Sources returnpage

Armstrong, Edwin Howard

Category: Scientist


Edwin Howard Armstrong (December 18, 1890 – January 31, 1954) was an American electrical engineer and inventor, best known for developing the regeneration or feedback circuit [1912], the superheterodyne circuit [1918] and FM (frequency modulation 1933) radio.

A fourth invention, known as superregeneration made in 1922 is not as widely known as the other three.  He was perhaps the last of the great individualistic inventors, a man who refused to be swallowed up by the great powerful corporations of America.

Radio was founded on seven basic inventions, all of them the work of individuals without ties to industry and all of whom produced their inventions by a mixture of observation and experimentation, finally surmounted by sudden flashes of inspiration:

  • Marconi invented four circuit tuning
  • Fessenden, Lee and Hogan invented the heterodyne
  • Edison and de Forest invented the vacuum tube
  • Lowenstein invented the audio amplifier
  • Armstrong invented the regenerative and superheterodyne circuits
  • Langmuir invented the high vacuum tube

Armstrong received numerous awards, including the first Medal of Honour awarded by the Institute of Radio Engineers (now IEEE), the 1941 Franklin Medal and the AIEEs Edison Medal "for distinguished contributions to the art of electric communication, notably the regenerative circuit, the superheterodyne, and frequency modulation".

For his wartime work on radio, the French government gave him the Legion of Honour in 1919.  In May 1955, his name was added by the International Telecommunication Union in Geneva to its list of great inventors – to take his place with Samuel Morse, Alexander Graham Bell, Nikola Tesla, Andre Marie Ampere, Michael Faraday, Karl Friedrich Gauss, Heinrich Hertz, Lord Kelvin, Guglielmo Marconi and James Clerk-Maxwell.

He received two honorary doctorates, from Columbia in 1929, and Muhlenberg College in 1941.  The Consumer Electronics Hall of Fame inducted him in 2000, "in recognition of his contributions and pioneering spirit that have laid the foundation for consumer electronics." Columbia University established the Edwin Howard Armstrong Professorship in the School of Engineering and Applied Science in his memory.  Philosophy Hall, the Columbia building where Armstrong developed FM, has been declared a National Historic Landmark.  Armstrong Hall at Columbia was named in his honour. It is currently home to the Goddard Institute for Space Studies, a research institute dedicated to atmospheric and climate science that is jointly operated by Columbia and the National Aeronautics and Space Administration. A second Armstrong Hall, also named for the inventor, is located at the United States Army Communications and Electronics Life Cycle Management Command (CECOM-LCMC) Headquarters at Aberdeen Proving Ground, Maryland.

In 1955, his wife Marion Armstrong founded the Armstrong Memorial Research Foundation, and participated in its work until her death in 1979 at the age of 81.

 Life and career

Armstrong was born in the Chelsea district of New York City, the oldest of John and Emily (Smith) Armstrong's three children.  At the age of eight, he contracted Sydenham's chorea (then known as St. Vitus' Dance), an infrequent but serious neurological disorder precipitated by rheumatic fever. For the rest of his life, Armstrong was afflicted with a physical tic exacerbated by excitement or stress. Due to this illness, he withdrew from public school and was home-tutored for two years. To improve his health, the Armstrong family moved to a house overlooking the Hudson River, at 1032 Warburton Avenue in Yonkers. The Smith family subsequently moved next door.

Armstrong's Paris Laboratory

Armstrong studied electrical engineering at Columbia University under the celebrated Michael J. Pupin. Radio was Armstrong's passion, and about a year before he graduated in 1913, he devised a circuit that revolutionized the radio art. Using a triode as an amplifier, he fed back part of the output to the input, and thereby obtained much greater amplification. Armstrong made a further discovery with this circuit: just when maximum amplification was obtained, the signal changed suddenly to a hissing or a whistling. He realized this meant that the circuit was generating its own oscillations, and thus that the triode could be used as a frequency generator. The first of these discoveries — of a powerful amplifier — vastly increased the sensitivity of radio receivers, while the second — of an oscillator — led to the use of the electron tube in transmitters and also in receivers for an added function, heterodyne reception.

