Who Invented Radio?

© 2005, Douglas T. Smith Editorial Services

This material originally appeared in WorldRadio, May 2006

Historical accounts of discovery and invention sometimes sidestep the truth. The development of radio provides a case in point.

It's nothing short of uncanny how history attributes certain inventions or discoveries to the wrong person. Many myths propagate indefinitely because unwitting teachers reprogram each new class with the same questionable assertions. The history of radio communications is replete with examples, some of which I'll mention here; but any field involving discovery or invention seems to suffer as much.

Ask anyone, "Who discovered America?" Those who have an answer are likely to say it was Christopher Columbus: It's in the history books. We even have a national holiday for the man, although those same history books clearly relate that he was greeted by native Caribbeans on his arrival! It seems you can't successfully argue that he was the first European over here, either.

Ask, "Who invented the light bulb?" and you'll get "Edison" — wrong. Who discovered Halley's comet, Edmund Halley? Nope. In mathematics, who discovered Simpson's rule? Definitely not Thomas Simpson. It was known long before he was born. Who discovered Taylor series? Not Brook Taylor but probably James Gregory. Maclaurin series? Not Colin Maclaurin. Cramer's rule? It was Maclaurin!

Who discovered the calculus, Newton or Leibniz? Isaac Newton almost certainly had the thing before Gottfried Leibniz, but Leibniz published it first, well before Newton did. Ordinarily that would be enough to establish priority, but Newton was President of the Royal Society in Great Britain and he was surrounded by friends who attested that he discovered it first. The ensuing row shook European scientific communities to their foundations. Had Leibniz not published, he might have been forgotten despite his brilliance.

The answer to, "Who invented radio?" usually is "Marconi" and that's almost certainly incorrect. Why are our historical accounts so tainted? What is it about human nature that assigns credit where seemingly undue? Well, that credit isn't necessarily undue. In each case above, who got credit was the fellow who took the concept to fruition and brought it to the people. Guglielmo Marconi and Thomas Edison were marketing geniuses as well as immensely capable engineers. Halley used theory to predict the orbit and return of that comet — a famous feat. Simpson and Maclaurin wrote popular books, expounding on the equations that today bear their names. Newton's place in scientific history is firmly cemented but Leibniz gets his spot, too.

As particularly interesting examples, let's explore those matters of priority that arose during the infancy of radio — a period around the turn of the last century ripe with discovery and invention. The lives and livelihoods of certain men are central: Heinrich Hertz, Reginald Fessenden, Alexander Popov, Edwin Armstrong and Lee deForest. Nikola Tesla and Guglielmo Marconi play only supporting roles in some of following stories since so much has already been written about them, but we'll get to them nevertheless. Much, but not all, of the controversy centers on what lawyers do.

Facts and Folklore of Early Radio Development

It's been said that you can patent a ham-and-cheese sandwich if you prepare your application cleverly enough. In your description of the invention, you might include some "legalese" like, "A plurality of slices of the cooked flesh of Sus scrofa interspersed with a plurality of pieces of curdled bovine lactations...." In the early days of radio, it must have been at least as difficult for patent examiners to understand radio-related inventions. Priority was even more difficult to determine — as it is even now. However, hindsight allows an intriguing chronological look at the facts and folklore surrounding a unique era.

Magnetism and the Telegraph

In 1819, Danish physicist Hans Oersted (1777-1851) discovered that his compass needle deflected when held near a dc-current-carrying wire. The proof of a relationship between current and magnetism rocked the scientific world and sent physicists such as Frenchmen Andr Ampre (1775-1836) and Dominique Arago (1786-1853) scurrying to duplicate Oersted's experiments and explain them. Ampre eventually formulated the proper relationships and, evidently, invented the solenoid. He showed that it acted like a bar magnet when dc current was passed through it.

Michael Faraday (1791-1867) in the U.K. followed quickly on Ampre's heels by reproducing Oersted's experiments and publishing his initial results in 1821.1 During his continued research, Faraday put forth the concept of a magnetic field and laid some of the foundations for the subsequent theoretical work of James Maxwell (1831-1879). Faraday built the first dynamo (1821) and discovered electromagnetic induction in the year Maxwell was born.2 Induction is the basis for electric motors and transformers, which Faraday also built. In addition, he discovered that the polarization of light rotates in a magnetic field, strongly anticipating the later theory that light is electromagnetic in nature.

