(here's another term paper by yours truly.)
Radio is generally referred to as the system of broadcasting sound. It is a system of communication which uses electromagnetic waves propagated through space. In wireless telegraphy, television, telephone transmission, radar, navigation systems, space communication and radio broadcasting, radio waves are used.
Radio had no single inventor. It grew out of numerous international efforts. In 1866, Mahlon Loomis, an American dentist, successfully demonstrated "wireless telegraphy." Loomis was able to make a meter connected to one kite cause another one to move, marking the first known instance of wireless aerial communication. From 1875, many scientists, drawing on the theory of James Clerk Maxwell (a British physicist who published his theory of electromagnetic waves in 1873), began to explore the possibility of using electromagnetic waves to communicate between two fixed points, that is, to transmit messages over distances without wires. German physicist, Heinrich Rudolf Hertz (whose name has been given to frequency/cycle per second- hertz or Hz) was the first to generate waves electrically by creating an oscillating electric discharge which radiated some of its energy as electromagnetic waves but these could not travel great distances. Guglielmo Marconi, an Italian electrical engineer, proved the feasibility of radio communication. He sent and received his first radio signal in Italy in 1895. By 1899, he flashed the first wireless signal across the English Channel and two years later received the letter "S", telegraphed from England to Newfoundland. This was the first successful transatlantic radiotelegraph message. In 1894, Marconi had developed a receiver or “coherer” and an improved spark oscillator connected to a crude antenna which succeeded in transmitting radio waves over significant distances. He transmitted signals for a distance beyond 1.6km in 1896, established commercial communication between England and France in 1899 and sent a message across the Atlantic in 1901. Radio, thus, came to the attention of governmental agencies and business interests. (In addition to Marconi, two of his contemporaries, Nikola Tesla and Nathan Stufflefield, took out patents for wireless radio transmitters. Nikola Tesla is now credited with being the first person to patent radio technology; the Supreme Court overturned Marconi's patent in 1943 in favour of Tesla.) However, this was still wireless telegraphy (or the transmission of signals) rather than wireless telephony (or the transmission of sound itself).
By 1903, a Marconi station located in Wellfleet, Massachusetts, carried an exchange or greetings between President Theodore Roosevelt and King Edward VII. In 1905, the naval battle of Port Arthur in the Russo-Japanese war was reported by wireless and in 1906 the U.S. Weather Bureau experimented with radiotelegraphy to speed notice of weather conditions. On Christmas Eve, 1906, Reginald Fessenden, an American, succeeded in transmitting both speech and music over several hundreds of miles from the Massachusetts coast. Others followed in the United States, Britain and Europe as years rolled by. The creation of the “vacuum tube oscillator” helped the steady transition from telegraphy to telephony by providing a continuous signal. The development of the radio valve proved to be vital in the transition from wireless to broadcasting. In 1904, John Ambrose Fleming, a British electrical engineer, experimented with the first diode (or a thermionic two-electrode valve) and in 1907, Lee de Forest created a triode by inserting a third electrode into the valve to amplify weak signals and transmit radio-telephone messages farther than thought possible. In 1912, the first transpacific radiotelegraph service linked San Francisco with Hawaii.
Before World War 1, radio was little appreciated as it was regarded as a private means of point-to-point communication and not as a public means of mass communication though anyone with a receiver could receive the broadcast signals. Coastal, marine, army and intelligence officers were the first significant users of radio. During World War 1, radio enforced communication and governments commandeered all wireless stations. The war stimulated technical research, boosted large-scale production of the thermionic valve and got many soldiers, sailors and airmen acquainted with radio. After 1918, when these men returned home with primitive receivers of their own, they helped to popularise radio. At this time people began to regard radio as a means of mass communication.
