HD Radio is a trademarked term for Xperi's in-band on-channel digital radio technology used by AM and FM radio stations to transmit audio and data by using a digital signal embedded "on-frequency" above and below a station's standard analog signal, providing the means to listen to the same program in either HD or as a standard broadcast. The HD format provides the means for a single radio station to broadcast one or more different programs in addition to the program being transmitted on the radio station's analog channel, it was developed by iBiquity. In September 2015 iBiquity was acquired by DTS bringing the HD Radio technology under the same banner as DTS' eponymous theater surround sound systems.. It was acquired by Xperi in 2016, it was selected by the U. S. Federal Communications Commission in 2002 as a digital audio broadcasting method for the United States, is the only digital system approved by the FCC for digital AM/FM broadcasts in the United States, it is known as NRSC-5, with the latest version being NRSC-5-D.
Other digital radio systems include FMeXtra, Digital Audio Broadcasting, Digital Radio Mondiale, Compatible AM-Digital. While HD Radio does allow for an all-digital mode, this system is used by some AM and FM radio stations to simulcast both digital and analog audio within the same channel as well as to add new FM channels and text information. Although HD Radio broadcasting's content is free-to-air, listeners must purchase new receivers in order to receive the digital portion of the signal. By May 2018, HD Radio technology was claimed to be used by more than 3500 individual services in the United States; this compares with more than 2200 services operating with the DAB system. HD Radio increases the bandwidth required in the FM band to 400 kHz for the analog/digital hybrid version; this makes adoption outside the United States problematic. In the United States the FM broadcast band channels have a spacing of 200 kHz, as opposed to the 100 kHz, normal elsewhere; the 200 kHz spacing means that in practice, stations having concurrent or adjacent coverage areas will not be spaced at less than 400 kHz in order to respect protection ratios which would not be met with 200 kHz spacing.
This leaves space for the digital sidebands. Outside the US, spacing can be 300 kHz; the FCC has not indicated any intent to force off analog radio broadcasts as it has with analog television broadcasts, as it would not result in the recovery of any radio spectrum rights which could be sold. Thus, there is no deadline. In addition, there are many more analog AM/FM radio receivers than there were analog televisions, many of these are car stereos or portable units that cannot be upgraded. Digital information is transmitted using OFDM with an audio compression algorithm called HDC.. HD Radio equipped stations pay a one-time licensing fee for converting their primary audio channel to iBiquity's HD Radio technology, 3% of incremental net revenues for any additional digital subchannels; the cost of converting a radio station can run between $100,000 and $200,000. Receiver manufacturers pay a royalty. If the primary digital signal is lost the HD Radio receiver will revert to the analog signal, thereby providing seamless operation between the newer and older transmission methods.
The extra HD-2 and HD-3 streams are not simulcast on analog, causing the sound to drop-out or "skip" when digital reception degrades. Alternatively the HD Radio signal can revert to a more-robust 20 kilobit per second stream, though the sound is reduced to AM-like quality. Datacasting is possible, with metadata providing song titles or artist information. IBiquity Digital claims that the system approaches CD quality audio and offers reduction of both interference and static. Sending pure digital data through the 20 kilohertz AM channel is equivalent to sending data through two 33 kbit/s analog telephone lines, thus limiting the maximum throughput possible. By using spectral band replication the HDC+SBR codec is able to simulate the recreation of sounds up to 15,000 Hz, thus achieving moderate quality on the bandwidth-tight AM band; the HD Radio AM hybrid mode offers two options which can carry 40 or 60 kbit/s of data, but most AM digital stations default to the more-robust 40 kbit/s mode which features redundancy.