Joseph Henry (1797-1878) was a professor at Princeton from 1832 to 1846. While Faraday was doing his experiments, Henry was doing similar work, apparently unaware of Faraday's. His chief research was in electromagnetism, wherein he discovered the phenomenon of self-inductance. Henry experimented by winding coils and found relationships between coil structure and inductance. He was among the early researchers to use iron cores to build electromagnets. One he built at Princeton lifted 3500 pounds. He also demonstrated non-inductive coils in which the wire was folded back on itself. That method is still used today to make low-inductance wirewound resistors.

Henry rigged a pair of wires onto Nassau Hall at Princeton, between which he was able to send signals by induction (1831). The system used an electromagnet at the receiving end that closed a switch; the switch, in turn, carried a stronger electric current that rang a bell. In effect, that was the invention of the electromagnetic relay.3 Samuel Morse (1791-1872) had a copy of one of Henry's papers and consulted him prior to developing a telegraph. Henry was later called to testify in a patent suit involving that telegraph (Morse v. O'Reilly, 1849). Although Henry had been very helpful to Morse, his testimony that the underlying principle of the telegraph had previously been known to him, Charles Wheatstone (1802-1875) and William Cooke (1806-1879) resulted in a great deal of controversy, although Morse won that and other suits.4 Wheatstone and Cooke had patented their telegraph in 1837; Morse didn't first test his until 1838.

However, the men with priority were Henry (the first wireless telegraph?) and Pavel Schilling (c. 1780-1836), who invented the type of needle telegraph (1832) that Wheatstone and Cooke used. Schilling was evidently the first to use an organized code for signalling of discrete characters. Thus, the popular wisdom found in so many almanacs and other books, written by lazy writers, saying that Morse invented the telegraph is wrong. Morse was, of course, a successful developer and promoter of his own variation of the device and of a certain coding system. By the way, the thing known today as the Wheatstone bridge was not invented by Wheatstone but by Samuel Christie (1784-1865). Wheatstone himself acknowledged that freely, but it was he who first applied the circuit in the modern way.

Electromagnetic Waves

From 1860 to 1868, James Maxwell was a professor at King's College, London. Many of his great investigations had to do with the kinetic theory of gases but his greatest work was devoted to electromagnetism. He extended the work of Ampre, Faraday and others to produce a set of 20 equations in 20 variables. First presented to the Royal Society in 1846 and formally published in 1865,5 the equations described the interaction of changing electric and magnetic fields (and matter) and predicted the existence of electromagnetic waves travelling at a fixed speed. The predicted speed was so close to what had been measured for over 150 years as the speed of light that Maxwell was prompted to write:

This velocity is so nearly that of light, that it seems we have strong reason to conclude that light itself (including radiant heat, and other radiations if any) is an eletromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws.

Using the best measured data available at the time for other physical constants, Maxwell computed 3.1x108 m/s, which is within 4% of today's accepted value of 2.9979x108 m/s. He was right about the electromagnetic wave nature of light (and radio waves) but Maxwell believed that a medium, dubbed the "luminiferous ther," must be omnipresent to propagate the waves.

Subsequent experiments proved that such a medium doesn't exist in its then-perceived sense. The search for reconciliation inspired Albert Einstein (1879-1955) to develop his special theory of relativity (1905), although he claimed ignorance of the famous Michelson-Morley experiment at the time.

In 1884, Oliver Heaviside (1850-1925) reformulated Maxwell's original equations using vector calculus. He boiled the 20 equations in 20 variables down to two equations in two variables. Similar work was done by Heinrich Hertz (1857-1894), also in 1884. Hertz usually gets more credit because his rendition in differential form with four equations — basically the laws discovered by Ampre, Faraday, Charles-Augustine de Coulomb (1736-1806) and Karl Gauss (1777-1855) — are what we now call Maxwell's equations, even though they're really Maxwell-Ampre-Faraday-Coulomb-Gauss-Hertz equations as a set. Both Heaviside and Hertz discarded the idea of a luminiferous ther.

