Read complete books and articles on: Radio History

Radio - transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially to the radio receiver.

Uses of Radio Waves

The prime purpose of radio is to convey information from one place to another through the intervening media (i.e., air, space, nonconducting materials) without wires. Besides being used for

Radio - transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially to the radio receiver.

Uses of Radio Waves

The prime purpose of radio is to convey information from one place to another through the intervening media (i.e., air, space, nonconducting materials) without wires. Besides being used for transmitting sound and television signals, radio is used for the transmission of data in coded form. In the form of radar it is used also for sending out signals and picking up their reflections from objects in their path. Long-range radio signals enable astronauts to communicate with the earth from the moon and carry information from space probes as they travel to distant planets (see space exploration). For navigation of ships and aircraft the radio range, radio compass (or direction finder), and radio time signals are widely used. Radio signals sent from global positioning satellites can also be used by special receivers for a precise indication of position. Various remote-control devices, including rocket and artificial satellite operations systems and automatic valves in pipelines, are activated by radio signals. The development of the transistor and other microelectronic devices (see microelectronics) led to the development of portable transmitters and receivers. Cellular and cordless telephones are actually radio transceivers. Many telephone calls routinely are relayed by radio rather than by wires; some are sent via radio to relay satellites. Some celestial bodies and interstellar gases emit relatively strong radio waves that are observed with radio telescopes composed of very sensitive receivers and large directional antennas (see radio astronomy).

Transmission and Reception of Radio Waves

For the propagation and interception of radio waves, a transmitter and receiver are employed. A radio wave acts as a carrier of information-bearing signals; the information may be encoded directly on the wave by periodically interrupting its transmission (as in dot-and-dash telegraphy) or impressed on it by a process called modulation. The actual information in a modulated signal is contained in its sidebands, or frequencies added to the carrier wave, rather than in the carrier wave itself. The two most common types of modulation used in radio are amplitude modulation (AM) and frequency modulation (FM). Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting.

In its most common form, radio is used for the transmission of sounds (voice and music) and pictures (television). The sounds and images are converted into electrical signals by a microphone (sounds) or video camera (images), amplified, and used to modulate a carrier wave that has been generated by an oscillator circuit in a transmitter. The modulated carrier is also amplified, then applied to an antenna that converts the electrical signals to electromagnetic waves for radiation into space. Such waves radiate at the speed of light and are transmitted not only by line of sight but also by deflection from the ionosphere.

Receiving antennas intercept part of this radiation, change it back to the form of electrical signals, and feed it to a receiver. The most efficient and most common circuit for radio-frequency selection and amplification used in radio receivers is the superheterodyne. In that system, incoming signals are mixed with a signal from a local oscillator to produce intermediate frequencies (IF) that are equal to the arithmetical sum and difference of the incoming and local frequencies. One of those frequencies is applied to an amplifier. Because the IF amplifier operates at a single frequency, namely the intermediate frequency, it can be built for optimum selectivity and gain. The tuning control on a radio receiver adjusts the local oscillator frequency. If the incoming signals are above the threshold of sensitivity of the receiver and if the receiver is tuned to the frequency of the signal, it will amplify the signal and feed it to circuits that demodulate it, i.e., separate the signal wave itself from the carrier wave.

There are certain differences between AM and FM receivers. In an AM transmission the carrier wave is constant in frequency and varies in amplitude (strength) according to the sounds present at the microphone; in FM the carrier is constant in amplitude and varies in frequency. Because the noise that affects radio signals is partly, but not completely, manifested in amplitude variations, wideband FM receivers are inherently less sensitive to noise. In an FM receiver, the limiter and discriminator stages are circuits that respond solely to changes in frequency. The other stages of the FM receiver are similar to those of the AM receiver but require more care in design and assembly to make full use of FM's advantages. FM is also used in television sound systems. In both radio and television receivers, once the basic signals have been separated from the carrier wave they are fed to a loudspeaker or a display device (usually a cathode-ray tube), where they are converted into sound and visual images, respectively.

