AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands.
109-683: WLQV (1500 AM ) is a commercial radio station licensed to Detroit, Michigan . It is owned by the Salem Media Group and broadcasts a Christian talk and teaching radio format . It uses paid brokered programming where hosts buy time on the station and may seek donations to their ministries during their programs. Religious leaders heard on WLQV include David Jeremiah , John MacArthur , Alistair Begg , Jim Daly , Tony Evans and Charles Stanley . The studios are on Radio Plaza in Ferndale, Michigan . By day, WLQV transmits with 50,000 watts ,
218-473: A country music format and changed its call sign to WDEE. Many joked at the time that the call letters stood for "We've Done Everything Else". Former WJBK personality Marc Avery recalled in 1971, when interviewed for the WDRQ program "The History of Detroit Radio", that WJBK had been considering switching to country as far back as the early 1960s. At the time, 1340 WEXL was the only full-time country music station in
327-465: A "chain". The Radio Corporation of America (RCA), General Electric , and Westinghouse organized a competing network around its own flagship station, RCA's WJZ (now WABC) in New York City, but were hampered by AT&T's refusal to lease connecting lines or allow them to sell airtime. In 1926 AT&T sold its radio operations to RCA, which used them to form the nucleus of the new NBC network. By
436-841: A 10 shilling receiver license fee. Both highbrow and mass-appeal programmes were carried by the National and Regional networks. The period from the early 1920s through the 1940s is often called the "Golden Age of Radio". During this period AM radio was the main source of home entertainment, until it was replaced by television. For the first time entertainment was provided from outside the home, replacing traditional forms of entertainment such as oral storytelling and music from family members. New forms were created, including radio plays , mystery serials, soap operas , quiz shows , variety hours , situation comedies and children's shows . Radio news, including remote reporting, allowed listeners to be vicariously present at notable events. Radio greatly eased
545-557: A central station to all parts of the United States", he was unable to overcome the inherent distance limitations of this technology. The earliest public radiotelegraph broadcasts were provided as government services, beginning with daily time signals inaugurated on January 1, 1905, by a number of U.S. Navy stations. In Europe, signals transmitted from a station located on the Eiffel Tower were received throughout much of Europe. In both
654-596: A concerted attempt to specify performance of AM receivers through the 1993 AMAX standard, a joint effort of the EIA and the NAB, with FCC backing... The FCC rapidly followed up on this with codification of the CQUAM AM stereo standard, also in 1993. At this point, the stage appeared to be set for rejuvenation of the AM band. Nevertheless, with the legacy of confusion and disappointment in the rollout of
763-617: A consortium, the British Broadcasting Company (BBC), established on 18 October 1922, which was given a monopoly on broadcasting. This enterprise was supported by a tax on radio sets sales, plus an annual license fee on receivers, collected by the Post Office. Initially the eight stations were allowed regional autonomy. In 1927, the original broadcasting organization was replaced by a government chartered British Broadcasting Corporation . an independent nonprofit supported solely by
872-552: A continuous-wave (CW) transmitter. Fessenden began his research on audio transmissions while doing developmental work for the United States Weather Service on Cobb Island, Maryland. Because he did not yet have a continuous-wave transmitter, initially he worked with an experimental "high-frequency spark" transmitter, taking advantage of the fact that the higher the spark rate, the closer a spark-gap transmission comes to producing continuous waves. He later reported that, in
981-399: A day. WJBK also published Detroit's first printed survey of the station's most popular songs for distribution at local record stores, dubbed "Formula 45" (which became the station's catchphrase). WJBK's chief competitor in the format during the late 1950s and early 1960s was WXYZ 1270 AM, and the two stations were frequently neck-and-neck in the ratings. Since WJBK had retained ownership of
1090-568: A few " telephone newspaper " systems, most of which were established in Europe, beginning with the Paris Théâtrophone . With this in mind, most early radiotelephone development envisioned that the device would be more profitably developed as a "wireless telephone" for personal communication, or for providing links where regular telephone lines could not be run, rather than for the uncertain finances of broadcasting. The person generally credited as
1199-463: A few hundred ( Hz ), to increase its rotational speed and so generate currents of tens-of-thousands Hz, thus producing a steady continuous-wave transmission when connected to an aerial. The next step, adopted from standard wire-telephone practice, was to insert a simple carbon microphone into the transmission line, to modulate the carrier wave signal to produce AM audio transmissions. However, it would take many years of expensive development before even
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#17330860026401308-477: A formal license application by January 15, 1928, as the first step in determining whether they met the new "public interest, convenience, or necessity" standard. On May 25, 1928, the FRC issued General Order 32 , which notified 164 stations, including WJBK, that "From an examination of your application for future license it does not find that public interest, convenience, or necessity would be served by granting it." However,
1417-642: A group of nine stations and a satellite network. "CBSL" owned WLQV until its sale to Salem. Under Yinger's ownership the station went by the name "Victory 1500", using the same brand name as then-sister stations WSNL in Flint and WLCM in Lansing. In February 2006, WLQV was sold to Salem Communications , the country's largest owner of Christian-oriented stations. The station was traded for cash and two stations in Cincinnati, Ohio . WLQV's operations were handled thereafter by