Hertz was a professor at Karlsruhe University in Germany from 1885 to 1888. One of his great discoveries was the photoelectric effect (1887). The discovery was apparently inadvertent and Hertz didn't pursue its explanation, leaving that task to others. (Einstein did it in 1905,6 a very good year for ol' Al.) By 1886, Hertz had set up an experiment by which electromagnetic energy could be transmitted across a room, producing a spark between the electrodes of an open metallic ring. Reasoning that he was working with the waves Maxwell had predicted, he went on to show that the waves travelled at the speed of light but had much longer wavelengths. He found that the waves were reflected by conducting objects and even focused by concave surfaces, as in reflecting optical telescopes. By timing those reflections over a fixed distance, Hertz had discovered radar (!) without ever knowing it. He also demonstrated the waves' diffraction, polarization, interference and velocity. Hertz even managed to achieve resonant circuits, sustaining damped oscillations around particular frequencies.

Thus to set the record straight, Hertz was not the first to demonstrate the action of electromagnetic waves at a distance; that credit must go to Henry. But most would not call Henry's experiments radio. Hertz rightfully gets credit for experimenting with and developing the first radio transmitter and receiver. His students were quite positively impressed, but his own comments as to the practical value of his discoveries were not as enthusiastic: "It's of no use whatever.... This is just an experiment that proves Maestro Maxwell was right...." Some of his results published in 18887 were read by a young man vacationing in the Alps. His name was Guglielmo Marconi. More on him later.

On the Eastern Front

Alexander Popov (1859-1905) is seldom mentioned outside Russia as the father of radio. But a paternity case can certainly be made.

Born the son of a priest, Popov became interested in the natural sciences at an early age. After graduating from St. Petersburg University in 1882, he took employment with the university. About a year later, he accepted a position at the Russian Navy's Torpedo School, which boasted of the best technical facilities and libraries in the whole of Russia. By 1894, Popov had succeeded in assembling a reasonable generator for transmitting electromagnetic waves.8 The receivers of the day were dismal, however. Remember that this was only six years after the seminal experiments of Hertz, of which Popov was well aware. He was also aware of the work of Edouard Branley (1844-1940), who showed that the electrical resistance of finely divided metal particles decreased in proximity to a spark discharge.9 That formed the basis for Branley's radio-wave detector (1892), evidently the first of its kind, although Oliver Lodge (1851-1940) was working on a similar scheme at almost exactly the same time.

Popov was evidently unaware of the work of David Hughes (1831-1900), who is also variously credited with being the first to transmit and receive radio waves. Hughes invented a "coherer," a term coined by Lodge for a sensitive receiver of radio signals, based on the Branley principle. Lodge and Popov are also often credited with being the first persons to transmit and receive radio signals — in 1894, one year before Marconi allegedly did it but two years after Branley and six years after Hertz. It's ironic that those luminaries of early telecommunications had such trouble communicating with one another!

Wireless Telephony, Part 1

Nathan Stubblefield (1858-1928) was born the son of a lawyer in Murray, Kentucky. In 1892, he demonstrated wireless telephony using a pair of black boxes and rods stuck into the ground at each end of the link. The devices evidently worked through electromagnetic means at audio frequencies. Eventually, word of the demonstrations Stubblefield was conducting reached the St. Louis Post Dispatch. After mail contact, a reporter showed up at Stubblefield's door in January, 1902. The subsequent story published by the Post Dispatch related an account of good voice contact over a path of about a mile.

The article won the inventor an invitation to demonstrate his equipment in Philadelphia, which he did successfully by all accounts. One of his next voyages was to Washington, D.C., where gathered scientists were said to be amazed. During that demonstration, one of the devices was placed on a steamship floating in the Potomac River and several others were positioned along the shoreline. The Washington Evening Star's May 21, 1902 issue featured a huge headline and story on its success. Stubblefield filed a patent application for his invention in 1907; the patent was granted the following year. Eventually, he committed to New York investors who formed The Wireless Telephone Company of America to promote and sell the product. Some of them artificially pumped up the price of the public stock in the company, then sold and disappeared. Disgusted, Stubblefield went home and stayed there until his death, after which his equipment and notes weren't all found.

