Radio broadcasting is an audio (sound) broadcasting service, traditionally broadcast through the air as radio waves (a form of electromagnetic radiation) from a transmitter to an antenna and a thus to a receiving device. Stations can be linked in radio networks to broadcast common programming, either in syndication or simulcast or both. Audio broadcasting also can be done via cable FM, local wire networks, satellite and the Internet. Cable Radio or Cable FM is a concept similar to that of Cable television, bringing Radio signals into Homes and Businesses via A television network is a distribution network for Television content whereby a central operation provides programming for many Television stations This article is about artificial satellites For natural satellites also known as moons see Natural satellite. The Internet is a global system of interconnected Computer networks
The earliest radio stations were simply radiotelegraphy systems and did not carry audio. The pre-history and early history of radio is the history of Technology that produced radio instruments that use Radio waves Within the Timeline of The first claimed audio transmission that could be termed a broadcast occurred on Christmas Eve in 1906, and was made by Reginald Fessenden. Christmas Eve, December 24, is the day before Christmas Day, the celebrated birthday of Jesus. Year 1906 ( MCMVI) was a Common year starting on Monday (link will display full calendar of the Gregorian calendar (or a Common year starting Reginald Aubrey Fessenden ( October 6, 1866 &ndash July 22, 1932) born in East Bolton, Quebec, Canada, was While many early experimenters attempted to create systems similar to radiotelephone devices where only two parties were meant to communicate, there were others who intended to transmit to larger audiences. A radiotelephone is a communications device that allows two or more people to talk using Radio. Charles Herrold started broadcasting in California in 1909 and was carrying audio by the next year. Charles David 'Doc' Herrold, ( November 16, 1875 – July 1, 1948) was an American Radio broadcasting California ( is a US state on the West Coast of the United States, along the Pacific Ocean. Year 1909 ( MCMIX) was a Common year starting on Friday (link will display full calendar of the Gregorian calendar (or a Common year starting
For the next decade, radio tinkerers had to build their own radio receivers. KDKA AM of Pittsburgh, Pennsylvania (owned by Westinghouse) started broadcasting as the first licensed "commercial" radio station on November 2, 1920. KDKA (1020 AM) is a Radio station in Pittsburgh Pennsylvania and is often said to be the oldest commercial radio station in the United States The Commonwealth of Pennsylvania ( often colloquially referred to as PA (its abbreviation by natives and Northeasterners is a state located in the Northeastern Founded in 1886 as Westinghouse Electric Company and later renamed Westinghouse Electric Corporation by George Westinghouse. Events 1570 - A Tidal wave in the North Sea devastates the coast from Holland to Jutland, killing more than 1000 Year 1920 ( MCMXX) was a Leap year starting on Thursday (link will display 1920 of the Gregorian calendar The commercial designation came from the type of license—they didn't start airing advertisements until a few years later. Advertising is a form of Communication that typically attempts to persuade potential Customers to Purchase or to consume more of a particular Brand The first broadcast was the results of the U.S. presidential election, 1920. The United States presidential election of 1920 was dominated by the Aftermath of World War I and the hostile reaction to Woodrow Wilson, the Democratic president The Montreal station that became CFCF-AM began program broadcasts on May 20, 1920, and the Detroit station that became WWJ began program broadcasts beginning on August 20, 1920, although neither held a license at the time. Montreal, or Montréal in French ( pronounced in French, in English) is the largest city in the Canadian province of Quebec Events 325 - The First Council of Nicaea &ndash the first Ecumenical Council of the Christian Church is held Year 1920 ( MCMXX) was a Leap year starting on Thursday (link will display 1920 of the Gregorian calendar WWJ (Newsradio 950 is Detroit, Michigan 's only 24-hour All-news radio station Events 636 - Battle of Yarmouk: Arab forces led by Khalid ibn al-Walid take control of Syria and Palestine
Radio Argentina began regularly scheduled transmissions from the Teatro Coliseo in Buenos Aires on August 27, 1920, making its own priority claim. Buenos Aires is the Capital and largest city of Argentina. It is geographically located on the southern shore of the Río de la Plata, on the southeastern Events 479 BC - Greco-Persian Wars: Persian forces led by Mardonius are routed by Pausanias, the Spartan The station got its license on November 19, 1923. Events 1095 - The Council of Clermont, called by Pope Urban II to discuss sending the First Crusade to the Holy Land Year 1923 ( MCMXXIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar. 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. 