1526-512: A home audio device prior to the introduction of the high-fidelity , long-playing record in the late 1940s. Listening habits changed in the 1960s due to the introduction of the revolutionary transistor radio (Regency TR-1, the first transistor radio released December 1954), which was made possible by the invention of the transistor in 1948. (The transistor was invented at Bell labs and released in June 1948.) Their compact size — small enough to fit in
1635-469: A listening site at Plymouth, Massachusetts. An American Telephone Journal account of the December 21 alternator-transmitter demonstration included the statement that "It is admirably adapted to the transmission of news, music, etc. as, owing to the fact that no wires are needed, simultaneous transmission to many subscribers can be effected as easily as to a few", echoing the words of a handout distributed to
1744-479: A majority of early broadcasting stations operated on mediumwave frequencies, whose limited range generally restricted them to local audiences. One method for overcoming this limitation, as well as a method for sharing program costs, was to create radio networks , linking stations together with telephone lines to provide a nationwide audience. In the U.S., the American Telephone and Telegraph Company (AT&T)
1853-503: A national scale. The introduction of nationwide talk shows, most prominently Rush Limbaugh 's beginning in 1988, was sometimes credited with "saving" AM radio. However, these stations tended to attract older listeners who were of lesser interest to advertisers, and AM radio's audience share continued to erode. In 1961, the FCC adopted a single standard for FM stereo transmissions, which was widely credited with enhancing FM's popularity. Developing
1962-399: A policy allowing AM stations to simulcast over FM translator stations. Translators had previously been available only to FM broadcasters, in order to increase coverage in fringe areas. Their assignment for use by AM stations was intended to approximate the station's daytime coverage, which in cases where the stations reduced power at night, often resulted in expanded nighttime coverage. Although
2071-482: A prototype alternator-transmitter would be ready, and a few years beyond that for high-power versions to become available. Fessenden worked with General Electric 's (GE) Ernst F. W. Alexanderson , who in August 1906 delivered an improved model which operated at a transmitting frequency of approximately 50 kHz, although at low power. The alternator-transmitter achieved the goal of transmitting quality audio signals, but
2180-423: A result, AM radio tends to do best in areas where FM frequencies are in short supply, or in thinly populated or mountainous areas where FM coverage is poor. Great care must be taken to avoid mutual interference between stations operating on the same frequency. In general, an AM transmission needs to be about 20 times stronger than an interfering signal to avoid a reduction in quality, in contrast to FM signals, where
2289-446: A second attempt at Top 40 in 1969 with a lineup of disc jockeys that included K.O. Bayley, Lee 'Baby' Simms, Tom Dean, Jim Hampton and CKLW mainstay Tom Shannon, but it lasted only a few months. The WJBK call letters are no longer used in radio; they were retained on WJBK-TV, now owned by Fox Television Stations and airs network programming from Fox , along with a local news operation. At midnight on December 26, 1969, WJBK flipped to
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#17330860026402398-452: A shirt pocket — and lower power requirements, compared to vacuum tubes, meant that for the first time radio receivers were readily portable. The transistor radio became the most widely used communication device in history, with billions manufactured by the 1970s. Radio became a ubiquitous "companion medium" which people could take with them anywhere they went. The demarcation between what is considered "experimental" and "organized" broadcasting
2507-427: A short-range "wireless telephone" demonstration, that included simultaneously broadcasting speech and music to seven locations throughout Murray, Kentucky. However, this was transmitted using induction rather than radio signals, and although Stubblefield predicted that his system would be perfected so that "it will be possible to communicate with hundreds of homes at the same time", and "a single message can be sent from
2616-615: A small chain of religious stations in the Midwest, bought WLQV in December 1993. Under the ownership of Yinger (a former Gannett GSM and GM of Satellite Radio Network), WLQV retained the Christian talk format and generated a loyal following with a niche group of listeners. The station's programming featured nationally-known evangelists and teachers such as Billy Graham , Dr. J. Vernon McGee, Charles Stanley and others, along with Detroit-area pastors and preachers. This formula stayed in place through
2725-636: A subsidiary of Salem, Caron Broadcasting. The studios were moved from suburban Livonia to downtown Detroit's Penobscot Building . In mid-September 2006 the station moved from the Penobscot Building to its new studio site in Royal Oak Township . Except for minor changes in programming and station structure, the Christian talk and teaching format continues. WLQV is the flagship radio voice of University of Detroit Mercy men's basketball , with play-by-play provided by Dan Hasty. For several years in
2834-461: A widespread audience — dates back to the founding period of radio development, even though the earliest radio transmissions, originally known as "Hertzian radiation" and "wireless telegraphy", used spark-gap transmitters that could only transmit the dots-and-dashes of Morse code . In October 1898 a London publication, The Electrician , noted that "there are rare cases where, as Dr. [Oliver] Lodge once expressed it, it might be advantageous to 'shout'
2943-493: A year later, the call letters changed to WLQV, meant to designate the word "love". It flipped to a Christian radio format. In 1985, the station made one last return to playing Top 40 music as it became WCZY again. Unlike its first time as WCZY, this time it was a 100% simulcast of the FM station, which by then had changed from easy listening to Adult Top 40 . With Z95.5 featuring future Radio Hall of Fame inductee Dick Purtan , much