HD Radio provides a pure digital mode, which lacks an analog signal for fallback and instead reverts to a 20 kbit/s signal during times of poor reception. The pure digital mode transmissions will stay within the AM station's channel instead of spilling into the channels next to the station transmitting "HD radio" as the hybrid stations do; the AM version of HD Radio technology uses the 20 kHz channel, overlaps 5 kHz into the opposite sideband of the adjacent channel on both sides. When operating in pure digital mode, the AM HD Radio signal fits inside a standard 20 kHz channel or an extended 30 kHz channel, at the discretion of the station manager; as AM radio stations are spaced at 9 kHz or 10 kHz intervals, much of the digital information overlaps adjacent channels when in hybrid mode. Some nigh
FM broadcasting is a method of radio broadcasting using frequency modulation technology. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio. FM broadcasting is capable of better sound quality than AM broadcasting, the chief competing radio broadcasting technology, so it is used for most music broadcasts. Theoretically wideband AM can offer good sound quality, provided the reception conditions are ideal. FM radio stations use the VHF frequencies; the term "FM band" describes the frequency band in a given country, dedicated to FM broadcasting. Throughout the world, the FM broadcast band falls within the VHF part of the radio spectrum. 87.5 to 108.0 MHz is used, or some portion thereof, with few exceptions: In the former Soviet republics, some former Eastern Bloc countries, the older 65.8–74 MHz band is used. Assigned frequencies are at intervals of 30 kHz; this band, sometimes referred to as the OIRT band, is being phased out in many countries.
In those countries the 87.5–108.0 MHz band is referred to as the CCIR band. In Japan, the band 76–95 MHz is used; the frequency of an FM broadcast station is an exact multiple of 100 kHz. In most of South Korea, the Americas, the Philippines and the Caribbean, only odd multiples are used. In some parts of Europe and Africa, only multiples are used. In the UK odd or are used. In Italy, multiples of 50 kHz are used. In most countries the maximum permitted frequency error is specified, the unmodulated carrier should be within 2000 Hz of the assigned frequency. There are other unusual and obsolete FM broadcasting standards in some countries, including 1, 10, 30, 74, 500, 300 kHz. However, to minimise inter-channel interference, stations operating from the same or geographically close transmitter sites tend to keep to at least a 500 kHz frequency separation when closer frequency spacing is technically permitted, with closer tunings reserved for more distantly spaced transmitters, as interfering signals are more attenuated and so have less effect on neighboring frequencies.
Frequency modulation or FM is a form of modulation which conveys information by varying the frequency of a carrier wave. With FM, frequency deviation from the assigned carrier frequency at any instant is directly proportional to the amplitude of the input signal, determining the instantaneous frequency of the transmitted signal; because transmitted FM signals use more bandwidth than AM signals, this form of modulation is used with the higher frequencies used by TV, the FM broadcast band, land mobile radio systems. The maximum frequency deviation of the carrier is specified and regulated by the licensing authorities in each country. For a stereo broadcast, the maximum permitted carrier deviation is invariably ±75 kHz, although a little higher is permitted in the United States when SCA systems are used. For a monophonic broadcast, again the most common permitted. However, some countries specify a lower value for monophonic broadcasts, such as ±50 kHz. Random noise has a triangular spectral distribution in an FM system, with the effect that noise occurs predominantly at the highest audio frequencies within the baseband.
This can be offset, to a limited extent, by boosting the high frequencies before transmission and reducing them by a corresponding amount in the receiver. Reducing the high audio frequencies in the receiver reduces the high-frequency noise; these processes of boosting and reducing certain frequencies are known as pre-emphasis and de-emphasis, respectively. The amount of pre-emphasis and de-emphasis used is defined by the time constant of a simple RC filter circuit. In most of the world a 50 µs time constant is used. In the Americas and South Korea, 75 µs is used; this applies to both stereo transmissions. For stereo, pre-emphasis is applied to the left and right channels before multiplexing; the use of pre-emphasis becomes a problem because of the fact that many forms of contemporary music contain more high-frequency energy than the musical styles which prevailed at the birth of FM broadcasting. Pre-emphasizing these high frequency sounds would cause excessive deviation of the FM carrier. Modulation control devices are used to prevent this.
Systems more modern than FM broadcasting tend to use either programme-dependent variable pre-emphasis. Long before FM stereo transmission was considered, FM multiplexing of other types of audio level information was experimented with. Edwin Armstrong who invented FM was the first to experiment with multiplexing, at his experimental 41 MHz station W2XDG located on the 85th floor of the Empire State Building in New York City; these FM multiplex transmissions started in November 1934 and consisted of the main channel audio program and three subcarriers: a fax program, a synchronizing signal for the fax program and a telegraph “order” channel. These original FM multiplex subcarriers were amplitude modulated. Two musical programs, consisting of both the Red and Blue Network program feeds of the NBC Radio Network, were transmitted using the same system of subcarrier modulation as part of a studio-to-transmitter link system. In April 1935, the AM subcarriers were replaced with much improved results.
