Radio

African-American radio can be divided into three general periods of historical development: blackface radio (1920–1941), black-appeal radio (1942–1969), and black-controlled radio (1970 to the present). Blackface radio was characterized by the appropriation of African-American music and humor by white entertainers, who performed their secondhand imitations for a predominantly white listening audience. During this period, black people were essentially outside of the commercial broadcasting loop; they were marginal as both radio entertainers and consumers. In the era of black-appeal radio, African Americans entered into the industry as entertainers and consumers, but the ownership and management of the stations targeting the black radio market remained mostly in the hands of white businessmen. This situation constrained the development of independent black radio operations, while the radio industry in general prospered from it. During the most recent period, African Americans have striven to own and operate their own radio stations, both commercial and public. In addition, they have established black-controlled radio networks and trade organizations. However, the percentage of African-American-owned stations still lags far behind the percentage of black listeners.

The appropriation of black song, dance, and humor by white entertainers who blackened their faces with charcoal goes back to the early days of slavery. The resulting radical stereotypes were embedded in the blackface minstrel tradition, which dominated American popular entertainment in the antebellum period, and remained resilient enough in the postbellum years to reappear in film and radio in the early decades of the twentieth century. Popular black music styles like blues and jazz were first performed on the radio by such white performers as Sophie Tucker, the first singer to popularize W. C. Handy's "Saint Louis Blues," and Paul Whiteman, the so-called king of jazz in the 1920s. A parallel trend developed with respect to black humor with the emergence of Amos 'n' Andy (starring Freeman Gosden and Charles Correll) as radio's most popular comedy series.

Indeed, Amos 'n' Andy was radio's first mass phenomenon: a supershow that attracted 53 percent of the national audience, or 40 million listeners, during its peak years on the NBC network in the early 1930s. In addition, the series provoked the black community's first national radio controversy. Robert Abbot, editor of the Chicago Defender, defended Gosden and Correll's caricatures of black urban life as inoffensive and even humane. Robert Vann, editor of the Pittsburgh Courier, countered by criticizing the series as racist in its portrayal of African Americans. He also launched a petition campaign to have the program taken off the air that amassed 740,000 signatures—but to no avail, for the Federal Radio Commission ignored it. Meanwhile, Amos 'n' Andy dominated black comedy on radio throughout its heyday as the "national pastime" in the 1930s. In addition to Gosden and Correll, the other major blackface radio entertainers of the era included George Mack and Charles Moran, known as the Two Black Crows on the CBS network, as well as Marlin Hunt, who created and portrayed the radio maid Beulah on the series of the same name.

During the period when blackface comedy performed by whites dominated the portrayal of African Americans over the airways, its audience was mostly white; fewer than one in ten black households owned a radio receiver. There were black entertainers and actors who managed to get hired by the radio industry in the pre–World War II era, and for the most part they were restricted to playing stereotyped roles. The renowned black comedian Bert Williams was the first important black performer to be linked to commercial broadcasting, in the 1920s; he was featured on a New York station doing the same routines he popularized while performing in blackface on the Broadway stage. During the Great Depression, as if to add insult to injury, a number of black actors and actresses who auditioned for radio parts were told that they needed to be coached in the art of black dialect by white coaches if they wanted the jobs. This perverse chain of events happened to at least three African-American performers: Lillian Randolph (Lulu and Leander Show ), Johnny Lee (Slick and Slim Show ), and Wonderful Smith (Red Skelton Show ). The most famous black comic to appear regularly on network radio in the 1930s was Eddie Anderson, who played the role of the butler and chauffeur Rochester on the Jack Benny Show. Anderson was often criticized in the black press for playing a stereotypical "faithful servant" role, even as he was being praised for his economic success and celebrity.

After blackface comedy, the African-American dance music called jazz was the next most popular expression of black culture broadcast over the airways in the 1920s and 1930s. As was the case with humor, the major radio jazz bands were made up of white musicians, and were directed by white bandleaders such as Paul Whiteman, B. A. Rolfe, and Ben Bernie. The first black musicians to be broadcast with some regularity on network radio were New York bandleaders Duke Ellington and Noble Sissle. A number of influential white radio producers such as Frank and Ann Hummert, the king and queen of network soap operas, began to routinely include black doctors, teachers, and soldiers in their scripts. In addition, the federal government produced its own radio series, entitled Freedom's People, to dramatize the participation of African Americans in past wars, and it recruited Paul Robeson as a national and then international radio spokesman for the U.S. war effort. But at the end of the war, the government withdrew from the domestic broadcasting sphere, allowing the logic of the marketplace to reassert itself. Then with the advent of the new television networks, and their subsequent domination of the national broadcasting market, radio was forced to turn to local markets in order to survive as a commercial enterprise. Inadvertently, this led to the discovery of a "new Negro market" in regions where African Americans' numbers could no longer be ignored by broadcasters. This was especially the case in large urban centers, where nine out of ten black families owned radios by the late 1940s. The result of this convergence of economic necessity and a mushrooming listening audience was the emergence of black-appeal radio stations and the rise of the African-American disc jockey—two interrelated developments that transformed the landscape of commercial radio in the postwar era.

A few black DJs were playing records over the airways in the 1930s; they worked through a brokerage system that charged them an hourly fee for airtime. The disc jockeys, in turn, solicited advertising aimed at the local black community and broadcast it in conjunction with recorded "race" music. Jack L. Cooper pioneered this approach in Chicago on his radio show The All Negro Hour, which first aired on WSBC in 1929. At first, he developed a live variety show with local black talent, but within two years he had switched to recorded music in order to cut costs. He played jazz discs, hosted a popular "missing persons" show, pitched ads, made community-service announcements, and also developed a series of weekend religious programs. This format was successful enough to make him into a millionaire; by the end of the 1930s, he had a stable of African-American DJs working for him on a series of black-appeal programs broadcast on two stations. In the 1940s Cooper was challenged as Chicago's premier black disc jockey by Al Benson, who also built up a small radio empire on local outlets with his own style of black-appeal programming. Cooper targeted the middle-class African-American audience; he played the popular big-band jazz recordings of the day and prided himself in speaking proper English over the air. Benson played the down-home blues of the era and spoke in the vernacular of the new ghetto populace, most of whom were working-class southern migrants. A new era of black radio was at hand.

By the end of the 1940s there was a growing number of aspiring DJs in urban black communities ready to take advantage of the new "Negro-appeal" formats springing up on stations throughout the country. In Memphis, Nat D. Williams was responsible for broadcasting the first African-American radio show there, on WDIA in 1948; he also created the station's new black-appeal format and launched the careers of numerous first-generation African-American DJs over WDIA's airways. Two of the most important were Maurice "Hot Rod" Hulbert, who moved on to become the dean of black disc jockeys in Baltimore, on WBEE; and Martha Jean "the Queen" Stienburg, who later became the most popular black DJ in Detroit, on WCHB. In 1950, WERD, in Atlanta, became the first African-American-owned radio station in the country when it was purchased by J. B. Blayton, Jr. He appointed his son as station manager and then hired Jack "the Rapper" Gibson as program director. Other black-appeal stations that came into prominence during the early 1950s included WEDR in Birmingham, Alabama; WOOK in Washington, D.C.; WCIN in Cincinnati; WABQ in Cleveland; KXLW in St. Louis; and KCKA in Kansas City, which became the second African-American-owned radio outlet in the nation in 1952. By 1956 more than four hundred radio stations in the United States were broadcasting black-appeal programming. Each of these operations showcased its own homegrown African-American disc jockeys, who were the centerpiece of the on-air sound.

The powerful presence and influence of the African-American DJs on the airways in urban America in the 1950s stemmed from two sources. On the one hand, they were the supreme arbiters of black musical tastes; they could make or break a new record release, depending on how much they played and promoted it. On the other hand, the black disc jockeys were also the new electronic griots of the black oral tradition, posturing as social rappers and cultural rebels. As such, they collectively constituted a social grapevine that was integral not just to the promotion of rhythm and blues but also to the empowerment of the growing civil rights movement in the South. Such black-appeal radio stations as WERD in Atlanta and WDIA in Memphis, as well as Al Benson's shows in Chicago, played a vital role in informing people about the early civil rights struggles. In a speech to black broadcasters late in his life, civil rights leader the Rev. Dr. Martin Luther King, Jr., paid special tribute to disc jockeys Tall Paul White (WEDR, Birmingham), Purvis Spann (WVON, Chicago), and Georgie Woods (WHAT, Philadelphia) for their important contributions to the civil rights efforts in their respective cities.

During the 1950s African-American radio DJs also had a profound effect on commercial radio in general. Some stations—such as WLAC in Nashville, a high-powered AM outlet heard at night throughout the South—devoted a hefty amount of their evening schedules to rhythm-and-blues records. In addition, the white disc jockeys at WLAC (John R., Gene Noble, Hoss Allen, and Wolfman Jack) adopted the on-air styles, and even dialect, of the black DJs. Many of their listeners, both black and white, thought that WLAC's disc jockeys were African Americans. This was also the case on WJMR in New Orleans, where the white DJs who hosted the popular Poppa Stoppa Show were actually trained to speak in black dialect by the creator of the show, an African-American college professor named Vernon Winslow. Other white DJs who became popular by emulating the broadcast styles of their black counterparts included Dewey Phillips in Memphis; Zenas "Daddy" Sears in Atlanta; Phil Mckernan in Oakland, California; George "Hound Dog" Lorenz in Buffalo, New York; and Allen Freed in Cleveland. Freed moved on to become New York City's most famous rock-and-roll disc jockey before his fall from grace as the result of payola scandals in the early 1960s.

Payola, the exchange of money for record airplay, was a common practice throughout the radio industry. It was an easy way for disc jockeys to supplement the low wages they were paid by their employers. Hence, many well-known black DJs were adversely affected by the payola exposés. Some lost their jobs when their names were linked to the ongoing investigations, and an unfortunate few were even the targets of income-tax-evasion indictments. The industry's solution to the payola problem was the creation of the "top forty" radio format, which in effect gave management complete control over the playlists of records to be aired on their stations. Formerly, the playlists had been determined by the individual DJs. This change led to the demise of both the white rock-and-roll disc jockeys and the black "personality" DJs associated with rhythm and blues, and then "soul" music. Black-appeal stations were centralized even further by the emergence of five soul radio chains in the 1960s, all of which were white-owned and -managed. By the end of the decade, these corporations controlled a total of twenty stations in key urban markets with large African-American populations, including New York, Chicago, Memphis, and Washington, D.C. The chain operations not only established standardized top-forty soul formats at their respective outlets, thus limiting the independence of the black DJs they employed, but they also eliminated most of the local African-American news and public-affairs offerings on the stations.