In 1920/21, the first true and licensed radio station named KDKA (now known as CBS), established by the Westinghouse Electric Corporation, began regular broadcast in Pittsburgh, Pennsylvania, in the United States. The station aired entertainment oriented programmes along with recorded music played by a phonograph placed before the microphone. This station was not a commercial station and the primary purpose for its establishment was to boost sales of radios manufactured by the Westinghouse Electric Corporation. Other manufacturers soon followed Westinghouse’s lead and as a result, the next two years saw the establishment of hundreds of stations in the United States and Europe. In Britain, the “chaos of the ether” caused leading radio manufacturers to set up the British Broadcasting Company (BBC) which broadcast its first programmes in November 1922. In America, radio manufacturing grew faster than car manufacturing for a short time and listeners on both sides of the Atlantic grew by the millions. A good number of armature radio stations sprang up during the 1920s. Radio became an exalted household utility. The perception that the medium of radio (being a tool of propaganda) had the power to influence public opinion, fashioned the development of international broadcasting. State Universities such as University of Iowa, Ohio State University and the University of Wisconsin operated radio stations which broadcast educational radio programs to rural areas. Radio receivers’ qualities of being cheap and portable in addition to FM broadcasting were the factors which helped to ensure the survival of radio during the 1930s when the rival medium of television had its biggest impact. The radio, though still in existence, ceased to be the major mass medium of the twentieth century. Between 1949 and 1958, the BBC’s average evening radio audience fell from about nine million to about three and half million listeners. All radio stations saw their earnings halved. (Radio seemed to receive a boost in 1952 when Sony Corporation invented the pocket-size transistor radio.) It faced decline until it found new roles for itself and new ways of reaching people. BBC’s first director-general, John Reith, developed an approach often described as paternalistic, which offered listeners “something a little better” than they thought they wanted and a varied output was seen as a way of introducing listeners to a subject they had not previously sought. Radio, Reith believed, had the power, and therefore the responsibility in a democratic society, to lead opinion and tastes rather than merely reflecting them. Even in the United States, some early figures in radio, such as David Sarnoff, argued that broadcasting represented a “job of entertaining, informing, and educating the nation, and should therefore be distinctly regarded as a public service”. In 1940, the BBC introduced a Forces Programme to entertain the troops of the British Expeditionary Force with dance music, sport, and variety. Its tone was overwhelmingly light and it soon attracted a larger share of listeners than the more traditional Home Service. Modern telecommunications technology now even allows for large-scale opinion-polling during live broadcasts.
Electromagnetic waves in a uniform atmosphere travel in straight lines and as the Earth’s surface is approximately spherical, long distance radio communication is made possible by the reflection of radio waves from the Earth’s ionosphere which allows radio programmes to be received nationally and internationally. However, this produced interference between rival signals. What people actually listened to was, and still is, crucially dependent, not just on what programme-makers construct but on the allocation of wavelengths and the distribution of transmitters. The discovery that electromagnetic waves could carry radio signals over the horizon had raised the prospect of broadcasting on an international scale but governments and broadcasting organizations rapidly realized the inherent problems of the growth in the medium; if radio stations operated on the same, or very similar wavelengths, listeners would suffer severe interference in reception. In 1925, an international agreement over the allocation of wavelengths was reached in Europe through the so-called Geneva Plan of the Union Internationale de Radiophonie and in the United States, Congress passed the Radio Act in 1927 to create the Federal Radio Commission. Regulation of the world’s electromagnetic spectrum has since been enacted largely by national governments through the International Telecommunication Union based in Geneva; however, from these earlier dates onward, transmission technology has been concerned primarily with the range and frequency of the signal being broadcast.
An American named Edwin Armstrong invented the “FM” or “frequency modulation” which is very different from “AM” or “amplitude modulation”. Both terms apply to techniques for imposing a meaningful pattern of variations on an otherwise unvaried stream of energy during transmission, but they have also come to be applied to whole categories of broadcast radio. Throughout the first half of the century, most standard radio broadcasting was achieved using the AM technique and today, some music and a great deal of speech radio, which does not necessarily demand high-quality reception, is still found on the AM dial. FM reaches only to the horizon, so a transmitter’s remit is local rather than national in scale. This geographical restriction has the advantage of reducing interference, and coverage is therefore more stable, day or night. The signal itself is inherently static-free, unlike that for AM, and a suitable receiving-set can take advantage of its more generous frequency range and dynamic range to reproduce high-fidelity sound. FM’s quality advantage over AM, exaggerated further with the development of stereo, has proved particularly suitable for the broadcasting of music and explains the rapid growth in the number of FM stations (often associated with rock and pop) in the 1960s, 1970s, and 1980s. Both AM and FM radio depend on traditional analogue technology, where the signal consists of a continuously changing pattern corresponding to the continuous flow of sound captured by a microphone. Such signals are inherently vulnerable to all sorts of distortions which restrict their ability to carry information without degradation.