3052-416: Is a combination of live and pre-recorded programming. The prerecorded clips are usually run from a playlist. As music storage and playback using personal computers became common, the term "playlist" was adopted by various media player software programs intended to organize and control music on a PC. Such playlists may be defined, stored, and selected to run either in sequence or if a random playlist function
3161-400: Is available on YouTube as a playlist of thirteen consecutive video chapters. The term originally came about in the early days of Top 40 radio formats in the 1950s when stations would devise (and, eventually, publish) a limited list of songs to be played. The term would go on to refer to the entire catalog of songs that a given radio station (of any format) would draw from. Additionally,
3270-737: Is available on the Internet. Pandora is one of the few music services that is free (no subscription required) to users. The user can select genres that are played back at random on Pandora's playlists. A celebrity playlist is a list of songs prepared by a celebrity and represented in popular publications and on the radio as such. On video hosting service websites such as YouTube and Vimeo , users can make playlists of select videos from themselves or other users for topical purposes; paid accounts can upgrade playlists of their own videos to "shows". Most media players , such as Winamp , can easily create custom playlists from one's media library. For example, in
3379-406: Is comparable to or better in audio quality than a standard analog broadcast". Despite the various actions, AM band audiences continued to contract, and the number of stations began to slowly decline. A 2009 FCC review reported that "The story of AM radio over the last 50 years has been a transition from being the dominant form of audio entertainment for all age groups to being almost non-existent to
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3488-497: Is largely arbitrary. Listed below are some of the early AM radio broadcasts, which, due to their irregular schedules and limited purposes, can be classified as "experimental": People who weren't around in the Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for
3597-476: Is located off Dix Highway ( U.S. Route 25 ), just south of I-75 in Lincoln Park . The station has a highly directional antenna system. There had been 12 towers arranged in 4 parallel sets of 3 towers from the time of the upgrade to 50,000 watts in the early 1960s until the demolition of the easternmost three towers. The original mid-50s Lincoln Park array featured four pairs of two towers. A view of this array
3706-456: Is selected, in a random order. Playlists' uses include allowing a particular desired musical atmosphere to be created and maintained without constant user interaction or allowing a variety of different styles of music to be played, again without maintenance. Several computer playlist formats for multimedia players, such as PLS , can pass a playlist or URL to the player. In the case of radio stations it can also link many audio players directly to
3815-468: Is simply a list of songs that can be played once or in a loop . The term has several specialized meanings in the realms of television broadcasting , radio broadcasting and personal computers . A video playlist can also be a list of recorded titles on a digital video disk (DVD). On the internet, a playlist can be a list of chapters in a movie serial ; for example, Flash Gordon in the Planet Mongo
3924-454: Is visible in aerial images and topographic maps of the era. This site is just west of Dix Highway, near its intersection with Emmons Boulevard. In the early 1990s, the easternmost set of towers was taken down to make room for a Super Kmart store which opened in 1994. That store closed in 2003 during Kmart's second round of bankruptcy and reopened as a Meijer in 2004. AM broadcasting The earliest experimental AM transmissions began in
4033-556: The Electronic Industries Association (EIA) and the National Association of Broadcasters (NAB) with the intention of helping AM stations, especially ones with musical formats, become more competitive with FM broadcasters by promoting better quality receivers. However, the stereo AM and AMAX initiatives had little impact, and a 2015 review of these events concluded that Initially the consumer manufacturers made
4142-657: The Emergency Alert System (EAS). Some automakers have been eliminating AM radio from their electric vehicles (EVs) due to interference from the electric motors , but the lawmakers argue that this is a safety risk and that car owners should have access to AM radio regardless of the type of vehicle they drive. The proposed legislation would require all new vehicles to include AM radio at no additional charge, and it would also require automakers that have already eliminated AM radio to inform customers of alternatives. A proper solution would be to switch to DRM30 as indicated in
4251-479: The Federal Emergency Management Agency (FEMA) expressed concerns that this would reduce the effectiveness of emergency communications. In May 2023, a bipartisan group of lawmakers in the United States introduced legislation making it illegal for automakers to eliminate AM radio from their cars. The lawmakers argue that AM radio is an important tool for public safety due to being a component of
4360-431: The electrolytic detector and thermionic diode ( Fleming valve ) were invented by Reginald Fessenden and John Ambrose Fleming , respectively. Most important, in 1904–1906 the crystal detector , the simplest and cheapest AM detector, was developed by G. W. Pickard . Homemade crystal radios spread rapidly during the next 15 years, providing ready audiences for the first radio broadcasts. One limitation of crystals sets
4469-430: The " capture effect " means that the dominant signal needs to only be about twice as strong as the interfering one. To allow room for more stations on the mediumwave broadcast band in the United States, in June 1989 the FCC adopted a National Radio Systems Committee (NRSC) standard that limited maximum transmitted audio bandwidth to 10.2 kHz, limiting occupied bandwidth to 20.4 kHz. The former audio limitation