The first FM subcarrier transmissions emanating from Major Armstrong's experimental station KE2XCC at Alpine, New Jersey occurred in 1948. These transmissions consisted of two-cha
Broadcast relay station
A broadcast relay station known as a satellite station, relay transmitter, broadcast translator, re-broadcaster, repeater or complementary station, is a broadcast transmitter which repeats the signal of a radio or television station to an area not covered by the originating station. It expands the broadcast range of a television or radio station beyond the primary signal's original coverage or improves service in the original coverage area; the stations may be used to create a single-frequency network. They may be used by an FM or AM radio station to establish a presence on the other band. A re-broadcaster may be owned by a community group, rather than the owner of the primary station. WHLS/WHLX in Port Huron, Michigan purchased a translator and switched to an alternative rock format shortly afterwards without mentioning the original FM translator, except for its required top-of-the-hour ID. No AM frequencies have been mentioned. 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 signal on another frequency.
These stations are used in television and radio to cover areas which are not adequately covered by a station's main signal. They can be used to expand market coverage by duplicating programming on another band. Relays which broadcast within the parent station's coverage area on the same channel 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 a single-frequency network. Analog television stations cannot have same-channel boosters unless opposite 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 uses several medium-power stations on 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 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 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; the use of virtual channels is another alternative, although this may cause 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. 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 licensed like any other station. Although this is unregulated in the U. S. and permitted in Canada, the U. S. Federal Communications Commission 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 cover large, sparsely populated regions or operate as statewide non-commercial educational radio and television systems. A television re-broadcaster sells local advertising for broadcast only on the local transmitter, 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 licensed stations.
In some cases, a semi-satellite is a autonomous full-service station, 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. A financially weak owned broadcaster in a small market can become a de facto semi-satellite by curtailing local production and relying on a owned station in a larger city for programming. 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 have originate nothing. If programming from 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 maintain a national network
Height above average terrain
Height above average terrain, or effective height above average terrain, is a measure of how high an antenna site is above the surrounding landscape. HAAT is used extensively in FM radio and television, as it is more important than effective radiated power in determining the range of broadcasts. For international coordination, it is measured in meters by the Federal Communications Commission in the United States, as Canada and Mexico have extensive border zones where stations can be received on either side of the international boundaries. Stations that want to increase above a certain HAAT must reduce their power accordingly, based on the maximum distance their station class is allowed to cover; the FCC procedure to calculate HAAT is: from the proposed or actual antenna site, either 12 or 16 radials were drawn, points at 2, 4, 6, 8, 10 miles radius along each radial were used. The entire radial graph could be rotated to achieve the best effect for the station; the altitude of the antenna site, minus the average altitude of all the specified points, is the HAAT.
This can create some unusual cases in mountainous regions—it is possible to have a negative number for HAAT. The FCC has divided the Contiguous United States into three zones for the determination of spacing between FM and TV stations using the same frequencies. FM and TV stations are assigned maximum ERP and HAAT values, depending on their assigned zones, to prevent co-channel interference; the FCC regulations for ERP and HAAT are listed under Title 47, Part 73 of the Code of Federal Regulations. Maximum HAAT: 150 metres Maximum ERP: 50 kilowatts Minimum co-channel separation: 241 km Maximum HAAT: 600 metres Maximum ERP: 100 kilowatts Minimum co-channel separation: 290 km. In all zones, maximum ERP for analog TV transmitters is. In addition, Zone I-A consists of all of California south of 40° north latitude, Puerto Rico and the U. S. Virgin Islands. Zones I and I-A have the most "grandfathered" overpowered stations, which are allowed the same extended coverage areas that they had before the zones were established.
