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82-406: A broadcast relay station , also known as a satellite station , relay transmitter , broadcast translator (U.S.), re-broadcaster (Canada), repeater ( two-way radio ) or complementary station (Mexico), is a broadcast transmitter which repeats (or transponds ) the signal of a radio or television station to an area not covered by the originating station. These expand the broadcast range of

164-481: A CKWS-TV re-transmitter in Brighton, Ontario , and three TVOntario sites) went digital as part of a move to a lower frequency but do not provide high-definition television , digital subchannels or any functions beyond that of the original analogue site. Like a TV station, a radio re-broadcaster may have a distinct call sign or use the call sign of the originating station followed by a numeric suffix. The numeric suffix

246-412: A communication channel , it is progressively degraded due to loss of power. For example, when a telephone call passes through a wire telephone line , some of the power in the electric current which represents the audio signal is dissipated as heat in the resistance of the copper wire. The longer the wire, the more power is lost, and the smaller the amplitude of the signal at the far end. So with

328-408: A single-frequency network . Analog television stations cannot have same-channel boosters unless opposite ( perpendicular ) polarization is used, due to video synchronization issues such as ghosting . In the U.S., no new on-channel UHF signal boosters have been authorized since July 11, 1975. A distributed transmission system (DTS or DTx) uses several medium-power stations (usually digital) on

410-542: A $ 1,000 federal-government subsidy for a portion of the additional equipment. Many other translators went dark after the digital-transition deadline, or did not apply for new channels after UHF channels 52–69 were removed from the bandplan. Some small translators operated by directly converting a parent station's signal to another frequency for rebroadcast, without any other local signal processing or demodulation. W07BA (a 16-watt repeater for WSYR-TV in Syracuse, New York )

492-424: A DC current source to increase the power of the alternating current audio signal on the line. Since the telephone is a duplex (bidirectional) communication system, the wire pair carries two audio signals , one going in each direction. So telephone repeaters have to be bilateral, amplifying the signal in both directions without causing feedback, which complicates their design considerably. Telephone repeaters were

574-412: A booster. All U.S. translator and booster stations are low-power and have a class D license, making them secondary to other stations (including the parent); they must accept interference from full-power (100 watts or more on FM) stations, while not causing any of their own. Boosters must not interfere with the parent station in the community of license . Licenses are automatically renewed with that of

656-406: A broadcast operation common among most over-the-air television stations and television networks . Master control is distinct from a PCR in television studios where the activities such as switching from camera to camera are coordinated. A transmission control room (TCR) is usually smaller in size and is a scaled-down version of centralcasting . The master control room in a US television station

738-723: A call sign consisting of three letters from anywhere in Canada's ITU -prefix range followed by three digits (such as CFU758 or VEK565). Other stations in this license class have been assigned conventional Cxxx call signs. Former re-broadcasters have occasionally been converted to originating stations, retaining their former call sign; examples include CITE-FM-1 in Sherbrooke , CBF-FM-8 in Trois-Rivières and CBAF-FM-15 in Charlottetown . In Mexico , translator and booster stations are given

820-435: A central source for broadcast at a GPS-synchronized time. A DTS does not use broadcast repeaters in the conventional sense, since they cannot receive a signal from a main terrestrial broadcast transmitter for rebroadcast; to do so would introduce a re-transmission delay destroying the required synchronization, causing interference between transmitters. The use of virtual channels is another alternative, although this may cause

902-421: A city, or neighboring police departments). They may provide links to the public switched telephone network as well, or satellite network ( BGAN , INMARSAT , MSAT ) as an alternative path from source to the destination. Typically a repeater station listens on one frequency, A, and transmits on a second, B. All mobile stations listen for signals on channel B and transmit on channel A. The difference between

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984-700: A contract with the Quintana Roo state network . The other network, operated by the Sistema Público de Radiodifusión del Estado Mexicano (SPR), has 26 stations (16 operational); most are digital. The SPR transmitters are almost exclusively in cities where the IPN never built stations, and carry Canal Once as one of the five educational networks in the multiplex of the digital station. Twenty-six of Mexico's 32 states also own and operate television services, and 16 use more than one transmitter. The largest (by number of stations)

