In 1937, Edwin Armstrong built a 425-foot radio tower on the Palisades in New Jersey, from which he could see the far tip of Long Island miles away. It was from this tower that FM radio was launched as a broadcast medium.

Armstrong had long been dissatisfied with the quality of the AM signal, which is easily upset by the weather and other stations. By 1933 he had devised a method of transmission – frequency modulation (FM) – that could eliminate such interference from other signals.

The prolific Armstrong also invented the regenerative circuit, the superheterodyne and the feedback circuit, which raised the sensitivity of radio receivers. His continuous-wave oscillator made it practical to transmit sound as well as Morse code via radio. Later, Armstrong’s circuits also made possible the transmission of images, paving the way for today’s satellite communications.

As a student at Columbia University, Armstrong was already famous. The superheterodyne circuit he invented in 1917 gave the Allied armies in World War I a valuable edge in radio communications.

However Armstrong had trouble winning commercial acceptance of FM. The national radio networks knew that FM threatened their own operations, and mobilized their influence to thwart it. Radio giant RCA, the parent company of NBC, refused to license Armstrong’s invention on terms he could accept, and launched a long, bitter legal feud over patents. Armstrong fought the case all the way to the Supreme Court, but RCA wont the right to use FM on its own terms. Armstrong committed suicide in 1954 in Manhattan.