufactured in two different types: "indoor" antennas, to be located on top of or next to the television set, and "outdoor" antennas, mounted on a mast on top of the owner's house. They can also be mounted in a loft or attic, where the dry conditions and increased elevation are advantageous for reception and antenna longevity. Outdoor antennas are more expensive and difficult to install, but are necessary for adequate reception in fringe areas far from television stations. The most common types of indoor antennas are the dipole and loop antennas, and for outdoor antennas the yagi, log periodic, and for UHF channels the multi-bay reflective array antenna.
An ATSCtuner, often called an ATSC receiver or HDTV tuner, is a type of television tuner that allows reception of digital television (DTV) television channels that use ATSC standards, as transmitted by television stations in North America, parts of Central America, and South Korea. Such tuners are usually integrated into a television set, VCR, digital video recorder (DVR), or set-top box which provides audio/video output connectors of various types.
WHNE-LD, virtual and VHF digital channel 3, is a low-powered television station licensed to Detroit, Michigan, United States. The station is owned by Tait Broadcasting. The station's transmitter and studio offices are located in Oak Park, Michigan.
WSPX-TV, virtual channel 56, is an Ion Television owned-and-operated station licensed to Syracuse, New York, United States. The station is owned by the Ion Media subsidiary of the E. W. Scripps Company. WSPX-TV's studios are located on Basile Rowe in East Syracuse, and its transmitter is located on Sevier Road in Pompey, New York.
Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and UHF bands - Stockholm, 1961". Band I ranges from 47 to 68 MHz for the European Broadcasting Area, and from 54 to 88 MHz for the Americas and it is primarily used for television broadcasting in compliance with ITU Radio Regulations. With the transition to digital TV, most Band I transmitters have already been switched off.
In the United States, digital television broadcasts, or DTV, can be received via cable, via internet, via satellite, or via digital terrestrial television — much like analog television broadcasts have been. Full-power analog television broadcasts, however, were required by U.S. federal law to cease by June 12, 2009. Low-power and TV Translator stations were required to cease analog broadcasts on July 13, 2021, with Class A analog stations signing off on September 1, 2015. Also by law, digital broadcasts — when transmitted as over-the-air signals — must conform to ATSC standards. It is unclear whether satellite operators are free to use their own proprietary standards; and many standards exist for Internet television.
Analog passthrough is a feature found on some digital-to-analog television converter boxes. Boxes without analog passthrough only allow digital TV to be viewed on older, analog-only TVs. Those with analog passthrough allow both digital and analog television to be viewed on older TVs.
The digital transition in the United States is the switchover from analog to exclusively digital broadcasting of terrestrial television programming. According to David Rehr, then president and CEO of the National Association of Broadcasters, this transition represented "the most significant advancement of television technology since color TV was introduced." For full-power TV stations, the transition went into effect on June 12, 2009, with stations ending regular programming on their analog signals no later than 11:59 p.m. local time that day.
In North American digital terrestrial television broadcasting, a distributed transmission system is a form of single-frequency network in which a single broadcast signal is fed via microwave, landline, or communications satellite to multiple synchronised terrestrial radio transmitter sites. The signal is then simultaneously broadcast on the same frequency in different overlapping portions of the same coverage area, effectively combining many small transmitters to generate a broadcast area rivalling that of one large transmitter or to fill gaps in coverage due to terrain or localised obstacles.
This is a list of low-powered television stations (LPTV) in the United States transmitting on VHF channel 6 and operating as radio stations capable of being picked up by standard FM receivers. These stations are colloquially known as "Franken-FMs", a reference to Frankenstein's monster, because TV stations functioning as radio stations had not been envisioned by the Federal Communications Commission (FCC).
TV radio, TV band radio, and TV audio radio are common names for a type of radio receiver that can play the audio portion of a TV channel. The actual name of the device may comprise a list of all frequency bands the device can receive, one or two of which includes the TV channel bands.
UHF television broadcasting is the use of ultra high frequency (UHF) radio for over-the-air transmission of television signals. UHF frequencies are used for both analog and digital television broadcasts. UHF channels are typically given higher channel numbers, like the US arrangement with VHF channels (initially) 1 to 13, and UHF channels (initially) numbered 14 to 83. Compared with an equivalent VHF television transmitter, to cover the same geographic area with a UHF transmitter requires a higher effective radiated power, implying a more powerful transmitter or a more complex antenna. However, the additional channels allow more broadcasters in a given region without causing objectionable mutual interference.
The Pan-American television frequencies are different for terrestrial and cable television systems. Terrestrial television channels are divided into two bands: the VHF band which comprises channels 2 through 13 and occupies frequencies between 54 through 216 MHz, and the UHF band, which comprises channels 14 through 36 and occupies frequencies between 470 and 700 MHz. These bands are different enough in frequency that they often require separate antennas to receive, and separate tuning controls on the television set. The VHF band is further divided into two frequency ranges: VHF low band between 54 and 88 MHz, containing channels 2 through 6, and VHF high band between 174 and 216 MHz, containing channels 7 through 13. The wide spacing between these frequency bands is responsible for the complicated design of rooftop TV antennas. The UHF band has higher noise and greater attenuation, so higher gain antennas are often required for UHF.