1066-643: A digital uplink. Although many translators continued analog broadcasts and a minority transitioned to digital, some rural communities expected to find all local translator signals gone as a result of the originating stations' transition. By law, full-service local broadcasters are the primary occupants of the FM broadcast band; LPFM and translators are secondary occupants, with theoretically-equal status. In practice, frequencies assigned to translators become unavailable to new LPFM stations or existing stations wishing to upgrade. Some distinctions place small, local LPFM operators at

1148-495: A disadvantage: Repeater There are several different types of repeaters; a telephone repeater is an amplifier in a telephone line , an optical repeater is an optoelectronic circuit that amplifies the light beam in an optical fiber cable ; and a radio repeater is a radio receiver and transmitter that retransmits a radio signal. A broadcast relay station is a repeater used in broadcast radio and television . When an information-bearing signal passes through

1230-548: A limited amount of regional content; Televisa prefers to use its non-national Gala TV network and Televisa Regional stations as outlets for local production. A number of translators also serve areas with little or no signal in their defined coverage area, known as equipos complementarios de zona de sombra ('shadow channels'). Most shadow channels air the same programming as their parent station. The northern and central regional network Multimedios Televisión in Monterrey uses

1312-422: A linear amplifier, and may include electronic filters to compensate for frequency and phase distortion in the line. The digital repeater is used in channels that transmit data by binary digital signals , in which the data is in the form of pulses with only two possible values, representing the binary digits 1 and 0. A digital repeater amplifies the signal, and it also may retime, resynchronize, and reshape

1394-403: A long enough wire the call will not be audible at the other end. Similarly, the greater the distance between a radio station and a receiver , the weaker the radio signal , and the poorer the reception. A repeater is an electronic device in a communication channel that increases the power of a signal and retransmits it, allowing it to travel further. Since it amplifies the signal, it requires

1476-518: A newscast. There is no strict rule for the call sign of a television re-broadcaster. Some transmitters have call signs different from the parent station ( CFGC in Sudbury is a re-broadcaster of CIII ), and others use the call sign of the originating station followed by a number (such as the former CBLFT-17 in Sarnia , Ontario). The latter type officially includes the television station's -TV suffix between

1558-435: A parent station's conversion to digital television. Translators which received an analog over-the-air signal from a full-service television station for rebroadcast needed to convert their receiving equipment, like individual viewers used digital converter boxes . Although the signal transmitted by the repeater may have remained analog, the uplink had to be changed. Twenty-three percent of the 4,000 licensed translators received

1640-495: A predictable level of reliable communication over the designed coverage area. Repeaters can be divided into two types depending on the type of data they handle: This type is used in channels that transmit data in the form of an analog signal in which the voltage or current is proportional to the amplitude of the signal, as in an audio signal. They are also used in trunklines that transmit multiple signals using frequency division multiplexing (FDM). Analog repeaters are composed of

1722-475: A re-broadcaster of CKSB-FM . A broadcaster is limited to two stations on one band in a market, but a possible means to obtain a third FM signal in-market is to use a re-broadcaster of the AM station to move the signal to low-power FM. In Sarnia, Blackburn Radio owns CFGX-FM (99.9) and CHKS-FM (106.3); its third Sarnia station, CHOK (1070 kHz), uses an FM repeater for city coverage as Country 103.9 FM (although

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1804-607: A semi-satellite is a formerly autonomous full-service station which is programmed remotely through centralcasting or broadcast automation to avoid the cost of a local staff. CBLFT , an owned-and-operated station of the French-language network Ici Radio-Canada Télé in Toronto , is a de facto semi-satellite of its stronger Ottawa sibling CBOFT ; its programming has long been identical or differed only in local news and advertising. A financially weak privately owned broadcaster in

1886-679: A small market can become a de facto semi-satellite by gradually curtailing local production and relying on a commonly owned station in a larger city for programming; WWTI in Watertown, New York , relies on WSYR-TV in this manner. Broadcast automation allows the substitution of syndicated programming or digital subchannel content which the broadcaster was unable to obtain for both cities. Some defunct full-service stations (such as CJSS-TV in Cornwall, Ontario , now CJOH-TV-8 ) have become full satellite stations and originate nothing. If programming from

1968-436: A source of electric power . The term "repeater" originated with telegraphy in the 19th century, and referred to an electromechanical device (a relay ) used to regenerate telegraph signals. Use of the term has continued in telephony and data communications . In computer networking , because repeaters work with the actual physical signal, and do not attempt to interpret the data being transmitted, they operate on