Wireless Telephony, Part 2

Reginald Fessenden (1866-1932) was born in Canada the son of an Anglican minister. When he was about ten years of age, his father was invited to witness one of Alexander Bell's (1847-1922) demonstrations of his telephone apparatus. Reginald tagged along. Father and son later discussed what they had witnessed and Reginald purportedly asked, "Why do they need wires?"10

The young Fessenden read Scientific American avidly and nurtured a scientific curiousity throughout his life. He closely followed the stories about Thomas Edison (1847-1931) and his inventions. He eventually applied for a job with Edison and got it. Later, he also worked for George Westinghouse (1846-1914). He was a professor at Purdue University and a department head at Western Pennsylvania University. All those positions gave him the resources he needed to pursue at least parts of his goal of wireless telephony.

Along the way, Fessenden was heavily involved in wireless telegraphy. During employment with the U.S. Weather Bureau, he successfully designed and installed several wireless telegraph stations, one of which was at Cobb Island in the Potomac near Washington, D.C. In late December of 1900, he managed to connect a microphone to his transmitter and send his voice over the relatively short distance of about a mile. That was almost a year before Marconi's announcement of a transatlantic CW message. By January of 1906, Fessenden had successfully transmitted voice signals across the Atlantic between Scotland and Massachusetts.

On Christmas Eve, 1906, Fessenden prepared a surprise. He began by transmitting "CQ CQ CQ..." in Morse to get the attention of nearby ships at sea. Then he picked up his microphone and spoke, undoubtedly astonishing all those lads floating around out there with their headphones on! Into their ears came a full range of sound instead of raspy CW notes. Fessenden became the world's first disc jockey as he queued up an Edison wax-cylinder recording of Handel and transmitted it — probably The Messiah, but that's just a guess. His wife and secretary had promised to read some passages from the Bible but when the time came, they stood paralyzed at the microphone, the first victims of "mike fright." Fessenden repeated the feat on New Year's Eve.

Fessenden also supposedly invented the heterodyne system for receivers. The heterodyne system in those days used a steady signal source slightly removed from the signal of interest to mix it downward in frequency to audio, where amplification was easy to achieve. The definition of heterodyning isn't that different today except that now, the steady signal source (oscillator) can be more than just slightly removed from the channel frequency.

Fessenden held over 500 patents during his lifetime, including those for the radiotelephone and the heterodyne principle, as well as for radar, sonar, depthfinders, microfilm photography and a myriad of other really useful inventions.

A Dynamic Duo

Before you try to decide who was the inventor of radio, take a look at one name that habitually appears in the answer and another that doesn't: Marconi and Tesla.

Guglielmo Marconi (1874-1937) was first an entrepeneur and second an engineer. He wanted to make money and achieve fame. He did both well before he was 30. Nikola Tesla (1856-1943) evidently had slightly different ambitions. So much has been written about the backgrounds of those two men that more is largely superfluous. But their battles for priority over the invention of radio is classic.

History records that Nikola Tesla was born at midnight during an electrical storm. He discovered and invented all manner of things. His first patent for a radio communications device (No. 645,576) was filed when he was 41 and granted in 1900. In the interim, he demonstrated a remotely controlled boat for the U.S. Navy, and also for the public in Madison Square Garden (1898).11 For some reason, such remote controls were considered mere toys until the 1960s.

After his death in 1943, the U.S. Supreme Court upheld Tesla's U.S. Patent No. 645,576. The litigation first arose in the Court of Claims, essentially between Marconi's and Tesla's claims to be the inventor of radio. The action centered on radio-frequency tuning of circuits. But Hertz had done more than simply anticipate Marconi and Tesla in that regard.