Engineering and Technology history Wiki

In 1901, Reginald Fessenden had introduced to radio the heterodyne principle: if two tones of frequencies A and B are combined, one may hear a tone with frequency A minus B. Armstrong used this principle in devising what came to be called the superheterodyne receiver. The essential idea is to convert the high-frequency received signal to one of intermediate frequency by heterodyning it with an oscillation generated in the receiver, then amplifying that intermediate-frequency signal before subjecting it to the detection and amplification usual in receivers. RCA marketed the superheterodyne beginning in 1924, and soon licensed the invention to other manufacturers. It became — and remains today — the standard type of radio receiver.

Armstrong [right] with his Edison Medal

In the early 1920s, Armstrong turned his attention to what seemed to him, and to many other radio engineers, as the greatest problem, namely, the elimination of static. He wrote, "This is a terrific problem. It is the only one I ever encountered that, approached from any direction, always seems to be a stone wall." Armstrong eventually found a solution in frequency modulation, which is a different way of impressing an audio signal on a radio-frequency carrier wave. In the usual technique, known as amplitude modulation (AM), the amplitude of the carrier wave is regulated by the amplitude of the audio signal. With frequency modulation, the audio signal alters instead the frequency of the carrier, shifting it down or up to mirror the changes in amplitude of the audio wave. He soon found it necessary to use a much broader bandwidth than AM stations used (today an FM radio channel occupies 200 kHz, twenty times the bandwidth of an AM channel), but doing so gave not only relative freedom from static but also much higher sound-fidelity than AM radio offered.

With the four patents for his FM techniques that he obtained in 1933, Armstrong set about gaining the support of RCA for his new system. RCA engineers were impressed, but the sales and legal departments saw FM as a threat to RCA's corporate position [it was based entirely on AM]. David Sarnoff, the head of RCA, had already decided to promote television vigorously and [saw that] the company did not have the resources to develop a new radio medium at the same time [in other words FM was a threat not an opportunity to their business]. ....

Armstrong did gain some support from General Electric and Zenith, but it was largely on his own that he carried out the development and field testing of a practical broadcasting system. He gradually gained the interest of engineers, broadcasters, and radio listeners, and in 1939 FM broadcasts were coming from twenty or so experimental stations. These stations could not, according to FCC rules, sell advertising or derive income in any other way from broadcasting, but finally, in 1940, the FCC decided to authorize commercial FM broadcasting, allocating the region of the spectrum from 42 MHz to 50 MHz to forty FM channels. In October of that year, it granted permits for 15 stations. Zenith and other manufacturers marketed FM receivers, and by the end of 1941, nearly 400,000 sets had been sold.

U.S. entry into the war brought a halt both to the granting of licenses for FM stations and to the production of FM receivers. After the war, FM broadcasting was dealt a severe blow when the FCC made one of its most unpopular decisions, moving the FM spectrum allocation (to the range from 88 to 108 MHz) and thus making obsolete the 400,000 receivers, as well as the transmitters of dozens of broadcasters.


So Armstrong made the mistake of not realising that existing companies have nothing to gain by change and will oppose it, and that if you have a new idea, you go to new  start-ups and enthusiasts who will take the idea forward for you, because it represents a new opportunity and they have nothing of the past to weigh them down. 

As for the regulators.... It appears that the head of the FCC had been offered a job by a company who would benefit from the change of regulations.  This breach of trust, resulted in a later change of the law, such that in theory regulators cannot become employees of the companies they regulate.  Given the debacle of the CDC and the pharmaceutical industry, it appears this law is no longer enforced or has been surrepticiously repealed.  Regulation in the USA is an unholy mess even now.

In 1934, Armstrong filled the vacancy left by John H. Morecroft's death, receiving an appointment as a Professor of Electrical Engineering at Columbia, a position he held the remainder of his life.