When internet based radio became feasible in the mid '90s, the new medium required no licensing and the stations could broadcast from anywhere in the world without the need for "over the air" transmitters. This greatly reduced the overhead for establishing a station, and in 1996, George Maat started 'A' Net Station (A. N. E. T. ) and began broadcasting commercial free from Antarctica.
MIT developed the "Radio Locator" List of Radio Stations. . After stations started streaming audio on the internet, Radio-Locator added this to their search engine so anyone could locate a station's website and listen to a station offering a worldwide stream. This list also tracks "terrestrial" radio stations who may not have live audio on the net, or even a website, but are able to find station information by various other search queries.
The best known are the AM and FM stations; these include both commercial, public and nonprofit varieties as well as student-run campus radio stations and hospital radio stations can be found throughout the developed world. See also Frequency modulation, FM band FM broadcasting is a broadcast Technology invented by Edwin Howard Armstrong that Public broadcasting refers to radio television and other electronic media outlets that receive some or all of their funding from the public A non-profit organization ( abbreviated "NPO" also "not-for-profit" is a legally constituted Organization whose objective is to support or engage Campus radio (also known as college radio, university radio or student radio) is a type of Radio station that is run by the students of a college Hospital radio is a form of audio Broadcasting produced specifically for the in-patients of Hospitals It is primarily found in the United Kingdom. The term developed country, or advanced country, is used to categorize countries with developed Economies in which the tertiary and quaternary sectors
Although now being eclipsed by internet-distributed radio, there are many stations that broadcast on shortwave bands using AM technology that can be received over thousands of miles (especially at night). Shortwave Radio operates between the frequencies of 3000 KHz (3 For example, the BBC has a full schedule transmitted via shortwave. These broadcasts are very sensitive to atmospheric conditions and sunspots.
AM stations were the earliest broadcasting stations to be developed. AM refers to amplitude modulation, a mode of broadcasting radio waves by varying the amplitude of the carrier signal in response to the amplitude of the signal to be transmitted. Amplitude modulation ( AM) is a technique used in electronic communication most commonly for transmitting information via a Radio Carrier wave
One of the advantages of AM is that its unsophisticated signal can be detected (turned into sound) with simple equipment. If a signal is strong enough, not even a power source is needed; building an unpowered crystal radio receiver was a common childhood project in the early years of radio.
AM broadcasts occur on North American airwaves in the medium wave frequency range of 530 to 1700 kHz (known as the "standard broadcast band"). Medium Wave (MW is a part of the Medium frequency (MF radio band used mainly for AM broadcasting. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. The band was expanded in the 1990s by adding nine channels from 1620 to 1700 kHz. The 1990s collectively refers to the years between and including 1990 and 1999 Channel, in communications (sometimes called communications channel) refers to the medium used to convey Information from a Channels are spaced every 10 kHz in the Americas, and generally every 9 kHz everywhere else. The Americas are the lands of the Western hemisphere or New World, consisting of the Continents of North America and South America
Many countries outside of the U.S. use a similar frequency band for AM transmissions. The United States of America —commonly referred to as the Europe also uses the long wave band. The longwave Radio band is a range of frequencies used for AM broadcasting, which extends from 148 In response to the growing popularity of FM radio stereo radio stations in the late 1980s and early 1990s, some North American stations began broadcasting in AM stereo, though this never gained popularity, and very few receivers were ever sold. The 1980s was the decade spanning from January 1 1980 to December 31 1989. The 1990s collectively refers to the years between and including 1990 and 1999 AM Stereo is a term given to a number of mutually incompatible techniques for Broadcasting stereo audio in the AM band in a manner
AM radio has some serious shortcomings.