2050-491: A station's main signal. They can also be used to expand market coverage by duplicating programming on another band. Relays which broadcast within (or near) the parent station's coverage area on the same channel (or frequency) are known in the U.S. as booster stations. Signals from the stations may interfere with each other without careful antenna design. Radio interference can be avoided by using atomic time , obtained from GPS satellites , to synchronize co-channel stations in

2132-576: A studio control room (SCR) or a "gallery" – the latter name comes from the original placement of the director on an ornately carved bridge spanning the BBC 's first studio at Alexandra Palace , which was once referred to as like a minstrels' gallery . The vast majority of devices in a PCR are interfaces for rack-mounted equipment that is located in the Central Apparatus Room (CAR). The central apparatus room (CAR) houses equipment that

2214-418: A studio is similar to, and derived from, movie studios, with a few amendments for the special requirements of television production. A professional television studio generally has several rooms, which are kept separate for noise and practicality reasons. These rooms are connected via ' talkback ' or an intercom , and personnel will be divided among these workplaces. The studio floor is the actual stage on which

2296-409: A television or radio station beyond the primary signal's original coverage or improves service in the original coverage area. The stations may be (but are not usually) used to create a single-frequency network . They may also be used by an AM or FM radio station to establish a presence on the other band. Relay stations are most commonly established and operated by the same organisations responsible for

2378-449: A three-digit number (201 through 300, corresponding to 88.1 to 107.9 MHz), followed by a pair of sequentially-assigned letters. The format is similar to that used by numbered television translators, where the number refers to the permanent channel assignment. The largest terrestrial radio-translator system in the U.S. in October 2008 belonged to KUER-FM , the non-commercial radio outlet of

2460-693: A translator may broadcast programming from the originating station's HD2 subchannel as the translator's main analogue signal. W237DE (95.3 MHz in Harrisburg, Pennsylvania ) broadcasts the format formerly carried by WTCY (1400 AM, now WHGB ), receiving the signal from a WNNK (104.1 FM) HD2 digital subchannel for analogue rebroadcast from the WNNK tower site on 95.3. It is legally an FM repeater of an FM station, although each signal would be heard with unique content by users with analogue FM radio receivers. Commercial stations may own their translators (or boosters) when

2542-463: A two-hour delay behind the originating station; there is a one-hour delay in Sonora , and Quintana Roo (one hour ahead of central Mexico in 2015) receives programs one hour later than they are broadcast to most of the rest of Mexico. Ten to 15 FM shadow channels exist, and they are required to be co-channel with the stations they re-transmit. Quintana Roo has the most FM shadow channels (seven), about half

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2624-414: A wire line or a radio link. While the repeater station is designed for simultaneous reception and transmission, mobile units need not be equipped with the bulky and costly duplexers, as they only transmit or receive at any time. Mobile units in a repeater system may be provided with a "talkaround" channel that allows direct mobile-to-mobile operation on a single channel. This may be used if out of reach of

2706-460: Is Telemax , Sonora 's state network, with 59 transmitters. Many state-network transmitters broadcast at a low effective radiated power (ERP). A few stations are owned by municipalities or translator associations. Like state networks, they transmit at very low power. Transmitters re-broadcasting Mexico City stations to Baja California and other communities along the Pacific coast normally operate on

2788-551: Is a re-broadcaster (also in Anzac) of Edmonton 's CITV . A station's re-broadcasters are not necessarily named in the same manner; CBLT had re-transmitters with their own call signs (some used CBLT followed by a number, and some used CH numbers). CBC and Radio-Canada owned-and-operated re-transmitters were shut down on August 1, 2012, along with most TVOntario transmitters (which often were located at Radio-Canada sites) and some Aboriginal Peoples Television Network (APTN) transmitters in

2870-514: Is a re-broadcaster of Vancouver 's CHAN . Re-broadcasters of this type are numbered sequentially in the order they were licensed by the CRTC, and their call signs are unrelated to the parent station or other re-broadcasters. Although the next number in the sequence (CH2650 in Anzac, Alberta ) is a re-broadcaster of CHAN, this is because CH2649 and CH2650 were licensed simultaneously; the following number, CH2651,