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4578-558: The "Jack the Bellboy" name after Ed McKenzie left the station, there were several more "Jack the Bellboy"s at Radio 15 during the late 1950s and early 1960s, including Tom Clay (known for creating a romantic aura on the air), Dave Shafer, Terry Knight and Robin Walker. Other popular WJBK personalities included longtime morning host Marc Avery, midday host Clark Reid and afternoon drive personality Robert E. Lee (who claimed to be an actual descendant of
4687-587: The 1930s, most of the major radio stations in the country were affiliated with networks owned by two companies, NBC and CBS . In 1934, a third national network, the Mutual Radio Network , was formed as a cooperative owned by its stations. A second country which quickly adopted network programming was the United Kingdom, and its national network quickly became a prototype for a state-managed monopoly of broadcasting. A rising interest in radio broadcasting by
4796-660: The 1940s two new broadcast media, FM radio and television , began to provide extensive competition with the established broadcasting services. The AM radio industry suffered a serious loss of audience and advertising revenue, and coped by developing new strategies. Network broadcasting gave way to format broadcasting: instead of broadcasting the same programs all over the country, stations individually adopted specialized formats which appealed to different audiences, such as regional and local news, sports, "talk" programs, and programs targeted at minorities. Instead of live music, most stations began playing less expensive recorded music. In
4905-536: The 2010s, WLQV was the Detroit-area affiliate of the Rocket Sports Radio Network, broadcasting University of Toledo football and select men's basketball games, as well as the coach's shows for both sports. On November 18, 2016, sister station WDTK moved its FM translator , W268CN, from 92.7 FM to 101.5 FM. At the same time, 92.7 W224CC became the FM translator for WLQV. The station's transmitter
5014-528: The AM radio industry in the United States developed technology for broadcasting in stereo . Other nations adopted AM stereo, most commonly choosing Motorola's C-QUAM, and in 1993 the United States also made the C-QUAM system its standard, after a period allowing four different standards to compete. The selection of a single standard improved acceptance of AM stereo , however overall there was limited adoption of AM stereo worldwide, and interest declined after 1990. With
5123-521: The British public pressured the government to reintroduce the service, following its suspension in 1920. However, the government also wanted to avoid what it termed the "chaotic" U.S. experience of allowing large numbers of stations to operate with few restrictions. There were also concerns about broadcasting becoming dominated by the Marconi company. Arrangements were made for six large radio manufacturers to form
5232-411: The Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for the first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio. The idea of broadcasting — the unrestricted transmission of signals to
5341-662: The United States and France this led to a small market of receiver lines geared for jewelers who needed accurate time to set their clocks, including the Ondophone in France, and the De Forest RS-100 Jewelers Time Receiver in the United States The ability to pick up time signal broadcasts, in addition to Morse code weather reports and news summaries, also attracted the interest of amateur radio enthusiasts. It
5450-523: The antenna wire. This meant that the full transmitter power flowed through the microphone, and even using water cooling, the power handling ability of the microphones severely limited the power of the transmissions. Ultimately only a small number of large and powerful Alexanderson alternators would be developed. However, they would be almost exclusively used for long-range radiotelegraph communication, and occasionally for radiotelephone experimentation, but were never used for general broadcasting. Almost all of
5559-474: The audience has continued to decline. In 1987, the elimination of the Fairness Doctrine requirement meant that talk shows, which were commonly carried by AM stations, could adopt a more focused presentation on controversial topics, without the distraction of having to provide airtime for any contrasting opinions. In addition, satellite distribution made it possible for programs to be economically carried on
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#17330860026405668-404: The characteristics of arc-transmitters . Fessenden attempted to sell this form of radiotelephone for point-to-point communication, but was unsuccessful. Fessenden's work with high-frequency spark transmissions was only a temporary measure. His ultimate plan for creating an audio-capable transmitter was to redesign an electrical alternator , which normally produced alternating current of at most
5777-403: The commission estimated that fewer than 250 AM stations were transmitting hybrid mode signals. On October 27, 2020, the FCC voted to allow AM stations to eliminate their analog transmissions and convert to all-digital operation, with the requirement that stations making the change had to continue to make programming available over "at least one free over-the-air digital programming stream that
5886-475: The continued migration of AM stations away from music to news, sports, and talk formats, receiver manufacturers saw little reason to adopt the more expensive stereo tuners, and thus radio stations have little incentive to upgrade to stereo transmission. In countries where the use of directional antennas is common, such as the United States, transmitter sites consisting of multiple towers often occupy large tracts of land that have significantly increased in value over
5995-437: The continuous wave AM transmissions made prior to 1915 were made by versions of the arc converter transmitter, which had been initially developed by Valdemar Poulsen in 1903. Arc transmitters worked by producing a pulsating electrical arc in an enclosed hydrogen atmosphere. They were much more compact than alternator transmitters, and could operate on somewhat higher transmitting frequencies. However, they suffered from some of
