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.
118-614: WDIA (1070 AM ) is a radio station based in Memphis, Tennessee . Active since 1947, it soon became the first radio station in the United States that was programmed entirely for African Americans . It featured black radio personalities ; its success in building an audience attracted radio advertisers suddenly aware of a "new" market among black listeners. The station had a strong influence on music, hiring musicians early in their careers, and playing their music to an audience that reached through
236-465: 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
354-841: 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
472-507: A 12,800-square-foot (1,190 m ) exhibit in the former Y & M building, which opened September 28, 2002. Through the years, there has been controversy over composition of the board of the museum Foundation and of the mission of the museum, as people have differing opinions. These issues came to a head in December 2007, as the museum foundation was asking the state, which owned the property, to extend its lease for 50 years rent-free. Bailey,
590-525: A 1968 Cadillac and 1959 Dodge parked outside the motel, a re-creation of the burned shell of a Greyhound bus used by Freedom Riders , and a bus representative of the Montgomery bus boycott . The site first opened as the 16-room Windsor Hotel in 1924, and was later known as the Marquette Hotel. In 1945, Walter Bailey purchased it and renamed it for his wife Loree and the song " Sweet Lorraine ". During
708-593: A DJ position on an afternoon show previously hosted by Maurice "Hot Rod" Hulbert. King credits his days on the station for building his audience and launching his career, describing the station as providing a sense of freedom. Williams ended his show in 1972 following a stroke . Thomas continued to work at WDIA until he died in 2001. Bobby O'Jay became a popular host and was a mainstay until his death on May 3, 2022. The station's management had been mostly white. In 1972, Chuck Scruggs became its first black general manager and vice president, serving for 12 years. Scruggs played
826-501: 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
944-411: A circuit court judge, said he was disappointed with the museum's emphasis on history. He said that he had envisioned it as an institution to inspire activism. By 2007, members of the board included whites from the corporate world. Bailey and other community activists criticized the board as "too white" and claimed they were shutting out the community. Beverly Robertson, then director of the museum, defended
1062-596: 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
1180-617: 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
1298-552: 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
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#17328522805611416-420: A design to save historical aspects of the site. The Nashville, Tennessee firm McKissack and McKissack was tapped to design a modern museum on those portions of the grounds that were not directly related to the assassination. A groundbreaking ceremony for the museum was held on January 27, 1989. The museum was dedicated on July 4, 1991, and officially opened to the public on September 28, 1991. D'Army Bailey
1534-568: 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
1652-463: 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
1770-512: 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
1888-418: 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
2006-789: A major role in organizing the foundation and raising money to preserve the Lorraine Motel and found the National Civil Rights Museum in Memphis. In addition, he contributed to the redevelopment of Beale Street and Soulsville, USA . In the 1970s and 1980s, the owners of WDIA also owned KDIA , a similarly formatted station in the San Francisco Bay Area . This callsign, however, is now assigned to an unrelated Christian -programmed station. In 1996, Clear Channel Communications , since rebranded as iHeartMedia, bought WDIA. In 2020
2124-479: 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)
2242-503: 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
2360-399: 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
2478-482: 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
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#17328522805612596-479: A restaurant near the motel, liable for King's wrongful death . Within days of the assassination, King's supporters began asking Bailey to build a permanent memorial at the motel, with one early suggestion being an eternal flame similar to the one at the grave of John F. Kennedy . On May 2, 1968, one of the caravans of marchers headed to participate in the Poor People's March on Washington started its journey at
2714-423: 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
2832-497: A result, she was ordered to leave her spot on the sidewalk outside the motel. On July 16, 1990, Smith was forcibly carried from that spot and dumped on the opposite side of the street. Since her vigil began, Smith has spoken to thousands of museum visitors, including former president Jimmy Carter . Carter visited the museum site in December 1991 when his daughter Amy graduated from the Memphis College of Art , but did not enter
2950-452: 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
3068-427: 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
3186-461: 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'
3304-576: Is about six blocks east of the Mississippi River . The main 4.14-acre (16,800 m ) site includes the museum, the Lorraine Motel, and associated buildings. The museum also owns the Young and Morrow Building at 422 Main Street. This was where James Earl Ray initially confessed (and later recanted) to shooting King. The complex includes Canipe's Amusement Store at 418 Main Street, next to the rooming house where
3422-406: 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
3540-652: Is known for its community efforts throughout the years. A.C. Williams, a former disc jockey for the station, helped create the Goodwill Fund in 1954, and the station's identification announcement became, “You’re Listening to 50,000 Watts of Goodwill, W-D-I-A Memphis.”. Originally, the fund provided transportation to school for disabled black children. Later the fund expanded to include college scholarships, establish boy clubs, provide 125 Little League Teams to Memphis and neighboring communities, and help provide low cost supplemental housing (Wilson). "We have raised over $ 900,000 over
