Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables , or in more recent systems, light pulses through fibre-optic cables . This contrasts with broadcast television , in which the television signal is transmitted over-the-air by radio waves and received by a television antenna , or satellite television , in which the television signal is transmitted over-the-air by radio waves from a communications satellite and received by a satellite dish on the roof. FM radio programming, high-speed Internet , telephone services , and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation.
76-488: The Ridge Hill transmitting station is a broadcasting and telecommunications facility located 8.5 miles SE of Hereford in Herefordshire , and close to the border of Gloucestershire . The station transmits the full complement of digital terrestrial multiplexes and an additional ITV West Multiplex. It includes a cable stayed steel lattice mast which has a height of 164.6 metres (540 ft), which in addition to
152-424: A cable converter box with decoding equipment in homes , the latter also enables subscription -based channels, pay-tv and pay-per-view services. In his essay, John Durham Peters wrote that communication is a tool used for dissemination. Peters stated, " Dissemination is a lens—sometimes a usefully distorting one—that helps us tackle basic issues such as interaction, presence, and space and time ... on
228-482: A dish antenna . The term broadcast television can refer to the television programs of such networks. The sequencing of content in a broadcast is called a schedule . As with all technological endeavors, a number of technical terms and slang have developed. A list of these terms can be found at List of broadcasting terms . Television and radio programs are distributed through radio broadcasting or cable , often both simultaneously. By coding signals and having
304-405: A dedicated analog circuit-switched service. Other advantages include better voice quality and integration to a Voice over Internet Protocol (VoIP) network providing cheap or unlimited nationwide and international calling. In many cases, digital cable telephone service is separate from cable modem service being offered by many cable companies and does not rely on Internet Protocol (IP) traffic or
380-543: A high elevation. At the outset, cable systems only served smaller communities without television stations of their own, and which could not easily receive signals from stations in cities because of distance or hilly terrain. In Canada, however, communities with their own signals were fertile cable markets, as viewers wanted to receive American signals. Rarely, as in the college town of Alfred, New York , U.S. cable systems retransmitted Canadian channels. Although early ( VHF ) television receivers could receive 12 channels (2–13),
456-466: A higher rate. At the local headend, the feed signals from the individual television channels are received by dish antennas from communication satellites . Additional local channels, such as local broadcast television stations, educational channels from local colleges, and community access channels devoted to local governments ( PEG channels) are usually included on the cable service. Commercial advertisements for local business are also inserted in
532-405: A local VHF television station broadcast. Local broadcast channels were not usable for signals deemed to be a priority, but technology allowed low-priority signals to be placed on such channels by synchronizing their blanking intervals . TVs were unable to reconcile these blanking intervals and the slight changes due to travel through a medium, causing ghosting . The bandwidth of the amplifiers also
608-463: A microwave-based system, may be used instead. Coaxial cables are capable of bi-directional carriage of signals as well as the transmission of large amounts of data . Cable television signals use only a portion of the bandwidth available over coaxial lines. This leaves plenty of space available for other digital services such as cable internet , cable telephony and wireless services, using both unlicensed and licensed spectra. Broadband internet access
684-564: A rarity, found in an ever-dwindling number of markets. Analog television sets are accommodated, their tuners mostly obsolete and dependent entirely on the set-top box. Cable television is mostly available in North America , Europe , Australia , Asia and South America . Cable television has had little success in Africa , as it is not cost-effective to lay cables in sparsely populated areas. Multichannel multipoint distribution service ,
760-455: A receiver box. The cable company will provide set-top boxes based on the level of service a customer purchases, from basic set-top boxes with a standard-definition picture connected through the standard coaxial connection on the TV, to high-definition wireless digital video recorder (DVR) receivers connected via HDMI or component . Older analog television sets are cable ready and can receive
836-766: A series of signal amplifiers and line extenders. These devices carry the signal to customers via passive RF devices called taps. The very first cable networks were operated locally, notably in 1936 by Rediffusion in London in the United Kingdom and the same year in Berlin in Germany, notably for the Olympic Games , and from 1948 onwards in the United States and Switzerland. This type of local cable network