6104-423: The country format and became WCXI "Country 11", featuring Deano Day and other former WDEE personalities. In the latter part of 1979, after less than a year, due to a highly directional signal and WCXI overtaking WDEE in the ratings, the country format was abandoned. WDEE's call sign was changed to WCZY and ran a more contemporary version of sister station WCZY-FM 's highly rated easy listening music format. About
6213-434: The decades, to the point that the value of land exceeds that of the station itself. This sometimes results in the sale of the transmitter site, with the station relocating to a more distant shared site using significantly less power, or completely shutting down operations. The ongoing development of alternative transmission systems, including Digital Audio Broadcasting (DAB), satellite radio, and HD (digital) radio, continued
6322-567: The decline of the popularity of the traditional broadcast technologies. These new options, including the introduction of Internet streaming, particularly resulted in the reduction of shortwave transmissions, as international broadcasters found ways to reach their audiences more easily. In 2022 it was reported that AM radio was being removed from a number of electric vehicle (EV) models, including from cars manufactured by Tesla, Audi, Porsche, BMW and Volvo, reportedly due to automakers concerns that an EV's higher electromagnetic interference can disrupt
6431-406: The defunct Playlist.com and Webjay , allow users to categorize, edit, and listen to playlists online. Other sites focus on playlist creation aided by personalized song recommendations, ratings, and reviews. On certain sites, users create and share annotated playlists, giving visitors the option to read contextual information or reviewer comments about each song while listening. Some sites only allow
6540-569: The demonstration witnesses, which stated "[Radio] Telephony is admirably adapted for transmitting news, stock quotations, music, race reports, etc. simultaneously over a city, on account of the fact that no wires are needed and a single apparatus can distribute to ten thousand subscribers as easily as to a few. It is proposed to erect stations for this purpose in the large cities here and abroad." However, other than two holiday transmissions reportedly made shortly after these demonstrations, Fessenden does not appear to have conducted any radio broadcasts for
6649-687: The diagram above. AM radio technology is simpler than later transmission systems. An AM receiver detects amplitude variations in the radio waves at a particular frequency, then amplifies changes in the signal voltage to operate a loudspeaker or earphone . However, the simplicity of AM transmission also makes it vulnerable to "static" ( radio noise , radio frequency interference ) created by both natural atmospheric electrical activity such as lightning, and electrical and electronic equipment, including fluorescent lights, motors and vehicle ignition systems. In large urban centers, AM radio signals can be severely disrupted by metal structures and tall buildings. As
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#17330860026406758-756: The early 1900s. However, widespread AM broadcasting was not established until the 1920s, following the development of vacuum tube receivers and transmitters. AM radio remained the dominant method of broadcasting for the next 30 years, a period called the " Golden Age of Radio ", until television broadcasting became widespread in the 1950s and received much of the programming previously carried by radio. Later, AM radio's audiences declined greatly due to competition from FM ( frequency modulation ) radio, Digital Audio Broadcasting (DAB), satellite radio , HD (digital) radio , Internet radio , music streaming services , and podcasting . Compared to FM or digital transmissions , AM transmissions are more expensive to transmit due to
6867-672: The early 1970s, WDEE was purchased by Combined Communications, whch in turn was purchased by the Gannett Company. (Previous to Combined ownership, WDEE was part of a broadcast chain owned by Globe Broadcasting, owned by the Harlem Globetrotters .) Also during this time, WDEE-FM changed to news/talk as WDRQ-FM. That lasted until 1972, when Charter Broadcasting bought WDRQ and switched to Top 40, using such memorable slogan as "I Q in My Car". Four decades and several formats later, that station
6976-600: The expectation is that listeners will primarily be tuning into the FM signal rather than the nominally "primary" AM station. A 2020 review noted that "for many owners, keeping their AM stations on the air now is pretty much just about retaining their FM translator footprint rather than keeping the AM on the air on its own merits". In 2018 the FCC, led by then-Commission Chairman Ajit Pai , proposed greatly reducing signal protection for 50 kW Class A " clear channel " stations. This would allow co-channel secondary stations to operate with higher powers, especially at night. However,
7085-445: The fall of 1900, he successfully transmitted speech over a distance of about 1.6 kilometers (one mile), which appears to have been the first successful audio transmission using radio signals. However, at this time the sound was far too distorted to be commercially practical. For a time he continued working with more sophisticated high-frequency spark transmitters, including versions that used compressed air, which began to take on some of
7194-401: The first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio. Following World War I, the number of stations providing a regular broadcasting service greatly increased, primarily due to advances in vacuum-tube technology. In response to ongoing activities, government regulators eventually codified standards for which stations could make broadcasts intended for
7303-620: The general public, for example, in the United States formal recognition of a "broadcasting service" came with the establishment of regulations effective December 1, 1921, and Canadian authorities created a separate category of "radio-telephone broadcasting stations" in April 1922. However, there were numerous cases of entertainment broadcasts being presented on a regular schedule before their formal recognition by government regulators. Some early examples include: Because most longwave radio frequencies were used for international radiotelegraph communication,
