The Development of Radio
Think about radio, and what often comes to mind is the crystal clear music and spoken words broadcast by FM stations across America. But radio wasn't always so advanced -- or so popular. Like many technologies, it evolved gradually and gained acceptance slowly. Today, radio continues to evolve as it competes with other technologies to attract and hold an audience.
The first steps toward inventing radio involved discovering electromagnetic waves and their potential. Hans Christian Oersted was the first to proclaim, in 1820, that a magnetic field is created around a wire that has a current running through it. In 1830, English physicist Michael Faraday confirmed Oersted's theory, and established the principle of electromagnetic induction.
In 1864, James Clerk Maxwell, an experimental physics professor at Cambridge University, published a theoretical paper stating that electromagnetic currents could be perceived at a distance. Maxwell also boldly postulated that such waves travelled at the speed of light. In the late 1880s, German physicist Heinrich Hertz tested Maxwell's theory. He succeeded in producing electromagnetic waves, and confirmed Maxwell's prediction about their speed.
Not long after, Guglielmo Marconi, an Italian inventor, brought electromagnetic waves out of the laboratory and into the world.
He began with short-distance broadcasts in his own back yard. In September, 1899, he astounded the world by telegraphing the results of the America's Cup yacht races from a ship at sea to a land-based station in New York. By the end of 1901, Marconi had founded his own commercial wireless company and broadcast the first transatlantic signal.
For a time, wireless broadcasts were limited to coded dots and dashes. But on December 24, 1906, Canadian-born physicist Reginald Fessenden changed that by sending the first long-distance transmission of human voice and music from his station at Brant Rock, Massachusetts. His signal was received as far away as Norfolk, Virginia. The stage for commercial voice and music broadcasts was set.
A steady stream of inventions pushed radio forward. In 1907, American inventor Lee De Forest introduced his patented Audion signal detector--which allowed radio frequency signals to be amplified dramatically. Another American inventor, Edwin Armstrong, developed the superheterodyne circuit in 1918, and in 1933 discovered how FM broadcasts could be produced. FM provided a clearer broadcast signal than AM, but RCA's top executive, David Sarnoff, was pushing for the development of television. Sarnoff withheld FM from the public for more than a decade.
Still, the public demand for radio grew exponentially. Entertainment broadcasting began in about 1910, and included De Forest's own program, which he aired from the Metropolitan Opera House in New York City. An entertainment broadcasting venture based in Wilkinsburg, Pennsylvania, became the first commercial radio station, KDKA, in 1920. The station WWJ, in Detroit, Michigan, also one of the firsts, began commercial broadcasting in the same year. Among the early proponents of entertainment broadcasting was Sarnoff, who used radio to create corporate empires at RCA and NBC.
The period between the late 1920s and the early 1950s is considered the Golden Age of Radio, in which comedies, dramas, variety shows, game shows, and popular music shows drew millions of listeners across America. But in the 1950s, with the introduction of television, the Golden Age faded. Still, radio remained a pop-culture force. Developments like stereophonic broadcasting, which began in the 1960s, helped radio maintain its popularity.
Among contemporary developments in radio is Digital Audio Broadcasting, or DAB. In the works since the late 1980s, it had not received FCC approval as of early 1999. According to proponents, DAB provides compact disc-quality sound without interference at any distance. DAB listeners can also become watchers: information such as programming schedules, and traffic and weather information, can be digitally displayed--on stereo "monitors" or LCD screens.
Already more than 100 years old, radio is still a powerful force in American life. According to a 1998 Arbitron report, over 95 percent of Americans listen to radio at least once a week. And with new technologies like DAB, the humble radio wave will likely retain its power for some time to come.