In spite of the trend toward top-forty soul formats, a number of black personality DJs managed to survive and even prosper in the 1960s. The most important were Sid McCoy (WGES, WCFL), Purvis Spann (WVON), and Herb Kent (WVON) in Chicago; LeBaron Taylor and Georgie Woods (both WDAS) in Philadelphia; Eddie O'Jay in Cleveland (WABQ) and Buffalo (WUFO); Skipper Lee Frazier (KCOH) in Houston; the Magnificent Montegue (KGFJ) in Los Angeles; and Sly Stone (KSOL) in San Francisco. LeBaron Taylor and Sly Stone went on to successful careers in the music industry—Taylor as a CBS record executive and Stone as a pioneering pop musician. The Magnificent Montegue's familiar invocation, "Burn, baby, burn," used to introduce the "hot" records he featured on his show, inadvertently became the unofficial battle cry of the 1967 Watts rebellion. The new mood of black militancy sweeping the nation also found its way into the ranks of the African-American DJs, especially among the younger generation just entering the radio industry. Two of the more influential members of this "new breed," as they came to be known, were Del Shields (WLIB) in New York and Roland Young (KSAN, KMPX) in San Francisco. Both men independently pioneered innovative black music formats, mixing together jazz, soul, and salsa recordings.

The 1970s ushered in the current era of black-owned and -controlled radio operations, both stations and networks. In 1970, of the more than 300 black-formatted stations, only sixteen were owned by African Americans. During the next decade, the number of black-owned stations rose to 88, while the number of formatted stations surpassed 450. Some of the more prominent African Americans who became radio station owners during this era included entertainers James Brown and Stevie Wonder, Chicago publisher John Johnson, and New York City politician Percy Sutton. In particular, Sutton's Harlem-based Inner City Broadcasting (WLIB-AM, WBLS-FM) has been the national trendsetter in a black-owned and -operated radio from the early 1970s to the present. In 1977 African-American broadcasters organized their own trade organization, the National Association of Black-Owned Broadcasters. By 1990 there were 206 black-owned radio stations—138 AM and 68 FM—in the country.

It was also during the 1970s that two successful black radio networks were launched: the Mutual Black Network, founded in 1972, which became the Sheridan Broadcasting Network in 1979; and the National Black Network, started in 1973. Both of these operations provide news, talk shows, public affairs, and cultural features to their affiliate stations throughout the nation. In the 1980s the Sheridan network had more than one hundred affiliates and 6.2 million weekly listeners; in addition to news and public affairs, it offered a wide range of sports programming, including live broadcasts of black college football and basketball games. The National network averaged close to one hundred affiliates and four million weekly listeners in the 1980s; its most popular programs, in addition to its news reports, were journalist Roy Woods's One Man's Opinion and Bob Law's Night Talk. In 1991 Sheridan Broadcasting Corporation purchased National Black Network to form the American Urban Radio Network (AURN). As of 2005 AURN is the only African-Americanowned network radio company in the United States, broadcasting three hundred weekly news, entertainment, sports, and information programs to more than 475 radio stations that reach some twenty-five million listeners nationwide.

Two major formats have dominated black-owned commercial radio in the 1970s and 1980s—"talk" and "urban contemporary." Talk radio formats emerged on African-American AM stations in the early 1970s; in essence they featured news, public affairs, and live listener call-in shows. By this time, the FM stations dominated the broadcasting of recorded music because of their superior reproduction of high-fidelity and stereo signals. The AM stations were left with talk by default. Inner City Broadcasting initiated the move toward talk radio formats among African-American stations when it turned WLIGAM, which it purchased in New York City in 1972, into "your total news and information station" that same year. The logic of the commercial radio market encouraged many of the other black AM operations, such as WOL-AM in Washington, D.C., to follow suit. Likewise, Inner City Broadcasting also pioneered the urban contemporary format on WBLS-FM during this same period. Much of the credit for the new format is given to Frankie Crocker, who was the station's program director at the time. To build up WBLS's ratings in the most competitive radio market in the country, Crocker scuttled the station's established jazz programming in favor of a crossover format featuring black music currently on the pop charts along with popular white artists with a black sound. The idea was to appeal to an upscale black and white audience. The formula worked to perfection; WBLS became the top station in the New York market, and scores of other stations around the country switched to the new urban contemporary format. One example was WHUR-FM, owned by Howard University in Washington, D.C. The station's original jazz and black-community-affairs format was sacked in favor of the urban contemporary approach in the mid-1970s. The new format allowed WHUR to become one of the top-rated stations in the Washington market. In the process, it gave birth to an innovative new nighttime urban contemporary style called "quiet storm," after the Smokey Robinson song of the same name. The architect of this novel format was Melvin Lindsey, a former Howard student and WHUR intern. In 1980 WOL-AM in Washington, D.C., was purchased by Catherine and Dewey Hughes. Catherine Hughes later bought out her now ex-husband's interest, and WOL-AM was the start of Radio One, Inc., the seventh-largest radio broadcasting company (as of 2003) to target African-American and urban listeners. Radio One owns and/or operates sixty-nine radio stations in twenty-two urban markets.

The 1970s and 1980s also marked the entrance of African Americans into the public broadcasting sphere. By 1990 thirty-two public FM stations were owned and operated by black colleges around the country, and another twelve were controlled by black community boards of directors. These stations are not subject to the pervasive ratings pressures of commercial radio, giving them more leeway in programming news, public affairs, talk, and unusual cultural features. Many of these stations—such as WCLK-FM, owned by Clarke College in Atlanta; WSHAFM, owned by Shaw College in Raleigh, North Carolina; and WVAS-FM, from Alabama State University in Montgomery—have adopted the jazz formats abandoned by African-American-owned commercial FM stations. Others, such as WPFW-FM in Washington, D.C. (the number one black public radio outlet in the country), have developed a more ambitious "world rhythms" format embracing the many musics of the African diaspora. In general, the growth of black public radio has expanded the variety and diversity of African-American programming found on the airways, while also increasing the numbers of African Americans working in radio.

However, since the passage of the 1996 Telecommunications Act, independent black radio stations have struggled to survive. The Telecom Act has allowed conglomerates in a single market to have radio holdings that receive up to 40 percent of the market's advertising revenue and has eliminated the forty-station nationwide ownership limit; broadcasters may purchase up to eight radio stations in large markets and five in small markets. This has led to a consolidation in which conglomerates, with greater financial resources, have benefited while black-owned stations with less capital have gone up for sale. According to the U.S. Department of Commerce, from 1995 to 1996 the number of black-owned FM stations dropped from 86 to 64 and AM radio stations from 109 to 101; in 1997 there were 169 minority-owned broadcasters but by 2001 the number was 149. The largest black-controlled radio broadcaster (and seventh-largest in the country), Radio One, owns 69 radio stations; in contrast, Clear Channel, the largest U.S. radio broadcaster, owned 1,200 stations as of 2003—76 of which targeted black and urban audiences. Single-station owners are going the way of the dodo, but various entrepreneurs are acquiring their own, albeit small, clusters of stations to maintain a presence within the industry by offering grassroots community appeal and diversity of programming—and marketing that programming to more than the African-American market in order to survive and grow.

See also Jazz; Minstrels/Minstrelsy; Rhythm and Blues; Robeson, Paul; Walker, George; Williams, Bert

Bibliography

Baraka, Rhonda. "American Urban Radio Networks." Billboard (October 13, 2001): 25.

Barlow, William. Voice Over: The Making of Black Radio. Philadelphia, Pa: Temple University Press, 1999.

Dates, Jannette, and William Barlow, eds. Split Image: African Americans in the Mass Media. Washington, D.C.: Howard University Press, 1989.

Dawkins, Walter. "Battle for the Airwaves!" Black Enterprise (May 2003): 64–70.

Downing, John. "Ethnic Minority Radio in the USA." Howard Journal of Communication 1, no. 4 (1989): 135–148.

Edmerson, Estelle. "A Descriptive Study of the American Negro in U.S. Professional Radio, 1922–1953." M.A. thesis, University of California at Los Angeles, 1954.

Ferretti, Frank. "The White Captivity of Black Radio." Columbia Journalism Review (summer 1970): 35–39.

George, Marsha Washington. Black Radio…Winner Takes All. Philadelphia, Pa: Xlibris Corp., 2002.

Jones, Charisse. "Owning the Airwaves." Essence (October 1998): 112–120.

Tyson, Timothy B. Radio Free Dixie: Robert F. Williams and the Roots of Black Power. Chapel Hill: University of North Carolina Press, 1999.

Ward, Brian. Radio and the Struggle for Civil Rights in the South. Gainesville: University Press of Florida, 2004.

Williams, Gilbert A. Legendary Pioneers of Black Radio. West-port, Conn.: Praeger Publishers, 1998.

william barlow (1996)

christine tomassini (2005)

Radio

The history of radio

Radio and the electromagnetic spectrum

How radio signals are created

Modulation

Demodulation

Wavelengths, frequencies, and antennas

Radio signals and energy

Radio signal propagation

Shortwave radio

Regulation of radio transmissions

The future of radio

Resources

Radio is the transmission and reception of long-wavelength electromagnetic waves. Radio makes it possible to establish wireless one-way or two-way communication between transmitters and receivers. Radio signals can carry speech, music, telemetry, or digitally-encoded entertainment. They also occur naturally throughout the universe. Cordless telephones and wireless computer components use low-power radio transmitters and receivers to connect without wires. Cellular telephones use a network of computer-controlled low power radio transmitters to enable users to place telephone calls away from phone lines.

The history of radio

In the nineteenth century, in Scotland, James Clerk Maxwell (1831–1879) described the theoretical basis for radio transmissions with a set of four equations known ever since as Maxwell’s field equations. Maxwell was the first scientist to use mechanical analogies and powerful mathematical modeling to create a successful description of the physical basis of the electromagnetic spectrum. His analysis provided the first insight into the phenomena that would eventually become radio. He deduced correctly that the changing magnetic field created by accelerating charge would generate a corresponding changing electric field. The resulting changing electric field would, he predicted, regenerate a changing magnetic field in turn, and so on. Maxwell showed that these interdependent changing electric and magnetic fields would together be a part of a self-sufficient phenomenon required to travel at the speed of light.

Not long after Maxwell’s remarkable revelation about electromagnetic radiation, Heinrich Hertz (1857–1894) demonstrated the existence of radio waves by transmitting and receiving a microwave radio signal over a considerable distance. Hertz’s apparatus was crude by modern standards but it was important because it provided experimental evidence in support of Maxwell’s theory.