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#1732782436683912-442: A signal that will reach the target audience . Broadcasters typically arrange audiences into entire assemblies. In terms of media broadcasting, a radio show can gather a large number of followers who tune in every day to specifically listen to that specific disc jockey . The disc jockey follows the script for their radio show and just talks into the microphone . They do not expect immediate feedback from any listeners. The message
988-722: A single station or television station , it is sent through the studio/transmitter link to the transmitter and hence from the television antenna located on the radio masts and towers out to the world. Programming may also come through a communications satellite , played either live or recorded for later transmission. Networks of stations may simulcast the same programming at the same time, originally via microwave link, now usually by satellite. Distribution to stations or networks may also be through physical media, such as magnetic tape , compact disc (CD), DVD , and sometimes other formats. Usually these are included in another broadcast, such as when electronic news gathering (ENG) returns
1064-417: A special telephone interface at the customer's premises that converts the analog signals from the customer's in-home wiring into a digital signal, which is then sent on the local loop (replacing the analog last mile , or plain old telephone service (POTS) to the company's switching center, where it is connected to the public switched telephone network ( PSTN ). The biggest obstacle to cable telephone service
1140-476: A story to the station for inclusion on a news 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 a radio station or television station to an antenna and radio receiver , or may come through cable television or cable radio (or wireless cable ) via the station or directly from a network. The Internet may also bring either internet radio or streaming media television to
1216-581: A wireless communication using the then-newly discovered phenomenon of radio waves , showing by 1901 that they could be transmitted across the Atlantic Ocean. This was the start of wireless telegraphy by radio. Audio radio broadcasting began experimentally in the first decade of the 20th century. On 17 December 1902, a transmission from the Marconi station in Glace Bay , Nova Scotia, Canada, became
1292-422: Is achieved over coaxial cable by using cable modems to convert the network data into a type of digital signal that can be transferred over coaxial cable. One problem with some cable systems is the older amplifiers placed along the cable routes are unidirectional thus in order to allow for uploading of data the customer would need to use an analog telephone modem to provide for the upstream connection. This limited
1368-726: Is broadcast across airwaves throughout the community, but 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 is the field of electrical engineering , and now to some extent computer engineering and information technology , which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential parts of broadcast engineering, being their own subsets of electrical engineering. Broadcast engineering involves both
1444-401: Is particularly true of performances of musical artists on radio when they visit for an in-studio concert performance. Similar situations have occurred in television production (" The Cosby Show is recorded in front of a live television studio audience ") and news broadcasting . A broadcast may be distributed through several physical means. If coming directly from the radio studio at
1520-593: Is referred to as over the air (OTA) or terrestrial broadcasting and in most countries requires a broadcasting license . Transmissions using a wire or cable, like cable television (which also retransmits OTA stations with their consent ), 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 via streaming digital technology have increasingly been referred to as broadcasting as well. In 1894, Italian inventor Guglielmo Marconi began developing
1596-476: Is that the public may learn the outcome of an event before the recording is broadcast, which may be a spoiler . Prerecording may be used to prevent announcers from deviating from an officially approved script during a live radio broadcast, as occurred with propaganda broadcasts from Germany in the 1940s and with Radio Moscow in the 1980s. Many events are advertised as being live, although they are often recorded live (sometimes called " live -to- tape "). This
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#17327824366831672-482: Is the need for nearly 100% reliable service for emergency calls. One of the standards available for digital cable telephony, PacketCable , seems to be the most promising and able to work with the quality of service (QOS) demands of traditional analog plain old telephone service (POTS) service. The biggest advantage to digital cable telephone service is similar to the advantage of digital cable, namely that data can be compressed, resulting in much less bandwidth used than
1748-421: 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 broadcasting electronic media audio and video to the general public: There are several means of providing financial support for continuous broadcasting: Broadcasters may rely on a combination of these business models . For example, in
1824-492: The DVB-C , DVB-C2 stream to IP for distribution of TV over IP network in the home. Many cable companies offer internet access through DOCSIS . In the most common system, multiple television channels (as many as 500, although this varies depending on the provider's available channel capacity) are distributed to subscriber residences through a coaxial cable , which comes from a trunkline supported on utility poles originating at