One of the most powerful of these stations is WBCT in Grand Rapids, which operates at 320,000 watts and 238 meters HAAT. Zone III consists of all of Florida and the areas of Alabama, Louisiana and Texas within 241.4 kilometers of the Gulf of Mexico. Zone II is all the rest of the Continental United States and Hawaii. Above mean sea level Above ground level Canadian Radio-television and Telecommunications Commission List of broadcast station classes United States Federal Communications Commission 47 CFR Part 73 Index FCC: Mass Media Calculated Contours FCC: HAAT Calculator "Superpower" Grandfathered FM stations
A webcast is a media presentation distributed over the Internet using streaming media technology to distribute a single content source to many simultaneous listeners/viewers. A webcast may either be distributed live or on demand. Webcasting is "broadcasting" over the Internet; the largest "webcasters" include existing radio and TV stations, who "simulcast" their output through online TV or online radio streaming, as well as a multitude of Internet only "stations". Webcasting consists of providing non-interactive linear streams or events. Rights and licensing bodies offer specific "webcasting licenses" to those wishing to carry out Internet broadcasting using copyrighted material. Webcasting is used extensively in the commercial sector for investor relations presentations, in e-learning, for related communications activities. However, webcasting does not bear much, if any, relationship to web conferencing, designed for many-to-many interaction; the ability to webcast using cheap/accessible technology has allowed independent media to flourish.
There are many notable independent shows that broadcast online. Produced by average citizens in their homes they cover many interests and topics. Webcasts relating to computers and news are popular and many new shows are added regularly. Webcasting differs from podcasting in that webcasting refers to live streaming while podcasting refers to media files placed on the Internet. Webcasting is the distribution of media files through the internet; the earliest graphically-oriented web broadcasts were not streaming video, but were in fact still frames which were photographed with a web camera every few minutes while they were being broadcast live over the Internet. One of the earliest instances of sequential live image broadcasting was in 1991 when a camera was set up next to the Trojan Room in the computer laboratory of the University of Cambridge, it provided a live picture every few minutes of the office coffee pot to all desktop computers on that office's network. A couple of years its broadcasts went to the Internet, became known as the Trojan Room Coffee Pot webcam, gained international notoriety as a feature of the fledgling World Wide Web.
In 1996 an American college student and conceptual artist, Jenny Ringley, set up a web camera similar to the Trojan Room Coffee Pot's webcam in her dorm room. That webcam photographed her every few minutes while it broadcast those images live over the Internet upon a site called JenniCam. Ringley wanted to portray all aspects of her lifestyle and the camera captured her doing everything – brushing her teeth, doing her laundry, having sex with her boyfriend, her website generated millions of hits upon the Internet, became a pay site in 1998, spawned hundreds of female imitators who would use streaming video to create a new billion dollar industry called camming, brand themselves as camgirls or webcam models. One of the earliest webcast equivalent of an online concert and one of the earliest examples of webcasting itself was by Apple Computer's Webcasting Group in partnership with the entrepreneurs Michael Dorf and Andrew Rasiej. Together with David B. Pakman from Apple, they launched the Macintosh New York Music Festival from July 17–22, 1995.
This event audio webcast concerts from more than 15 clubs in New York City. Apple webcast a concert by Metallica on June 10, 1996 live from Slim's in San Francisco. In 1995, Benford E. Standley produced one of the first audio/video webcasts in history. On October 31, 1996, UK rock band Caduseus broadcast their one-hour concert from 11 pm to 12 midnight at Celtica in Machynlleth, Wales, UK – the first live streamed audio and simultaneous live streamed video multicast – around the globe to more than twenty direct "mirrors" in more than twenty countries. In September 1997, Nebraska Public Television started webcasting Big Red Wrap Up from Lincoln, Nebraska which combined highlights from every Cornhusker football game, coverage of the coaches' weekly press conferences, analysis with Nebraska sportswriters, appearances by special guests and questions and answers with viewers. On August 13, 1998, it is believed the first webcast wedding took place, between Alan K'necht and Carrie Silverman in Toronto Canada.
On October 22, 1998, the first Billy Graham Crusade was broadcast live to a worldwide audience from the Raymond James Stadium in Tampa Florida courtesy of Dale Ficken and the WebcastCenter in Pennsylvania. The live signal was broadcast via satellite to PA encoded and streamed via the BGEA website; the first teleconferenced/webcast wedding to date is believed to have occurred on December 31, 1998. Dale Ficken and Lorrie Scarangella wed on this date as they stood in a church in Pennsylvania, were married by Jerry Falwell while he sat in his office in Lynchburg, Virginia. All major broadcasters now have a webcast of their output, from the BBC to CNN to Al Jazeera to UNTV in television to Radio China, Vatican Radio, United Nations Radio and the World Service in radio. On November 4, 1994, Stef van der Ziel distributed the first live video images over the web from the Simplon venue in Groningen. On November 7, 1994, WXYC, the college radio station of the University of North Carolina at Chapel Hill became the first radio station in the world to broadcast its signal over the internet.