Development of Radio Technology

Radio is based on the studies of James Clerk Maxwell, who developed the mathematical theory of electromagnetic waves, and Heinrich Hertz, who devised an apparatus for generating and detecting them. Guglielmo Marconi, recognizing the possibility of using these waves for a wireless communication system, gave a demonstration (1895) of the wireless telegraph, using Hertz's spark coil as a transmitter and Edouard Branly's coherer (a radio detector in which the conductance between two conductors is improved by the passage of a high-frequency current) as the first radio receiver. The effective operating distance of this system increased as the equipment was improved, and in 1901, Marconi succeeded in sending the letter S across the Atlantic Ocean using Morse code. In 1904, Sir John A. Fleming developed the first vacuum electron tube, which was able to detect radio waves electronically. Two years later, Lee de Forest invented the audion, a type of triode, or three-element tube, which not only detected radio waves but also amplified them.

The beginning of radio telephony—the transmission of music and speech—also began in 1906 with the work of Reginald Fessiden and Ernst F. W. Alexanderson. However, it was not until Edwin H. Armstrong patented (1913) the circuit for the regenerative receiver that long-range radio reception became practicable. The major developments in radio initially were for ship-to-shore communications. Following the establishment (1920) of station KDKA at Pittsburgh, Pa., the first commercial broadcasting station in the United States, technical improvements in the industry increased, as did radio's popularity. Particularly in the United States, the radio receiver became a standard household fixture. Subsequent research gave rise to countless technical improvements and to such applications as radio facsimile, radar, and television.

Radios that combine transmitters and receivers are now widely used for communications. Police and military forces and various businesses commonly use such radios to maintain contact with dispersed individuals or groups. Citizens band (CB) radios, two-way radios operating at frequencies near 27 megahertz, most typically used in vehicles for communication while traveling, became popular in the 1970s. Cellular telephones, despite the name, are another popular form of radio used for communication.

Bibliography

See A. and W. Marcus, Elements of Radio (6th ed. 1973); D. L. Schilling, Principles of Communications Systems (2d ed. 1986).

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16 of the Best Books and Articles on: Radio History

as selected by Questia librarians

1.

Listening to Radio, 1920-1950 » Read Now
by Ray Barfield. 222 pgs.

Collections: Entire Library

This fresh and engaging account of early radio's contributions to U.S. social and cultural life brings together varied perspectives of listeners who recall the programs that delighted and enchanted them. Radio, the first electronic medium to enter the home, is examined as a chief purveyor of family...
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This fresh and engaging account of early radio's contributions to U.S. social and cultural life brings together varied perspectives of listeners who recall the programs that delighted and enchanted them. Radio, the first electronic medium to enter the home, is examined as a chief purveyor of family entertainment and as a bridge across regional differences. Barfield draws from over 150 accounts, providing a forum and a context for listeners of early radio to share their memories - from their first impressions of "that magical box" to favorite shows. Opening chapters trace the changing perceptions of radio as a "guest" or an "invader" in U.S. homes during the exuberant 1920s, the cash-scarce 1930s, and the rapidly changing World War II and post-war years. Later chapters offer listener responses to every major program type, including news reporting and commentary, sportscasts, drama, comedy series, crime and terror shows, educational and cultural programs, children's adventure series, soap operas, audience participation shows, and musical presentations.
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2.

The Sound of Your Life: A Record of Radio's First Generation » Read Now
by Columbia Broadcasting System. 133 pgs.

Collections: Entire Library

...worst flood in American history spilled through their radio into their living...recording, a milestone in radio history, another 3 months to...service they required, radio...
3.

Telecommunications, Mass Media, and Democracy: The Battle for the Control of U.S. Broadcasting, 1928-1935 » Read Now
by Robert W. McChesney. 400 pgs.

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This work shows in detail the emergence and consolidation of U.S. commercial broadcasting economically, politically, and ideologically. This process was met by organized opposition and a general level of public antipathy that has been almost entirely overlooked by previous scholarship. McChesney...
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This work shows in detail the emergence and consolidation of U.S. commercial broadcasting economically, politically, and ideologically. This process was met by organized opposition and a general level of public antipathy that has been almost entirely overlooked by previous scholarship. McChesney highlights the activities and arguments of this early broadcast reform movement of the 1930s. The reformers argued that commercial broadcasting was inimical to the communication requirements of a democratic society and that the only solution was to have a dominant role for nonprofit and noncommercial broadcasting. Although the movement failed, McChesney argues that it provides important lessons not only for communication historians and policymakers, but for those concerned with media and how they are used.
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4.

