Jump to content

Invention of radio

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 86.27.191.227 (talk) at 02:29, 15 September 2008 (american perspective just refers to US patents etc). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

This article covers the main arguments about who had what part in the early development of radio.
"Great Radio Controversy" redirects here. For the album by the band Tesla, see The Great Radio Controversy
For the general history of radio, see History of radio.

Within the timeline of radio, several people were involved in the invention of radio and there were many key inventions in what became the modern systems of wireless.[1] Radio development began as "wireless telegraphy".[1] During its early development and long after wide use of the technology, disputes persisted as to who could claim sole credit for the invention. The matter was important for both economic, as well as political and nationalistic reasons.


Early speculation and experiment

Several scientists speculated that light might be some kind of wave connected with electricity or magnetism.

Around 1830 Francesco Zantedeschi suggested a connection between light, electricity, and magnetism .[2]

In 1832 Joseph Henry performed experiments detecting electromagnetic effects over a distance of 200 feet and postulated the existence of electromagnetic waves.

In 1846 Michael Faraday speculated that light was a wave disturbance in a force field"[3] .

Scientific theory of radio waves

Based on the experimental work of Faraday and other physicists, James Clerk Maxwell developed a theory of electromagnetism that predicted the existence of electromagnetic waves. He did not transmit or receive radio waves.

Laboratory confirmation and experiment

Hughes

In 1879, during experiments with his induction balance, David E. Hughes transmitted signals which he attributed to electromagnetic waves. Hughes' contemporaries claimed that the detected effects were due to electromagnetic induction. Hughes used his apparatus to transmit Morse code using a transmitter controlled by clockwork.

Hertz

Heinrich Rudolf Hertz was the experimental physicist who confirmed Maxwell's work in the laboratory.[4] From 1886 to 1888 inclusive in his UHF experiments, he showed that the properties of radio waves were consistent with Maxwell’s electromagnetic theory. He demonstrated that radio radiation had all the properties of waves (now called electromagnetic radiation), and discovered that the electromagnetic equations could be reformulated into a partial differential equation called the wave equation. Hertz did not devise systems for actual general use or described the application of the technology.

Hertz’s setup for a source and detector of radio waves (then called Hertzian waves[5] or Hertz waves in his honor), comprised a primitive radio system capable of transmitting and receiving radio waves through free space.[6] His transmitter was not at all efficient and was severely limited in power output. Its dipole antenna differed from the vertical quarter-wavelength antenna that was subsequently adopted by Marconi and others in that it was not grounded.[7]

Hertz used the damped oscillating currents in a dipole antenna, triggered by a high-voltage electrical capacitive spark discharge, as his source of radio waves. His detector in some experiments was another dipole antenna connected to a narrow spark gap. A small spark in this gap signified detection of the radio wave. When he added cylindrical reflectors behind his dipole antennas, Hertz could detect radio waves about 20 metres from the transmitter in his laboratory. He did not try to transmit further because he wanted to prove electromagnetic theory, not to develop wireless communications.

Hertz seemed uninterested in the practical importance of his experiments. He stated that "It's of no use whatsoever ... this is just an experiment that proves Maestro Maxwell was right - we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there."[8] Asked about the ramifications of his discoveries, Hertz replied, "Nothing, I guess." Hertz also stated, "I do not think that the wireless waves I have discovered will have any practical application."[8] Hertz died in 1894, so the art of radio was left to others to implement into a practical useful form. His discoveries would later be taken up by entrepreneurs looking to make their fortunes. Marconi's 1895 experiments followed Hertz's work (among others') by using a spark source in what became known as a spark-gap transmitter.

Tesla

Around July 1891, Tesla constructed various apparatus that produced between 15,000 to 18,000 cycles per second. Transmission and radiation of radio frequency energy was a feature exhibited in the experiments by Tesla which he proposed might be used for the telecommunication of information.[9][10]

After 1892, Tesla delivered a widely reported presentation before the Institution of Electrical Engineers of London in which he suggested that messages could be transmitted without wires. Later, a variety of Tesla's radio frequency systems were demonstrated during another widely known lecture, presented to meetings of the National Electric Light Association in St. Louis, Missouri and the Franklin Institute in Philadelphia. According to the IEEE, "the apparatus that he employed contained all the elements of spark and continuous wave that were incorporated into radio transmitters before the advent of the vacuum tube".[11] However, "he almost perversely rejected the notion of transmission by Hertzian waves, which he considered to be wasteful of energy."[11][12][13]

Bose

Jagdish Chandra Bose in his lab.