Translated versions including Subtitling are now possible using SMIL Synchronized Multimedia Integration Language. A wedcast of a wedding. Allows family and friends of the couple to watch the wedding in real time on the Internet, it is sometimes used for weddings in exotic locations, such as Cancun and the Riviera Maya, Hawaii or the Caribbean, for which it is expensive or difficul
In broadcasting and radio communications, a call sign is a unique designation for a transmitter station. In the United States of America, they are used for all FCC-licensed transmitters. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or cryptographically encoded to disguise a station's identity; the use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose; this pattern continued in radiotelegraph operation. These were not globally unique, so a one-letter company identifier was added. By 1912, the need to identify stations operated by multiple companies in multiple nations required an international standard. Merchant and naval vessels are assigned call signs by their national licensing authorities.
In the case of states such as Liberia or Panama, which are flags of convenience for ship registration, call signs for larger vessels consist of the national prefix plus three letters. United States merchant vessels are given call signs beginning with the letters "W" or "K" while US naval ships are assigned call signs beginning with "N". Both ships and broadcast stations were assigned call signs in this series consisting of three or four letters. Ships equipped with Morse code radiotelegraphy, or life boat radio sets, Aviation ground stations, broadcast stations were given four letter call signs. Maritime coast stations on high frequency were assigned three letter call signs; as demand for both marine radio and broadcast call signs grew American-flagged vessels with radiotelephony only were given longer call signs with mixed letters and numbers. Leisure craft with VHF radios may not be assigned call signs, in which case the name of the vessel is used instead. Ships in the US still wishing to have a radio license are under FCC class SA: "Ship recreational or voluntarily equipped."
Those calls follow the land mobile format of the initial letter K or W followed by 1 or 2 letters followed by 3 or 4 numbers. U. S. Coast Guard small boats have a number, shown on both bows in which the first two digits indicate the nominal length of the boat in feet. For example, Coast Guard 47021 refers to the 21st in the series of 47-foot motor lifeboats; the call sign might be abbreviated to the final two or three numbers during operations, for example: Coast Guard zero two one. Aviation mobile stations equipped with radiotelegraphy were assigned five letter call signs.. Land Stations in Aviation were assigned four letter call signs; these call signs were phased out in the 1960s when flight radio officers were no longer required on international flights. USSR kept FRO's for the Moscow-Havana run until around 2000. All signs in aviation are derived from several different policies, depending upon the type of flight operation and whether or not the caller is in an aircraft or at a ground facility.
In most countries, unscheduled general aviation flights identify themselves using the call sign corresponding to the aircraft's registration number. In this case, the call sign is spoken using the International Civil Aviation Organization phonetic alphabet. Aircraft registration numbers internationally follow the pattern of a country prefix, followed by a unique identifier made up of letters and numbers. For example, an aircraft registered as N978CP conducting a general aviation flight would use the call sign November-niner-seven-eight-Charlie-Papa. However, in the United States a pilot of an aircraft would omit saying November, instead use the name of the aircraft manufacturer or the specific model. At times, general aviation pilots might omit additional preceding numbers and use only the last three numbers and letters; this is true at uncontrolled fields when reporting traffic pattern positions or at towered airports after establishing two-way communication with the tower controller. For example, Skyhawk eight-Charlie-Papa, left base.