2952-460: Is always sequential. For a re-broadcaster of an FM station, the numeric suffix is appended to the FM suffix; re-broadcasters of CJBC-FM in Toronto are numbered CJBC-FM-1, CJBC-FM-2, etc. If an AM station has a re-broadcaster on the FM band, the numeric suffix falls between the four-letter call sign and the FM suffix; CKSB-1-FM is an FM re-broadcaster of the AM station CKSB , and CKSB-FM-1 would be

3034-403: Is amplified and retransmitted, often on another frequency, to provide coverage beyond the obstruction. Usage of a duplexer can allow the repeater to use one antenna for both receive and transmit at the same time. Radio repeaters improve communication coverage in systems using frequencies that typically have line-of-sight propagation . Without a repeater, these systems are limited in range by

3116-550: Is generally done only if the station originates programming. Class A television stations are assigned calls with -CA and -CD suffixes. Digital stations which use numbers receive a -D suffix, such as W42BD-D. All are despite the fact that most of the full-power digital television stations had their -DT (originally -HD) suffixes dropped by the FCC before -D and -LD were implemented. Digital LPTV stations have their digital RF channel numbers as part of their digital call sign, which may differ from

3198-414: Is too noisy or runs too hot to be located in the production control room (PCR). It also makes sure that coax cable , SDI cable , fibre-optic cable or other wire lengths and installation requirements keep within manageable lengths, since most high-quality wiring runs only between devices in this room. This can include the actual circuitry and connections between: Master control is the technical hub of

3280-604: Is unregulated in the U.S. and widely permitted in Canada , the U.S. Federal Communications Commission (FCC) regulates radio formats to ensure diversity in programming. U.S. satellite stations may request an FCC exemption from requirements for a properly staffed broadcast studio in the city of license . The stations often cover large, sparsely populated regions or operate as statewide non-commercial educational radio and television systems. A television re-broadcaster often sells local (or regional) advertising for broadcast only on

3362-604: The University of Utah , with 33 translator stations ranging from Idaho to New Mexico and Arizona . Unlike FM radio, low-power television stations may operate as translators or originate their own programming. Translator stations are given call signs which begin with W (east of the Mississippi River ) or K (west of the Mississippi, like regular stations) followed by a channel number and two serial letters for each channel;

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3444-413: The digital transition . Although no digital television mandates were forced on existing low-power television stations, Congress passed legislation in 2008 funding low-power stations which went digital by the conversion date or shortly thereafter. Some low-power stations were forced to change frequency to accommodate full-power stations which moved to UHF or operated digital companion channels on UHF during

3526-462: The physical layer , the first layer of the OSI model ; a multiport Ethernet repeater is usually called a hub . This is used to increase the range of telephone signals in a telephone line. They are most frequently used in trunklines that carry long distance calls. In an analog telephone line consisting of a pair of wires, it consists of an amplifier circuit made of transistors which use power from

3608-458: The virtual channel (the analog number). Numbered broadcast translators which are moved to another frequency are normally issued new call signs to reflect the updated channel assignment. This is not true of displaced translators using another frequency temporarily under a special technical authority. Although K55KD could retain its call sign while it was displaced temporarily to channel 57 to resolve interference to MediaFLO users, W81AA received

3690-501: The AM signal remains the station's official primary transmitter). Low-power radio re-broadcasters may have a call sign consisting of VF followed by four numbers; a call sign of this type may also denote a low-power station which originates its own programming. Some stations licensed under the CRTC's experimental-broadcasting guidelines, a special class of short-term license (similar to special temporary authority ) sometimes granted to newer campus and community radio operations, may have

3772-483: The Commission's rules to re-transmit all or part of the programming of a parent station that is typically commonly owned". Since most satellite stations operate in small or sparsely-populated areas with an insufficient economic base to support full-service operations, many received FCC authorization on a case-by-case basis to flash cut from analog to digital on the same channel instead of simulcasting in both formats during

3854-502: The E6 repeater was the final major type used in the Bell System before the low cost of digital transmission made all voiceband repeaters obsolete. Frequency frogging repeaters were commonplace in frequency-division multiplexing systems from the middle to late 20th century. This is a type of telephone repeater used in underwater submarine telecommunications cables . This is used to increase