7412-417: The general public, or to have even given additional thought about the potential of a regular broadcast service, and in a 1908 article providing a comprehensive review of the potential uses for his radiotelephone invention, he made no references to broadcasting. Because there was no way to amplify electrical currents at this time, modulation was usually accomplished by a carbon microphone inserted directly in
7521-453: The immediate Detroit market. WDEE distinguished itself with its slick, contemporary (" countrypolitan ") approach to the country format, designed for mass appeal, and was one of the first stations to program country and western music with a Top 40-style presentation. The move paid off with frequent top-five showings in the Detroit ratings during the 1970s. With only a thousand watts of power, WEXL
7630-541: The isolation of rural life. Political officials could now speak directly to millions of citizens. One of the first to take advantage of this was American president Franklin Roosevelt , who became famous for his fireside chats during the Great Depression . However, broadcasting also provided the means to use propaganda as a powerful government tool, and contributed to the rise of fascist and communist ideologies. In
7739-411: The lack of any way to amplify the signals meant they were somewhat weak. On December 21, 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, Massachusetts, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. As part of the demonstration, speech was transmitted 18 kilometers (11 miles) to
7848-419: The late 1960s and 1970s, top 40 rock and roll stations in the U.S. and Canada such as WABC and CHUM transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. For young people, listening to AM broadcasts and participating in their music surveys and contests was the social media of the time. In the late 1970s, spurred by the exodus of musical programming to FM stations,
7957-506: The legendary Confederate Civil War general and opened his show every afternoon with a "Rebel Yell"). In 1962, WJBK was granted a daytime power increase. It was powered at 50,000 watts by day and 5,000 watts at night. Then, WKNR "Keener 13" was launched at 1310 AM on Halloween 1963, burying the Motor City's Top 40 competition - including WJBK. It featured a shorter playlist and a tighter, more energetic presentation than any other station in
8066-512: The market. WJBK gave up the fight in 1964 and switched to an easy listening music format. In 1966 the station tweaked to an early version of what would today be called Adult Contemporary , featuring a mix of adult Hot 100 chart hits from the likes of the Mamas & the Papas , B.J. Thomas , Nancy Sinatra and Bob Dylan , and select album cuts. Through the changes, ratings remained low. The station made
8175-446: The market. The station also launched the career of Casey Kasem , later the long-time host of American Top 40 . In 1954, WJBK moved to its current frequency at 1500 AM with 10,000 watts. By this time, Storer Broadcasting owned WJBK-AM-FM as well as WJBK-TV, Detroit's CBS -TV network affiliate . In 1956, WJBK became the first radio station in Detroit to feature the Top 40 format 24 hours
8284-399: The marketplace decide" which was best. The lack of a common standard resulted in consumer confusion and increased the complexity and cost of producing AM stereo receivers. In 1993, the FCC again revised its policy, by selecting C-QUAM as the sole AM stereo implementation. In 1993, the FCC also endorsed, although it did not make mandatory, AMAX broadcasting standards that were developed by
8393-402: The maximum for American AM stations; to protect other stations from interference at night, WLQV reduces power to 10,000 watts. It uses a directional antenna with a nine- tower array . The transmitter is on Hazel Avenue near Dix Highway and Interstate 75 in Lincoln Park, Michigan . Programming is also heard on 99-watt FM translator W224CC at 92.7 MHz in Detroit. On October 7, 1925,
8502-432: The message, spreading it broadcast to receivers in all directions". However, it was recognized that this would involve significant financial issues, as that same year The Electrician also commented "did not Prof. Lodge forget that no one wants to pay for shouting to the world on a system by which it would be impossible to prevent non-subscribers from benefiting gratuitously?" On January 1, 1902, Nathan Stubblefield gave
8611-439: The mid-2000s. Yinger oversaw and completed WLQV's longstanding application for increased nighttime power. In 2003, WLQV began operating with 9 towers at night, 10,000 watts of power, ending an eighteen-year standoff with WTOP and KSTP . Both stations were also broadcasting on 1500 AM and were concerned that WLQV would interfere with their signals. By this time, Yinger's company was known as "The Christian Broadcasting System",
8720-448: The multiple incompatible AM stereo systems, and failure of the manufacturers (including the auto makers) to effectively promote AMAX radios, coupled with the ever-increasing background of noise in the band, the general public soon lost interest and moved on to other media. On June 8, 1988, an International Telecommunication Union (ITU)-sponsored conference held at Rio de Janeiro, Brazil adopted provisions, effective July 1, 1990, to extend
8829-537: The necessity of having to transmit a high power carrier wave to overcome ground losses, and the large antenna radiators required at the low broadcast frequencies, but can be sent over long distances via the ionosphere at night; however, they are much more susceptible to interference, and often have lower audio fidelity. Thus, AM broadcasters tend to specialize in spoken-word formats, such as talk radio , all-news radio and sports radio , with music formats primarily for FM and digital stations. People who weren't around in
8938-405: The new frequencies. It was now estimated that the expanded band could accommodate around 300 U.S. stations. However, it turned out that the number of possible station reassignments was much lower, with a 2006 accounting reporting that, out of 4,758 licensed U.S. AM stations, only 56 were now operating on the expanded band. Moreover, despite an initial requirement that by the end of five years either