3658-497: 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
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3776-772: Is located at 450 Mulberry Street, with all properties except the Lorraine Motel owned by the Lorraine Civil Rights Museum Foundation. The motel is owned by the State of Tennessee and operated by the Foundation under a 20-year lease with the Tennessee State Museum in Nashville. The main museum is located on the south edge of downtown Memphis , in what is now called the South Main Arts District . It
3894-645: 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
4012-621: The Beale Street Historic District and the WDIA radio station were added from Memphis to the United States Civil Rights Trail . [REDACTED] Radio portal AM broadcasting The earliest experimental AM transmissions began in 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
4130-556: 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
4248-615: 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. AM radio technology
4366-479: 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
4484-879: The Mississippi Delta to the Gulf Coast. The station started the WDIA Goodwill Fund to help and empower black communities. Owned by iHeartMedia , the station's studios are located in Southeast Memphis, and the transmitter site is in North Memphis. WDIA went on the air June 7, 1947, from studios on Union Avenue. The owners, John Pepper and Bert Ferguson, were both white, and the format was a mix of country and western and light pop , as well as " homemaker shows", network shows and block programming that included soap operas and classical music . The original frequency
4602-450: The South Main Arts District . Smith continued to live inside the closed motel, which was surrounded with an eight-foot-tall chain-link fence, for several weeks. On March 2, 1988, four sheriff's deputies forcibly carried her out of the building, while she shouted, "You people are making a mistake [...] If King were alive he wouldn't want this." Before the eviction, Smith had told reporters, "If I can't live at The Lorraine, I'll camp out on
4720-431: 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
4838-472: The segregation era, Bailey operated the hotel as upscale lodging that catered to a black clientele. After the Civil Rights Act of 1964 banned segregated businesses, Bailey believed he needed to improve the facility to compete with other hotels that were no longer whites-only. He expanded the complex significantly later that year, adding a second floor, a swimming pool, and drive-up access for new rooms on
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4956-430: 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
5074-587: 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
5192-660: 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
5310-504: The 1968 assassination of Martin Luther King Jr. Two other buildings and their adjacent property, also connected with the King assassination, have been acquired as part of the museum complex. After renovations, the museum reopened in 2014 with an increase in the amount of multimedia and interactive displays, as well as various short films to show highlights. The museum is owned and operated by
5428-469: The 2014 reopening, a major new exhibit featured is a replica of the U.S. Supreme Court room where oral argument was heard in 1954 in the seminal Brown v. Board of Education , in which the Court ruled that segregation in public schools was unconstitutional. This was a major victory for the civil rights movement. The museum has several interactive kiosks where patrons can access audio, images, text and video about
5546-528: 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
5664-521: 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
5782-558: The Lorraine Civil Rights Museum Foundation, based in Memphis. The Lorraine Motel is owned by the Tennessee State Museum and leased long term to the Foundation to operate as part of the museum complex. In 2016, the museum was honored by becoming a Smithsonian Affiliate museum . It is also a contributing property to the South Main Street Historic District of the National Register of Historic Places . The complex
5900-399: The Lorraine Motel in early April 1968, while working to organize protests around the ongoing Memphis sanitation strike . While standing on the balcony outside his room on the evening of April 4, King was shot once in the face by an unseen assassin. King was rushed to St. Joseph's Hospital , where he was pronounced dead about an hour later. James Earl Ray , a resident of a rooming house across
6018-636: The Lorraine Motel. King's widow, Coretta Scott King , and his successor as president of the Southern Christian Leadership Conference , Ralph Abernathy , unveiled a memorial plaque at the motel shortly before the march started. In June, Room 306 was converted into a shrine to King's memory which was opened to the public. Touring the Dr. Martin Luther King Memorial Room was initially free, but later cost an admission fee of $ 1. In
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#17328522805616136-411: 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
6254-465: The U.S., for example) subject to international agreements. National Civil Rights Museum The National Civil Rights Museum is a complex of museums and historic buildings in Memphis, Tennessee ; its exhibits trace the history of the civil rights movement in the United States from the 17th century to the present. The museum is built around the former Lorraine Motel , which was the site of
6372-662: 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
6490-523: 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
6608-474: 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
6726-407: The board and the museum's operation. Gregory Duckett, a board member, disagreed with Bailey's interpretation, saying the museum was never designed as an activist institution. Robertson noted that many board members were African Americans who had been activists and also entered corporate life. In 2007, the state agreed to a 20-year lease, while taking over major maintenance of the complex. It required