1900-774: The Nipkow disk and thus became known as the mechanical television . It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning on 30 September 1929. However, for most of the 20th century, televisions depended on the cathode-ray tube invented by Karl Braun . The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on 7 September 1927. After World War II , interrupted experiments resumed and television became an important home entertainment broadcast medium, using VHF and UHF spectrum. Satellite broadcasting
1976-616: The high band 7–13 of North American television frequencies . Some operators as in Cornwall, Ontario , used a dual distribution network with Channels 2–13 on each of the two cables. During the 1980s, United States regulations not unlike public, educational, and government access (PEG) created the beginning of cable-originated live television programming. As cable penetration increased, numerous cable-only TV stations were launched, many with their own news bureaus that could provide more immediate and more localized content than that provided by
2052-458: The studio and transmitter aspects (the entire airchain ), as well as remote broadcasts . Every station has a broadcast engineer , though one may now serve an entire station group in a city. In small media markets the engineer may work on a contract basis for one or more stations as needed. Cable television A cable channel (sometimes known as a cable network ) is a television network available via cable television. Many of
2128-485: The United States have switched to or are in the course of switching to digital cable television since it was first introduced in the late 1990s. Most cable companies require a set-top box ( cable converter box ) or a slot on one's TV set for conditional access module cards to view their cable channels, even on newer televisions with digital cable QAM tuners, because most digital cable channels are now encrypted, or scrambled , to reduce cable service theft . A cable from
2204-642: The United States, National Public Radio (NPR) and the Public Broadcasting Service (PBS, television) supplement public membership subscriptions and grants with funding from the Corporation for Public Broadcasting (CPB), which is allocated bi-annually by Congress. US public broadcasting corporate and charitable grants are generally given in consideration of underwriting spots which differ from commercial advertisements in that they are governed by specific FCC restrictions, which prohibit
2280-421: The advocacy of a product or a "call to action". The first regular television broadcasts started in 1937. Broadcasts can be classified as recorded or live . The former allows correcting errors, and removing superfluous or undesired material, rearranging it, applying slow-motion and repetitions, and other techniques to enhance the program. However, some live events like sports television can include some of
2356-405: The agenda of any future communication theory in general". Dissemination focuses on the message being relayed from one main source to one large audience without the exchange of dialogue in between. It is possible for the message to be changed or corrupted by government officials once the main source releases it. There is no way to predetermine how the larger population or audience will absorb
Ridge Hill transmitting station - Misplaced Pages Continue
2432-455: The altitude of the site gives an aerial height of 363 metres (1,191 ft) above mean sea level . Ridge Hill supplies its signal to 17 relays which allow coverage into "fringe" areas not able to receive a good signal from the main transmitter. All 5 analogue programme channels were broadcast plus the full 6 digital MUXES although the multiplexes were scattered across the band requiring a wideband aerial for most consumers. Digital switchover
2508-531: The aspects including slow-motion clips of important goals/hits, etc., in between the live television telecast. American radio-network broadcasters habitually forbade prerecorded broadcasts in the 1930s and 1940s, requiring radio programs played for the Eastern and Central time zones to be repeated three hours later for the Pacific time zone (See: Effects of time on North American broadcasting ). This restriction
2584-404: The basic selection. By subscribing to additional tiers, customers could get specialty channels, movie channels, and foreign channels. Large cable companies used addressable descramblers to limit access to premium channels for customers not subscribing to higher tiers, however the above magazines often published workarounds for that technology as well. During the 1990s, the pressure to accommodate
2660-563: The cable box itself, these midband channels were used for early incarnations of pay TV , e.g. The Z Channel (Los Angeles) and HBO but transmitted in the clear i.e. not scrambled as standard TV sets of the period could not pick up the signal nor could the average consumer de-tune the normal stations to be able to receive it. Once tuners that could receive select mid-band and super-band channels began to be incorporated into standard television sets, broadcasters were forced to either install scrambling circuitry or move these signals further out of
2736-429: The cable company's local distribution facility, called the headend . Many channels can be transmitted through one coaxial cable by a technique called frequency division multiplexing . At the headend, each television channel is translated to a different frequency . By giving each channel a different frequency slot on the cable, the separate television signals do not interfere with each other. At an outdoor cable box on