In most countries, the aircraft call sign or "tail number"/"tail letters" are linked to the international radio call sign allocation table and follow a convention that aircraft radio stations receive call signs consisting of five letters. For example, all British civil aircraft have a five-letter call sign beginning with the letter G. Canadian aircraft have a call sign beginning with C–F or C–G, such as C–FABC. Wing In Ground-effect vehicles in Canada are eligible to receive C–Hxxx call signs, ultralight aircraft receive C-Ixxx call signs. In days gone by American aircraft used five letter call signs, such as KH–ABC, but they were replaced prior to World War II by the current American system of civilian aircraft call signs. Radio call signs used for communication in manned spaceflight is not formalized or regulated to the same degree as for aircraft; the three nations curren
Radio broadcasting is transmission by radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both; the signal types can be digital audio. The earliest radio stations did not carry audio. For audio broadcasts to be possible, electronic detection and amplification devices had to be incorporated; the thermionic valve was invented in 1904 by the English physicist John Ambrose Fleming. He developed a device he called an "oscillation valve"; the heated filament, or cathode, was capable of thermionic emission of electrons that would flow to the plate when it was at a higher voltage. Electrons, could not pass in the reverse direction because the plate was not heated and thus not capable of thermionic emission of electrons. Known as the Fleming valve, it could be used as a rectifier of alternating current and as a radio wave detector; this improved the crystal set which rectified the radio signal using an early solid-state diode based on a crystal and a so-called cat's whisker.
However, what was still required was an amplifier. The triode was patented on March 4, 1906, by the Austrian Robert von Lieben independent from that, on October 25, 1906, Lee De Forest patented his three-element Audion, it wasn't put to practical use until 1912 when its amplifying ability became recognized by researchers. By about 1920, valve technology had matured to the point where radio broadcasting was becoming viable. However, an early audio transmission that could be termed a broadcast may have occurred on Christmas Eve in 1906 by Reginald Fessenden, although this is disputed. While many early experimenters attempted to create systems similar to radiotelephone devices by which only two parties were meant to communicate, there were others who intended to transmit to larger audiences. Charles Herrold started broadcasting in California in 1909 and was carrying audio by the next year.. In The Hague, the Netherlands, PCGG started broadcasting on November 6, 1919, making it, arguably the first commercial broadcasting station.
In 1916, Frank Conrad, an electrical engineer employed at the Westinghouse Electric Corporation, began broadcasting from his Wilkinsburg, Pennsylvania garage with the call letters 8XK. The station was moved to the top of the Westinghouse factory building in East Pittsburgh, Pennsylvania. Westinghouse relaunched the station as KDKA on November 2, 1920, as the first commercially licensed radio station in America; the commercial broadcasting designation came from the type of broadcast license. The first licensed broadcast in the United States came from KDKA itself: the results of the Harding/Cox Presidential Election; the Montreal station that became CFCF began broadcast programming on May 20, 1920, the Detroit station that became WWJ began program broadcasts beginning on August 20, 1920, although neither held a license at the time. In 1920, wireless broadcasts for entertainment began in the UK from the Marconi Research Centre 2MT at Writtle near Chelmsford, England. A famous broadcast from Marconi's New Street Works factory in Chelmsford was made by the famous soprano Dame Nellie Melba on 15 June 1920, where she sang two arias and her famous trill.
She was the first artist of international renown to participate in direct radio broadcasts. The 2MT station began to broadcast regular entertainment in 1922; the BBC was amalgamated in 1922 and received a Royal Charter in 1926, making it the first national broadcaster in the world, followed by Czech Radio and other European broadcasters in 1923. Radio Argentina began scheduled transmissions from the Teatro Coliseo in Buenos Aires on August 27, 1920, making its own priority claim; the station got its license on November 19, 1923. The delay was due to the lack of official Argentine licensing procedures before that date; this station continued regular broadcasting of entertainment and cultural fare for several decades. Radio in education soon followed and colleges across the U. S. began adding radio broadcasting courses to their curricula. Curry College in Milton, Massachusetts introduced one of the first broadcasting majors in 1932 when the college teamed up with WLOE in Boston to have students broadcast programs.
Broadcasting service is – according to Article 1.38 of the International Telecommunication Union´s Radio Regulations – defined as «A radiocommunication service in which the transmission are intended for direct reception by the general public. This service may include sound transmissions, television transmissions or other types of transmission.» Definitions identical to those contained in the Annexes to the Constitution and Convention of the International Telecommunication Union are marked "" or "" respectively. A radio broadcasting station is associated with wireless transmission, though in practice broadcasting transmission take place using both wires and radio waves; the point of this is that anyone with the appropriate receiving technology can receive the broadcast. In line to ITU Radio Regulations each broadcasting station shall be classified by the service in which it operates permanently or temporarily. Broadcasting by radio takes several forms; these include FM stations. There are several subtypes, namely commercial broadcasting, non-commercial educational public broadcasting and non-profit varieties as well as community radio, student-run campus radio stations, and