Guglielmo Marconi (1874–1937) was awarded the Nobel Prize in physics in 1909 to commemorate his development of wireless telegraphy after he was able to send a long-wave radio signal across the Atlantic Ocean.

The first radio transmitters to send messages, Marconi’s equipment included, used high-voltage spark discharges to produce the charge acceleration needed to generate powerful radio signals. Spark transmitters could not carry speech or music information. They could only send coded messages by turning the signal on and off using a telegraphy code similar to the land-line Morse code.

Spark transmitters were limited to the generation of radio signals with very-long wavelengths, much longer than those used for the present AM-broadcast band in the United States. The signals produced by a spark transmitter were very broad with each signal spread across a large share of the usable radio spectrum. Only a few radio stations could operate at the same time without interfering with each other. Mechanical generators operating at a higher frequency than those used to produce electrical power were used in an attempt to improve on the signals developed by spark transmitters.

A technological innovation enabling the generation of cleaner, narrower signals was needed. Electron tubes provided that breakthrough, making it possible to generate stable radio frequency signals that could carry speech and music. Broadcast radio quickly became established as a source of news and entertainment.

Continual improvements to radio transmitting and receiving equipment opened up the use of successively higher and higher radio frequencies. Short waves, as signals with wavelengths less than 200m are often called, were found to be able to reach distant continents. International broadcasting on shortwave frequencies followed, allowing listeners to hear programming from around the world.

The newer frequency-modulation system, FM, was inaugurated in the late 1930s. For more than 25 years it struggled for acceptance, but it eventually became the most important method of domestic broadcast. FM offers many technical advantages over AM, including almost complete immunity to the lightning-caused static that plagues AM broadcasts. The FM system improved the sound quality of broadcasts, far exceeding the fidelity of the AM radio stations of the time. The FM system was the creation of E. H. Armstrong, perhaps the most prolific inventor among all those who made radio possible.

In the late 1950s, stereo capabilities were added to FM broadcasts along with the ability to transmit additional programs on each station that could not be heard without a special receiver. A very high percentage of FM broadcast stations today carry these hidden programs that serve special audiences or markets. This extra program capability, called SCA for Subsidiary Communications Authorization, can be used for stock market data, pager services, or background music for stores and restaurants.

Radio and the electromagnetic spectrum

Radio utilizes a small part of the electromagnetic spectrum, the set of related wave-based phenomena that includes radio along with infrared light, visible light, ultraviolet light, x rays, and gamma rays. Picture the electromagnetic spectrum as a piano keyboard: radio will be located where the piano keys produce the low frequency musical notes. Radio waves have lengths from many miles down to a fraction of a foot.

Radio waves travel at the velocity of electromagnetic radiation. A radio signal moves fast enough to complete a trip around the earth in about 1/7 second.

How radio signals are created

Jiggle a collection of electrons up and down one million times a second and a 1-megahertz radio signal will be created. Change the vibration frequency and the frequency of the radio signal will change.

Radio transmitters are alternating voltage generators. The constantly changing voltage from the transmitter creates a changing electric field within the antenna. This alternating field pushes and pulls on the conduction electrons in the wire that are free to move. The resulting charge acceleration produces the radio signal that moves away from the antenna. The radio signal causes smaller sympathetic radio frequency currents in any distant electrical conductor that can act as a receiving antenna.

Modulation

A radio signal by itself is like a mail truck without letters. A radio signal alone, without superimposed information, is called a carrier wave. An unmodulated radio signal conveys only the information that there was once a source for the signal picked up by the receiver. Adding information to a carrier signal is a process called modulation. To modulate a radio carrier means that it is changed in some way to correspond to the speech, music, or data it is to carry.

The simplest modulation method is also the first used to transmit messages. The signal is turned on and off to transmit the characters of an agreed code. Text messages can be carried by the signal modulated in this way. unique patterns stand for letters of the alphabet, numerals, and punctuation marks.

The least complicated modulation method capable of transmitting speech or music varies the carrier signal’s instantaneous power. The result is called amplitude modulation, or AM. Another common system varies the signal’s instantaneous frequency at an informational rate. The result is frequency modulation, FM.

If radio is to transmit speech and music, information must be carried that mimics the pattern of changing air pressure the ear would experience hearing the original sound. To transmit sounds these air-pressure changes are converted into electrical signals, amplified electronically, then used to modulate the carrier.

Amplitude modulation was the first process to have the capability of transmitting speech and varied the radio signal’s instantaneous power at a rate that matched the original sound vibrations in the air. A better modulation technology followed that varied the instantaneous frequency of the radio signal but not the amplitude. Frequency modulation, or FM, has advantages compared to AM but both AM and FM are still in use.

Sound can be converted to digital data, transmitted, then used to reconstruct the original waveform in the receiver. It seems likely that a form of digital modulation will eventually supplant both FM and AM.

Demodulation

Radio receivers recover modulation information in a process called demodulation or detection. The radio carrier is discarded after it is no longer needed. The radio carrier’s cargo of information is converted to sound using a loudspeaker or headphones or processed as data.

Wavelengths, frequencies, and antennas

Each radio signal has a characteristic wavelength just as is the case for a sound wave. The higher the frequency of the signal, the shorter will be the wavelength. Antennas for low- frequency radio signals are long. Antennas for higher frequencies are shorter, to match the length of the waves they will send or receive.

It is a characteristic of all waves, not just radio signals, that there is greater interaction between waves and objects when the length of the wave is comparable to the object’s size. Just as only selected sound wavelengths fit easily into the air column inside a bugle, only chosen frequencies will be accepted by a given antenna length. Antennas, particularly transmitting antennas, function poorly unless they have a size that matches the wavelength of the signal presented to them. The radio signal must be able to fit on the antenna as a standing wave. This condition of compatibility is called resonance. If a transmitter is to be able to “feed” energy into an antenna, the antenna must be resonant or it will not “take power” from the transmitter. A receiver antenna is less critical, since inefficiency can be compensated by signal amplification in the receiver, but there is improvement in reception when receiving antennas are tuned to resonance.

If an antenna’s physical length is inappropriate, capacitors or inductors may be used to make it appear electrically shorter or longer to achieve resonance.

Near 100 MHz, near the center of the FM broadcast band in most of the world, signals have a wavelength of approximately three meters. At 1 MHz, near the center of the U.S. AM broadcast band, the signal’s wavelength is 327 yards (300 m), about three times the length of a football field. One wavelength is about 1 ft (0.3 m) at the ultra-high frequency used by cellular telephones.

Radio signals and energy

Energy is required to create a radio signal. Radio signals use the energy from the transmitter that accelerates electric charge in the transmitting antenna. A radio signal carries this energy from the transmitting antenna to the receiving antenna. Only a small fraction of the transmitter’s power is normally intercepted by any one receiving antenna, but even a vanishingly-small received signal can be amplified electronically millions of times as required.

Radio signal propagation

Radio signals with very short wavelengths generally follow straight line paths much as do beams of light, traveling from transmitter to receiver as a direct wave. Radio signals with very long wavelengths follow the curvature of Earth, staying close to the surface as signals called ground waves.

Radio signals with intermediate wavelengths often reflect from layers of electrically-charged particles high above Earth’s surface. These signals are known as skywaves. The layers of electrically-charged particles found between 25-200 mi (40–322 km) above Earth are collectively known as the ionosphere. The ionosphere is renewed each day when the sun’s radiation ionizes atoms in the rarefied air at this height. At higher altitudes the distance between ions causes the ionization to persist even after the sun sets.

A good way to become familiar with radio propagation is to listen for distant AM-broadcast radio at various times of the day. A car radio works well for this experiment because they often have better sensitivity and selectivity than simpler personal radios.

During the daylight hours, on the standard-broadcast band, only local stations will normally be heard. It is unlikely that you will hear stations from more than 150 mi (241 km). As the sun sets you will begin to hear signals from greater distances.

AM-broadcast reception is generally limited to ground-wave radio signals when the sun is high in the sky. There is a very dense layer of the ionosphere at a height of approximately 25 mi (40 km) that is continually created when the sun is high in the sky. This D layer, as it is called, absorbs medium wavelength radio signals so that skywave signals cannot reflect back to earth. The D layer dissipates quickly as the sun sets because the sun’s rays are needed to refresh the ionization of this daytime-only feature of the ionosphere. After dark, when the D layer has disappeared, you will hear strong signals from far away cities.

After the D layer has disappeared, skywave signals reflect from a much higher layer of the ionosphere called the F layer. The F layer acts as a radio mirror, bouncing skywaves back to earth far from their source. The F layer degrades in darkness as does the D layer, but since the ions are separated more widely at higher altitude, the F layer functions as a significant radio mirror until dawn. Toward morning stations at intermediate distances fade, leaving only skywave signals that reflect from the thinning ionosphere at a very shallow angle.

Signal absorption by the D layer is less at shorter wavelengths. Stations using higher frequencies can use skywave in the daytime. High frequencies pass through the D layer. Skywave radio circuits are usually best in the daytime for higher frequencies, just at the time that the standard-broadcast band is limited to groundwave propagation.

Forecasting long distance radio signal propagation conditions depends upon predicting conditions on the sun. It is the changing radiation from the sun that affects long distance radio circuits when the ionosphere changes as Earth rotates. On the sunlit side of Earth the ionosphere is most strongly ionized. On the night side of Earth the radio ionosphere begins to dissipate at sunset until it is almost insignificant as a radio mirror in the early morning hours. When the ionosphere is at its best as a reflector it can support communication between any locations on Earth.

When the ionosphere is more densely ionized it will reflect radio signals with a shorter wavelength than when the ionization is weaker. At any one time, between any two distant locations on Earth, there is a limiting upper frequency that can be used for radio communication. Signals higher in frequency than this maximum-usable frequency, F layer called the MUF, pass through the ionosphere without returning to earth. Slightly lower than the MUF, signals are reflected with remarkable efficiency. A radio signal using less power than a flashlight can be heard on the opposite side of Earth just below the MUF. The MUF tends to be highest when the sun is above the midpoint between two sites in radio communication.

The 11-year solar sunspot cycle has a profound effect on radio propagation. When the average number of sunspots is large, the sun is more effective in building the radio ionosphere. When the sun’s surface is quiet the maximum-usable frequency is usually very low, peaking at less than half the MUF expected when the sun surface is covered with sunspots.

From time to time, the sun bombards Earth with charged particles that disrupt radio transmissions. When solar flares are aimed toward Earth, the earth’s magnetic field is disturbed in a way that can cause an almost complete loss of skywave radio propagation. Microwave radio signals are not significantly disturbed by the magnetic storms since microwaves do not depend upon ionospheric reflection.