Digital processing, which breaks a signal down into a stream of individual energy pulses assigned a binary code, can resist distortion and convey far more information. Most contemporary large-scale radio broadcasters have begun to develop digital audio broadcasting, which promises a quality of sound equivalent to that of a CD and an increase in the number of radio services available within the existing electromagnetic spectrum. The technology of the radio receiving-set has also changed dramatically since the origins of broadcasting. The first commercially available radio receivers were crystal sets, which required headphones. They soon gave way to valve receivers with loudspeakers, which enabled people to listen in groups. Growing demand led to larger-scale production of valve receivers, and the price of sets dropped throughout the 1930s. Even so, the wireless valve remained a relatively expensive item to replace, consumed much primary power and meant large and cumbersome sets. In 1948, the first manufactured transistor revolutionized reception. It allowed radios to be built that were more reliable, used far less power, and, crucially, were much smaller and cheaper. Transistor radios were mobile in a way that the television sets of the 1950s and 1960s could never be.
The essential components of a modern radio receiver are:
Radio had no single inventor. It grew out of numerous international efforts. In 1866, Mahlon Loomis, an American dentist, successfully demonstrated "wireless telegraphy." Loomis was able to make a meter connected to one kite cause another one to move, marking the first known instance of wireless aerial communication. From 1875, many scientists, drawing on the theory of James Clerk Maxwell (a British physicist who published his theory of electromagnetic waves in 1873), began to explore the possibility of using electromagnetic waves to communicate between two fixed points, that is, to transmit messages over distances without wires. German physicist, Heinrich Rudolf Hertz (whose name has been given to frequency/cycle per second- hertz or Hz) was the first to generate waves electrically by creating an oscillating electric discharge which radiated some of its energy as electromagnetic waves but these could not travel great distances. Guglielmo Marconi, an Italian electrical engineer, proved the feasibility of radio communication. He sent and received his first radio signal in Italy in 1895. By 1899, he flashed the first wireless signal across the English Channel and two years later received the letter "S", telegraphed from England to Newfoundland. This was the first successful transatlantic radiotelegraph message. In 1894, Marconi had developed a receiver or “coherer” and an improved spark oscillator connected to a crude antenna which succeeded in transmitting radio waves over significant distances. He transmitted signals for a distance beyond 1.6km in 1896, established commercial communication between England and France in 1899 and sent a message across the Atlantic in 1901. Radio, thus, came to the attention of governmental agencies and business interests. (In addition to Marconi, two of his contemporaries, Nikola Tesla and Nathan Stufflefield, took out patents for wireless radio transmitters. Nikola Tesla is now credited with being the first person to patent radio technology; the Supreme Court overturned Marconi's patent in 1943 in favour of Tesla.) However, this was still wireless telegraphy (or the transmission of signals) rather than wireless telephony (or the transmission of sound itself).
By 1903, a Marconi station located in Wellfleet, Massachusetts, carried an exchange or greetings between President Theodore Roosevelt and King Edward VII. In 1905, the naval battle of Port Arthur in the Russo-Japanese war was reported by wireless and in 1906 the U.S. Weather Bureau experimented with radiotelegraphy to speed notice of weather conditions. On Christmas Eve, 1906, Reginald Fessenden, an American, succeeded in transmitting both speech and music over several hundreds of miles from the Massachusetts coast. Others followed in the United States, Britain and Europe as years rolled by. The creation of the “vacuum tube oscillator” helped the steady transition from telegraphy to telephony by providing a continuous signal. The development of the radio valve proved to be vital in the transition from wireless to broadcasting. In 1904, John Ambrose Fleming, a British electrical engineer, experimented with the first diode (or a thermionic two-electrode valve) and in 1907, Lee de Forest created a triode by inserting a third electrode into the valve to amplify weak signals and transmit radio-telephone messages farther than thought possible. In 1912, the first transpacific radiotelegraph service linked San Francisco with Hawaii.