Following college graduation, he had received a $600 one-year appointment as a laboratory assistant at Columbia, after which he nominally worked as a research assistant, for a salary of $1 a year, under Professor Pupin. Unlike most engineers, Armstrong never became a corporate employee. He set up a self-financed independent research and development laboratory at Columbia, and owned his patents outright.

Professor Pupin died on March 13th 1935, aged 77 and Armstrong took over Professor Pupin's chair at the head of the Marcellus Hartley Research Laboratory.  Armstrong was appointed with a glowing letter from Nicholas Murray Butler, President of Columbia University, warmly paying tribute to his inventive genius and to the continuing glory that it brought to the school.  He was still paid a salary of $1 a year, which he never collected.  The most important thing to him was that he had the freedom to do research as he pleased in the oldest traditions of great universities and great discoveries.  As such it is worthwhile briefly looking at his method.

Armstrong and the scientific method

in the attic where it all started, years later

Armstrong was a wonderful example of a scientist who genuinely used the scientific method.  He spent years observing the area, right from his childhood he was playing with equipment, filling the attic of their house with anything he could afford or find to progress his understanding, with no other purpose than to find out and observe.

Man of High Fidelity: Edwin Howard Armstrong – A biography by Lawrence Lessing

He got his friend Bill Russell to help him build several antennae kites, with which he sought to improve reception.  These were no ordinary kites, but sturdy structures seven feet tall, requiring a windlass to reel them in and out of the upper story windows on Warburton Avenue.  They were invariably flown in the stormiest weather.  When the wind was high enough, they were often left tethered outside to fly through the night.


We have numerous examples on this site of men, just like Armstrong, who because of their shyness, because they had been ill and did not have to go to school, used this time to find out.  It rather demonstrates that school is not in fact a place of learning for the gifted – or even the not so gifted.  That observation and ‘playing’ is the most effective means by which children learn, and all you have to do is find out what they are really interested in – as the Rudolf Steiner schools do. 

Once Armstrong had an hypothesis, however, he immediately set up experiments to test it. 

Man of High Fidelity: Edwin Howard Armstrong – A biography by Lawrence Lessing

Through most of the years between 1928 to 1934, when FM was being developed, laboratory records show activity going on seven days a week and often far into the night, and on all holidays except Christmas.
Armstrong worked along with that singular absorption and detachment that, even in relaxation, never allowed his mind to cease from turning over the problems with which he was grappling.  He lived plainly, even austerely.  He would wear the same necktie day after day until it frayed away and shoes until they were out at the soles.  His luncheon invariably consisted of a cheese sandwich and a glass of milk, taken hastily in a small shop on Amsterdam Avenue.  Tom Styles, who liked more leisure and variety, once got him into a French restaurant.  Armstrong, to mark the occasion, ordered two cheese sandwiches and a glass of milk.


Equally important is that although Armstrong used equipment to find out more, he did not use text books.  Nor in his early student years, did he attend lectures, except in subjects where he respected the lecturer’s knowledge of an area.  Generally speaking the lecturers he admired were those like him – men who did experiments and did not use chalk, talk and text books - practical men of experience, as opposed to theoretical scientists.

Man of High Fidelity: Edwin Howard Armstrong – A biography by Lawrence Lessing

Sometimes months were needed to set up and try one experiment.  By 1933, he had made and recorded over 100,000 measurements.  In addition to this, the whole early development  of FM was carried on by Armstrong alone, a feat probably unique for an invention of this size and importance.

The reason that Armstrong came up with so many inventions, where others had covered similar ground but had ultimately not gone that extra mile, is that he combined an extraordinary memory - the ability to hold a vast amount of detail in his mind, for days, weeks and even years without forgetting it, - with the intuitive ‘big picture’ eureka moment of the visionary. There are many people that can tunnel down holes into more and more detail, getting themselves bound up in mathematical formula and complexity, but unless they can come out of those holes and look across the landscape they will make no discoveries.  In blue sky thinking there are no formula, there are no complex mathematical or conceptual descriptions – there are pictures and analogies and symbols.