3936-579: The TV channel number of the analogue signal they replaced. TVOntario's CICO-DT-53 (digital UHF 26, Belleville ) is an example; the station was converted in 2011 to vacate an out-of-core analogue channel (UHF 53), and retains CICO-TV-53's former analogue UHF television call-sign numbering as a surviving TVO repeater. Low-power re-broadcasters may have a call sign consisting of the letters CH followed by four numbers; for example, CH2649 in Valemount , British Columbia ,

4018-416: The actions that will be recorded and viewed take place. A typical studio floor has the following characteristics and installations: While a production is in progress, people composing a television crew work on the studio floor. The production control room is the place in a television studio in which the composition of the outgoing program takes place. The production control room is occasionally also called

4100-543: The basis of economic hardship, where a rural location unable to support a full-service originating station may be able to sustain a full-power re-broadcaster. Some stations (such as KVRR in Fargo, North Dakota ) are chains of as many as four full-power transmitters, each with its own call sign and license, covering a large, sparsely-populated region. LPTV stations may also choose a four-letter call sign with an -LP suffix (shared with low-power FM ) for analog or -LD for digital; this

4182-465: The call sign and the number, although it is often omitted from media directories. The numbers are usually applied sequentially, beginning with "1", and denote the chronological order in which the station's rebroadcast transmitters began operation. Some broadcasters may use a system in which the number is the transmitter's broadcast channel, such as CJOH-TV-47 in Pembroke, Ontario . A broadcaster cannot mix

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4264-600: The call sign of the parent station. Most television stations in Mexico are operated as repeaters of the networks they broadcast. Translator stations in Mexico are given call signs beginning with XE and XH. Televisa and Azteca maintain two national networks apiece. Televisa's Las Estrellas network includes 128 stations (the most in Mexico), and Azteca's networks have 88 and 91 stations. The stations may insert local advertising. Azteca's stations in larger cities may include local news and

4346-463: The curvature of the Earth and the blocking effect of terrain or high buildings. A repeater on a hilltop or tall building can allow stations that are out of each other's line-of-sight range to communicate reliably. Radio repeaters may also allow translation from one set of radio frequencies to another, for example to allow two different public service agencies to interoperate (say, police and fire services of

4428-420: The far north. Private commercial broadcasters operate full-power re-broadcasters to obtain "must carry" status on cable television systems. Transmitters in small markets with one (or no) originating stations were, in most cases, not required to convert to digital even if operating at full power. Transmitters broadcasting on UHF channels 52–69 were required to vacate the channels by August 31, 2011; some (such as

4510-450: The first stations on a channel are AA, AB, AC and so on). Television channels have two digits, from 02 to 36 (formerly 02 to 83; 02 to 69 and 02 to 51); FM radio channels are numbered from 200 (87.9 MHz) to 300 (107.9 MHz), one every 0.2 MHz (for example, W42BD or K263AF). An X after the number in these call signs does not indicate an experimental broadcasting license (as it may in other services), since all 26 letters are used in

4592-431: The first type of repeater and were some of the first applications of amplification. The development of telephone repeaters between 1900 and 1915 made long-distance phone service possible. Now, most telecommunications cables are fiber-optic cables which use optical repeaters (below). Before the invention of electronic amplifiers, mechanically coupled carbon microphones were used as amplifiers in telephone repeaters. After

4674-603: The local transmitter, and may air a limited amount of programming distinct from its parent station. Some "semi-satellites" broadcast local news or separate news segments during part of the newscast . CHEX-TV-2 in Oshawa , Ontario , aired daily late-afternoon and early-evening news and community programs separate from its parent station, CHEX-TV in Peterborough, Ontario . The FCC prohibits this on U.S. FM translator stations, only permitting it on fully licensed stations. In some cases,

4756-560: The national Public Broadcasting Service . In Canada, "re-broadcaster" or "re-broadcasting transmitter" are the terms most commonly used by the Canadian Radio-television and Telecommunications Commission (CRTC). A television re-broadcaster may sell local or regional advertising for broadcast only on the local transmitter. Rarely, they may air limited programming distinct from their parent station. Some "semi-satellites" broadcast local newscasts or separate news segments in part of

4838-416: The national total. Three more FM shadows are authorized: XETIA-FM / XEAD-FM ( Ajijic , Jalisco ) and XHRRR-FM (Tecolula, Veracruz ). In July 2009, the basic FCC regulations concerning translators were: There is one way programming may differ between a main station and an FM translator: an HD Radio signal may contain digital subchannels with different programming from the main analogue channel, and

