Broadcasting

"Broadcast" redirects here. For other uses, seeBroadcast (disambiguation).

Broadcastingis thedistributionofaudioor video content to a dispersedaudiencevia any electronicmass communications medium,but typically one using theelectromagnetic spectrum(radio waves), in aone-to-manymodel.Broadcasting began withAM radio,which came into popular use around 1920 with the spread ofvacuum tuberadio transmittersandreceivers.Before this, most implementations of electronic communication (earlyradio,telephone,andtelegraph) wereone-to-one,with the message intended for a single recipient. The termbroadcastingevolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about.It was later adopted for describing the widespread distribution of information by printed materialsor by telegraph.Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.

A broadcasting antenna inStuttgart

Over-the-air broadcasting is usually associated withradioandtelevision,though more recently, both radio and television transmissions have begun to be distributed by cable (cable television). The receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology and equipment (e.g., a radio or television set) can receive the signal. The field of broadcasting includes both government-managed services such aspublic radio,community radioandpublic television,and privatecommercial radioandcommercial television.The U.S. Code of Federal Regulations, title 47, part 97 definesbroadcastingas "transmissions intended for reception by the general public, either direct or relayed".Private or two-waytelecommunicationstransmissions do not qualify under this definition. For example,amateur( "ham" ) andcitizens band(CB) radio operators are not allowed to broadcast. As defined,transmittingandbroadcastingare not the same.

Transmission of radio and television programs from a radio or television station to home receivers byradio wavesis referred to asover the air(OTA) orterrestrialbroadcasting and in most countries requires abroadcasting license.Transmissions using a wire or cable, likecable television(which also retransmits OTA stations with theirconsent), are also considered broadcasts but do not necessarily require a license (though in some countries, a license is required). In the 2000s, transmissions of television and radio programs viastreamingdigital technology have increasingly been referred to as broadcasting as well.

History

Main article:History of broadcasting

The earliest broadcasting consisted of sending telegraph signals over the airwaves, usingMorse code,a system developed in the 1830s bySamuel Morse,physicistJoseph HenryandAlfred Vail.They developed anelectrical telegraphsystem which sent pulses ofelectric currentalong wires which controlled anelectromagnetthat was located at the receiving end of the telegraph system. A code was needed to transmit natural language using only these pulses, and the silence between them. Morse therefore developed the forerunner to modernInternational Morse code.This was particularly important for ship-to-ship and ship-to-shore communication, but it became increasingly important for business and general news reporting, and as an arena for personal communication by radio amateurs.

In 1894, Italian inventorGuglielmo Marconibegan developing a wireless communication using the then-newly discovered phenomenon ofradio waves,showing by 1901 that they could be transmitted across the Atlantic Ocean.This was the start ofwireless telegraphyby radio. Audio radio broadcasting began experimentally in the first decade of the 20th century. On 17 December 1902, a transmission from the Marconi station inGlace Bay,Nova Scotia, Canada, became the world's first radio message to cross the Atlantic from North America. In 1904, a commercial service was established to transmit nightly news summaries to subscribing ships, which incorporated them into their onboard newspapers.

World War Iaccelerated the development of radio formilitary communications.After the war, commercial radioAM broadcastingbegan in the 1920s and became an important mass medium for entertainment and news.World War IIagain accelerated the development of radio for the wartime purposes of aircraft and land communication, radio navigation, and radar.Development of stereoFM broadcastingof radio began in the 1930s in the United States and the 1970s in the United Kingdom, displacing AM as the dominant commercial standard.

On 25 March 1925,John Logie Bairddemonstrated the transmission of moving pictures at the London department storeSelfridges.Baird's device relied upon theNipkow diskand thus became known as themechanical television.It formed the basis of experimental broadcasts done by theBritish Broadcasting Corporationbeginning on 30 September 1929.However, for most of the 20th century, televisions depended on thecathode ray tubeinvented byKarl Braun.The first version of such a television to show promise was produced byPhilo Farnsworthand demonstrated to his family on 7 September 1927.AfterWorld War II,interrupted experiments resumed and television became an important home entertainment broadcast medium, usingVHFandUHFspectrum.Satellite broadcastingwas initiated in the 1960s and moved into general industry usage in the 1970s, with DBS (Direct Broadcast Satellites) emerging in the 1980s.

