On November 6, 1935, Edwin Armstrong presented a paper entitled “A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation” to a collection of engineers. While the subject seems at first glance to be loftily academic, Armstrong was explaining for one of the first times his new advancement in radio transmission and specifically the new technology he called FM radio.
Edwin Armstrong had been a shy child. After picking up a disease that gave him a nervous tic, Armstrong removed himself from school for a number of years. While in relative isolation, he learned about nascent radio technology, and became proficient enough that he was explicitly asked to join the Army Signal Corps during the First World War to set up radio networks in Europe. He’d already developed several important early radio technologies before joining the effort, and licensed all of his patents to the government for wartime use at no cost. After the war he set his sights on pursuing the technology of Frequency Modulation.
At this point, all radio signals were transmitted using AM technology. AM, or amplitude modulation, embeds the information to be carried on a radio by varying the amplitude, or volume, of a radio wave. If you imagine a wave, changing the amplitude makes the peaks and valleys higher and lower, but doesn’t alter their length or frequency. While this technology worked, it was also prone to interference as electrical disturbances in the environment easily changed the amplitude of the radio wave, corrupting the signal and resulting in static and interference. Armstrong’s frequency modulation instead embedded information in the frequency of a signal. Frequency is the measure of how many peaks and valleys there are in a signal in a given amount of time. By embedding the information in the frequency of the signal, which was not subject to atmospheric interference like the amplitude, Armstrong made a technology that could transmit higher quality radio sound further and stronger than ever.
Armstrong, quite correctly, thought he was on to something big with this innovation. He took his idea to David Sarnoff, an acquaintance and the President of RCA, the dominant radio equipment manufacturer at the time. Sarnoff rejected FM technology outright as RCA was heavily invested in AM technology and even owned a number of AM broadcasting stations. Pressing on, Armstrong founded his own FM station and demonstrated the technology, proving its vast advantages over AM in sound quality and broadcast range. AM stations began adding FM transmitters that would broadcast the same content, but on the superior band. With the writing on the wall that FM was the future of radio broadcasting, RCA finally decided to get into the business of FM radio at Sarnoff’s direction, but they would do it independently of Armstrong.
RCA had soon filed its own patents on FM technology and claimed to have innovated the technique in-house, in contrast to the widely known fact, at least in the radio community, that Armstrong had invented it. This was reminiscent of the way that RCA engineers stole early television technology from Philo Farnsworth and marketed it as their own, also under direction from David Sarnoff. Knowing himself to be right and needing the revenue, Armstrong had to go to court to defend his patents. FM was, and still is, a major communications technology, and thus the earning potential was massive. Armstrong found the downside of working on his own his whole life in that he didn’t have a legal department to match with RCA’s, and the ingenious inventor wasted much of his own time and money waging war on RCA’s frivolous patents. This led him to a point where, as one friend of his estimated, Armstrong was spending 90% of his time fighting against RCA. In his lifetime, Armstrong wouldn’t win the case, and eventually committed suicide while battling depression.
Armstrong’s wife carried on the legal fight and eventually proved incontrovertibly that Armstrong had invented FM technology, and Armstrong’s estate began to receive the royalty payments it had been entitled to all those years. While the patent fight was most damaging to Armstrong in that it took money out of his pocket and forced him to waste his efforts in the courtroom, it also cost him his notability. FM radio was, and is, of monumental importance to literally billions of people, and yet we don’t give widespread recognition to the man who invented it. Perhaps because they were better businessmen, Edison, Bell, and Farnsworth have all earned their place in the firmament of American innovators. And whether or not he is a household name, Armstrong irrefutably earned his spot among them.