6844-404: 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
6962-403: 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
7080-459: The construction. In May 1987, the foundation reached an agreement with the state of Tennessee, Shelby County, and the city of Memphis to develop the museum. The foundation agreed to sell the property to the state, which would provide $ 4.4 million in funding to build a museum that would be designed and controlled by the foundation, while the city and county would each provide another $ 2.2 million. The motel closed to customers on January 10, 1988, when
7198-475: 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
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#17328522805617316-437: 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
7434-434: 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
7552-567: 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
7670-569: 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
7788-577: 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
7906-520: The ensuing auction with its only bid of $ 144,000. The group, which changed its name to the Lorraine Civil Rights Museum Foundation, stopped charging admission to tour Room 306 in March 1983. The foundation continued to operate the Lorraine as a single-room occupancy motel while seeking to raise funds to convert the building into a museum. However, it proved difficult to gather the millions of dollars needed for
8024-645: 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,
8142-445: 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
8260-401: 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
8378-400: The full civil rights movement. Visitors can search for text based on event, location, or theme. Many exhibits now feature "listening stations" where patrons with headphones can hear audio about the exhibit they are seeing; one features the voice of Malcolm X in a debate. More than 40 new short films throughout the museum also enhance the effect of the exhibits. The renovated museum opened to
8496-620: 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,
8614-417: 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
8732-541: 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
8850-411: 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
8968-419: 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,
9086-399: 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
9204-432: 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
9322-661: The moment of King's violent death, referring to it as the "James Earl Ray Memorial". In a 2018 column in the Memphis Commercial Appeal , Smith elaborated on her stance, saying, "Let's relocate the museum within Memphis, along with its Klan hoods, James Earl Ray rifle, and other negative memorabilia and turn the Lorraine into an establishment that Dr. King and Memphis can be rightly proud of and where visitors can experience his dream in action." The Foundation worked with Smithsonian Institution curator Benjamin Lawless to develop
9440-432: The motel annually. Based on the findings of this report, the county considered purchasing the motel and turning it into a memorial or museum. In April 1982, Bailey defaulted on a $ 140,000 construction loan, causing the lender to attempt foreclosure on the property. Bailey filed for bankruptcy a few days later, halting the foreclosure auction, and the news of the foreclosure provoked local business leaders to try to save
9558-470: The motel property, including an exhibition basketball game at the Mid-South Coliseum that featured Magic Johnson , Isiah Thomas , George Gervin , and Marques Johnson . However, these efforts raised only $ 96,568 of the needed $ 240,000 in time for the set deadline of October 28, 1982, leading the motel to be placed back on the auction block. The foundation took out a $ 50,000 loan and was able to win
9676-512: The motel. The Martin Luther King Memphis Memorial Foundation, a newly-established non-profit organization, agreed to purchase the motel from Bailey for $ 240,000, which it would need to raise from donors to finalize the sale. Later that year, the motel was added to the National Register of Historic Places , as part of the South Main Street Historic District . The foundation held a series of fundraising events to purchase
9794-448: 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
9912-457: The murder weapon with Ray's fingerprints was found. Included on these grounds is the brushy lot that stood between the rooming house and the motel. The museum exhibits a number of vehicles of historic value or which are otherwise relevant to the time period. Vehicles on display include an International Harvester garbage truck in an exhibit on the 1968 Memphis sanitation strike that brought King to Memphis, James Earl Ray's 1966 white Ford Mustang,
10030-559: The museum after listening to Smith's criticisms, which Amy agreed with. However, when Carter received an award in September 1994 for his humanitarian work in Haiti, he attended the award ceremony at the museum, leading Smith to feel that he had betrayed her. In addition to her criticism of the gentrification of the South Main neighborhood, Smith has also criticized the museum for its inherent focus on
10148-461: The museum board to hold annual public meetings and increase the number of African-American board members. The main museum closed in November 2012 for a $ 27.5 million renovation, to include changes to exhibits and upgrades to building systems. The exhibits were updated for historical accuracy and to add to their evocative power; the work was guided by a group of recognized civil rights scholars. Many of
10266-587: The museum's most popular exhibits did not change, such as Room 306 (where King was staying when he died), the replica sanitation truck (King came to Memphis to support an AFSCME sanitation workers' strike ), and the replica of the bus Rosa Parks rode in Montgomery, Alabama, before initiating the Montgomery bus boycott of 1955–1956. The original bus resides at the Henry Ford Museum in Dearborn, Michigan . In