Originally, all broadcasting was composed ofanalog signalsusinganalog transmissiontechniques but in the 2000s, broadcastersswitchedtodigital signalsusingdigital transmission.An analog signal is anycontinuous signalrepresenting some other quantity, i.e.,analogousto another quantity. For example, in an analogaudio signal,the instantaneous signalvoltagevaries continuously with thepressure of the sound waves.In contrast, adigital signalrepresents the original time-varying quantity as asampledsequence ofquantizedvalues which imposes somebandwidthanddynamic rangeconstraints on the representation. In general usage, broadcasting most frequently refers to the transmission of information and entertainment programming from various sources to the general public:

• Analog audioradio (AM, FM) vs.digital audio radio(HD radio),digital audio broadcasting(DAB),satellite radioanddigital Radio Mondiale(DRM)
• Analog televisionvs.digital television
• Wireless

The world's technological capacity to receive information through one-way broadcast networks more than quadrupled during the two decades from 1986 to 2007, from 432exabytesof (optimally compressed) information, to 1.9zettabytes.This is the information equivalent of 55 newspapers per person per day in 1986, and 175 newspapers per person per day by 2007.

Methods

In a broadcast system, the central high-poweredbroadcast towertransmits a high-frequencyelectromagnetic waveto numerous receivers. The high-frequency wave sent by the tower is modulated with a signal containing visual or audio information. The receiver is thentunedso as to pick up the high-frequency wave and ademodulatoris used to retrieve the signal containing the visual or audio information. The broadcast signal can be either analog (signal is varied continuously with respect to the information) or digital (information is encoded as a set of discrete values).

Historically, there have been several methods used for broadcastingelectronic mediaaudio and video to the general public:

• Telephonebroadcasting (1881–1932): the earliest form of electronic broadcasting (not counting data services offered by stocktelegraph companiesfrom 1867, ifticker-tapesare excluded from the definition). Telephone broadcasting began with the advent ofThéâtrophone( "Theatre Phone" ) systems, which were telephone-based distribution systems allowing subscribers to listen to liveoperaandtheatreperformances over telephone lines, created by French inventorClément Aderin 1881. Telephone broadcasting also grew to includetelephone newspaperservices for news and entertainmentprogrammingwhich were introduced in the 1890s, primarily located in largeEuropeancities. These telephone-basedsubscription serviceswere the first examples of electrical/electronic broadcasting and offered a wide variety of programming.
• Radio broadcasting(experimentally from 1906, commercially from 1920);audiosignals sent through the air asradio wavesfrom atransmitter,picked up by anantennaand sent to areceiver.Radio stationscan be linked inradio networksto broadcast commonradio programs,either inbroadcast syndication,simulcastorsubchannels.
  • Televisionbroadcasting (telecast), experimentally from 1925,commerciallyfrom the 1930s: an extension of radio to includevideosignals.
• Cable radio(also calledcable FM,from 1928) andcable television(from 1932): both viacoaxial cable,originally serving principally as transmission media for programming produced at either radio ortelevision stations,but later expanding into a broad universe of cable-originatedchannels.
• Direct-broadcast satellite(DBS) (fromc. 1974) andsatellite radio(fromc. 1990): meant for direct-to-home broadcast programming (as opposed to studio network uplinks and down-links), provides a mix of traditional radio or television broadcast programming, or both, with dedicated satellite radio programming. (See also:Satellite television)
• Webcastingof video/television (fromc. 1993) and audio/radio (fromc. 1994) streams: offers a mix of traditional radio and television station broadcast programming with dedicatedInternet radioandInternet television.

Economic models

There are several means of providing financial support for continuous broadcasting:

• Commercial broadcasting:for-profit, usually privately owned stations, channels, networks, or services providing programming to the public, supported by the sale of air time to advertisers forradioortelevision advertisementsduring or in breaks between programs, often in combination with cable orpay cablesubscription fees.
• Public broadcasting:usuallynon-profit,publicly owned stations or networks supported by license fees, government funds, grants from foundations, corporateunderwriting,audience memberships, contributions or a combination of these.
• Community broadcasting: a form ofmass mediain which atelevision station,or aradio station,is owned, operated orprogrammed,by a community group to provide programs of local interest known aslocal programming.Community stations are most commonly operated bynon-profit groupsorcooperatives;however, in some cases they may be operated by a localcollegeoruniversity,acable companyor a municipal government.
• Internet Webcast: the audience pays to recharge and buy virtual gifts for the anchor, and the platform converts the gifts into virtual currency. The anchor withdraws the virtual currency, which is drawn by the platform. If the anchor belongs to a trade union, it will be settled by the trade union and the live broadcasting platform, and the anchor will get the salary and part of the bonus. This is the most common profit model of live broadcast products.

Broadcasters may rely on a combination of thesebusiness models.For example, in the United States,National Public Radio(NPR) and thePublic Broadcasting Service(PBS, television) supplement public membership subscriptions and grants with funding from theCorporation for Public Broadcasting(CPB), which is allocated bi-annually by Congress. US public broadcasting corporate and charitable grants are generally given in consideration ofunderwriting spotswhich differ from commercial advertisements in that they are governed by specificFCCrestrictions, which prohibit the advocacy of a product or a "call to action".