2812-515: The cable to send data from the customer box to the cable headend, for advanced features such as requesting pay-per-view shows or movies, cable internet access , and cable telephone service . The downstream channels occupy a band of frequencies from approximately 50 MHz to 1 GHz, while the upstream channels occupy frequencies of 5 to 42 MHz. Subscribers pay with a monthly fee. Subscribers can choose from several levels of service, with premium packages including more channels but costing
2888-675: The case of no local CBS or ABC station being available – rebroadcast the programming from a nearby affiliate but fill in with its own news and other community programming to suit its own locale. Many live local programs with local interests were subsequently created all over the United States in most major television markets in the early 1980s. This evolved into today's many cable-only broadcasts of diverse programming, including cable-only produced television movies and miniseries . Cable specialty channels , starting with channels oriented to show movies and large sporting or performance events, diversified further, and narrowcasting became common. By
2964-439: The central high-powered broadcast tower transmits a high-frequency electromagnetic wave to numerous receivers. The high-frequency wave sent by the tower is modulated with a signal containing visual or audio information. The receiver is then tuned so as to pick up the high-frequency wave and a demodulator is used to retrieve the signal containing the visual or audio information. The broadcast signal can be either analog (signal
3040-508: The chosen channel into the TV set on Channel 2, 3 or 4. Initially, UHF broadcast stations were at a disadvantage because the standard TV sets in use at the time were unable to receive their channels. With the passage of the All-Channel Receiver Act in 1964, all new television sets were required to include a UHF tuner, nonetheless, it would still take a few years for UHF stations to become competitive. Before being added to
3116-453: The development of radio for the wartime purposes of aircraft and land communication, radio navigation, and radar. Development of stereo FM broadcasting of 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 Baird demonstrated the transmission of moving pictures at the London department store Selfridges . Baird's device relied upon
Ridge Hill transmitting station - Misplaced Pages Continue
3192-415: The fact that the descrambling circuitry was for a time present in these tuners, depriving the cable operator of much of their revenue, such cable-ready tuners are rarely used now – requiring a return to the set-top boxes used from the 1970s onward. The digital television transition in the United States has put all signals, broadcast and cable, into digital form, rendering analog cable television service
3268-505: 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 as public radio , community radio and public television , and private commercial radio and commercial television . The U.S. Code of Federal Regulations, title 47, part 97 defines broadcasting as "transmissions intended for reception by
3344-423: The general public, either direct or relayed". Private or two-way telecommunications transmissions do not qualify under this definition. For example, amateur ("ham") and citizens band (CB) radio operators are not allowed to broadcast. As defined, transmitting and broadcasting are not the same. Transmission of radio and television programs from a radio or television station to home receivers by radio waves
3420-412: The general public: 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 432 exabytes of (optimally compressed) information, to 1.9 zettabytes . This is the information equivalent of 55 newspapers per person per day in 1986, and 175 newspapers per person per day by 2007. In a broadcast system,
3496-457: The growing array of offerings resulted in digital transmission that made more efficient use of the VHF signal capacity; fibre optics was common to carry signals into areas near the home, where coax could carry higher frequencies over the short remaining distance. Although for a time in the 1980s and 1990s, television receivers and VCRs were equipped to receive the mid-band and super-band channels. Due to
3572-450: The headend, the electrical signal is translated into an optical signal and sent through the fiber. The fiber trunkline goes to several distribution hubs , from which multiple fibers fan out to carry the signal to boxes called optical nodes in local communities. At the optical node, the optical signal is translated back into an electrical signal and carried by coaxial cable distribution lines on utility poles, from which cables branch out to
3648-448: The instantaneous signal voltage varies continuously with the pressure of the sound waves . In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized values which imposes some bandwidth and dynamic range constraints on the representation. In general usage, broadcasting most frequently refers to the transmission of information and entertainment programming from various sources to
3724-460: The jack in the wall is attached to the input of the box, and an output cable from the box is attached to the television, usually the RF-IN or composite input on older TVs. Since the set-top box only decodes the single channel that is being watched, each television in the house requires a separate box. Some unencrypted channels, usually traditional over-the-air broadcast networks, can be displayed without