In November 1894, the Bengali Indian physicist, Jagdish Chandra Bose, demonstrated publicly the use of radio waves in Calcutta, but he was not interested in patenting his work.[14] In 1894, Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves, showing independently that communication signals can be sent without using wires. In 1896, the Daily Chronicle of England reported on his UHF experiments: "The inventor (J.C. Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable application of this new theoretical marvel." The 1895 public demonstration by Bose in Calcutta was before Marconi's wireless signalling experiment on Salisbury Plain in England in May 1897.[15][16] Bose did his demonstration shortly after Tesla had performed radio communication earlier in 1892 and 1893.

Bose was not interested in the commercial applications of the experiment's transmitter. He did not try to file patent protection for sending signals. In 1899, Bose announced the development of a "iron-mercury-iron coherer with telephone detector" in a paper presented at the Royal Society, London.[17] Later he received U.S. patent 755,840, "Detector for electrical disturbances" (1904), for a specific electromagnetic receiver. Though he did not file any patents for transmission, he is recognized for contributing to the development of radio.

Early Commercial exploitation

Edison

In 1885, T. A. Edison used a vibrator magnet for induction transmission. In 1888, Edison deployed a system of signalling on the Lehigh Valley Railroad. In 1892, Edison attained the wireless patent for this method using inductance (U.S. patent 465,971).

Tesla

Nikola Tesla : Serbian physicist, inventor, mechanical engineer and electrical engineer. According to Lord Kelvin, Tesla "contributed more to electrical science than any man up to his time."[18]

Radio frequency generation

The electromechanical engineer Nikola Tesla, who has been called called the father of wireless telegraphy,[19] was one of the first to patent a means to reliably produce radio frequency waves. Tesla's U.S. patent 447,920, "Method of Operating Arc-Lamps" (March 10, 1891), describes an alternator that produced high-frequency (for that time period) current of around 10,000 hertz. His innovation was suppression of the sound produced by arc lamps that were operated on alternating or pulsating current by using frequencies beyond the range of human hearing.

Continued research and patents

Early on in his research Tesla used his high voltage resonance transformer — the Tesla coil[20] — in radio-wave propagation experiments. The aerial consisted of a top-loaded electrical conductor that was connected to a high-voltage terminal of the transformer. The opposing high-voltage terminal was grounded. The secondary winding was driven by a primary circuit consisting of a few turns of heavy wire, a capacitor bank, a circuit controller, and a power supply transformer. The launching structure radiated as a Hertz wave antenna.

In Tesla's own words:

"The popular impression is that my wireless work was begun in 1893, but as a matter of fact I spent the two preceding years in investigations, employing forms of apparatus, some of which were almost like those of today. . . ."[21]


Nikola Tesla was issued the following radio-related patents:

  • Division of U.S. patent 645,576 "System of Transmission of Electrical Energy", March 20, 1900 (March 20, 1900; filed Sept. 2, 1897). In US645576, Tesla cited the well-known radiant energy phenomena and corrected previous errors in theory of behavior. Within this specification, Tesla declared, "The apparatus which I have shown will obviously have many other valuable uses - as, for instance, when it is desired to transmit intelligible messages to great distances [...]".
  • U.S. patent 649,621, "Apparatus for Transmission of Electrical Energy" (May 15, 1900; filed February 19, 1900). In US649621, Tesla established a system which was composed of a transmitting coil (or conductor) arranged and excited to cause oscillations (or currents) to propagate via conduction through the natural medium from one point to another remote point therefrom and a receiver coil, or conductor, of the transmitted signals.

Popov

Beginning in the early 1890s, Alexander Stepanovich Popov conducted experiments along the lines of Hertz's research. In 1894 he built his first radio receiver, which contained a coherer. Further refined as a lightning detector, he presented it to the Russian Physical and Chemical Society on May 7, 1895 — the day has been celebrated in the Russian Federation as "Radio Day". The paper on his findings was published the same year (December 15 1895). Popov had recorded, at the end of 1895, that he was hoping for distant signaling with radio waves.[22]


Marconi

Early years

Guglielmo Marconi : Italian-Irish electrical engineer and Nobel laureate known for the development of a practical wireless telegraphy system.