Recorded and live forms

Atelevision studioproduction control roominOlympia, Washington,August 2008

An "On Air" sign is illuminated, usually in red, while a broadcast or recording session is taking place.

Radio Mariastudio inSwitzerland

The first regular television broadcasts started in 1937. Broadcasts can be classified asrecordedorlive.The former allows correcting errors, and removing superfluous or undesired material, rearranging it, applyingslow-motionand repetitions, and other techniques to enhance the program. However, some live events likesports televisioncan include some of the aspects including slow-motion clips of important goals/hits, etc., in between thelive televisiontelecast. American radio-network broadcasters habitually forbade prerecorded broadcasts in the 1930s and 1940s, requiring radio programs played for the Eastern and Centraltime zonesto be repeated three hours later for the Pacific time zone (See:Effects of time on North American broadcasting). This restriction was dropped for special occasions, as in the case of the GermandirigibleairshipHindenburgdisaster atLakehurst, New Jersey,in 1937. DuringWorld War II,prerecorded broadcasts from war correspondents were allowed on U.S. radio. In addition, American radio programs were recorded for playback byArmed Forces Radioradio stationsaround the world.

A disadvantage of recording first is that the public may learn the outcome of an event before the recording is broadcast, which may be aspoiler.Prerecording may be used to preventannouncersfrom deviating from an officially approvedscriptduring alive radiobroadcast, as occurred withpropagandabroadcasts from Germany in the 1940s and withRadio Moscowin the 1980s. Many events are advertised as being live, although they are often recorded live (sometimes called "live-to-tape"). This is particularly true of performances of musical artists on radio when they visit for an in-studioconcertperformance. Similar situations have occurred intelevision production( "The Cosby Showis recorded in front of alive televisionstudioaudience") andnews broadcasting.

A broadcast may be distributed through several physical means. If coming directly from theradio studioat a single station ortelevision station,it is sent through thestudio/transmitter linkto thetransmitterand hence from thetelevision antennalocated on theradio masts and towersout to the world. Programming may also come through acommunications satellite,played either live or recorded for later transmission. Networks of stations maysimulcastthe same programming at the same time, originally viamicrowavelink, now usually by satellite. Distribution to stations or networks may also be through physical media, such asmagnetic tape,compact disc(CD),DVD,and sometimes other formats. Usually these are included in another broadcast, such as whenelectronic news gathering(ENG) returns a story to the station for inclusion on anews programme.

The final leg of broadcast distribution is how the signal gets to the listener or viewer. It may come over the air as with aradio stationortelevision stationto anantennaandradio receiver,or may come throughcable televisionorcable radio(orwireless cable) via the station or directly from a network. TheInternetmay also bring eitherinternet radioorstreaming mediatelevision to the recipient, especially withmulticastingallowing the signal andbandwidthto be shared. The termbroadcast networkis often used to distinguish networks that broadcast over-the-air television signals that can be received using atunerinside atelevision setwith atelevision antennafrom so-called networks that are broadcast only viacable television(cablecast) orsatellite televisionthat uses adish antenna.The termbroadcast televisioncan refer to thetelevision programsof such networks.

Social impact

Radio stationWTULstudio,Tulane University,New Orleans

The sequencing of content in a broadcast is called aschedule.As with all technological endeavors, a number of technical terms andslanghave developed. A list of these terms can be found atList of broadcasting terms.Televisionandradioprograms are distributed through radio broadcasting orcable,often both simultaneously. By coding signals and having acable converter boxwithdecodingequipment inhomes,the latter also enablessubscription-based channels,pay-tvandpay-per-viewservices. In his essay,John Durham Peterswrote thatcommunicationis a tool used for dissemination. Peters stated, "Disseminationis a lens—sometimes a usefully distorting one—that helps us tackle basic issues such as interaction, presence, and space and time... on the agenda of any futurecommunication theoryin general ".Dissemination focuses on the message being relayed from one main source to one largeaudiencewithout the exchange ofdialoguein between. It is possible for the message to bechanged or corrupted by government officialsonce the main source releases it. There is no way to predetermine how the larger population or audience will absorb the message. They can choose to listen, analyze, or ignore it. Dissemination in communication is widely used in the world of broadcasting.

Broadcasting focuses on getting a message out and it is up to the general public to do what they wish with it. Peters also states that broadcasting is used to address an open-ended destination.There are many forms of broadcasting, but they all aim to distribute a signal that will reach the targetaudience.Broadcasters typically arrange audiences into entire assemblies.In terms of media broadcasting, aradio showcan gather a large number of followers who tune in every day to specifically listen to that specificdisc jockey.The disc jockey follows the script for his or her radio show and just talks into themicrophone.He or she does not expect immediate feedback from any listeners. The message is broadcast across airwaves throughout the community, but there the listeners cannot always respond immediately, especially since many radio shows are recorded prior to the actual air time. Conversely, receivers can select opt-in or opt-out of getting broadcast messages using an Excel file, offering them control over the information they receive

Broadcast engineering

Main article:Broadcast engineering

Broadcast engineering is the field ofelectrical engineering,and now to some extentcomputer engineeringandinformation technology,which deals withradioandtelevisionbroadcasting.Audio engineeringandRF engineeringare also essential parts of broadcast engineering, being their ownsubsetsof electrical engineering.