3800-490: The late 1980s, cable-only signals outnumbered broadcast signals on cable systems, some of which by this time had expanded beyond 35 channels. By the mid-1980s in Canada, cable operators were allowed by the regulators to enter into distribution contracts with cable networks on their own. By the 1990s, tiers became common, with customers able to subscribe to different tiers to obtain different selections of additional channels above
3876-423: The maximum number of channels that could be broadcast in one city was 7: channels 2, 4, either 5 or 6, 7, 9, 11 and 13, as receivers at the time were unable to receive strong (local) signals on adjacent channels without distortion. (There were frequency gaps between 4 and 5, and between 6 and 7, which allowed both to be used in the same city). As equipment improved, all twelve channels could be utilized, except where
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#17327824366833952-405: 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
4028-451: The nearest network newscast. Such stations may use similar on-air branding as that used by the nearby broadcast network affiliate, but the fact that these stations do not broadcast over the air and are not regulated by the FCC, their call signs are meaningless. These stations evolved partially into today's over-the-air digital subchannels, where a main broadcast TV station e.g. NBC 37* would – in
4104-408: The old analog cable without a set-top box. To receive digital cable channels on an analog television set, even unencrypted ones, requires a different type of box, a digital television adapter supplied by the cable company or purchased by the subscriber. Another new distribution method that takes advantage of the low cost high quality DVB distribution to residential areas, uses TV gateways to convert
4180-504: The programming at the headend (the individual channels, which are distributed nationally, also have their own nationally oriented commercials). Modern cable systems are large, with a single network and headend often serving an entire metropolitan area . Most systems use hybrid fiber-coaxial (HFC) distribution; this means the trunklines that carry the signal from the headend to local neighborhoods are optical fiber to provide greater bandwidth and also extra capacity for future expansion. At
4256-454: The programming without cost. Later, the cable operators began to carry FM radio stations, and encouraged subscribers to connect their FM stereo sets to cable. Before stereo and bilingual TV sound became common, Pay-TV channel sound was added to the FM stereo cable line-ups. About this time, operators expanded beyond the 12-channel dial to use the midband and superband VHF channels adjacent to
4332-476: The range of reception for early cable-ready TVs and VCRs. However, once consumer sets had the ability to receive all 181 FCC allocated channels, premium broadcasters were left with no choice but to scramble. The descrambling circuitry was often published in electronics hobby magazines such as Popular Science and Popular Electronics allowing anybody with anything more than a rudimentary knowledge of broadcast electronics to be able to build their own and receive
4408-423: The recipient, especially with multicasting allowing the signal and bandwidth to be shared. The term broadcast network is often used to distinguish networks that broadcast over-the-air television signals that can be received using a tuner inside a television set with a television antenna from so-called networks that are broadcast only via cable television ( cablecast ) or satellite television that uses
4484-561: The same channels are distributed through satellite television . Alternative terms include non-broadcast channel or programming service , the latter being mainly used in legal contexts. The abbreviation CATV is used in the US for cable television and originally stood for community antenna television , from cable television's origins in 1948; in areas where over-the-air TV reception was limited by distance from transmitters or mountainous terrain, large community antennas were constructed, and cable
4560-544: The signal from Mendip ) in addition to the existing ITV1 Central service on channel 25. This is known as "Ridge Hill West". This followed the restructuring of ITV Regional News and the abolition of the Central South region. As a result, the existing ITV1 Central service now carries news from the West Midlands region. Since April 2011, analogue television has not been broadcast from Ridge Hill. BBC2
4636-449: The signal to the customer's building through a service drop , an overhead or underground cable. If the subscriber's building does not have a cable service drop, the cable company will install one. The standard cable used in the U.S. is RG-6 , which has a 75 ohm impedance , and connects with a type F connector . The cable company's portion of the wiring usually ends at a distribution box on the building exterior, and built-in cable wiring in
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#17327824366834712-418: The signals are typically encrypted on modern digital cable systems, and the set-top box must be activated by an activation code sent by the cable company before it will function, which is only sent after the subscriber signs up. If the subscriber fails to pay their bill, the cable company can send a signal to deactivate the subscriber's box, preventing reception. There are also usually upstream channels on