FM-broadcast signals are seldom heard reliably further than the distance to the horizon. This is because the frequencies assigned to these services were deliberately chosen to be too high to expect the ionosphere to reflect them back to earth. FM signals are received as direct waves, not skywaves. The limited range of FM stations is an advantage because frequency assignments can be duplicated in cities that are in fairly close proximity without encountering unacceptable interference. This protection is much harder to achieve where skywave propagation may permit an interfering signal to be heard at a great distance.

KEY TERMS

Antenna— An electrical conductor used to send out or receive radio waves.

Capacitor— Electrical component that cancels magnetic property of wire.

D Layer— Arbitrary designation for the lowest layer of the ionosphere.

Electric field— The concept used to describe how one electric charge exerts force on another, distant electric charge.

Electron tube— Active device based on control of electrons with electric fields.

F layer— Arbitrary designation for the highest layer of the ionosphere.

Gamma ray— Electromagnetic radiation with the shortest wavelengths.

Inductor— Electrical component that adds magnetic property to wire.

Infrared light— Light with wavelengths longer than those of visible light.

Ionized— Missing one or more electrons, resulting in a charged atom.

Magnetic field— Effect in space resulting from the motion of electric charge.

MegaHertz— One million cycles per second; MHz.SI abbreviation for MegaHertz.

Morse code— Dot and dash code used to send messages over telegraph wires.

Resonance— The enhancement of the response of a system to a force, when that force is applied at a particular frequency known as the resonant frequency.

Selectivity— Receiver property enabling reception of only wanted signals.

Sensitivity— Receiver property enabling reception of weak signals.

Standing wave— A stationary pattern of activity resulting from interference.

Sunspot— Cooler and darker areas on the surface of the Sun. They appear dark only because they are cooler than the surrounding surface. Sunspots appear and disappear in cycles of approximately 11 years.

Telemetry— Engineering and scientific measurements transmitted by radio.

X ray— Electromagnetic radiation of very short wavelength, and very high energy.

Shortwave radio

Shortwave radio services may change frequency often as the ionosphere’s reflectivity varies. Unlike domestic broadcast stations that stay on a single assigned frequency, shortwave broadcast stations move frequency to take advantage of hour-to-hour and season-to-season changes in the ionosphere. As the 11-year sunspot cycle waxes and wanes, shortwave stations throughout the world move to shorter wavelengths when there are more sunspots and to longer wavelength bands when sunspots are minimal.

Listening to shortwave radio requires more effort than listening to local domestic radio. The best frequencies to search change from one hour to the next throughout the day. Due to the effect of the sun, shortwave signals sometimes may disappear for days at a time, then reappear with astounding strength. Many shortwave stations do not broadcast at all hours of the day. In addition, a station must be targeting your part of the world specifically; otherwise the signal will probably be weak.

Regulation of radio transmissions

The part of the electromagnetic spectrum that can be used for radio communication cannot accommodate everyone who might wish to use this resource. Access is controlled and technical standards are enforced by law. With few exceptions, radio transmissions are permitted only as authorized by licenses.

Since 1934 in the United States, licensing and equipment approval has been the responsibility of the Federal Communications Commission. Similar regulation is the rule in other countries. Technical standards are required by radio regulation. Just as traffic laws improve highway safety, laws and regulations that encourage the fair use of the limited radio spectrum help to avoid conflicts between users.

The future of radio

Radio broadcasting now includes a digital system known as DAB (digital audio broadcasting) that an achieve compact-disc quality in radio reception. Recent innovations in satellite radio systems allow radio programming to be beamed into space where it is processed by orbiting satellites that then widely disseminate a return signal toward the ground. Users of special receivers that can decode the satellite systems can thus enjoy programming thousands of miles from the source (ground broadcasting stations are also used to ensure quality reception in urban areas where building might inhibit reception of signal from the satellite. The digitized audio signal is so much lower in power than the “main” programming that it is inaudible to listeners with standard analog receivers.

Resources

BOOKS

American Radio Relay League. The ARRL Handbook for Radio Communications 2007. Newington, CT: American Radio Relay League, 2006.

Someda, Carlo G. Electromagnetic Waves. 2nd ed. Boca Raton, FL: CRC, 2006.

Donald Beaty

Radio

Hollywood's involvement with radio predates the movies' ability to talk. From the earliest years of broadcasting, farsighted film producers and studio heads saw in radio a promotional medium made to order for enhancing the popular reach and appeal of their valuable entertainment empires. As sound film debuted and brought members of the "radio trust"—RCA and AT&T—into closer connection with film operations, several major studios made countermoves into the business of network radio. Though largely excluded from network ownership, the studios formed an alliance with the advertising agencies, which by the mid-1930s were producing the bulk of commercial programs on the air. "Prestige" radio production had moved to Hollywood by the late 1930s, and the lively process of mutual influence and exchange enriched both industries, setting the stage for Hollywood's increasing domination of television beginning in the late 1950s. Yet even as television took over the entertainment genres and cultural functions that had been created by network radio, the film industry, by expanding into other areas of media production and distribution, remained a player in the radio business. In the twenty-first century, all five major over-the-air television networks (NBC/Universal, CBS/Viacom/Paramount, ABC/Disney, Fox, and CW [formerly WB and UPN] as well as the majority of cable channels either bear a studio's name or are part of a filmmedia conglomerate. Producers, writers, directors, stars, and properties flow seamlessly from one medium to the other. This process began in radio.

EARLY EXPERIMENTATION

In the days before regulatory and network standardization, when the main business of radio was inviting various representatives of entertainment businesses on the air to publicize themselves, it seemed natural that Hollywood, with its immense reservoirs of talent under contract, should join in to publicize that other "national" medium, the cinema. One of the earliest cases of filmradio cooperation took place not in Hollywood but on the stage of the Capitol Theater in New York City, part of the Loew's/MGM chain. In 1923 theater manager Samuel L. Rothafel entered into an agreement with the American Telephone and Telegraph Corporation (AT&T) to broadcast his prefilm stage show over the new station WEAF. The results were so positive that it quickly became a regular feature, called Roxy and His Gang, one of the earliest hits of radio broadcasting. Soon other movie theaters jumped on the bandwagon.

Many big-city theaters featured elaborate stage shows and enormous theater organs, whose musical accompaniments animated their film showings. Concerts by theater organists were broadcast over WMAC, WGN, and KWY in Chicago and in many other cities starting in 1925. In 1925 Harry Warner of Warner Bros. put forth a prediction and a challenge:

I am in favor of the motion picture industry, after the wave-length situation has been adjusted (as it will be)—building and maintaining its own broadcasting stations in New York and Los Angeles, and possibly in the Middle West. Through these sources … programs could be devised to be broadcast before and after show hours, tending to create interest in all meritorious pictures being released or playing at that time. Nights could be assigned to various companies, calling attention to their releases and advising where they were playing in that particular locality. Artists could talk into the microphone and reach directly millions of people who have seen them on the screen but never came in contact with them personally or heard their voices. Such programs would serve to whet the appetites of the radio audience and make it want to see the persons they have heard and the pictures they are appearing in.
(Motion Picture World, 11 April 1925)

Warner followed up on this vision by opening up station KFWB in Los Angeles that same year, and a second one, WBPI, in New York City in 1926. In the summer of 1926, Sam Warner took a portable transmitter on a cross-country tour, broadcasting from theaters showing Warner Bros. films.

By 1927 the major studios could see the sound era rapidly approaching. Earlier, they had jointly agreed to a "stand still" position, in order to see whether the RCA or the AT&T sound system would predominate. Either way, Hollywood studios would in effect find themselves in technical thrall to the interests behind NBC, at this point (with CBS still struggling to get organized) the only broadcasting network with national reach. RCA was NBC's parent company; AT&T had an exclusive arrangement with NBC for the provision of landlines, the backbone of network broadcasting. Simultaneously, regulators in Washington were working on passage of the Radio Act of 1927, which promised a reorganization of the radio spectrum with an express mandate to bring the "chaos" of radio under control. Studios increased the pace of radio experimentation, attempting to get a foot-hold in the promising new business before restrictions might potentially be imposed, either by Washington or by contractual limitations from sound-on-film technology providers.

In May 1927 Paramount announced plans to form the Keystone Network, in partnership with the Postal Telegraph Company, one of AT&T's only competitors, "for dramatizing and advertising first-run motion pictures." As a backup plan, Paramount head Adolph Zukor also approached the interests behind the proposed NBC competitor, United Independent Broadcasters (later to become CBS) to suggest a partnership that he proposed might be renamed the Paramount Broadcasting System. In September MGM announced an ambitious project with the Loew's theater chain: a planned network based on movie materials and promotion that would link over sixty stations in more than forty cities. In December, to give audiences a taste of things to come, MGM experimented with the world's first "telemovie": a dramatic, blow-by-blow account of Love (1927), MGM's adaptation of Tolstoy's Anna Karenina starring Greta Garbo and John Gilbert, delivered on-air by WPAP's announcer Ted Husing (usually known for his sports coverage) as it unreeled before his eyes in the Embassy Theater in New York. Despite much excitement in the industry, neither the Keystone Chain, the Paramount Broadcasting System, nor the Loew's/MGM network reached fruition. A combination of regulatory discouragement, exhibitor opposition, and competition from other sources diverted studios' radio ideas in other directions.

Upon the expiration of the "stand still" agreement in 1928, film studios jointly decided to go with AT&T subsidiary Western Electric's sound technology. Left out in the cold, RCA in 1929 formed its own studio, RKO Pictures, and ushered in the era of film-radio cooperation in earnest as RKO and NBC learned to share talent and properties, such as the RKO Theater of the Air. Faced with this unsettling prospect, in the summer of 1929, just months before the stock market crash, Paramount again approached CBS. A stock transfer was hammered out, by the terms of which Paramount received a 49 percent interest in CBS while CBS received a certain number of Paramount shares. In three years Paramount would have the option of either buying the rest of CBS or simply regaining its own stock by turning back CBS's. By 1932, however, the country was in the depths of the Depression, and while radio's fortunes continued upward, the film industry was in steep decline. Rather than further consolidate their mutual interests, Paramount withdrew its merger offer, and the brief alliance was over. RCA divested itself of most of its interest in RKO in the late 1930s under similar pressures. Studios would not attempt to enter networking again until the television era.

