In 1934, much of the world was in the grip of the Great Depression.

Wednesday, November 23, 2022 • 10:00 EST

Armstrong sought to improve the signal quality by instead varying the radio waves’ frequency, creating Frequency Modulation radio (FM). These laid the foundation for the success of radio broadcasting⁠— in fact, almost any radio you buy today will still incorporate these innovations. A club for FM radio enthusiasts started in pre-war New York, and launched its own magazine called FM. But in 1933, Armstrong brought about an even more revolutionary change in the broadcasting business: FM radio. At the time, radio was transmitted via Amplitude Modulation (AM), which varied the amplitude of the radio waves. But it would take further decades for FM radio to reach its potential. Seeking to kill FM radio before it could threaten his profits, Sarnoff’s company successfully lobbied the FCC to have the FM spectrum moved from Armstrong’s frequencies to the ones we use today: 88 to 108 MHz. Today over 2,000 FM stations broadcast in the United States, and FM signals are commonly used for microwave relay links and space communications. ( Continue reading.