Broadcast engineering involves both thestudioandtransmitteraspects (the entireairchain), as well asremote broadcasts.Everystationhas a broadcastengineer,though one may now serve an entire station group in a city. In smallmedia marketsthe engineer may work on acontractbasis for one or more stations as needed.

See also

• Analog television
• Bandplan
• Broadcast engineering
• Broadcast quality
• Broadcast television systems– contains the standards of the topic
• Broadcasting in the United States
• Cablecast
• Frank Conrad
• Dead air
• Digital television
• Electronic media
• European Broadcasting Union(EBU)
• List of broadcast satellites
• List of broadcasting terms
• List of radio awards
• List of television awards
• Narrowcasting
• NaSTA
• Nonbroadcast Multiple Access Network(NBMA)
• North American broadcast television frequencies
• Outside broadcast
• Radio Act of 1927,United States
• Reality television
• Society of Broadcast Engineers(SBE)
• Television broadcasting in Australia
• Television transmitter
• Transposer
• Wilkinsburg

Bibliography

• Carey, James (1989),Communication as Culture,New York and London: Routledge, pp. 201–30
• Kahn, Frank J., ed.Documents of American Broadcasting,fourth edition (Prentice-Hall, Inc., 1984).
• Lichty Lawrence W., and Topping Malachi C., eds,American Broadcasting: A Source Book on the History of Radio and Television(Hastings House, 1975).
• Meyrowitz, Joshua,Mediating Communication: What Happens?in Downing, J., Mohammadi, A., and Sreberny-Mohammadi, A. (eds),Questioning The Media(Thousand Oaks, CA: Sage 1995), pp. 39–53
• Peters, John Durham (2006),"Communication as Dissemination",Communication as…: Perspectives on Theory,Teller Road, Thousand Oaks California United States: SAGE Publications, Inc., pp. 211–222,doi:10.4135/9781483329055.n23,ISBN978-1-4129-0658-6,archivedfrom the original on 22 August 2022,retrieved22 August2022
• Thompson, J.,The Media and Modernity,in Mackay, H., and O'Sullivan, T. (eds),The Media Reader: Continuity and Transformation(London: Sage, 1999), pp. 12–27

• International bibliography – History of wireless and radio broadcasting

Further reading

• Barnouw Erik.The Golden Web(Oxford University Press, 1968);The Sponsor(1978);A Tower in Babel(1966).
• Covert Cathy, and Stevens John L.Mass Media Between the Wars(Syracuse University Press, 1984).ISBN978-0-8156-2307-6
• Tim Crook;International Radio Journalism: History, Theory and PracticeRoutledge, 1998
• John Dunning;On the Air: The Encyclopedia of Old-Time RadioOxford University Press, 1998
• Ewbank Henry and Lawton Sherman P.Broadcasting: Radio and Television(Harper & Brothers, 1952).
• Maclaurin W. Rupert.Invention and Innovation in the Radio Industry(The Macmillan Company, 1949).
• Robert W. McChesney;Telecommunications, Mass Media, and Democracy: The Battle for the Control of U.S. Broadcasting, 1928–1935Oxford University Press, 1994
• Gwenyth L. Jackaway;Media at War: Radio's Challenge to the Newspapers, 1924–1939Praeger Publishers, 1995
• Lazarsfeld Paul F.The People Look at Radio(University of North Carolina Press, 1946).
• Schramm Wilbur, ed.Mass Communications(University of Illinois Press, 1960).
• Schwoch James.The American Radio Industry and Its Latin American Activities, 1900–1939(University of Illinois Press, 1990).ISBN978-0-252-01690-5
• Slater Robert.This... is CBS: A Chronicle of 60 Years(Prentice Hall, 1988).ISBN978-0-13-919234-0
• Sterling Christopher H.Electronic Media, A Guide to Trends in Broadcasting and Newer Technologies 1920–1983(Praeger, 1984).ISBN978-0-275-91277-2
• Sterling Christopher, and Kittross John M.Stay Tuned: A Concise History of American Broadcasting(Wadsworth, 1978).
• Wells, Alan,World Broadcasting: A Comparative View,Greenwood Publishing Group,1996.ISBN1-56750-245-8

External links

• Radio Locator,for American radio station with format, power, and coverage information.
• Jim Hawkins' Radio and Broadcast Technology Page– History of broadcast transmitter
• Indie Digital Cinema Services– Broadcast Industry Glossary