Both de Forest and Armstrong noticed the ‘howling phenomenon’ in the regeneration audion at its highest amplification, but it was Armstrong who investigated it and instead of trying to eliminate it, as de Forest did, he realised the receiver could also be a transmitter.  And by doing so he not only discovered the improved receiver for which the wireless age had been searching, but also and what was least expected, a transmitter which could make sustained and reliable radio broadcasts.


Armstrong’s upbringing and beliefs had a profound effect upon the way his life evolved.  He was a fighter of extraordinary stamina for justice and honesty.  His life was in part dedicated to standing up and battling for principles, usually against the powers of the world, from large corporations, to corrupt officials, and to a misinformed, sometimes corrupt and ignorant judiciary.

Armstrong's Edison Medal citation, for example, noted the importance of his work stating, "This keystone of radio development was later to become involved in fourteen years of litigation and which, in the end, was decided by lay courts based on errors of fact and judgment which were contrary to the scientific facts."

Armstrong spent much of his life and a great deal of his money in long debilitating court fights over protection of his patents.  He held 42 patents and he fought tenaciously, spurred by his sense of justice and the need to protect the individual inventor in general.  Sadly, justice did not come to his aid, in fact was notably absent.  The battle took its toll and his end was a tragic one.

Armstrong's father worked for the American branch of the Oxford University Press, which published Bibles and standard classical works, eventually advancing to the position of vice president. His parents first met at the North Presbyterian Church, located at 31st Street and Ninth Avenue. Armstrong’s mother was described as “gentle and deeply religious”.  When the church moved north, the Smiths and Armstrongs followed, and a great clan of church-going relatives filled Howard’s life.  The church dominated all their lives, John Armstrong was a trustee and he often led prayers at church meetings.

Armstrong's boyhood home, 1032 Warburton Avenue, overlooking the
Hudson River in Yonkers, New York, c. 1975. It was demolished in November
1982 due to fire damage.  The room with the cupola over it was his laboratory

Presbyterianism is a part of the Reformed tradition within Protestantism which traces its origins to the British Isles, particularly Scotland.  Each Church is governed by representative assemblies of elders.

Presbyterian theology typically emphasizes the sovereignty of God, the authority of the Scriptures, and the necessity of grace through faith in Christ. It is also a deeply moral theology – one that emphasises justice, right and wrong using the example of Jesus.

Over his work table in the attic, where he did all his early experiments as a boy, hung a framed and illuminated Biblical text, a gift from his mother, that read "Call Upon Me in the Day of Trouble:  I Will Deliver Thee"

Armstrong lived his faith throughout his whole life.  In one of the major disputes in which he was involved over FM he stated publicly before a body of engineers:

“whether those gentlemen who pretend to learning in the intricacies of the law will ultimately apply the word sinful, non-sinful or perhaps illegal to what has happened to FM during the past ten years, I do not know.  What I do know is that the verdict of history will be that a crime has been committed against the radio art”.

And indeed the lying, reneging on agreements , betrayals, and conspiracies that were perpetrated over FM in particular, actually set the USA as a whole way behind the rest of the world.  Corporate America is corrupt, but appears to spend its entire time shooting itself in the foot.

Paul Godley with a superheterodyne

When one reads about his battles and the toll they took,  the temptation is to think, why did he keep pushing, keep trying to redress ‘wrongs’ when it seemed almost hopeless?  The answer is that he was self-directed, moral, combative, independent and free, and he was fighting on behalf of all like him. 

He was one of the people in human culture and invention who move things on.  People who always strive for the best there is, not a shoddy compromise based on negotiation and power politics.  Armstrong was a man of principle - a rare breed in the America of then and now – and America along with all the other corrupt nations sorely needs more Armstrongs.