RADIO GOES HOLLYWOOD

As the Depression continued, film industry profits suffered as theaters went out of business and box-office receipts slowed to a trickle. Radio, however, continued to thrive. As advertising agencies began to take the broadcast medium seriously as an outlet for their customers' campaigns, a new and influential partnership was about to emerge. Dissatisfied with CBS and NBC's staid approach to programming, several aggressive advertising firms turned their attention to Hollywood's untapped potential for radio-based product promotion. One of the biggest players in this Hollywood-agency alliance was the J. Walter Thompson Company (JWT), whose plan for radio advertising envisioned big-budget, starstudded productions sponsored by JWT clients over the major radio networks. By the mid-1930s JWT was producing at least five shows out of each year's top ten, most of them featuring Hollywood talent, such as The Chase and Sanborn Hour (with Edgar Bergen and Charlie McCarthy), Rudy Vallee's Fleischmann Yeast Hour, andLux Radio Theatre. Other major agencies included Young and Rubicam, Blackett-Sample-Hummert, and Dancer Fitzgerald. When in 1936 AT&T, as a result of an investigation by the FCC, reduced its land line rates to the West Coast, a "rush to Hollywood" resulted, and most major agencies along with the two national networks opened up studios in Los Angeles. Radio had gone Hollywood.

This productive and profitable association would have great impact on both the radio and film industries. A variety of radio programs developed that centered on movie industry stars, properties, and Hollywood celebrities. The most prestigious was the movie adaptation format pioneered by JWT's Lux Radio Theatre. Hosted by celebrity director Cecil B. DeMille (1881–1959), Lux presented hour-long radio adaptations of recent Hollywood film releases, introduced and narrated by DeMille and featuring well-known film stars. Others in this format, often referred to at the time as "prestige drama," included The Screen Guild Theater, Hollywood Premiere, Academy Award Theater, Dreft Star Playhouse, Hollywood Startime, and the Screen Directors' Playhouse. A popular feature of these programs was the intimate, casual interviews with famous stars; DeMille, for instance, would chat at the end of each show with that night's leading actors, often casually working in a mention of the sponsor's product. Here audiences could enjoy a new, more intimate relationship with stars and celebrities that had formerly been available only in the pages of fan magazines. Chatting about their upcoming pictures, a recent performance experience, or even domestic details and romantic tidbits, allowed the celebrity to step off the screen and into the familiar space of the living room.

The second major venue for Hollywood stars and film promotion was radio's leading genre, the big-name variety show. Fleischmann Yeast Hour, The Jack Benny Program, The Fred Allen Show, and many others featured regular guest appearances from Hollywood's A-list stars, often promoting their latest pictures or acting out skits related to film properties. Supporting roles were often filled by B-list actors and actresses, some of whom went on to considerable broadcast fame. Many stars eventually began hosting such programs themselves, especially in the late 1930s and early 1940s. Adolph Menjou and John Barrymore served as hosts for The Texaco Star Theater; Al Jolson appeared on radio almost exclusively after 1935; William Powell and Herbert Marshall hosted Hollywood Hotel at various times.

Some directors got into the act as well. Orson Welles's dramatic radio debut in 1938 on The Mercury Theatre on the Air, most notably his 30 October broadcast of War of the Worlds, helped secure his contract with RKO to produce, among other films, Citizen Kane (1941). Welles would frequently return to radio, as a variety show guest, guest host, and producer of lesserknown programs. Many accounts of the Mercury Theatre on the Air years agree that, once the first couple of broadcasts were past, the group Welles had gathered around him—notably John Houseman and Howard Koch—actually did most of the dramatic selection and adaptation work; nevertheless Welles's inimitable sense of drama and timing as well as his penchant for reflexive and confrontational material permeated the productions. And Welles would bring a heightened awareness of the potential of sound as an expressive medium with him to Citizen Kane and much of his other film work. Alfred Hitchcock, too, established a reputation on American radio, as well as film, before becoming a television personality.

CROSSOVER CAREERS

Many Hollywood stars extended their careers on radio, some of them also moving into television in its early years. Groucho Marx made frequent appearances not only on comedy-variety programs but on the rising genre of humorous quiz shows. In 1947 he became the host of ABC radio's popular You Bet Your Life, which made the transition to television in 1950 and ran until 1957. Ed Wynn started out in film, moved to radio and television, then played comic parts in a series of films in the 1950s and 1960s. Robert Young became established as a reliable second leading man in the 1930s and 1940s, then debuted the long-running Father Knows Best franchise on radio, before moving to television. Especially for Hollywood's extensive B-list starts, radio in the late 1940s became a springboard both to television fame and, less frequently, back toward greater eminence in the film business.

It was a set of Hollywood's secondary ladies who made the deepest mark on one of broadcasting's most enduring genres, the situation comedy, first on radio, then on television. Such B-list performers and comediennes as Lucille Ball, Dinah Shore, Joan Davis, Eve Arden, Hattie McDaniel, and Ann Sothern began by building up reputations as frequent radio guest stars in the 1930s and early 1940s. When World War II removed many male comedians from the air, as well as increasing the prominence and importance of the female audience at home, the film industry supplied key talent to move into prime time. Out of this conjunction the sitcom was born, taking comedy in a new direction—away from the stand-up, gag-based variety format and toward a new genre based on recurring characters in humorous situations, emphasizing domestic settings.

Joan Davis was the first to step into the leading-lady spotlight, as she moved from a supporting cast position on The Rudy Vallee Show in 1941 to primary status when Vallee left the program to go into the military in 1943. Renamed The Sealtest Village Store, it featured Davis as a frustrated, man-chasing spinster; she would go on to take the headline role in The Joan Davis Show on CBS in 1945, and from there to television in the sitcom I Married Joan (NBC, 1952–1955). Lucille Ball, the best-known of radio's film comediennes, moved, like Davis, from an RKO contract to star in My Favorite Husband (CBS, 1948–1951), though her fame came with the debut of I Love Lucy in 1950 on CBS-TV. Ann Sothern took her fame as the star of MGM's Maisie films to radio in a situation comedy of the same name in 1949; she went on to star in television sitcoms for the next twelve years. Eve Arden, who starred in a long line of B-movies from the 1920s through the 1940s, including a series of Republic Studios features based on the Lucky Strike Your Hit Parade radio series, debuted as Our Miss Brooks on CBS in 1948. Hattie McDaniel, the first African American actress to win an Emmy, for her role in Gone with the Wind (1939), made her radio headliner debut in the long-running Beulah in 1947. These pioneering woman-centered situation comedies used the star power of their Hollywood-based leading ladies to draw ever larger audiences to this new form, and to take them from radio to television in the early 1950s.

Other properties moved from film to radio, many of them adaptations from fiction or comics. Dashiell Hammett's The Thin Man first mutated into a series of films starring William Powell and Myrna Loy beginning in 1937; it became a radio program in 1941 and later shifted to television. Series like The Lone Ranger and The Green Hornet prospered in film, radio, and television formats. The film industry also came to increasingly rely on the star-producing capabilities of radio, with radio personalities starring in many popular Hollywood films. One of the first of these crossovers was Check and Double Check for RKO (1930), starring Freeman Gosden and Charles Correll as the characters they played in the Amos 'n' Andy show on radio. Movies like The Big Broadcast of 1936—and 1937 and 1938—were produced specifically to consolidate radio stars' popularity with the film-viewing public, and to cement the Hollywood-radio relationship. Other stars who had first made it big on radio found significant new success in films, like the "Road" pictures starring Bing Crosby, Bob Hope, and Dorothy Lamour (Road to Zanzibar [1941], Road to Morocco [1942], Road to Rio [1947], et al.). Rudy Vallee, Eddie Cantor, and Jack Benny all met with box-office success in films that often highlighted their roles as radio stars and featured the exciting world of radio behind the scenes. This tradition continued, as Howard Stern's 1997 movie about his radio career, Private Parts, attests. Other memorable films about radio and its role in American life include The Hucksters (1947), an indictment of advertising-dominated radio and its effects on American postwar society; George Lucas's classic American Graffiti (1973), with its memorable top-40 soundtrack and a cameo by the legendary DJ Wolfman Jack; and Woody Allen's Radio Days (1987), a highly nostalgic look at life before television.

AFTER TV

Although the nature of radio changed dramatically once TV came onto the scene, some studios did maintain a persistent presence in radio ownership and production. Warner Bros., Paramount, RKO, and MGM all owned radio stations, and also got in on television station ownership early. MGM went into syndicated radio program production and distribution in the late 1940s, with such programs as The MGM Theater of the Air and Maisie. Just as film companies diversified into television, they also began to acquire interests in the music industry, the new backbone of radio. For example, the Disney Corporation holds extensive interests in music recording, and through its merger with ABC in 1995 came to own radio stations that reach 24 percent of US households. Twentieth Century Fox was purchased by Rupert Murdoch's News Corporation in the 1980s and is now linked with satellite music channels worldwide. News Corp. also owns the Australian Mushroom and Festival record labels. And in this age of synergy, the tie between movies and music has become tighter than ever before, with movie soundtracks used to promote artists and recordings, and soundtrack releases often achieving billions in sales.

In the era of new media, where the lines between film, radio, television, music, recordings, and the Internet seem to be growing blurrier every day, the integrated entertainment corporations formerly designated by the term "Hollywood" have fingers in nearly every form of media that reaches into the home—or anywhere the viewer might be. Now Internet radio technology gives companies the ability to go online with their own "radio" services. DisneyRadio.com already provides a schedule of music and features from its films and artists, oriented toward children. Television shows on studio-owned networks promote recordings distributed by the company's record arm, which become hits on pop radio. Recording stars launch film careers; film and television stars, like Janeane Garofalo and Al Franken, start radio careers. Although in the United States the days of radio drama and comedy faded long ago, transferring their stars and audiences to television, the film industry continues to play a vital behind-the-scenes role linking radio to a host of other media. Without Hollywood, American radio could never have risen to the heights of creativity and popularity it achieved in its heyday. Without radio, Hollywood as we know it today would be missing some of its brightest lights and most memorable ingredients. The twenty-first century's digital media promise to bring these two media venues into an ever closer relationship.

SEE ALSO Sound;Technology;Television

FURTHER READING

Dunning, John. On the Air: The Encyclopedia of Old-Time Radio. New York: Oxford University Press, 1998.

Gomery, Douglas. "Toward an Economic History of the Cinema: The Coming of Sound to Hollywood." In The Cinematic Apparatus, edited by Stephen Heath and Teresa de Lauretis, 38–46. New York: St. Martin's Press, 1982.

Hilmes, Michele. "Femmes Boff Program Toppers: Women Break into Prime Time, 1943–1948." In Transmitting the Past: Historical and Cultural Perspectives on Broadcasting, edited by Susan Brinson and J. Emmett Winn, 137–160. Tuscaloosa: University of Alabama Press, 2004.