9047-428: The new policy, by 2011 there were approximately 500 in operation, and as of 2020 approximately 2,800 of the 4,570 licensed AM stations were rebroadcasting on one or more FM translators. In 2009 the FCC stated that "We do not intend to allow these cross-service translators to be used as surrogates for FM stations". However, based on station slogans, especially in the case of recently adopted musical formats, in most cases
9156-411: The original station or its expanded band counterpart had to cease broadcasting, as of 2015 there were 25 cases where the original standard band station was still on the air, despite also operating as an expanded band station. HD Radio is a digital audio broadcasting method developed by iBiquity . In 2002 its "hybrid mode", which simultaneously transmits a standard analog signal as well as a digital one,
9265-433: The overheating issues of needing to insert microphones directly in the transmission antenna circuit. Vacuum tube transmitters also provided high-quality AM signals, and could operate on higher transmitting frequencies than alternator and arc transmitters. Non-governmental radio transmissions were prohibited in many countries during World War I, but AM radiotelephony technology advanced greatly due to wartime research, and after
9374-441: The primary early developer of AM technology is Canadian-born inventor Reginald Fessenden . The original spark-gap radio transmitters were impractical for transmitting audio, since they produced discontinuous pulses known as " damped waves ". Fessenden realized that what was needed was a new type of radio transmitter that produced steady "undamped" (better known as " continuous wave ") signals, which could then be "modulated" to reflect
9483-637: The reception of AM transmissions and hurt the listening experience, among other reasons. However the United States Congress has introduced a bill to require all vehicles sold in the US to have an AM receiver to receive emergency broadcasts. The FM broadcast band was established in 1941 in the United States, and at the time some suggested that the AM band would soon be eliminated. In 1948 wide-band FM's inventor, Edwin H. Armstrong , predicted that "The broadcasters will set up FM stations which will parallel, carry
9592-799: The same deficiencies. The lack of any means to amplify electrical currents meant that, like the alternator transmitters, modulation was usually accomplished by a microphone inserted directly in the antenna wire, which again resulted in overheating issues, even with the use of water-cooled microphones. Thus, transmitter powers tended to be limited. The arc was also somewhat unstable, which reduced audio quality. Experimenters who used arc transmitters for their radiotelephone research included Ernst Ruhmer , Quirino Majorana , Charles "Doc" Herrold , and Lee de Forest . Advances in vacuum tube technology (called "valves" in British usage), especially after around 1915, revolutionized radio technology. Vacuum tube devices could be used to amplify electrical currents, which overcame
9701-400: The same program, as over their AM stations... eventually the day will come, of course, when we will no longer have to build receivers capable of receiving both types of transmission, and then the AM transmitters will disappear." However, FM stations actually struggled for many decades, and it was not until 1978 that FM listenership surpassed that of AM stations. Since then the AM band's share of
9810-411: The sharing of the playlist data with the actual music being delivered by other channels (e.g., Plurn), others provide a closed catalog of content from which the playlists can be generated, and sites like imeem allow users to upload the music to central servers to be shared and accessed by any user of the site. iPods can also be used to build playlists. Pandora is another music streaming service that
9919-410: The sounds being transmitted. Fessenden's basic approach was disclosed in U.S. Patent 706,737, which he applied for on May 29, 1901, and was issued the next year. It called for the use of a high-speed alternator (referred to as "an alternating-current dynamo") that generated "pure sine waves" and produced "a continuous train of radiant waves of substantially uniform strength", or, in modern terminology,
10028-600: The station first signed on the air. Its original call sign was WJBK and it was licensed to nearby Ypsilanti , broadcasting on 1290 kHz . The call letters were randomly assigned from a sequential roster of available call signs. Two years later, WJBK moved to 1360 kHz. Following the establishment of the Federal Radio Commission (FRC), stations were initially issued a series of temporary authorizations starting on May 3, 1927. In addition, they were informed that if they wanted to continue operating, they needed to file
10137-468: The station successfully convinced the commission that it should remain licensed. On November 11, 1928, the FRC implemented a major reallocation of station transmitting frequencies, as part of a reorganization resulting from its implementation of General Order 40 . WJBK was assigned to 1370 kHz. In 1940, WJBK was re-licensed to Detroit, broadcasting on 1490 AM. It was owned by John F. Hopkins, with its studios at 6559 Hamilton Avenue. An FM station at 93.1
10246-421: The station's live streaming audio, bypassing any need for a web browser. (In that case, the playlist file is typically downloaded from the station's live streaming web page, if offered. The files are similar to Internet shortcut files in appearance and internal structure, except used by media players rather than web browsers.) Some Internet streaming services , such as Spotify , Amazon Music , 8tracks , and
10355-411: The technology for AM broadcasting in stereo was challenging due to the need to limit the transmissions to a 20 kHz bandwidth, while also making the transmissions backward compatible with existing non-stereo receivers. In 1990, the FCC authorized an AM stereo standard developed by Magnavox, but two years later revised its decision to instead approve four competing implementations, saying it would "let