Guglielmo Marconi, who has been called called the father of radio,[23] is said to have read about the experiments that Hertz did in the 1880s while he was on vacation in 1894 and about Nikola Tesla's work in the just-published book Inventions, Researches and Writings of Nikola Tesla. It was at this time that Marconi began to understand that radio waves could be used for wireless communications.[24]

Marconi's early apparatus was a development of Hertz’s laboratory apparatus into a system designed for communications purposes. At first Marconi used a transmitter to ring a bell in a receiver in his attic laboratory. He then moved his experiments out-of-doors on the family estate near Bologna, Italy, to communicate further. He replaced Hertz’s vertical dipole with a vertical wire topped by a metal sheet, with an opposing terminal connected to the ground. On the receiver side, Marconi replaced the spark gap with a metal powder coherer, a detector developed by Edouard Branly and other experimenters. Marconi transmitted radio signals for about a mile at the end of 1895.[25]

By 1895, Marconi introduced to the public a device in London, asserting it was his invention. Despite Marconi's statements to the contrary, though, the apparatus resembles Tesla's descriptions in the widely translated articles.[26] Marconi's later practical four-tuned system was pre-dated by N. Tesla, Oliver Lodge, and J. S. Stone.[27] Marconi’s late-1895 transmission of signals was for around a mile.[28]

Marconi's reputation is largely based on these accomplishments in radio communications and commercializing a practical system. His demonstrations of the use of radio for wireless communications, equipping ships with life saving wireless communications, establishing the first transatlantic radio service, and building the first stations for the British short wave service, have marked his place in history.

Marconi's U.S. patent 586,193 (July 13, 1897) (and the reissued U.S. patent RE11913) disclosed a two-circuit system for the transmission and reception of "Hertzian waves" (though he would later acknowledge that in the early wireless systems the "waves do not propagate in the same manner as free radiation from a classical Hertzian oscillator, but glide along the surface of the Earth"[29]). The transmitter was an antenna circuit, with an aerial plate and a ground plate, and a spark gap. Induced signals in the circuit were caused to discharge through a spark gap, producing oscillations which were radiated. The receiver contained an antenna circuit, an aerial plate and a ground plate, and a coherer. Marconi's apparatus was to be resonant (commonly called by various researcheres at the time syntonic). This was done by the careful determination of the size of the aerial plates.

Transatlantic transmissions

In 1901, Marconi claimed to have received daytime transatlantic radio frequency signals at a wavelength of 366 metres (820 kHz).[30][31][32] This Poldhu to Newfoundland transmission claim has been criticized.[33] Critics have claimed that it is more likely that Marconi received stray atmospheric noise from atmospheric electricity in this experiment.[34] The transmitting station in Poldhu, Cornwall used a spark-gap transmitter that could produce a signal just below the medium frequency and with high power levels.[35] The message received was the morse letter 'S' - three dots. Dr Jack Belrose has recently contested this, however, based on theoretical work as well as a reenactment of the experiment; he believes that Marconi heard only random atmospheric noise and mistook it for the signal. There are various science historians who agree with Jack Belrose that the Atlantic was not bridged in 1901,[36] but other science historians have taken the position that this was the first trans-atlantic radio transmission.

In 1902, Marconi transmitted from his station in Glace Bay, Nova Scotia, Canada, across the atlantic and on 18 January 1903 a Marconi station built near Wellfleet, Massachusetts in 1901 sent a message of greetings from Theodore Roosevelt, the President of the United States, to King Edward VII of the United Kingdom, marking the first transatlantic radio transmission originating in the United States.

Marconi would later found the Marconi Company and would jointly receive the 1909 Nobel Prize in Physics with Karl Ferdinand Braun.

20th century patents

Shortly after the turn of the 20th century, the US Patent Office reawarded Marconi a patent for radio. The U.S. patent RE11913 was granted on June 4, 1901. Marconi's U.S. patent 676,332 was awarded on June 11, 1901, also. This system was more advanced than his previous works.

Summary of "inventors of radio"

Name Pro Con Earliest transmission
Bose Researched coherers.[37][38]

Transmitted microwaves over distance of 75 feet in 1895.[39][40]

Had transmitted microwaves nearly a mile by 1896.[41][42][43]