——. Hollywood and Broadcasting: From Radio to Cable. Urbana: University of Illinois Press, 1990.

Jewell, Richard B. "Hollywood and Radio: Competition and Partnership in the 1930s." Historical Journal of Film, Radio and Television 4, no. 2 (1984): 125–141.

Lucich, Bernard. "The Lux Radio Theatre." In American Broadcasting: A Sourcebook on the History of Radio and Television, edited by Lawrence W. Lichty and Malachi C. Topping, 391–393. New York: Hastings House, 1975.

Rothafel, Samuel L. Broadcasting: Its New Day. New York: Century, 1925.

Smoodin, Eric. "Motion Pictures and Television, 1930–1945." Journal of the University Film and Video Association (Summer 1982): 3–18.

Michele Hilmes

Radio

Radio is the technology and practice that enables the transmission and reception of information carried by long-wave electromagnetic radiation . Radio makes it possible to establish wireless two-way communication between individual pairs of transmitter and receiver, and it is used for one-way broadcasts to many receivers. Radio signals can carry speech , music, telemetry , or digitally-encoded entertainment. Radio is used by the general public, within legal guidelines, or it it is used by private business or governmental agencies. Cordless telephones are possible because they use low-power radio transmitters to connect without wires. Cellular telephones use a network of computer-controlled low power radio transmitters to enable users to place telephone calls away from phone lines.

The history of radio

In the nineteenth century, in Scotland, James Clerk Maxwell described the theoretical basis for radio transmissions with a set of four equations known ever since as Maxwell's Field Equations. Maxwell was the first scientist to use mechanical analogies and powerful mathematical modeling to create a successful description of the physical basis of the electromagnetic spectrum . His analysis provided the first insight into the phenomena that would eventually become radio. He deduced correctly that the changing magnetic field created by accelerating charge would generate a corresponding changing electric field. The resulting changing electric field would, he predicted, regenerate a changing magnetic field in turn, and so on. Maxwell showed that these interdependent changing electric and magnetic fields would together be a part of a self-sufficient phenomenon required to travel at the speed of light .

Not long after Maxwell's remarkable revelation about electromagnetic radiation, Heinrich Hertz demonstrated the existence of radio waves by transmitting and receiving a microwave radio signal over a considerable distance. Hertz's apparatus was crude by modern standards but it was important because it provided experimental evidence in support of Maxwell's theory.

Guglielmo Marconi was awarded the Nobel Prize in physics in 1909 to commemorate his development of wireless telegraphy after he was able to send a long-wave radio signal across the Atlantic Ocean.

The first radio transmitters to send messages, Marconi's equipment included, used high-voltage spark discharges to produce the charge acceleration needed to generate powerful radio signals. Spark transmitters could not carry speech or music information. They could only send coded messages by turning the signal on and off using a telegraphy code similar to the landline Morse code.

Spark transmitters were limited to the generation of radio signals with very-long wavelengths, much longer than those used for the present AM-broadcast band in the United States. The signals produced by a spark transmitter were very broad with each signal spread across a large share of the usable radio spectrum . Only a few radio stations could operate at the same time without interfering with each other. Mechanical generators operating at a higher frequency than those used to produce electrical power were used in an attempt to improve on the signals developed by spark transmitters.

A technological innovation enabling the generation of cleaner, narrower signals was needed. Electron tubes provided that breakthrough, making it possible to generate stable radio frequency signals that could carry speech and music. Broadcast radio quickly became established as source of news and entertainment.

Continual improvements to radio transmitting and receiving equipment opened up the use of successively higher and higher radio frequencies. Short waves, as signals with wavelengths less than 200m are often called, were found to be able to reach distant continents. International broadcasting on shortwave frequencies followed, allowing listeners to hear programming from around the world.

The newer frequency-modulation system, FM, was inaugurated in the late 1930s and for more than 25 years struggled for acceptance until it eventually became the most important mode of domestic broadcast radio. FM offers many technical advantages over AM, including an almost complete immunity to the lightning-caused static that plagues AM broadcasts. The FM system improved the sound quality of broadcasts tremendously, far exceeding the fidelity of the AM radio stations of the time. The FM system was the creation of E. H. Armstrong, perhaps the most prolific inventor of all those who made radio possible.

In the late 1950s, stereo capabilities were added to FM broadcasts along with the ability to transmit additional programs on each station that could not be heard without a special receiver. A very high percentage of FM broadcast stations today carry these hidden programs that serve special audiences or markets. This extra program capability, called SCA for Subsidiary Communications Authorization, can be used for stock market data, pager services, or background music for stores and restaurants.

Radio and the electromagnetic spectrum

Radio utilizes a small part of the electromagnetic spectrum, the set of related wave-based phenomena that includes radio along with infrared light, visible light, ultraviolet light, x rays , and gamma rays. Picture the electromagneticspectrum as a piano keyboard: radio will be located where the piano keys produce the low frequency musical notes. Radio waves have lengths from many miles down to a fraction of a foot.

Radio waves travel at the velocity of electromagnetic radiation. A radio signal moves fast enough to complete a trip around the earth in about 1/7 second.

How radio signals are created

Jiggle a collection of electrons up and down one million times a second and a 1-MegaHertz radio signal will be created. Change the vibration frequency and the frequency of the radio signal will change.

Radio transmitters are alternating voltage generators. The constantly changing voltage from the transmitter creates a changing electric field within the antenna . This alternating field pushes and pulls on the conduction electrons in the wire that are free to move. The resulting charge acceleration produces the radio signal that moves away from the antenna. The radio signal causes smaller sympathetic radio frequency currents in any distant electrical conductor that can act as a receiving antenna.

Modulation

A radio signal by itself is like a mail truck without letters. A radio signal alone, without superimposed information, is called a carrier wave. An unmodulated radio signal conveys only the information that there was once a source for the signal picked up by the receiver. Adding information to a carrier signal is a process called modulation. To modulate a radio carrier means that it is changed in some way to correspond to the speech, music, or data it is to carry.

The simplest modulation method is also the first used to transmit messages. The signal is turned on and off to transmit the characters of an agreed code. Text messages can be carried by the signal modulated in this way. Unique patterns stand for letters of the alphabet, numerals, and punctuation marks.

The least complicated modulation method capable of transmitting speech or music varies the carrier signal's instantaneous power. The result is called amplitude modulation, or AM. Another common system varies the signal's instantaneous frequency at an informational rate . The result is frequency modulation, FM.

If radio is to transmit speech and music, information must be carried that mimics the pattern of changing air pressure the ear would experience hearing the original sound. To transmit sounds these air-pressure changes are converted into electrical signals, amplified electronically, then used to modulate the carrier.

Amplitude modulation was the first process to have the capability of transmitting speech and varied the radio signal's instantaneous power at a rate that matched the original sound vibrations in the air. A better modulation technology followed that varied the instantaneous frequency of the radio signal but not the amplitude. Frequency modulation, or FM, has advantages compared to AM but both AM and FM are still in use.

Sound can be converted to digital data, transmitted, then used to reconstruct the original waveform in the receiver. It seems likely that a form of digital modulation will eventually supplant both FM and AM.

Demodulation

Radio receivers recover modulation information in a process called demodulation or detection. The radio carrier is discarded after it is no longer needed. The radio carrier's cargo of information is converted to sound using a loudspeaker or headphones or processed as data.

Wavelengths, frequencies, and antennas

Each radio signal has a characteristic wavelength just as is the case for a sound wave. The higher the frequency of the signal, the shorter will be the wavelength. Antennas for low-frequency radio signals are long. Antennas for higher frequencies are shorter, to match the length of the waves they will send or receive.

It is a characteristic of all waves, not just radio signals, that there is greater interaction between waves and objects when the length of the wave is comparable to the object's size. Just as only selected sound wavelengths fit easily into the air column inside a bugle, only chosen frequencies will be accepted by a given antenna length. Antennas, particularly transmitting antennas, function poorly unless they have a size that matches the wavelength of the signal presented to them. The radio signal must be able to fit on the antenna as a standing wave. This condition of compatibility is called resonance . If a transmitter is to be able to "feed" energy into an antenna, the antenna must be resonant or it will not "take power" from the transmitter. A receiver antenna is less critical, since inefficiency can be compensated by signal amplification in the receiver, but there is improvement in reception when receiving antennas are tuned to resonance.

If an antenna's physical length is inappropriate, capacitors or inductors may be used to make it appear electrically shorter or longer to achieve resonance.

Near 100 MHz, near the center of the FM broadcast band in most of the world, signals have a wavelength of approximately three meters. At 1 MHz, near the center of the U.S. AM broadcast band, the signal's wavelength is 327 yds (300 m), about three times the length of a football field. One wavelength is about 1 ft (0.3 m) at the ultra-high frequency used by cellular telephones.

Radio signals and energy

Energy is required to create a radio signal. Radio signals use the energy from the transmitter that accelerates electric charge in the transmitting antenna. A radio signal carries this energy from the transmitting antenna

to the receiving antenna. Only a small fraction of the transmitter's power is normally intercepted by any one receiving antenna, but even a vanishingly-small received signal can be amplified electronically millions of times as required.

Radio signal propagation

Radio signals with very short wavelengths generally follow straight line paths much as do beams of light, traveling from transmitter to receiver as a direct wave. Radio signals with very long wavelengths follow the curvature of the earth, staying close to the surface as signals called ground waves.

Radio signals with intermediate wavelengths often reflect from layers of electrically-charged particles high above the earth's surface. These signals are known as skywaves. The layers of electrically-charged particles found between 25-200 mi (40-322 km) above the earth are collectively known as the ionosphere. The ionosphere is renewed each day when the sun's radiation ionizes atoms in the rarefied air at this height. At higher altitudes the distance between ions causes the ionization to persist even after the sun sets.

A good way to become familiar with radio propagation is to listen for distant AM-broadcast radio at various times of the day. A car radio works well for this experiment because they often have better sensitivity and selectivity than simpler personal radios.

During the daylight hours, on the standard-broadcast band, only local stations will normally be heard. It is unlikely that you will hear stations from more than 150 mi (241 km). As the sun sets you will begin to hear signals from greater distances.

AM-broadcast reception is generally limited to ground-wave radio signals when the sun is high in the sky. There is a very dense layer of the ionosphere at a height of approximately 25 mi (40 km) that is continually created when the sun is high in the sky. This D layer, as it is called, absorbs medium wavelength radio signals so that skywave signals cannot reflect back to earth. The D layer dissipates quickly as the sun sets because the sun's rays are needed to refresh the ionization of this daytime-only feature of the ionosphere. After dark, when the D layer has disappeared, you will hear strong signals from far away cities.