10384-524: The museum. Smith thought King would have objected to having millions of dollars spent on a memorial for him, evicting poor residents in the process, instead of policies and programs that would benefit the neighborhood community, which was generally lower-income and predominantly Black at the time. She saw the creation of the museum as part of a larger gentrification of the South Main Street area, pushing out poor residents as part of transforming it into
10502-537: 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
10620-405: 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
10738-428: 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
10856-411: 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,
10974-433: 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
11092-441: 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
11210-637: 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
11328-799: 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
11446-400: 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
11564-423: The sidewalk out front." After she was removed from the building and her belongings were dumped on the curb outside, she covered the items with a tarp and pitched a tent next to them. Smith has lived outside the museum ever since, in a round-the-clock vigil that has lasted for more than 35 years. Her presence caused delays in the construction of the museum, as the construction work risked endangering her safety. As
11682-410: 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,
11800-646: The south side of the complex. Accordingly, he then changed the name from the Lorraine Hotel to the Lorraine Motel . Many musicians stayed at the motel in the 1960s while recording at Memphis' Stax Records , including Ray Charles , Lionel Hampton , Aretha Franklin , Ethel Waters , Otis Redding , the Staple Singers and Wilson Pickett . Civil rights movement leader Martin Luther King Jr. stayed in Room 306 of
11918-408: The state took possession of the property. Former owner Walter Bailey moved out of his residence in the motel that day after living there for over 40 years. Bailey died later that year. When the motel closed, one of the remaining long-term tenants, Jacqueline Smith, refused to leave her room. Smith, who had lived at the motel since 1973 and had worked there as a housekeeper, protested the creation of
12036-486: The street from the motel, was convicted of King's murder in 1969. Ray pleaded guilty to the murder, but later recanted his confession. The King family, alongside many others, have long believed that Ray was not the culprit and that the assassination was carried out by a group of conspirators, possibly including agents of the U.S. federal government. In the Loyd Jowers trial in 1999, a Memphis jury found Loyd Jowers , owner of
12154-411: 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
12272-401: 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
12390-492: 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
12508-548: 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
12626-464: The years following the assassination, business at the motel declined and Bailey ran into increasing debts, even as the assassination site became a frequent destination for sightseers. Approximately 15,000 people signed the motel's guestbook in 1980, while a report by the Shelby County Office of Planning and Development that year estimated that 70,000 people took commercial tours that stopped at
12744-414: The years," A.C. Williams says. Many music legends got their start by working at WDIA, including B.B. King and Rufus Thomas . Elvis Presley was greatly influenced by the station. B.B. King joined WDIA in early 1949. He had a daily 15-minute show, promoting first a patent medicine called Pep-Ti-Kon, and later Lucky Strike cigarettes, the first major advertiser for the station. The next year, he took
12862-404: 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
12980-565: 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. AM broadcasts are used on several frequency bands. The allocation of these bands is governed by the ITU 's Radio Regulations and, on the national level, by each country's telecommunications administration (the FCC in
13098-480: Was 730 kHz. The station did not do well until Ferguson learned about "targeted programming" and realized there was one audience in Memphis no other radio station served. Half of the listeners who could hear WDIA's signal were African-American, and WDIA hired the first black disk jockey in the South. Nat D. Williams , a syndicated columnist and high-school teacher, started Tan Town Jubilee on October 25, 1948. This
13216-474: 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
13334-649: Was heard from the Missouri Bootheel to the Gulf Coast. WDIA reached 10% of the African-American population in United States. Future WJLB strong jock, Martha Jean "The Queen" Steinberg became known as "Princess Premium Stuff". Ernest Brazzell gave crop advice, and Robert Thomas became a DJ named “Honeyboy” after he won a citywide amateur competition. Among other notable personalities were Maurice "Hot Rod" Hulbert, Theo "Bless My Bones" Wade, and Ford Nelson, who continued as of 2013 as an active gospel DJ on WDIA. WDIA
13452-400: 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
13570-422: Was one of the first radio programs in the United States to appeal to black listeners. WDIA soon became the number-2 station in Memphis. After a switch to all-black programming, WDIA became the city's top station. In June 1954, WDIA was licensed to increase its power from 250 to 50,000 watts, which meant moving to 1070 kHz. Its powerful signal reached the Mississippi Delta ’s dense African-American population and
13688-468: 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
13806-490: Was the founding president of the museum. In 1999, the Foundation acquired the Young and Morrow Building, and its associated vacant lot on the West side of Mulberry, as part of the museum complex. A tunnel was built under the lot to connect the building with the motel. The Foundation became the custodian of the police and evidence files associated with the assassination, including the rifle and fatal bullet. The latter are on display in
13924-406: 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
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