Did not pursue commercialization. [44][45] 1895
Deforest[46] Developed the triode amplifier and the Audion tube. Late upon beginning research into space telegraphy. 1896[47][48]
Henry Henry detected electromagnetic effects at a distance of two hundred feet.[49][50][51] He was focused on wired telegraphy and researched self-inductance.[52][53] 1829[54]
Hertz By 1888, Hertz had studied and understood the work of Maxwell and, by design, produced the first clear and undisputed experimental evidence for the transmission and reception of radio waves.[8] Hertz took this work no further, did not exploit it commercially, and famously did not consider it useful.[8] 1888
Hughes In 1879, Hughes began research into radio waves. He noticed electrical interference in an induction balance he was working with.[55][56] The observed effect was due to radio waves and he discovered and improved the coherer.[57] Hughes was not trying to design equipment for wireless communication. His discovery was taken no further.[57] 1879[57][58]
Lodge On 14 August 1894 Lodge sent a radio message in Morse code.[59] Did not pursue further.[60] 1894
Loomis In 1872, received a patent for a "wireless telegraph". Patent utilizes atmospheric electricity to eliminate the overhead wire used by the existing telegraph systems. His patent U.S. patent 129,971 was for the purpose of receiving and imparting atmospheric electricity. None (n/a)
Marconi In summer 1895, Marconi sent signals 1.5 km.[61]

In 1896, applied for British patent protection for a radio system. In 1900, he was granted British patent No. 12,039.

Transmission over 6 km in March and May 1897.[62]

Transatlantic transmission on 12 December 1901.[63]

Tansmission over 3,378 km in February 1902.[64]

Transatlantic message on 17 December 1902.[65]

In 1897 Marconi founded "Wireless Telegraph and Signal Company"[66] and exploited the "Marconi System"[67][68][69][70] of radio commercially.

He shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun, "in recognition of their contributions to the development of wireless telegraphy".[71]

His 1901 transatlantic transmission is disputed.[33]

Many of Marconi's system components were developed by others.[72] Oliver Lodge claimed British patent of 1900 to contain his own ideas which he failed to patent.

1895
Maxwell By 1864 Maxwell had become the first person to demonstrate theoretically the existence of radio (electromagnetic) waves, which are used by all radio equipment.[73][74] Maxwell did not generate or receive radio waves.[75] None (n/a)
Popov Confirmed laboratory demonstration of radio on 17 May 1895. In March 1896 publicly demonstrated the sending of a signal 550 m between two campus buildings.[76] By 1900 he had reliable communications over 25 miles.[77] Was not the first to send signals significant distances.[78] 1895
Tesla

Tesla developed means to reliably produce radio frequency currents.[79]

In 1891 and afterwards, lectured about high-frequency devices and demonstrated devices using power without the use of wires.[80][81][82][83][84][85]

Referring to a demonstration of his wireless equipment in 1893 the IEE said "the apparatus that he employed contained all the elements of spark and continuous wave that were incorporated into radio transmitters before the advent of the vacuum tube".[86]

By 1895, stated that he had the ability to transmit signals under 50 miles.[87][88][89][90][91]

In 1897, Tesla applied for protection for the radio arts.[92] In 1900 Tesla was granted U.S. patent 645,576[93] and U.S. patent 649,621[94].

In 1898, demonstrated a radio controlled boat in Madison Square Garden that allowed secure communication[95][96] between transmitter and receiver.[97]

After 1915, assisted the Telefunken engineers in constructing the Telefunken Wireless Station (the "Arco-Slaby system"[67]) in Sayville, Long Island.

No independently confirmed radio transmissions before 1898.[dubious – discuss]

Primarily because of financial difficulties, Tesla never completed his "worldwide wireless system".[98] The Wardenclyffe Tower transceiver that he began at Shoreham on Long Island, New York was eventually torn down.

1898 [99][100]
Ward Ward was the first person to be granted a US patent relating to wireless telegraphy.[101][102] His patent U.S. patent 126,356 was for the purpose of receiving and imparting natural electricity.[103] None (n/a)

Tesla vs. Marconi

United States Patent Dispute
Marconi v. United States
Supreme Court of the United States
Argued April 9-12, 1943
Decided June 21, 1943
Full case nameMarconi Wireless Telegraph co. of America v. United States, United States v. Marconi Wireless Telegraph co. of America
Citations320 U.S. 1 (more)
Holding
The broad claims of the Marconi Patent No. 763,772, for improvements in apparatus for wireless telegraphy — briefly, for a structure and arrangement of four high-frequency circuits with means of independently adjusting each so that all four may be brought into electrical resonance with one another — held invalid because anticipated. P. 320 U. S. 38.
Court membership
Chief Justice
Harlan F. Stone
Associate Justices
Owen Roberts · Hugo Black
Stanley F. Reed · Felix Frankfurter
William O. Douglas · Frank Murphy
Robert H. Jackson · Wiley B. Rutledge
Case opinions
MajorityStone, joined by Roberts, Black, Reed, Douglas, Jackson, Rutledge
DissentRutledge
DissentFrankfurter