After the D layer has disappeared, skywave signals reflect from a much higher layer of the ionosphere called the F layer. The F layer acts as a radio mirror, bouncing skywaves back to earth far from their source. The F layer degrades in darkness as does the D layer, but since the ions are separated more widely at higher altitude, the F layer functions as a significant radio mirror until dawn. Toward morning stations at intermediate distances fade, leaving only skywave signals that reflect from the thinning ionosphere at a very shallow angle.

Signal absorption by the D layer is less at shorter wavelengths. Stations using higher frequencies can use skywave in the daytime. High frequencies pass through the D layer. Skywave radio circuits are usually best in the daytime for higher frequencies, just at the time that the standard-broadcast band is limited to groundwave propagation.

Forecasting long distance radio signal propagation conditions depends upon predicting conditions on the sun. It is the changing radiation from the sun that affects long distance radio circuits when the ionosphere changes as the earth rotates. On the sunlit side of the earth the ionosphere is most strongly ionized. On the night side of the earth the radio ionosphere begins to dissipate at sunset until it is almost insignificant as a radio mirror in the early morning hours. When the ionosphere is at its best as a reflector it can support communication between any locations on the earth.

When the ionosphere is more densely ionized it will reflect radio signals with a shorter wavelength than when the ionization is weaker. At any one time, between any two distant locations on the earth, there is a limiting upper frequency that can be used for radio communication. Signals higher in frequency than this maximum-usable frequency, F layer called the MUF, pass through the ionosphere without returning to earth. Slightly lower than the MUF, signals are reflected with remarkable efficiency. A radio signal using less power than a flashlight can be heard on the opposite side of the earth just below the MUF. The MUF tends to be highest when the sun is above the midpoint between two sites in radio communication.

The 11-year solar sunspot cycle has a profound effect on radio propagation. When the average number of sunspots is large, the sun is more effective in building the radio ionosphere. When the sun's surface is quiet the maximum-usable frequency is usually very low, peaking at less than half the MUF expected when the sun surface is covered with sunspots.

From time to time, the sun bombards the earth with charged particles that disrupt radio transmissions. When solar flares are aimed toward the earth, the earth's magnetic field is disturbed in a way that can cause an almost complete loss of skywave radio propagation. Microwave radio signals are not significantly disturbed by the magnetic storms since microwaves do not depend upon ionospheric reflection.

FM-broadcast signals are seldom heard reliably further than the distance to the horizon. This is because the frequencies assigned to these services were deliberately chosen to be too high to expect the ionosphere to reflect them back to earth. FM signals are received as direct waves, not skywaves. The limited range of FM stations is an advantage because frequency assignments can be duplicated in cities that are in fairly close proximity without encountering unacceptable interference . This protection is much harder to achieve where skywave propagation may permit an interfering signal to be heard at a great distance.

Shortwave radio

Shortwave radio services may change frequency often as the ionosphere's reflectivity varies. Unlike domestic broadcast stations that stay on a single assigned frequency, shortwave broadcast stations move frequency to take advantage of hour-to-hour and season-to-season changes in the ionosphere. As the 11-year sunspot cycle waxes and wanes, shortwave stations the world around move to shorter wavelengths when there are more sunspots and to longer wavelength bands when sunspots are minimal.

Listening to shortwave radio requires more effort than istening to local domestic radio. The best frequencies to search change from one hour to the next throughout the day. Due to the effect of the sun, shortwave signals sometimes may disappear for days at a time, then reappear with astounding strength. Many shortwave stations do not broadcast at all hours of the day. In addition, a station must be targeting your part of the world specifically; otherwise the signal will probably be weak.

Regulation of radio transmissions

The part of the electromagnetic spectrum that can be used for radio communication cannot accommodate everyone who might wish to use this resource. Access is controlled and technical standards are enforced by law. With few exceptions, radio transmissions are permitted only as authorized by licenses.

Since 1934 in the United States, licensing and equipment approval has been the responsibility of the Federal Communications Commission. Similar regulation is the rule in other countries. Technical standards are required by radio regulation. Just as traffic laws improve highway safety, laws and regulations that encourage the fair use of the limited radio spectrum help to avoid conflicts between users.

The future of radio

Radio broadcasting now includes a newer, better digital system known as DAB, digital-audio broadcasting. Early tests indicate that a switch to digital imparts compact-disc quality to radio programming. There are two possible modes for DAB. In Europe , completely new stations on a different band of frequencies is favored. In the United States it seems probable that digital information will transmitted as information superimposed on the programming modulation now used. The digitized audio can be so much lower in power than the "main" programming that it will be inaudible to listeners with analog receivers. Early program tests of this system have been successful and increases in audio quality have been significant.

Resources

books

The 1995 ARRL Handbook. The American Radio Relay League, 1995.

Hobson, Art. Physics: Concepts and Connections. New York: Prentice-Hall, Inc., 1995.

Jacobs, George, and Theodore J. Cohen. The Shortwave Propagation Handbook. Cowan Publishing Corp., 1970.

Ostdiek, Vern J., and Donald J. Bord. Inquiry Into Physics. St. Paul: West Publishing Company, 1995.

other

Now You're Talking. The American Radio Relay League, 1994.

Donald Beaty

KEY TERMS

Antenna

—An electrical conductor used to send out or receive radio waves.

Capacitor

—Electrical component that cancels magnetic property of wire.

D Layer

—Arbitrary designation for the lowest layer of the ionosphere.

Electric field

—The concept used to describe how one electric charge exerts force on another, distant electric charge.

Electron tube

—Active device based on control of electrons with electric fields.

F layer

—Arbitrary designation for the highest layer of the ionosphere.

Gamma ray

—Electromagnetic radiation with the shortest wavelengths.

Inductor

—Electrical component that adds magnetic property to wire.

Infrared light

—Light with wavelengths longer than those of visible light.

Ionized

—Missing one or more electrons, resulting in a charged atom.

Magnetic field

—Effect in space resulting from the motion of electric charge.

MegaHertz

—One million cycles per second; MHz.SI abbreviation for MegaHertz.

Morse code

—Dot and dash code used to send messages over telegraph wires.

Resonance

—The enhancement of the response of a system to a force, when that force is applied at a particular frequency known as the resonant frequency.

Selectivity

—Receiver property enabling reception of only wanted signals.

Sensitivity

—Receiver property enabling reception of weak signals.

Standing wave

—A stationary pattern of activity resulting from interference.

Sunspot

—Cooler and darker areas on the surface of the sun. They appear dark only because they are cooler than the surrounding surface. Sunspots appear and disappear in cycles of approximately 11 years.

Telemetry

—Engineering and scientific measurements transmitted by radio.

X ray

—Electromagnetic radiation of very short wavelength, and very high energy.

Radio

In September of 1895, Guglielmo Marconi, a young Italian inventor, pioneered wireless telegraphy when he transmitted a message to his brother, who was out of sight beyond a hill. By 1906, U.S. inventor Lee De Forest had greatly increased the potential of Marconi's work by developing a three-electrode vacuum-tube amplifier that made modern radio broadcasts possible. From these relatively humble beginnings radio quickly evolved to become the basis of an electronic media revolution that would shape the face of American popular culture during the middle years of the twentieth century. From the early 1920s to the mid-1950s radio both recorded and influenced popular culture in a way that no other media had ever done, forever changing the way information and entertainment would be disseminated and paving the way for television.

The first modern radio station came into being in 1920, when Westinghouse engineer Frank Conrad set up KDKA in East Pittsburgh, Pennsylvania, and began sending out programs "over the ether," in the parlance of the day. On November 2 of that year, KDKA broadcast the results of the Harding-Cox presidential election. However, at that time only about 5,000 Americans had radio receivers, so the broadcast went largely unnoticed. As Susan Smulyan writes in Selling Radio, the problem was that "when the first radio station began in 1920, no one knew how to make money from broadcasting." Nevertheless, a number of different groups soon realized that radio could be a powerful and important medium, which resulted in a battle for control of the airwaves.

One faction, spearheaded primarily by educators, believed that radio could be a tool for enriching people's lives. They wanted a government-funded national radio program that would be largely informational and educational. These groups would have to wait nearly fifty years to get their wish; on November 7, 1967, President Lyndon B. Johnson would sign the Public Broadcasting Act into law, resulting in the creation of the noncommercial National Public Radio and the Public Broadcasting (television) networks. But in 1920 the question for broadcasters was, "Who would pay for radio?" The general public was not yet ready to pay for its information and entertainment directly (that would come in the 1970s, with the growth of cable television beyond its humble beginnings as a source for programming in areas beyond the reach of airborne signals). In 1922 New York radio station WEAF—which would later become WNBC—solved the funding dilemma when it aired the first paid radio commercials. Although advertisers were initially unconvinced as to radio's ability to sell products, they eventually realized that it was an incredibly effective way to reach people in their homes. Accordingly, WEAF's commercialization set into motion the private control of U.S. public airwaves. In a now-famous quote, radio pioneer De Forest responded to radio's commercialization by asking, "What have you done with my child? You have sent him out on the street in rags of ragtime to collect money from all and sundry. You have made of him a laughingstock of intelligence, surely a stench in the nostrils of the gods of the ionosphere."

The concept of "selling time" for advertisements had immense ramifications for American popular culture. Since the inception of mass media advertising, the public's conception of life in the United States has become defined not by what people do, but by the products they consume; success or failure in the U.S. is largely defined by material possessions instead of by accomplishments. As Smulyan writes, "broadcasting's programs and structures," which paved the way for later media advertising like television commercials and website banners, were first "developed in radio." However, radio's contribution to popular culture is not exclusively confined to its role in the birth of modern advertising. Just as important are the medium's contributions to the ways in which people are informed and entertained.

Prior to the onset of the Depression, radio had already established its core of music, news, and entertainment programming. Of the three, music and news programming were the most predominant because they were the cheapest to produce; entertainment programming would not enter its golden age until the early 1930s. There were two ways of presenting music on radio: either by playing records or broadcasting musicians as they played live in a studio, concert hall, or hotel ballroom. The widespread integration of musical numbers into more complex variety shows was still a number years off. In addition to musical programming, news broadcasts and issue-based discussion shows also flourished in the 1920s. Never before had the dissemination of news been so immediate. Sports events like the World Series and news events like the infamous Scopes trial, which Chicago station WGN broadcast live, united Americans around their radios. From its earliest days, radio began the move towards instantaneous news.