Before World War 1, radio was little appreciated as it was regarded as a private means of point-to-point communication and not as a public means of mass communication though anyone with a receiver could receive the broadcast signals. Coastal, marine, army and intelligence officers were the first significant users of radio. During World War 1, radio enforced communication and governments commandeered all wireless stations. The war stimulated technical research, boosted large-scale production of the thermionic valve and got many soldiers, sailors and airmen acquainted with radio. After 1918, when these men returned home with primitive receivers of their own, they helped to popularise radio. At this time people began to regard radio as a means of mass communication.
In 1920/21, the first true and licensed radio station named KDKA (now known as CBS), established by the Westinghouse Electric Corporation, began regular broadcast in Pittsburgh, Pennsylvania, in the United States. The station aired entertainment oriented programmes along with recorded music played by a phonograph placed before the microphone. This station was not a commercial station and the primary purpose for its establishment was to boost sales of radios manufactured by the Westinghouse Electric Corporation. Other manufacturers soon followed Westinghouse’s lead and as a result, the next two years saw the establishment of hundreds of stations in the United States and Europe. In Britain, the “chaos of the ether” caused leading radio manufacturers to set up the British Broadcasting Company (BBC) which broadcast its first programmes in November 1922. In America, radio manufacturing grew faster than car manufacturing for a short time and listeners on both sides of the Atlantic grew by the millions. A good number of armature radio stations sprang up during the 1920s. Radio became an exalted household utility. The perception that the medium of radio (being a tool of propaganda) had the power to influence public opinion, fashioned the development of international broadcasting. State Universities such as University of Iowa, Ohio State University and the University of Wisconsin operated radio stations which broadcast educational radio programs to rural areas. Radio receivers’ qualities of being cheap and portable in addition to FM broadcasting were the factors which helped to ensure the survival of radio during the 1930s when the rival medium of television had its biggest impact. The radio, though still in existence, ceased to be the major mass medium of the twentieth century. Between 1949 and 1958, the BBC’s average evening radio audience fell from about nine million to about three and half million listeners. All radio stations saw their earnings halved. (Radio seemed to receive a boost in 1952 when Sony Corporation invented the pocket-size transistor radio.) It faced decline until it found new roles for itself and new ways of reaching people. BBC’s first director-general, John Reith, developed an approach often described as paternalistic, which offered listeners “something a little better” than they thought they wanted and a varied output was seen as a way of introducing listeners to a subject they had not previously sought. Radio, Reith believed, had the power, and therefore the responsibility in a democratic society, to lead opinion and tastes rather than merely reflecting them. Even in the United States, some early figures in radio, such as David Sarnoff, argued that broadcasting represented a “job of entertaining, informing, and educating the nation, and should therefore be distinctly regarded as a public service”. In 1940, the BBC introduced a Forces Programme to entertain the troops of the British Expeditionary Force with dance music, sport, and variety. Its tone was overwhelmingly light and it soon attracted a larger share of listeners than the more traditional Home Service. Modern telecommunications technology now even allows for large-scale opinion-polling during live broadcasts.
Electromagnetic waves in a uniform atmosphere travel in straight lines and as the Earth’s surface is approximately spherical, long distance radio communication is made possible by the reflection of radio waves from the Earth’s ionosphere which allows radio programmes to be received nationally and internationally. However, this produced interference between rival signals. What people actually listened to was, and still is, crucially dependent, not just on what programme-makers construct but on the allocation of wavelengths and the distribution of transmitters. The discovery that electromagnetic waves could carry radio signals over the horizon had raised the prospect of broadcasting on an international scale but governments and broadcasting organizations rapidly realized the inherent problems of the growth in the medium; if radio stations operated on the same, or very similar wavelengths, listeners would suffer severe interference in reception. In 1925, an international agreement over the allocation of wavelengths was reached in Europe through the so-called Geneva Plan of the Union Internationale de Radiophonie and in the United States, Congress passed the Radio Act in 1927 to create the Federal Radio Commission. Regulation of the world’s electromagnetic spectrum has since been enacted largely by national governments through the International Telecommunication Union based in Geneva; however, from these earlier dates onward, transmission technology has been concerned primarily with the range and frequency of the signal being broadcast.
