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FM broadcasting in the United States began in the 1930s at engineer and inventor Edwin Howard Armstrong's experimental station, W2XMN. The use of FM radio has been associated with higher sound quality in music radio. ==History of FM radio in the U.S.== In the United States FM radio stations broadcast at frequencies of 87.8–107.9 MHz. FM radio was developed in the United States by Edwin Armstrong. During the 1930s, there were a small number of experimental (known as "Apex") stations attempting to broadcast high fidelity audio using wide-bandwidth AM on VHF frequencies. In 1937 W1XOJ was the first FM radio station, granted a construction permit by the Federal Communications Commission (FCC). On June 17, 1936, FM radio was demonstrated to the FCC for the first time.〔United Press report, "Radio Set-up Eliminates All Noise," ''Ogden Standard-Examiner'', June 18, 1936, p1〕 On January 5, 1940, Edwin H. Armstrong demonstrated FM broadcasting in a long-distance relay network, via five stations in five States.〔 〕 FM radio was assigned the 42 to 50 MHz band of the spectrum in 1940. After World War II, the FCC moved FM to the frequencies between 88 and 108 MHz on June 27, 1945. The change in frequency was said to be for avoiding possible interference problems between stations in nearby cities and to make "room" for more FM radio channels. However, the FCC was influenced by RCA chairman David Sarnoff, who had the covert goal of disrupting the successful FM network that Edwin Armstrong had established on the old band. The 500,000 receivers built for the original FM radio band could be retrofitted with converters, but many were just replaced. The greater expense was to the radio stations themselves that had to rebuild their stations for the new FM radio band. The move of the FM band, an organized campaign of misinformation by RCA (a company that competed with FM radio by focusing on AM radio and the emerging technology of television), and adverse rulings by the FCC severely set back the development of FM radio. As late as 1947, in Detroit, there were only 3,000 FM receivers in use for the new band, and 21,000 obsolete ones for the old band.〔(From Fledgling to Floundering to Flourishing: A history of FM Broadcasting in Michigan from the 1930s through the 1960s )〕 On March 1, 1941 W47NV began operations in Nashville, Tennessee, becoming the first modern commercial FM radio station. However, FM radio did not recover from the setback until the upsurge in high fidelity equipment in the late 1950s. By the end of the 1970s, 50.1% of radio listeners were tuned to FM, ending AM's historical prevalence. By 1982, FM commanded 70% of the global audience and 84% among the 12- to 24-year-old demographic. The shift in popularity of FM radio over AM in United States during the 1970s has been called by record producer Steve Greenberg "a seismic technological shift that had torn apart the very idea of the mass audience upon which pop hits depended".〔 (AM radio would recover by shifting its focus to talk radio, which would be deregulated in the late 1980s after the repeal of the Fairness Doctrine.) During the 1970s, FM radio experienced a golden age of integrity programming, with disc jockeys playing what they wanted, including album cuts not designated as "singles" and lengthy progressive rock tracks. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「FM broadcasting in the United States」の詳細全文を読む スポンサード リンク
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