A broadcast auxiliary service or BAS is any

radio frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the uppe ...

system used by a

radio station Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radi ...

TV station A television station is a set of equipment managed by a business, organisation or other entity, such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth ...

, which is not part of its direct

broadcast Broadcasting is the distribution (business), distribution of sound, audio or video content to a dispersed audience via any electronic medium (communication), mass communications medium, but typically one using the electromagnetic spectrum (radio ...

to listeners or viewers. These are essentially internal-use backhaul channels not intended for actual

reception Reception is a noun form of ''receiving'', or ''to receive'' something, such as art, experience, information, people, products, or vehicles. It may refer to: Astrology * Reception (astrology), when a planet is located in a sign ruled by another p ...

by the public, but part of the

airchain In broadcast engineering for radio or television, the airchain or transmission chain (UK) (sometimes air chain (US) or just chain (UK)) is the path or route an audio or video signal takes on its way through a radio station or television station. ...

required to get those signals back to the broadcast studio from the field. usually to be integrated into a live production. Examples include: *

studio/transmitter link A studio transmitter link (or STL) sends a radio station's or television station's audio and video from the broadcast studio or origination facility to a radio transmitter, television transmitter or uplink facility in another location. This is ac ...

(STL) * transmitter/studio link (TSL) *

remote pickup unit A remote pickup unit or RPU is a radio system using special radio frequencies set aside for electronic news-gathering (ENG) and remote broadcasting. It can also be used for other types of point-to-point radio links. An RPU is used to send program ...

(RPU) *

electronic news gathering Electronic news-gathering (ENG) or electronic journalism (EJ) is usage of electronic video and audio technologies by reporters to gather and present news instead of using film cameras. The term was coined during the rise of videotape technol ...

(ENG) Several of these bands exist, but the most frequently used band is the 2 GHz

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequency, frequencies between 300 MHz and 300 GHz respectively. Different sources define different fre ...

BAS band for point-to-point transmission from mobile newsgathering units to mountaintop receivers. Seven 12-MHz wide channels exist in the band. In North America,

DVB-T DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Feb ...

, precisely the same modulation technique as European Broadcast, is used, using a constellation of

QPSK Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at ...

16QAM Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signal ...

, or

64QAM Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message sign ...

, enabling sufficient digital bandwidths at 6 MHz deviation for transmission of an

MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and fi ...

transport stream at 10 or more megabits per second, producing three "lower", "center", and "upper" overlapping 6 MHz channels within each 12 MHz channel. BAS-2018

2 GHz relocation

In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

between 2005 and 2010, the

Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisd ...

(FCC) moved

TV channel A television channel is a terrestrial frequency or virtual number over which a television station or television network is distributed. For example, in North America, "channel 2" refers to the terrestrial or cable band of 54 to 60 MHz, wit ...

s in the 2 GHz TV BAS band at the request of

Sprint Nextel Sprint Corporation was an American telecommunications company. Before it Merger of Sprint Corporation and T-Mobile US, merged with T-Mobile US on April 1, 2020, it was the fourth-largest mobile network operator in the United States, serving 54.3 ...

, so that it could use a portion which was adjacent to PCS frequencies it already uses. The

report and order In administrative law, rulemaking is the process that executive and independent agencies use to create, or ''promulgate'', regulations. In general, legislatures first set broad policy mandates by passing statutes, then agencies create more ...

resulting from this

rulemaking In administrative law, rulemaking is the process that executive and independent agencies use to create, or ''promulgate'', regulations. In general, legislatures first set broad policy mandates by passing statutes, then agencies create more de ...

specified that Sprint/Nextel must pay for every TV station using the band to buy and install new BAS equipment to work in the new band structure. Previously, there had been seven

analog TV Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...

channels, each 17 or 18 MHz wide, between 1990 and 2110 MHz. The new allocation created seven

digital TV Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advanc ...

channels, each 12 MHz wide, from 2025.5 to 2109.5 MHz. (There was also a "narrowed in place"

bandplan A frequency plan, bandplan, band plan or wavelength plan is a plan for using a particular band of radio frequencies, that are a portion of the electromagnetic spectrum. Each frequency plan defines the frequency range to be included, how channels ...

used as an interim measure, as the two bands overlap.)
Begun in 2005, the relocation was 94% complete as of October 2008, and was expected to be fully complete in mid 2009. After multiple extensions granted by the FCC, it was finally done in July 2010, with the completion of the

Anchorage Anchorage () is the largest city in the U.S. state of Alaska by population. With a population of 291,247 in 2020, it contains nearly 40% of the state's population. The Anchorage metropolitan area, which includes Anchorage and the neighboring ...

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...

TV market. The cleared band is now used for PCS,

AWS Amazon Web Services, Inc. (AWS) is a subsidiary of Amazon that provides on-demand cloud computing platforms and APIs to individuals, companies, and governments, on a metered pay-as-you-go basis. These cloud computing web services provide di ...

, and MSS services, including

mobile broadband Mobile broadband is the marketing term for Wireless broadband, wireless Internet access via mobile networks. Access to the network can be made through a portable modem, wireless modem, or a Tablet computer, tablet/smartphone (possibly Tetherin ...

External links

''Broadcast Engineering'' article on completion''TV Technology'' article on completion, with insider details
{{bcast-stub Broadcast engineering