Practical Radio

Finally enter two more giants who made radio communications practical: Lee De Forest (1873-1961) and Edwin Armstrong (1890-1954). De Forest received his advanced education at Yale. A curious experimenter, De Forest one evening tapped into the electrical system there and disabled it; he was suspended but allowed to complete his studies. His doctoral dissertation was a discussion of radio waves.12

The man's interest in radio led him to the invention of the vacuum-valve triode, or Audion, in 1906. He placed a grid between the cathode and anode of the vacuum diodes being used as radio-wave detectors at the time and discovered that amplification of signals was possible. He's reported to have said that he didn't know why it worked, it just did. The triode is undoubtedly one of the most important inventions of its time.

Armstrong attended Columbia University. With amplifiers in hand, both Armstrong and De Forest discovered that positive feedback resulted in large gains and even oscillation. Armstrong's patent for the regenerative receiver was filed on Oct. 29, 1913. Having invented the device that made regeneration possible, De Forest later filed his own patent, claiming that he had priority. Each man had sold their "rights" to corporate interests. The ensuing interference battle saw Armstrong, RCA and Westinghouse on one side and De Forest and AT&T on the other. De Forest and AT&T lost the initial court case, won the second and reached a stalemate in the third; but they took it all the way to the U.S. Supreme Court. The Justices ruled in De Forest's favor because they believed enough doubt existed about Armstrong's priority. Today, scholars conclude that the Justices didn't fully understand the technical details of the case and so condemn the decision. For some reason, the Chief Justice didn't participate in that decision.

It seems impossible that anyone playing with positive feedback didn't experience oscillation at some point. We might never know whose circuit oscillated first but it was Armstrong who made regenerative receivers and oscillators practical. He subsequently patented the superheterodyne receiver and the superregenerative receiver. Armstrong shares credit for the superheterodyne with at least two European inventors.

Even as the regeneration suit roared for 12 years, Armstrong invented and patented frequency modulation (FM, patent issued 1933). Rights to that invention also were denied him as David Sarnoff and RCA filed their own FM patent and convinced the FCC to move the FM broadcasting band from 42-49 MHz to 88-108 MHz to make room for television signals. The latter action rendered Armstrong's burgeoning FM business worthless in a single stroke. Most historians feel that the FCC set radio technology back decades with their decision. Some believe that this tradition, begun over 50 years ago, is alive and well today at the Commission.

Armstrong ended his own life, penniless and hopelessly depressed. His second wife Marion continued the FM patent battles against RCA. She finally prevailed in 1967.

In many ways, De Forest's fortunes paralleled Armstrong's. He was married four times, buried several failed companies and was defrauded by his business partners. He spent much of his money fighting those stupid lawsuits that the Patent Office and the fickle legal system could have obviated. He was sued by the U.S. Attorney for making false claims about regeneration to solicit investors and was indicted for mail fraud, but was later acquitted on all counts.

The Modern Scene

Today we're a bit clearer than we were 100 years ago about who did what, and when, but not by a lot. Even those immersed in the subjects have trouble answering the questions, "Who invented digital signal processing? Direct digital synthesis? Software radio?" Some of what seem like recent innovations were actually proposed long ago; only the subsequent development of advanced hardware and software made them practical.

What can we say about the pace of modern technological development and discovery? Surely, each generation has witnessed both revolution and doldrums; each had spokespersons guilty of saying, as did one unfortunate patent commissioner around the turn of the last century, "Everything that can be invented, has been invented." Well, we're still accelerating technically but it's unclear whether our ability to assimilate new technologies is matching our technical advancement. In other words, more and more is being accomplished by fewer and fewer.

In the limit, it doesn't matter who invents or discovers something so long as the invention or discovery benefits humankind. To put it another way: It may be increasingly difficult for many to participate in research and development, but those who achieve breakthroughs actually make life easier for the rest of us. For example, integrated circuits make it relatively simple to build an electronic compass today. A designer doesn't have to invent magnetostrictive sensors to be able to concentrate on finding a useful application for them.


Who invented radio? I say no one invented radio: It was discovered. Yes, certain valuable techniques were invented; but how can we assign all credit to one man? Why did we ever think that lawyers, bureaucrats and so-called jurists could decide? One wonders what Armstrong, De Forest and the rest could have accomplished by working together.


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