I just watched the following 1998 documentary video, also available on Amazon Prime as Phenomenon: The Lost Archives - Lost Lightning, The Missing Secrets of Nicola Tesla, (Season 1, Episode 9).
But to be sure, there is another side of the story besides what is told in this documentary. There's no doubt that Tesla was a key figure in the development of electrical technology, with many great innovations to his credit. The list includes, at least: AC motors and generators, high tension transformers ("Tesla coils"), high voltage capacitors, stroboscopy, spread spectrum radio, and the electronic "AND" gate. This is all illustrated with Tesla patents in the online brochure "
Pursuing Tesla's Vision" by Gary Peterson.
As to the claim that Tesla (not Marconi) invented radio, the situation is more complicated. It's generally agreed that James Clerk Maxwell proposed the theory of electromagnetic radio wave propagation, and predicted the existence of radio waves, in about 1864 based on experimental work by Michael Faraday. Maxwell's predictions were verified in a series of experiments by Heinrich Hertz between 1886 and 1889. In an article published in 1919, "
The True Wireless", Tesla explains that "
...the publication of Dr. Heinrich Hertz's results caused a
a thrill as had scarcely ever experienced before. At that time I was in the midst of pressing work in connection with the commercial introduction of my system of power transmission, but, nevertheless, caught the fire of enthusiasm and fairly burned with desire to behold the miracle with my own eyes." By 1891, Tesla explains, he had not only duplicated Hertz's results, but also built a much superior apparatus for himself. This, I understand, was Tesla's wireless device with four tuned circuits, two in the transmitter and two in the receiver. With the extra tuned circuits, Tesla's device was far more efficient than Hertz's equipment at converting electrical power into radio waves, as well as more sensitive in reception.
Although Tesla was well aware of the possibilities for telegraphy, his primary interest was in developing wireless power transmission. Thus, it was left to others to develop radio communications. Guglielmo Marconi started experimenting with radio equipment in 1894, adopting equipment invented by Hertz, Oliver Lodge, Edouard Branly, and eventually incorporating Tesla's four tuned circuit design as well. As his designs progressed, Marconi was able to transmit at distances beginning at 1/2 mile in 1895, increasing to 2 miles in 1896, 10 miles in 1897, and 2100 miles in 1902. Because of these accomplishments, Marconi became recognized as the inventor of radio technology. But as the US Supreme Court determined in a 1943 patent case decision, nothing that Marconi did wasn't anticipated in patents and scientific work by others.
Meanwhile, working on his power transmission technology, Tesla gradually became convinced that "Hertz waves" had little if anything to do with the effects he was observing in his laboratory. In his 1919 article, linked above, Tesla says:
In 1900... I made a last desperate attempt to prove that the disturbances emanating from the oscillator were ether vibrations akin to those of light, but met again with utter failure. For more than eighteen years I have been reading treatises, reports of scientific transactions, and articles on Hertz-wave telegraphy, to keep myself informed, but they have always imprest me like works of fiction.
The history of science shows that theories are perishable. With every new truth that is revealed, we get a better understanding of Nature and our conceptions and views are modified.... The Hertz-wave theory, by its fascinating hold on the imagination, has stifled creative effort in the wireless art and retarded it for twenty-five years.
As far as I can make it out, Tesla's competing view was that Hertz waves, if they existed at all, would not propagate for any significant distance. His goal was to create a power transmission system that would essentially use the earth as one conductor in a worldwide circuit, and conduction in the atmosphere and ionosphere as the other leg to complete the circuit. I believe he sought to generate tremendous high voltages in hopes of creating an ionized conduction path in the air.
This approach led to one spectacular failure after another, until Tesla's backers abandoned him in despair. His grand experimental tower at Wardenclyffe was foreclosed in 1915, and demolished in 1917 for scrap. The 1919 article gives little hint of the difficulties Tesla encountered, Tesla was clearly optimistic that his views would be vindicated shortly.
Of course, what actually happened is that evidence continued to accumulate in favor of the Maxwell theory. The surprising result that radio waves could propagate around obstacles and beyond line-of-sight was explained by the theory of the "Heaviside layer". As Tesla continued to hold fast to his analysis which was grounded in 19th-century pre-Maxwellian physics, he was increasingly seen as an old-fashioned crank and publicity seeker.
Tesla's 1891 invention of the four tuned circuit wireless device, can certainly be seen as a key innovation which later enabled Marconi in his success. The 1943 Supreme Court analysis acknowledged this, but also noted that Tesla himself did not fully anticipate the ultimate uses of the invention, and did not claim the utility for radio in his patent. Therefore, in the court's syllabus of their decision, they named Oliver Lodge and John Stone Stone as the holders of prior art patents, not Tesla.
For more analysis see:
http://www.teslaradio.com/pages/teslafaq/priority.htm
John Stone Stone himself graciously gave much of the credit to Tesla, as he explains here:
http://www.tfcbooks.com/mall/more/436ntpr.htm
I refer to an article by Tesla in The Century Magazine in its issue of June 1900, pages 175-211, and particularly to that section entitled "Wireless Telegraphy: The Secret of Tuning Errors in Hertzian Investigations; A Receiver of Wonderful Sensitiveness." Here as elsewhere, Tesla takes a fling at those who attribute the transfer of the energy of these high frequency currents to a distance as a process of radiation. In this he was more than half right, and whatever error be made in this connection was a failure to recognize that electromagnetic waves guided by the earth's surface, and therefore accompanied by currents in that surface, are in a sense still radiation, and that the two explanations of the phenomena are supplemental of one another and a comprehensive explanation of the phenomenon includes both the conception of the gliding electromagnetic waves and the currents in the earth's surface. I misunderstood Tesla. I think we all misunderstood Tesla. We thought he was a dreamer and visionary. He did dream and his dreams came true, he did have visions but they were of a real future, not an imaginary one. Tesla was the first man to lift his eyes high enough to see that the rarified stratum of atmosphere above our earth was destined to play an important role in the radio telegraphy of the future, a fact which had to obtrude itself on the attention of most of us before we saw it. But Tesla also perceived what many of us did not in those days, namely, the currents which flowed way from the base of the antenna over the surface of the earth and in the earth itself.
Appreciation
Tesla, with his almost preternatural insight into alternating current phenomenon that had enabled him some years before to revolutionize the art of electric power transmission through the invention of the rotary field motor, knew how to make resonance serve, not merely the role of a microscope to make visible the electric oscillations, as Hertz had done, but he made it serve the role of a stereopticon to render spectacular to large audiences the phenomena of electric oscillations and high frequency currents. It is worthy of note that in all these experiments he used frequencies from 10,000 to a few hundred thousand. He did more to excite interest and create an intelligent understanding of these phenomena in the years 1891-1893 than anyone else, and the more we learn about high frequency phenomena, resonance, and radiation today, the nearer we find ourselves approaching what we at one time were inclined, through a species of intellectual myopia, to regard as the fascinating but fantastical speculations of a man whom we are now compelled, in the light of modern experience and knowledge, to admit was a prophet. But Tesla was no mere lecturer and prophet. He saw to the fulfillment of his prophesies and it has been difficult to make any but unimportant improvements in the art of radio-telegraphy without traveling part of the way at least, along a trail blazed by this pioneer who, though eminently ingenious, practical, and successful in the apparatus he devised and constructed, was so far ahead of his time that the best of us then mistook him for a dreamer.