FM broadcasting in the United States

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.

In the United States FM radio stations broadcast at frequencies of 87.9–107.9 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. 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. 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.

...
Wikipedia