An American named Edwin Armstrong invented the “FM” or “frequency modulation” which is very different from “AM” or “amplitude modulation”. Both terms apply to techniques for imposing a meaningful pattern of variations on an otherwise unvaried stream of energy during transmission, but they have also come to be applied to whole categories of broadcast radio. Throughout the first half of the century, most standard radio broadcasting was achieved using the AM technique and today, some music and a great deal of speech radio, which does not necessarily demand high-quality reception, is still found on the AM dial. FM reaches only to the horizon, so a transmitter’s remit is local rather than national in scale. This geographical restriction has the advantage of reducing interference, and coverage is therefore more stable, day or night. The signal itself is inherently static-free, unlike that for AM, and a suitable receiving-set can take advantage of its more generous frequency range and dynamic range to reproduce high-fidelity sound. FM’s quality advantage over AM, exaggerated further with the development of stereo, has proved particularly suitable for the broadcasting of music and explains the rapid growth in the number of FM stations (often associated with rock and pop) in the 1960s, 1970s, and 1980s. Both AM and FM radio depend on traditional analogue technology, where the signal consists of a continuously changing pattern corresponding to the continuous flow of sound captured by a microphone. Such signals are inherently vulnerable to all sorts of distortions which restrict their ability to carry information without degradation.
Digital processing, which breaks a signal down into a stream of individual energy pulses assigned a binary code, can resist distortion and convey far more information. Most contemporary large-scale radio broadcasters have begun to develop digital audio broadcasting, which promises a quality of sound equivalent to that of a CD and an increase in the number of radio services available within the existing electromagnetic spectrum. The technology of the radio receiving-set has also changed dramatically since the origins of broadcasting. The first commercially available radio receivers were crystal sets, which required headphones. They soon gave way to valve receivers with loudspeakers, which enabled people to listen in groups. Growing demand led to larger-scale production of valve receivers, and the price of sets dropped throughout the 1930s. Even so, the wireless valve remained a relatively expensive item to replace, consumed much primary power and meant large and cumbersome sets. In 1948, the first manufactured transistor revolutionized reception. It allowed radios to be built that were more reliable, used far less power, and, crucially, were much smaller and cheaper. Transistor radios were mobile in a way that the television sets of the 1950s and 1960s could never be.
The essential components of a modern radio receiver are:
(1) an antenna for receiving the electromagnetic waves and converting them into electrical oscillations;
(2) amplifiers for increasing the intensity of these oscillations;
(3) detection equipment for demodulating;
(4) a speaker for converting the impulses into sound waves audible to the human ear; and
(5) in most radio receivers, oscillators to generate radio-frequency waves that can be mixed with the incoming waves.
The sensitivity of some modern radio receivers is so great that if the antenna signal can produce an alternating current involving the motion of only a few hundred electrons, this signal can be detected and amplified to produce an intelligible sound from the speaker. Most radio receivers can operate quite well with an input from the antenna of a few millionths of a volt. The dominant consideration in receiver design, however, is that very weak desired signals cannot be made useful by amplifying indiscriminately both the desired signal and undesired radio noise. Most modern radio receivers are of the super heterodyne type in which an oscillator generates a radio-frequency wave that is mixed with the incoming wave, thereby producing a radio-frequency wave of lower frequency; the latter is called intermediate frequency. To tune the receiver to different frequencies, the frequency of the oscillations is changed but the intermediate frequency always remains the same (at 455 kHz for most AM receivers and at 10.7 MHz for most FM receivers). The oscillator is tuned by altering the capacity of the capacitor in its tank circuit; the antenna circuit is similarly tuned by a capacitor in its circuit.