AM signals exhibit diurnal variation, traveling much longer distances at night. In a crowded channel environment this means that the power of regional channels which share a frequency must be reduced at night or directionally beamed in order to avoid interference, which reduces the potential nighttime audience. Some stations have frequencies unshared with other stations in North America; these are called clear channel stations. The term is also used in the context of T1 A clear channel, in its general sense is a communications channel, such as a radio Many of them can be heard across much of the country at night. (This is not to be confused with Clear Channel Communications, merely a brand name, which currently owns many U. Clear Channel Communications is a media conglomerate company based in the United States. S. radio stations. )
FM refers to frequency modulation, and occurs on VHF airwaves in the frequency range of 88 to 108 MHz everywhere (except Japan and Russia). Very high frequency (VHF is the Radio frequency range from 30 MHz to 300 MHz. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. For a topic outline on this subject see List of basic Japan topics. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending Japan uses the 76 to 90 MHz band. FM stations are much more popular in economically developed regions, such as Europe and the United States, especially since higher sound fidelity and stereo broadcasting became common in this format. The United States of America —commonly referred to as the Stereophonic sound, commonly called stereo, is the reproduction of Sound, using two or more independent audio channels through a Symmetrical
FM radio was invented by Edwin H. Armstrong in the 1930s for the specific purpose of overcoming the interference (static) problem of AM radio, to which it is relatively immune. Edwin Howard Armstrong ( December 18, 1890 &ndash January 31, 1954) was an American Electrical engineer and Inventor The 1930s were described as an abrupt shift to more radical and conservative lifestyles as countries were struggling to find a solution to the Great Depression. At the same time, greater fidelity was made possible by spacing stations further apart. Instead of 10 kHz apart, they are 200 kHz apart. (For example, the difference between the lowest current FM frequency in the U. S. , 88. 1 MHz, and the next lowest, 88. 3 MHz. This was far in advance of the audio equipment of the 1940s, but wide interchannel spacing was chosen to take advantage of the noise-suppressing feature of wideband FM. The 1940s decade ran from 1940 to 1949 Events and trends The 1940s was a period between the radical 1930s and the conservative 1950s which also leads the period to be
In fact, 200 kHz is not needed to accommodate an audio signal — 20 kHz to 30 kHz is all that is necessary for a narrowband FM signal. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. The 200 kHz bandwidth allowed room for ±75 kHz signal deviation from the assigned frequency plus a 20 kHz guardband to eliminate adjacent channel interference. The larger bandwidth allows for broadcasting a 15 kHz bandwidth audio signal plus a 38 kHz stereo "subcarrier" — a piggyback signal that rides on the main signal. Additional unused capacity is used by some broadcasters to transmit utility functions such as background music for public areas, GPS auxiliary signals, or financial market data. Music is an Art form in which the medium is Sound organized in Time. Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth
The AM radio problem of interference at night was addressed in a different way. At the time FM was set up, the available frequencies were far higher in the spectrum than those used for AM radio - by a factor of approximately 100. Using these frequencies meant that even at far higher power, the range of a given FM signal was much lower, thus its market was more local than for AM radio. The reception range at night is the same as at daytime.
The original FM radio service in the U. S. was the Yankee Network, located in New England (see ). Regular FM broadcasting began in 1939, but did not pose a significant threat to the AM broadcasting industry. It required purchase of a special receiver. The frequencies used, 42 to 50 MHz, were not those used today. The change to the current frequencies, 88 to 108 MHz, began after the end of World War II, and it was to some extent imposed by AM radio owners so as to attempt to cripple what was by now realized to be a potentially serious threat. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including
FM radio on the new band had to begin from the ground floor. As a commercial venture it remained a little-used audio enthusiasts' medium until the 1960s. The more prosperous AM stations, or their owners, acquired FM licenses and often broadcast the same programming on the FM station as on the AM station ("simulcasting"). Simulcast is a Portmanteau of " simul taneous broad' cast' " and refers to programs or events broadcast across more than one The FCC limited this practice in the 1970s. This article is about the Decade 1970-1979 For the Year 1970 see 1970. By the 1980s, since almost all new radios included both AM and FM tuners (without any government mandate), FM became the dominant medium, especially in cities. Because of its greater range, AM remained more common in rural environments.