4788-592: The south west Midlands, including Herefordshire , and parts of Worcestershire. It also covers parts of the South West, specifically northern Gloucestershire . It does not, however, transmit BBC local programmes for Gloucestershire. These are covered by the Mendip transmitter which can be seen from the south and west of Gloucester city, and a very much smaller part of Cheltenham . From 4 December 2006 Ridge Hill broadcast ITV1 West on UHF channel 30 (rebroadcasting
4864-410: The spread of vacuum tube radio transmitters and receivers . Before this, most implementations of electronic communication (early radio , telephone , and telegraph ) were one-to-one , with the message intended for a single recipient. The term broadcasting evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing
4940-403: The subscriber's residence, the company's service drop cable is connected to cables distributing the signal to different rooms in the building. At each television, the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency ( baseband ), and it is displayed onscreen. Due to widespread cable theft in earlier analog systems,
5016-532: The upstream speed to 31.2 Kbp/s and prevented the always-on convenience broadband internet typically provides. Many large cable systems have upgraded or are upgrading their equipment to allow for bi-directional signals, thus allowing for greater upload speed and always-on convenience, though these upgrades are expensive. In North America , Australia and Europe , many cable operators have already introduced cable telephone service, which operates just like existing fixed line operators. This service involves installing
5092-451: The walls usually distributes the signal to jacks in different rooms to which televisions are connected. Multiple cables to different rooms are split off the incoming cable with a small device called a splitter . There are two standards for cable television; older analog cable, and newer digital cable which can carry data signals used by digital television receivers such as high-definition television (HDTV) equipment. All cable companies in
5168-452: The widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898. Over-the-air broadcasting is usually associated with radio and television , though more recently, both radio and television transmissions have begun to be distributed by cable ( cable television ). The receiving parties may include
5244-538: 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 I accelerated the development of radio for military communications . After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated
5320-413: Was closed on 6 April and the remaining five services on 20 April. Broadcasting Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium , but typically one using the electromagnetic spectrum ( radio waves ), in a one-to-many model. Broadcasting began with AM radio , which came into popular use around 1920 with
5396-480: Was completed on 20 April 2011 where the main 6 multiplexes are now located in the Group A antenna band. Since March 2018 MUXES 7 and 8 have been moved up to channels 55 and 56 respectively which are outside the A group , though these are due to be switched off between 2020 and 2022 In addition to its television output Ridge Hill transmits various radio stations including BBC Hereford and Worcester . The station covers
5472-454: Was dropped for special occasions, as in the case of the German dirigible airship Hindenburg disaster at Lakehurst, New Jersey , in 1937. During World War II , prerecorded broadcasts from war correspondents were allowed on U.S. radio. In addition, American radio programs were recorded for playback by Armed Forces Radio radio stations around the world. A disadvantage of recording first
5548-495: Was 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 of analog signals using analog transmission techniques but in the 2000s, broadcasters switched to digital signals using digital transmission . An analog signal is any continuous signal representing some other quantity, i.e., analogous to another quantity. For example, in an analog audio signal ,
5624-427: Was limited, meaning frequencies over 250 MHz were difficult to transmit to distant portions of the coaxial network, and UHF channels could not be used at all. To expand beyond 12 channels, non-standard midband channels had to be used, located between the FM band and Channel 7, or superband beyond Channel 13 up to about 300 MHz; these channels initially were only accessible using separate tuner boxes that sent
5700-559: Was mainly used to relay terrestrial channels in geographical areas poorly served by terrestrial television signals. Cable television began in the United States as a commercial business in 1950s. The early systems simply received weak ( broadcast ) channels, amplified them, and sent them over unshielded wires to the subscribers, limited to a community or to adjacent communities. The receiving antenna would be taller than any individual subscriber could afford, thus bringing in stronger signals; in hilly or mountainous terrain it would be placed at
5776-400: Was run from them to individual homes. In 1968, 6.4% of Americans had cable television. The number increased to 7.5% in 1978. By 1988, 52.8% of all households were using cable. The number further increased to 62.4% in 1994. To receive cable television at a given location, cable distribution lines must be available on the local utility poles or underground utility lines. Coaxial cable brings
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