10464-424: The term was used to refer to an ordered list of songs played during a given time period. Playlists are often adjusted based on time of day, known as dayparting . Cable TV and broadcast TV news channels often use video playlists to rerun prerecorded news stories. A given news story might initially be shown live and then placed into a playlist to be shown over and over again at a later time. News channel broadcasting
10573-401: The translator stations are not permitted to originate programming when the "primary" AM station is broadcasting, they are permitted to do so during nighttime hours for AM stations licensed for daytime-only operation. Prior to the adoption of the new policy, as of March 18, 2009, the FCC had issued 215 Special Temporary Authority grants for FM translators relaying AM stations. After creation of
10682-492: The upper end of the Region 2 AM broadcast band, by adding ten frequencies which spanned from 1610 kHz to 1700 kHz. At this time it was suggested that as many as 500 U.S. stations could be assigned to the new frequencies. On April 12, 1990, the FCC voted to begin the process of populating the expanded band, with the main priority being the reduction of interference on the existing AM band, by transferring selected stations to
10791-548: The war the availability of tubes sparked a great increase in the number of amateur radio stations experimenting with AM transmission of news or music. Vacuum tubes remained the central technology of radio for 40 years, until transistors began to dominate in the late 1950s, and are still used in the highest power broadcast transmitters. Unlike telegraph and telephone systems, which used completely different types of equipment, most radio receivers were equally suitable for both radiotelegraph and radiotelephone reception. In 1903 and 1904
10900-404: The youngest demographic groups. Among persons aged 12–24, AM accounts for only 4% of listening, while FM accounts for 96%. Among persons aged 25–34, AM accounts for only 9% of listening, while FM accounts for 91%. The median age of listeners to the AM band is 57 years old, a full generation older than the median age of FM listeners." In 2009, the FCC made a major regulatory change, when it adopted
11009-508: Was 15 kHz resulting in bandwidth of 30 kHz. Another common limitation on AM fidelity is the result of receiver design, although some efforts have been made to improve this, notably through the AMAX standards adopted in the United States. Playlist A playlist is a list of video or audio files that can be played back on a media player , either sequentially or in a shuffled order. In its most general form, an audio playlist
11118-444: Was added in 1947, WJBK-FM (now WUFL ). A TV station was launched the following year, WJBK-TV . In the late 1940s, WJBK was the home of one of Detroit's first radio disk jockeys , Ed McKenzie, known as "Jack the Bellboy". His late afternoon show combined the mainstream pop hits of the day with a good amount of R&B or "race" music as it was referred to at the time. It clicked with the young people and soon propelled him to #1 in
11227-474: Was approved by the FCC for use by AM stations, initially only during daytime hours, due to concerns that during the night its wider bandwidth would cause unacceptable interference to stations on adjacent frequencies. In 2007 nighttime operation was also authorized. The number of hybrid mode AM stations is not exactly known, because the FCC does not keep track of the stations employing the system, and some authorized stations have later turned it off. But as of 2020
11336-400: Was immediately recognized that, much like the telegraph had preceded the invention of the telephone, the ability to make audio radio transmissions would be a significant technical advance. Despite this knowledge, it still took two decades to perfect the technology needed to make quality audio transmissions. In addition, the telephone had rarely been used for distributing entertainment, outside of
11445-663: Was made of Purtan's "return" to AM radio. However, the simulcast ended during the summer of 1987 when WCZY-AM was sold, returned to a religious format and changed back to the WLQV call letters. In 1986, Gannett purchased the Detroit News . Under Federal Communications Commission guidelines against cross-ownership of newspapers and broadcasting stations within the same market, Gannett sold WLQV to former Gannett president Joe Dorton. In 1987, Mike Glinter's Satellite Radio Network purchased WLQV. Jon Yinger's Midwest Broadcasting Corporation, Too.,
11554-566: Was playing contemporary country music again, under Cumulus Media ownership as "Nash FM" until late 2023 when they were purchased by FLC and changed to a Christian music format. The WDEE calls later had a brief revival as a daytime-only classic-country music station in Reed City, Michigan , coincidentally also at AM 1500. This station has since gone off the air, but the calls survive on its onetime FM sister station, WDEE-FM , which runs an oldies format as "Sunny 97.3". In early 1979, WCAR picked up
11663-468: Was the first organization to create a radio network, and also to promote commercial advertising, which it called "toll" broadcasting. Its flagship station, WEAF (now WFAN) in New York City, sold blocks of airtime to commercial sponsors that developed entertainment shows containing commercial messages . AT&T held a monopoly on quality telephone lines, and by 1924 had linked 12 stations in Eastern cities into
11772-406: Was the lack of amplifying the signals, so listeners had to use earphones , and it required the development of vacuum-tube receivers before loudspeakers could be used. The dynamic cone loudspeaker , invented in 1924, greatly improved audio frequency response over the previous horn speakers, allowing music to be reproduced with good fidelity. AM radio offered the highest sound quality available in
11881-580: Was unable to compete with 50,000-watt WDEE and left the country format by 1974 for religious programming. WDEE's midday show, "The Fem Forum", in which host Tom Dean fielded calls from female listeners sharing their sexual frustrations, was a controversial feature for its time but also quite popular. Other personalities on the station during the 1970s included morning mainstay Deano Day, Hank O'Neil, Mike Scott, Dave Williams, Bob Burchett, Ray Otis, Randy Price, Doug Smith, Don Thompson, Jimmy Bare, Rosalee, Paul Allen, Bob Day, Ron Ferris, Dan Dixon and Rick Church. In
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