Communication theorists suggest that, if people tend to interpret the world largely through their ability to see it, then being deprived of visual clues will compel them to supply such clues for themselves. Thus, when listening to a radio play, one needs to imagine not only a character’s thoughts but also that person’s appearance and surroundings. Radio dramatists argue that this offers greater intellectual and emotional reward to a listener (as opposed to a viewer) and allows the writer to create stories and characters that are truly experimental or fantastical which is something the medium of television would have to struggle to recreate visually for the viewer. Since each individual listener will create a different mental image, radio is also often described as an “intimate” medium: the ability to create a unique picture of a person speaking on the radio allows the listener to form a close relationship with that speaker as imagined, rather than as someone pre-realized on the listener’s behalf. Listeners feel that they are being talked to personally rather than being talked at as part of a large undifferentiated mass, and they respond by forming close attachments to individual presenters. The advantages of radio include its provision of information, entertainment, a sense of intimacy, intellectual enhancement, motivation while working and many chances for phone-ins as well as its allowing for large-scale opinion-polling during live broadcasts.
References
1. Bellis, Mary (2006). The Invention of Radio. http://www.inventors.about.com/c/a.htm
.
2. Milestones in the Development of Radio and Television, (2000). [Online]. http://www.kidcyber.com.au
3. Lewis, Tom (2006). “A Godlike Presence”: The Impact of Radio on the 1920s and 1930s. San Francisco: Harper and Row Publishers.
4. White, T. H. (2003). United States Early Radio History. http://www.ipass.net/~whitetho/index.html
5. Microsoft Corporation (2005). Microsoft Encarta Encyclopaedia.
6. Farely, T. and Schmidt, K. (2006). Telecommunications History: Early Radio Notes.
Communication theorists suggest that, if people tend to interpret the world largely through their ability to see it, then being deprived of visual clues will compel them to supply such clues for themselves. Thus, when listening to a radio play, one needs to imagine not only a character’s thoughts but also that person’s appearance and surroundings. Radio dramatists argue that this offers greater intellectual and emotional reward to a listener (as opposed to a viewer) and allows the writer to create stories and characters that are truly experimental or fantastical which is something the medium of television would have to struggle to recreate visually for the viewer. Since each individual listener will create a different mental image, radio is also often described as an “intimate” medium: the ability to create a unique picture of a person speaking on the radio allows the listener to form a close relationship with that speaker as imagined, rather than as someone pre-realized on the listener’s behalf. Listeners feel that they are being talked to personally rather than being talked at as part of a large undifferentiated mass, and they respond by forming close attachments to individual presenters. The advantages of radio include its provision of information, entertainment, a sense of intimacy, intellectual enhancement, motivation while working and many chances for phone-ins as well as its allowing for large-scale opinion-polling during live broadcasts.
References
1. Bellis, Mary (2006). The Invention of Radio. http://www.inventors.about.com/c/a.htm
.
2. Milestones in the Development of Radio and Television, (2000). [Online]. http://www.kidcyber.com.au
3. Lewis, Tom (2006). “A Godlike Presence”: The Impact of Radio on the 1920s and 1930s. San Francisco: Harper and Row Publishers.
4. White, T. H. (2003). United States Early Radio History. http://www.ipass.net/~whitetho/index.html
5. Microsoft Corporation (2005). Microsoft Encarta Encyclopaedia.
6. Farely, T. and Schmidt, K. (2006). Telecommunications History: Early Radio Notes.
http://www.privateline.com/mt_telecomhistory/d_early_radio_notes
7. XCV Corporation Incorporated (2006). Electronics Museum – Review of 20th Century Progress in Electronic Devices (1900 – 1999). http://www.xcvcorp.com/index.html
7. XCV Corporation Incorporated (2006). Electronics Museum – Review of 20th Century Progress in Electronic Devices (1900 – 1999). http://www.xcvcorp.com/index.html
8. Aitken, Hugh G. J. (1976). "Syntony and Spark--The Origins of Radio". Liverpool: John-Wiley and Sons.
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