Working it Out Together: Radio Policy from Hoover to the Radio Act of 1927, in Journal of Broadcasting & Electronic Media » Read Now
by Louise Benjamin. 16 pgs.

Collections: Entire Library

...Archer, G. (1938). History of radio to 1926. New York: American...Journal of American History, 60, 116-140. Hoover, H. (1923). Memorandum to Radio Division, Director...
5.

The Modern Stentors: Radio Broadcasters and the Federal Government, 1920-1934 » Read Now
by Philip T. Rosen. 270 pgs.

Collections: Entire Library

...Includes index. 1. Radio broadcasting-- United States--History. I. Title. HE8698...communications by making radio ubiquitous, immediate...in modern American history has had...
6.

Media at War: Radio's Challenge to the Newspapers, 1924-1939 » Read Now
by Gwenyth L. Jackaway. 172 pgs.

Collections: Entire Library

Fought when radio was first introduced, the Press-Radio war was an attempt on the part of print journalists to block the emergence of radio news. For nearly a decade, the newspapers of America fought to keep broadcast journalism off the air, exerting various forms of economic, regulatory, and legal...
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Fought when radio was first introduced, the Press-Radio war was an attempt on the part of print journalists to block the emergence of radio news. For nearly a decade, the newspapers of America fought to keep broadcast journalism off the air, exerting various forms of economic, regulatory, and legal pressure against new competitors. This study traces the stages and forms of institutional self-defense utilized by the press. Far more than mere battles to protect profits, media wars are fights to preserve the institutional power that derives from controlling the channels of communication.
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7.

Time for Reason about Radio: From a Series of Broadcasts on CBS » Read Now
by Lyman Bryson, William C. Ackerman. 127 pgs.

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...that were unique in the history of American radio. It was the first time...greatly in 25 years of radio history, not only because the...permitted on news programs? Radio...
8.

Talking Radio: An Oral History of American Radio in the Television Age » Read Now
by Michael C. Keith. 226 pgs.

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Includes interviews with such well known personalities as Walter Cronkite, Dick Clark, Steve Allen, Art Linkletter, Paul Harvey, Howard K. Smith, Ed McMahon, Bruce Morrow, as well as more than fifty other individuals who were or continue to be actively involved in radio.
9.

Legendary Pioneers of Black Radio » Read Now
by Gilbert A. Williams. 198 pgs.

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After World War II, when thousands of African Americans left farms, plantations, and a southern way of life to migrate north, African American disc jockeys helped them make the transition to the urban life by playing familiar music and giving them tips on how to function in northern cities. These...
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After World War II, when thousands of African Americans left farms, plantations, and a southern way of life to migrate north, African American disc jockeys helped them make the transition to the urban life by playing familiar music and giving them tips on how to function in northern cities. These disc jockeys became cultural heroes and had a major role in the development of American broadcasting. This collection of interviews documents the personalities of the pioneers of Black radio, as well as their personal struggles and successes. The interviewees also define their roles in the civil rights movement and relate how their efforts have had an impact on how African Americans are portrayed over the air.
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10.

Conflicting Communication Interests in America: The Case of National Public Radio » Read Now
by Tom McCourt. 214 pgs.

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McCourt sees public broadcasting as increasingly under siege as the marketplace undermines public goods and services and as politics and culture are beset by fragmentation. In this first full-length scholarly examination of National Public Radio, he contrasts NPR's mission and its practices.
11.

National Public Radio: The Cast of Characters » Read Now
by Mary Collins. 152 pgs.

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...0-929765-19-2 1. National Public Radio--History. 2. Public radio-- United States--History. 3. Radio broadcasters--United States--History...Opponents argued that the...
12.

Voices in the Purple Haze: Underground Radio and the Sixties » Read Now
by Michael C. Keith. 208 pgs.