4920-730: The new call sign W65AM when channel 81 was deleted from the bandplan and the translator was moved to channel 65. On the rare occasion that a station moves back to its original channel, it receives its old call sign (which is not reused by another station). Low-power television stations are not required to simulcast a digital signal, nor were they required to cease analog operation in June 2009 like full-power stations. Full-power stations used for simulcasting another station were (like other full-service TV broadcasters) required to convert to digital in June 2009. The FCC defines "TV satellite stations" as "full-power broadcast stations authorized under Part 73 of

5002-472: The numbering systems under a single call sign; the transmitters are numbered sequentially or by their analogue channel. If sequential numbering reaches 99 (such as TVOntario 's former broadcast transmitters), the next transmitter is assigned a new call sign and numbered "1". Translators which share a frequency (such as CBLT 's former repeaters CBLET, CBLHT, CBLAT-2 and CH4113 on channel 12) are given distinct call signs. Digital re-broadcasters may be numbered by

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5084-495: The originating stations they repeat. Depending on technical and regulatory restrictions, relays may also be set up by unrelated organisations. In its simplest form, a broadcast translator is a facility created to receive a terrestrial broadcast over the air on one frequency and rebroadcast the same (or substantially identical) signal on another frequency. These stations are used in television and radio to cover areas (such as valleys or rural villages) which are not adequately covered by

5166-410: The parent station and do not require separate applications, although the renewal may be challenged with a petition to deny. FM booster stations are given the full call sign (including an -FM suffix , even if there is none assigned) of the parent station plus a serial number such as WXYZ-FM 1, WXYZ-FM2, etc. FM translator stations may use sequential numbered call signs consisting of K or W followed by

5248-512: The parent station must be removed or substituted due to local sports blackouts , the modified signal is that of a semi-satellite station. Most broadcasters outside North America, portions of South America, and Japan maintain a national network, and use relay transmitters to provide service to a region (or nation). Compared with other types of relays, the transmitter network is often created and maintained by an independent authority (funded with television license fees); several major broadcasters use

5330-454: The power of the signal, an electronic filter which reshapes the pulses, and a laser which converts the electrical signal to light again and sends it out the other fiber. However, optical amplifiers are being developed for repeaters to amplify the light itself without the need of converting it to an electric signal first. This is used to extend the range of coverage of a radio signal. The history of radio relay repeaters began in 1898 from

5412-481: The publication by Johann Mattausch in Austrian Journal Zeitschrift für Electrotechnik (v. 16, 35 - 36). But his proposal "Translator" was primitive and not suitable for use. The first relay system with radio repeaters, which really functioned, was that invented in 1899 by Emile Guarini-Foresio. A radio repeater usually consists of a radio receiver connected to a radio transmitter. The received signal

5494-464: The pulses. A repeater that performs the retiming or resynchronizing functions may be called a regenerator . Television studio A television studio , also called a television production studio , is an installation room in which video productions take place, either for the production of live television and its recording onto video tape or other media such as SSDs, or for the acquisition of raw footage for post-production . The design of

5576-401: The range of signals in a fiber-optic cable . Digital information travels through a fiber-optic cable in the form of short pulses of light. The light is made up of particles called photons , which can be absorbed or scattered in the fiber. An optical communications repeater usually consists of a phototransistor which converts the light pulses to an electrical signal, an amplifier to increase

5658-413: The repeater system, or for communications not requiring the attention of all mobiles. The "talkaround" channel may be the repeater output frequency; the repeater will not retransmit any signals on its output frequency. An engineered radio communication system designer will analyze the coverage area desired and select repeater locations, elevations, antennas, operating frequencies and power levels to permit

5740-482: The same channel to appear several times in a receiver – once for each relay station – and require the user to tune to the best one (which may change due to propagation issues such as weather). Although boosters or DTS cause all relay stations to appear as one signal, they require careful engineering to avoid interference. Some licensed stations simulcast another station. Relay stations in name only, they are generally licensed like any other station. Although this

5822-671: The same frequency to cover a broadcast area, rather than one high-power station with repeaters on a different frequency. Although digital television stations are technically capable of sharing a channel, this is more difficult with the 8VSB modulation and unvariable guard interval used in ATSC standards than with the orthogonal frequency-division multiplexing (OFDM) used in the European and Australian DVB-T standard. A distributed transmission system would have stringent synchronization requirements, requiring each transmitter to receive its signal from