Digital radio broadcasting has emerged, first in Europe (the UK in 1995 and Germany in 1999), and later in the United States, France, Holland, South Africa and many other countries worldwide. Digital radio describes Radio technologies which carry Information as a Digital signal, by means of a Digital modulation method The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Year 1995 ( MCMXCV) was a Common year starting on Sunday. Events of 1995 Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) The most simple system is named DAB Digital Radio, for Digital Audio Broadcasting, and uses the public domain EUREKA 147 (Band III) system. Digital Audio Broadcasting ( DAB) also known as Eureka 147, is a Digital radio technology for Broadcasting Radio stations used in The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone Digital Audio Broadcasting ( DAB) also known as Eureka 147, is a Digital radio technology for Broadcasting Radio stations used in DAB is used mainly in the UK and South Africa. Germany and Holland use the DAB and DAB+ systems, and France use the L-Band system of DAB Digital Radio.
In the United States digital radio isn't used in the same way as Europe and South Africa - instead the IBOC system is named HD Radio and owned by a consortium of private companies called iBiquity. In-band on-channel ( IBOC) is a method of transmitting Digital radio and Analog radio broadcast signals simultaneously on HD Radio is the name used by iBiquity for a system of digital transmission for audio broadcast stations A consortium is an association of two or more individuals companies organizations or governments (or any combination of these entities with the objective of participating iBiquity Digital Corporation is a company formed by the Merger of USA Digital Radio and Lucent Digital Radio, with the goal of creating An international non-profit consortium Digital Radio Mondiale (DRM), has introduced the public domain DRM system. Digital Radio Mondiale ( DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
It is expected that by the end of 2008 a digital radio will be available that can receive all these systems, in the same way that FM and AM can be received on the same radio. It is expected that for the next 10 to 20 years, all these systems will co-exist, while by 2015 to 2020 digital radio may predominate, at least in the developed countries.
Satellite radiobroadcasters are slowly emerging, but the enormous entry costs of space-based satellite transmitters, and restrictions on available radio spectrum licenses has restricted growth of this market. A satellite radio or subscription radio (SR is a Digital radio signal that is broadcast by a Communications satellite, which covers a much wider geographical Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz In the USA and Canada, just two services, XM Satellite Radio and Sirius Satellite Radio exist. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page
Many other non-broadcast types of radio stations exist. These include:
Radio program formats differ by country, regulation and markets. The term base station can be used in the context of Land surveying, Wireless computer networking, and Wireless communications. Police are agents or agencies usually of the executive, empowered to enforce the law and to effect public and social order through the legitimatized use of force Fire is the heat and light energy released during a Chemical reaction, in particular a combustion reaction. An ambulance is a Vehicle for transporting sick or injured people to from or between places of treatment for an Illness or Injury. A military is an Organization authorized by its Nation to use force usually including use of Weapons in defending its Country (or by attacking A taxicab, also taxi or cab, is a type of Public transport for a single passenger or small group of passengers typically for a non-shared ride A courier is a Person or company employed to deliver Messages packages and Mail. For the record label see Emergency Broadcast System Records. For the multimedia group see Emergency Broadcast Network. An amateur radio station is a facility equipped for Radiocommunications in the amateur radio service. This article is about Broadcast radio, for other uses see Radio (disambiguation. For instance, the U. S. Federal Communications Commission designates the 88–92 megahertz band in the U. S. for non-profit or educational programming, with advertising prohibited.
In addition, formats change in popularity as time passes and technology improves. Early radio equipment only allowed program material to be broadcast in real time, known as live broadcasting. As technology for sound recording improved, an increasing proportion of broadcast programming used pre-recorded material. A current trend is the automation of radio stations. Automation ( Ancient Greek: = self dictated) roboticization or industrial automation or Numerical control is the use of Control systems Some stations now operate without direct human intervention by using entirely pre-recorded material sequenced by computer control. A computer is a Machine that manipulates data according to a list of instructions.