Edwin Howard Armstrong


Edwin Howard Armstrong : biography

18 December 1890 – 31 January 1954

On January 31, 1954 Armstrong removed the air conditioner from the window and jumped to his death from the thirteenth floor of his New York City apartment. His body was found fully clothed, with a hat, overcoat and gloves, the next morning by a River House employee on a third-floor balcony. The New York Times described the contents of his two-page suicide note to his wife: "he was heartbroken at being unable to see her once again, and expressing deep regret at having hurt her, the dearest thing in his life." The note concluded, "God keep you and Lord have mercy on my Soul."

After his death, a friend of Armstrong estimated that 90 percent of his time was spent on litigation against RCA. Upon hearing the news, David Sarnoff supposedly remarked, "I did not kill Armstrong." 

MacInnis was able to formally establish Armstrong as the inventor of FM following protracted court proceedings over five of his basic FM patents. Until her death in 1979 she participated in the Armstrong Memorial Research Foundation that she founded.

Edwin Armstrong was buried in Locust Grove Cemetery, Merrimac, Massachusetts.


Armstrong received 42 patents in total; a selection are listed below:

  • : "Wireless Receiving System"
  • : "Electric Wave Transmission" (Note: Co-patentee with Mihajlo Pupin)
  • : "Antenna with Distributed Positive Resistance"
  • : "Method of Receiving High Frequency Oscillation"
  • : "Selectively Opposing Impedance to Received Electrical Oscillations" (Note: Co-patentee with M. I. Pupin)
  • : "Signaling System"
  • : "Wireless Receiving System for Continuous Wave"
  • : "Radio Signaling System" (Note: This is one of the patents issued for wideband FM in 1933.)
  • : "Radiosignaling" (Note: This is one of the patents issued for wideband FM in 1933.)
  • : "Radiosignaling" (Note: This is one of the patents issued for wideband FM in 1933.)

Patent disputes

Many of Armstrong’s inventions were ultimately claimed by others in patent lawsuits. In particular, the regenerative circuit, which Armstrong patented in 1914 as a "wireless receiving system," was subsequently patented by Lee De Forest in 1916; De Forest then sold the rights to his patent to AT&T. Between 1922 and 1934, Armstrong found himself embroiled in a patent war, between himself, RCA, and Westinghouse on one side, and De Forest and AT&T on the other. At the time, this action was the longest patent lawsuit ever litigated, at 12 years. Armstrong won the first round of the lawsuit, lost the second, and stalemated in a third. Before the Supreme Court of the United States, De Forest was granted the regeneration patent in what is today widely regarded as a misunderstanding of the technical facts by the Supreme Court justices.

By early 1923, however, Armstrong was a millionaire as a result of licensing his patents to RCA. In 1946 the FCC’s decision to use Armstrong’s FM system as the standard for NTSC television sound gave Armstrong another chance at royalty payments. However, RCA refused to pay him royalties and encouraged other television makers not to pay them either.


Armstrong invented a large part of the technology of modern radio. A modern biographer has written

It took decades following Armstrong’s death for FM broadcasting to meet and surpass the saturation of the AM band, and longer still for FM radio to become profitable for broadcasters. Two developments made a difference in the 1960s. One was the development of true stereophonic broadcasting on FM by General Electric, which resulted in the approval of an FM stereo broadcast standard by the FCC in 1961, and the conversion of hundreds of stations to stereo within a few years.

The other was an FCC rulemaking in 1966 that required broadcasters who owned both full-time AM stations and FM properties in the same city to program each of them with separate programming during a majority of the day. This meant FM no longer just simulcast AM with better sound quality, but offered unique program choices expanding what listeners could hear. Programmers took advantage by turning their FM stations into venues for formats from country to progressive rock to jazz and classical music, all with the enhanced quality that stereo sound could bring. For example, some AM stations paused Sunday morning music programming for religious voicetracks by ministers. Sister stations on FM continued the music programming.