5904-495: The same manner as other full-power broadcasters. This simulcasting is generally not regulated by the FCC, except when a station owner seeks an exemption from requirements such as restrictions on owning several full-service stations in the same market, limits on overlap in coverage area between commonly-owned stations, or requirements that each full-service station have a local studio and a skeleton staff capable of originating programming locally. These exemptions are normally justified on

5986-609: The same system to a smaller extent (its XHSAW-TDT is the shadow channel of main station XHAW-TDT in Monterrey), with regional output for local newscasts and advertising on a master schedule. There are two main national networks of non-commercial TV stations in Mexico. One is the Canal Once (or XEIPN-TDT) network, operated by the Instituto Politécnico Nacional (IPN). Operating 13 transmitters, it airs its programs under

6068-427: The same transmitters. In North America, a similar pattern of regional network broadcasting is sometimes used by state- or province-wide educational television networks. A state or province establishes an educational station and extends it with several full-power transmitters to cover the entire jurisdiction, with no capability for local-programming origination. In the U.S., such regional networks are member stations of

6150-581: The sequence. When the sequence is exhausted, another letter is added. This has already happened for translator on channels 7 and 13 in K territory; what is now KMNF-LD was assigned callsign K13AAR-D in September 2018 and K07AAH-D in May 2019. Numbered translator stations (a format such as W70ZZ) are typically low-power repeaters – often 100 watts (or less) on FM and 1,000 watts (or less) on television. The former translator band, UHF television channels 70 through 83 ,

6232-598: The signal. They may not transmit in the FM reserved band from 88 to 92 MHz , where only non-commercial stations are allowed. Non-commercial stations may broadcast in the commercial portion of the band. Unlike commercial stations, they can relay programming to translators via satellite if the translators are in the reserved band. Translators in the commercial band may only be fed by a direct on-air signal from another FM station (or translator). Non-fill-in commercial-band translators may not be fed by satellite, according to FCC rule 74.1231(b). All stations may use any means to feed

6314-505: The transition period. By 2008, low- and full-power channel 55 licensees were encouraged to relocate early to free spectrum for Qualcomm 's MediaFLO transmitters. By 2011, remaining LPTV broadcasters on UHF channels 52 through 69 were forced onto lower channels. Many transmitters on the original UHF 70–83 translator band had to move twice; channels 70–83 were lost to mobile phones in 1983, followed by channels 52–69 between 2009 and 2011. Many low-power translators were also directly affected by

6396-460: The translator (or booster) is in the parent station's primary service contour; they can only fill in where terrain blocks the signal. Boosters may only be owned by the primary station; translators outside a primary station's service contour cannot be owned by (or receive financial support from) the primary station. Most translators operate by receiving the main station's on-air signal with a directional antenna and sensitive receiver and re-transmitting

6478-432: The turn of the 20th century it was found that negative resistance mercury lamps could amplify, and they were used. The invention of audion tube repeaters around 1916 made transcontinental telephony practical. In the 1930s vacuum tube repeaters using hybrid coils became commonplace, allowing the use of thinner wires. In the 1950s negative impedance gain devices were more popular, and a transistorized version called

6560-415: The two frequencies may be relatively small compared to the frequency of operation, say 1%. Often the repeater station will use the same antenna for transmission and reception; highly selective filters called "duplexers" separate the faint incoming received signal from the billions of times more powerful outbound transmitted signal. Sometimes separate transmitting and receiving locations are used, connected by

6642-534: Was a simple piece of broadcast apparatus, shifting the main station's signal from channel nine to channel seven to cover a small valley in DeWitt . Syracuse became a UHF island , WSYR-TV's main ABC signal became a 100 kW digital broadcast on channel 17, and there is no longer a channel 9 signal to feed the repeater. Translators in remote locations with no commercial power were expected to have problems deploying equipment for

6724-511: Was originally occupied primarily by low-powered translators. The combination of low power and high frequency limited broadcast range. The band was reallocated to cellular telephone services during the 1980s, with the handful of remaining transmitters moved to lower frequencies. Full-power repeaters such as WPBS-TV 's identical-twin transmitter, WNPI-TV , are normally assigned TV call signs like other full-power stations. These "satellite stations" do not have numbered call signs, and must operate in

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