Armstrong regenerative radio

Corruption does not in fact pay, it creates a small clique of extremely wealthy individuals and a very very large number of people who are always struggling to make ends meet and who, these days, are sick as well, all lulled into believing things will one day be better.  Furthermore, it does not produce ‘excellence’ in anything – entertainment, education, cars and transport, clothes, food, medicine, software, or health. Corporate America is tacky and second rate, driven by profit and not ethics, money and not imagination or beauty.  The mentality of the mall.

Man of High Fidelity: Edwin Howard Armstrong – A biography by Lawrence Lessing

The qualities of persistence, stubbornness and absolute honesty that made him a peerless researcher and inventor of the first rank, made him inflexible and often inept in dealing with the world. ‘Because reason was the tool with which he worked’, wrote on of his friends….’he was violently antagonised by the inability or unwillingness of others to reach conclusions by the same method.  The plain truth that the world does not run upon reason eluded him’ …. This is a growing pattern in this century in which the apathy and docility of the people contrast strangely with the enormous violence done to individuals……. Armstrong was literally killed by a society on whose terms he strove valiantly and with high principles to serve, but which reneged on those terms and solemn contracts in the end to bedevil, betray and ultimately destroy him.

It is interesting to note that the funeral for Armstrong on 3rd February 1954 was held in the Fifth Avenue Presbyterian Church in New York.  The Reverend Dr Thornton B Penfield spoke as though he had been murdered.

His mind was brilliant and creative” he said “and he kept his genuineness and his integrity of spirit”.

 Armstrong's laboratory at Columbia


The last battle that Armstrong fought eventually killed him.  In 1953, he contracted what appeared to be encephalitis and lost weight, until he had a gaunt and haunted look. At 63, his finances were under threat of being exhausted by the long deliberately contracted battles he was forced to wage against those who had used his ideas but paid him no royalties.  His sister nicknamed ‘Cricket’ noticed he looked close to a breakdown.

Man of High Fidelity: Edwin Howard Armstrong – A biography by Lawrence Lessing

The passion that had sustained Armstrong for so many years and the endurance that was more than other men's were alike drained away. The remarkably close-woven fabric of his life stretched behind him, and, do what he might, was raveling out.

Armstrong on the WJZ Transmitter - ironically he had no
fear of heights

To the sense of rejection that had run through that fabric like a dark thread were now added remorse and a sense of having maimed his spirit by endless combat, which no man can engage in without suffering some grime to rub off on himself.

And who now cared about or even understood all those old battles, so technical in their ramifications and baffling to the popular mind?

 It was extraordinary how this civilization, which wears out the nerves and makes such exorbitant demands on individual brains, was at great pains to spare the mass of the people any effort to understand the issues raised by scientific advances. For himself, Armstrong was not retreating but simply dropping in the battle.

It was the quest that had counted, the drive for some impossible object the moments, details, devotions, clarities, zests and passion involved in pursuit of it, and now that these were dissolving his life was over.

Sometime on that Sunday night of January 31, 1954, he wrote a two-page letter to Marion Armstrong which in its full contents must remain in that last private file to which even common men are entitled. Its gist, however, was that he found it impossible to understand how he could have hurt "the dearest thing in the world to me."

"How deep and bitterly I regret," he said, "what has happened to us." His solvency was assured, he wrote, especially if the Telephone Company and R.C.A. "come through anywhere near making good . . , for they know they have been using my invention." He wrote of heartbreak and of the time when they were "happy and. free." Finally he wrote: "God keep you and the Lord have mercy on my soul."

He was completely and neatly dressed, in hat, overcoat, scarf and gloves. He did not walk out of the door, however, but out of the window, thirteen stories above the street, falling from the last high place to which he would ever climb. His body was found by a building maintenance worker the next morning, lying on a third-floor extension overlooking the river. Above him in the gray February sky the sooty seagulls plied their usual beat over the leaden East River, and around him stood Manhattan's once shining towers, from which all magic had fled, drab and gray in the light of mid- century.

Armstrong, Marion and a 'portable' radio


For iPad/iPhone users: tap letter twice to get list of items.