Radio networks also began appearing in the late 1920s: NBC was established in 1926, and CBS in 1927. Perhaps the most important effect these networks had on radio was their contribution to the establishment of a more national medium. The respective networks began buying up local stations, which became known as "affiliates." Locally produced shows gave way to uniform national shows that the networks broadcast over their affiliates. Concurrently, radio was becoming an item commonly found in every home. As noted by Fred MacDonald in Don't Touch That Dial, by the early 1930s approximately 90 percent of Americans had at least one radio in their homes. As a result, American regionalism began to disappear at an accelerated rate as Californians began to hear the same shows as people in Alabama and New Jersey. What in the late 1990s has come to be known as the "homogenization of American culture" can be traced back to the rise of the early radio networks.

Despite the success of radio in the 1920s, something was still missing. Although there were a few popular programs, radio shows had yet to fully come into their own; however, the Great Depression ushered in their "golden age." By the early 1930s, listeners had grown bored with mostly music, news, and talk, and many of them craved escape from the hard reality of their difficult financial circumstances. Radio responded by expanding its programming diversity and broadcasting shows in many genres, including Westerns, detective shows, dramas, soap operas, comedies, romances, and variety shows. Americans danced to the latest rhythms as played by bandleaders who broadcast live from hotel ballrooms, or gathered around their radio sets on Sunday morning to hear prominent preachers and choirs, precursors to the radio and television evangelists of a later era. Many radio shows of the period were serialized so fans could follow the ongoing weekly adventures of their favorite characters. The serialization of radio shows created a continuity in American entertainment that was unique to the medium at that time. The Lone Ranger, for example, was on the air for twenty-two years. Likewise, The Jack Benny Program enjoyed a twenty-six-year run. Perhaps MacDonald best sums up radio's importance during the Depression when he writes, "for audiences trapped by the economic depression and social uncertainty of the 1930s, radio became the great wellspring from which came escape, diversion, knowledge, and inspiration." As programmers realized that national shows needed national celebrities in order to achieve immediate success, they came to rely heavily on the many popular performers who had been displaced by the rise of electronic media—making radio stars out of ex-vaudevillians like the Marx Brothers, Burns and Allen, Jack Benny, and Fred Allen.

Conversely, in the early 1930s, entertainment's brightest lights—Hollywood movie stars—were reluctant to appear on radio. Most studios, and many stars, believed that appearing on radio would somehow lessen a star's cinematic appeal. Radio loved the movies, on the other hand: most stations ran movie reviews, and syndicated gossip columnists such as Louella Parsons and Walter Winchell often focused on Hollywood figures. Hollywood studios eventually came to the realization that increased exposure for their stars would most likely result in increased revenues for their films. By the early 1940s Hollywood actors, including Humphrey Bogart, Katharine Hepburn, Jimmy Stewart, James Cagney, and Clark Gable, routinely participated in radio reenactments of their films; at the same time a number of actors who got their start in radio, such as Don Ameche, Richard Widmark, Agnes Moorehead, and Art Carney, were beginning to appear in films. As the lines between the two media slowly blurred, America became more and more infatuated with its stars. As a result of the unprecedented media exposure stars received when they began to appear both on radio and in film, the cultural iconolatry of entertainers, which began in earnest with the silent movie stars of the late 1910s and early 1920s, reached new heights in the 1930s and 1940s.

Perhaps the most vivid example of the cultural influence radio had in its heyday is Orson Welles' October 30, 1938, broadcast of an adaptation of H. G. Wells' The War of the Worlds, which presented itself as a would-be Martian invasion broadcast in real time. Welles and the other actors meant the broadcast to be dramatic fiction, but millions took it seriously. Although the show did run an opening explanation, many who tuned in late were greeted by an announcer saying, "Ladies and gentlemen, we interrupt our program of dance music to bring you a special bulletin from the Intercontinental Radio News." Listeners mistakenly believed that Martians were invading the United States and that radio was covering it live. All over the country hysteria prevailed for several hours, and the power of radio to influence the American public was confirmed.

Just as radio entertainment became more diversified during the 1930s, so too did the ways in which news was presented. Whereas in the 1920s and early 1930s news had most often been simply read, a new type of reporter was coming into being in the mid-1930s: the broadcast journalist. Reporters began live coverage of developing stories and often offered on-air appraisals of news stories as they happened. Americans who had previously only heard reporters reading recaps of speeches, conferences, conventions, and military clashes began to hear them live. These live broadcasts of social and political events played a large role in America's national attitude of unity as it entered World War II. The public had been largely uninformed when America entered World War I, but because of radio and its broadcast journalists the American public was keenly aware of the cumulative series of events that had occurred prior to its entering World War II.

As radio grew, politicians realized its importance as a means through which to disseminate their ideology. In an extreme example, European leaders such as Mussolini and Hitler routinely broadcast their fervent speeches live. Although their message was often one of hatred and intolerance, both leaders—but especially Hitler—were brilliant and impassioned speakers who understood just how effective a propaganda tool radio could be. Perhaps the most fervent ideologue on U.S. radio in the late 1930s was Father Charles Coughlin, the "radio priest" of Royal Oak, Michigan, who commanded an audience of millions with tirades that became increasingly anti-Semitic and pro-Franco. On the home front, perhaps no U.S. leader used radio as effectively as President Franklin Delano Roosevelt. Beginning in 1933 and lasting until his death in 1945, Roosevelt took his message directly to the people in a series of live radio speeches. Roosevelt called some of these speeches "fireside chats," which were constructed to seem like personal conversations with the public. Opening each chat with the phrase, "My dear friends," Roosevelt carefully explained his policies and programs and used the intimate format to gain popular support from the American people. In addition, Rooseveltian sound bites such as "the only thing we have to fear is fear itself" (from his first inauguration) and "a date which will live infamy" (from his speech to Congress after Pearl Harbor) were immediately and permanently thrust into the nation'a popular culture, in part because they were broadcast live to an audience of millions.

Throughout U.S. involvement in World War II, radio played a crucial role in the public's perception of the war. Although not televised as the Vietnam War would later be, radio brought World War II into every American living room. From Britain and France's declaring war on Germany in 1939, to Roosevelt's "day of infamy" speech after the attack on Pearl Harbor, to the surrender ceremonies aboard the U.S.S. Missouri on September 2, 1945, Americans heard the war's major events as they happened. Perhaps the most memorable broadcasts of the war were Edward R. Murrow's reports during the London blitz of 1940, which helped solidify U.S. public opinion on behalf of the Allies. As the war proceeded, and despite strict censorship restrictions, other broadcast journalists reported from military hot spots and the government used radio to communicate with the nation. All through the war Americans turned to their radios for the latest news from the fronts. In addition to the first-hand accounts of those returning from overseas and newsreels, America's memories of World War II have been shaped largely by the immediacy offered by radio.

Although radio continued to enjoy tremendous popularity in the early 1950s, it was never quite the same after World War II. The war had given radio a uniformity of purpose and focus. With the war over, radio was forced to scramble to institute peacetime programming that could match the heady days of broadcasting during the war years. As traditional formats began to lose popularity, it became clear that new formats and ideas were needed; but radio was slow to change. Experimentation was limited by the cold war atmosphere of fear created by the anti-Communist movement of the late 1940s and early 1950s. Producers were afraid that anything different from the norm might be construed as subversive. Concurrently, television was beginning to gain a firm hold in American homes. Many of the shows that had long been broadcast on the radio made the transition to television. By 1960 the golden age of radio was over.

Radio has never fully regained the popularity it enjoyed during its forty-year heyday from 1920 to 1960. The rise of FM radio stations in the 1960s propelled rock 'n' roll to a position of cultural influence unequaled by any other musical genre. FM stations sounded better than AM stations, and came in stereo. The disc jockeys who played records took advantage of their new-found freedom to experiment with the FM dial as "free form" radio. Whereas radio news had chronicled the cultural events of the 1930s, 1940s, and 1950s, rock 'n' roll became the sound track for the cultural revolution ushered in by the Boomer generation in the 1960s and early 1970s. Before World War II, most radio programs, dramas, comedies, musical shows, or quiz shows, were fifteen-minute or half-hour programs; after the war, stations tended to devote round-the-clock programming to specific musical formats, such as rock 'n' roll, Top-40, classical, rhythm & blues, or jazz, for example. In the 1990s, talk radio enjoyed a resurgence, especially on the AM dial, with figures as diverse as Rush Limbaugh, Dr. Laura Schlessinger, and Howard Stern enjoying a cultural influence perhaps never equaled by their radio predecessors—to say nothing of the frank sex therapy dispensed by Dr. Ruth Westheimer and Dr. Judy Kurlansky.

During the height of radio's popularity, as Charles Siepmann writes, "The average man or woman spends more leisure hours in listening to the radio than in anything else—expect sleeping.… For radio—cheap, accessible, and generous in its provision for popular tastes—has come to be the poor man's library, his 'legitimate' theater, his vaudeville, his newspaper, his club. Never before has he met so many famous and interesting people, and never have these people been at once so friendly and so attentive to his wishes." On the eve of the year 2000, American audiences had immediate access to more news and entertainment options than any population in the history of the world; radio was the seed from which the structure of contemporary current mass media grew. But America's plethora of options reflects its culture: fractious, scattered, and able to agree on little. Conversely, for a brief forty years in the mid-twentieth century, radio contributed to the creation of at least the semblance of a united country and inspired the national imagination in a way no medium has done before or since.

—Robert C. Sickels

Further Reading:

Bray, John. The Communications Miracle: The Telecommunication Pioneers from Morse to the Information Superhighway. New York, Plenum Press, 1995.

Hilmes, Michele. Radio Voices: American Broadcasting, 1922-1952. Minneapolis, University of Minnesota, 1997.

Ladd, Jim. Radio Waves: Life and Revolution on the FM Dial. New York, St. Martin's Press, 1991.

MacDonald, Fred J. Don't Touch That Dial: Radio Programming in American Life, 1920-1960. Chicago, Nelson-Hall, 1979.

Maltin, Leonard. The Great American Broadcast: A Celebration of Radio's Golden Age. New York, Dutton, 1997.

Nachman, Gerald. Raised on Radio. New York, Pantheon Books, 1998.

Ryan, Thomas. American Hit Radio: A History of Popular Singles from 1955 to the Present. Rocklin, California, Prima Publishing, 1996.

Smulyan, Susan. Selling Radio: The Commercialization of American Broadcasting, 1920-1934. Washington, D.C., Smithsonian Institution Press, 1994.

Urban, George E. Radio Free Europe and the Pursuit of Democracy: My War within the Cold War. New Haven, Connecticut, Yale University Press, 1997.