Collections: Entire Library

During the fateful summer of 1966, a handful of restless and frustrated deejays in New York and San Francisco began to conceive of a whole new brand of radio, one which would lead to the reinvention of contemporary music programming. Gone were the screaming deejays, the two minute doowop hits, and...
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During the fateful summer of 1966, a handful of restless and frustrated deejays in New York and San Francisco began to conceive of a whole new brand of radio, one which would lead to the reinvention of contemporary music programming. Gone were the screaming deejays, the two minute doowop hits, and the goofy jingles. In were the counterculture sounds and sentiments that had seldom, if ever, made it to commercial radio. This new and unorthodox form of radio--this radical departure from the Top 40 establishment--reflected the social and cultural unrest of the period. Underground radio had been born of a desire to restore substance and meaning to a medium that had fallen victim to the bottom-line dictates of an industry devoted to profit. In this compelling and intriguing account of the counterculture radio movement, over 30 pioneers of the underground airwaves share insights and observations, and tell it like it was.
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13.

Redeeming the Dial: Radio, Religion & Popular Culture in America » Read Now
by Tona J. Hangen. 218 pgs.

Collections: Religious Studies, Entire Library

Blending cultural, religious, and media history, Tona Hangen offers a richly detailed glimpse into the world of religious radio. She uses recordings, sermons, fan mail, and other sources to tell the stories of the determined broadcasters and devoted listeners who, together, transformed American...
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Blending cultural, religious, and media history, Tona Hangen offers a richly detailed glimpse into the world of religious radio. She uses recordings, sermons, fan mail, and other sources to tell the stories of the determined broadcasters and devoted listeners who, together, transformed American radio evangelism from an on-air novelty in the 1920s into a profitable and wide-reaching industry by the 1950s.
Hangen traces the careers of three of the most successful Protestant radio evangelists--Paul Rader, Aimee Semple McPherson, and Charles Fuller--and examines the strategies they used to bring their messages to listeners across the nation. Initially shut out of network radio and free airtime, both of which were available only to mainstream Protestant and Catholic groups, evangelical broadcasters gained access to the airwaves with paid-time programming. By the mid-twentieth century millions of Americans regularly tuned into evangelical programming, making it one of the medium's most distinctive and durable genres. The voluntary contributions of these listeners helped bankroll religious radio's remarkable growth.
Revealing the entwined development of evangelical religion and modern mass media, Hangen demonstrates that the history of one is incomplete without the history of the other; both are essential to understanding American culture in the twentieth century.
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14.

Free Radio: Electronic Civil Disobedience » Read Now
by Lawrence Soley. 150 pgs.

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...Democracy , explained the history of why commercial radio today has become a form of...compelling. Regarding the history of Free Radio Berkeley, one has the impression...FM...
15.

Phantasmatic Radio » Read Now
by Allen S. Weiss. 128 pgs.

Collections: Philosophy, Entire Library

...study does not purport to be a history of experimental radio, but rather an open-ended disclosure...1877, 1913, 1948. 4 If the history of mainstream radio is a suppressed...
16.

On the Air: The Encyclopedia of Old-Time Radio » Read Now
by John Dunning. 824 pgs.

Collections: Entire Library

Now long out of print, John Dunning's Tune in Yesterday was the definitive one-volume reference on old-time radio broadcasting. Now, in On the Air, Dunning has completely rethought this classic work, reorganizing the material and doubling its coverage, to provide a richer and more informative...
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Now long out of print, John Dunning's Tune in Yesterday was the definitive one-volume reference on old-time radio broadcasting. Now, in On the Air, Dunning has completely rethought this classic work, reorganizing the material and doubling its coverage, to provide a richer and more informative account of radio's golden age. Here are some 1,500 radio shows presented in alphabetical order. The great programs of the '30s, '40s, and '50s are all here--Amos 'n' Andy, Fibber McGee and Molly, The Lone Ranger, Major Bowes' Original Amateur Hour, and The March of Time, to name only a few. For each, Dunning provides a complete broadcast history, with the timeslot, the network, and the name of the show's advertisers. He also lists major cast members, announcers, producers, directors, writers, and sound effects people--even the show's theme song. There are also umbrella entries, such as "News Broadcasts," which features an engaging essay on radio news, with capsule biographies of major broadcasters, such as Lowell Thomas and Edward R. Murrow. Equally important, Dunning provides a fascinating account of each program, taking us behind the scenes to capture the feel of the performance, such as the ghastly sounds of Lights Out (a horror drama where heads rolled and bones crunched), and providing engrossing biographies of the main people involved in the show. A wonderful read for everyone who loves old-time radio, On the Air is a must purchase for all radio hobbyists and anyone interested in 20th-century American history. It is an essential reference work for libraries and radio stations.
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