Radio patent decision

In 1943 a lawsuit regarding Marconi's US radio patents was resolved by the United States Supreme Court, who overturned most of these. The Marconi Company brought this suit in the Court of Claims to recover damages for infringement of four United States patents. Two, U.S. patent 763,772 and U.S. patent RE11913, were issued to Marconi, a third, U.S. patent 609,154, to Lodge, and a fourth, U.S. patent 803,684, to Fleming. The court held that the Marconi reissue patent was not infringed. In its consideration of radio communication systems, the United States courts accepted a "definition evolved out of the exhaustive depositions taken from many technical experts..."[104] as requiring "two tuned circuits each at the transmitter and receiver, all four tuned to the same frequency."[104][105][106]

The court found Marconi showed no invention over Stone (U.S. patent 714,756) by making the tuning of his antenna circuit adjustable, or by using Lodge's variable inductance for that purpose. The court decision was based on the proven prior work conducted by others, such as by Tesla, Oliver Lodge, and John Stone Stone, from which some of Marconi patents stemmed. At the time, the United States Army was involved in a patent infringement lawsuit with Marconi's company regarding radio, leading various observers to posit that the government nullified Marconi's other patents in order to moot any claims for compensation (as, it is speculated, the government's initial reversal to grant Marconi the patent right in order to nullify any claims Tesla had for compensation).

The U. S. Supreme Court stated that,

"The Tesla patent No. 645,576, applied for September 2, 1897 and allowed March 20, 1900, disclosed a four-circuit system, having two circuits each at transmitter and receiver, and recommended that all four circuits be tuned to the same frequency. [... He] recognized that his apparatus could, without change, be used for wireless communication, which is dependent upon the transmission of electrical energy."[107]

In making their decision, the court noted,

"Marconi's reputation as the man who first achieved successful radio transmission rests on his original patent, which became reissue No. 11,913, and which is not here [320 U.S. 1, 38] in question. That reputation, however well-deserved, does not entitle him to a patent for every later improvement which he claims in the radio field. Patent cases, like others, must be decided not by weighing the reputations of the litigations, but by careful study of the merits of their respective contentions and proofs."[108]

The court also stated that,

"It is well established that as between two inventors priority of invention will be awarded to the one who by satisfying proof can show that he first conceived of the invention."[109]

Priority of Patents

Priority of Marconi and Tesla US Patents

Timeline

Main article: Timeline of radio

The identity of the original inventor of radio, at the time called wireless telegraphy, is contentious. The key invention for the beginning of "wireless transmission of data using the entire frequency spectrum" has been attributed to various inventors and researchers. Below is a selection of pertinent events and individuals related to the development of radio.

Edwin Howard ArmstrongJulius Edgar LilienfeldBBCKarl Ferdinand BraunReginald FessendenLee De ForestJohn Ambrose FlemingWardenclyffe TowerReginald FessendenGuglielmo MarconiAlexander Stepanovich PopovNikola TeslaHeinrich Rudolf HertzThomas Alva EdisonDavid Edward HughesMahlon LoomisJames Clerk Maxwell


References and citation

Notes

  1. ^ a b The Invention of Radio inventors.about.com/od/rstartinventions/a/radio.htm
  2. ^ Brother Potamian (1913). "Francesco Zantedeschi article at the Catholic Encyclopedia". Wikisource. Retrieved 2007-06-16. {{cite web}}: Cite has empty unknown parameters: |month= and |coauthors= (help)
  3. ^ Baggott, Jim (2 September 1991). "The myth of Michael Faraday: Michael Faraday was not just one of Britain's greatest experimenters. A closer look at the man and his work reveals that he was also a clever theoretician". New Scientist. Retrieved 2008-09-06.
  4. ^ Massie, W. W., & Underhill, C. R. (1911). Wireless telegraphy and telephony popularly explained. New York: D. Van Nostrand.
  5. ^ Hertzian Waves (1901) Accessed 2008-08-11
  6. ^ Hertz wave
  7. ^ Peterson, Gary, "Comparing the Hertz-wave and Tesla wireless systems". Feed Line No. 9 Article
  8. ^ a b c d Eugenii Katz, "Heinrich Rudolf Hertz". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics.
  9. ^ "On Light and Other High Frequency Phenomena". Delivered before the Franklin Institute, Philadelphia, February 1893, and before the National Electric Light Association, St. Louis, March 1893.
  10. ^ "Experiments with Alternating Currents of High Potential and High Frequency". Delivered before the Institution of Electrical Engineers, London, February 1892.
  11. ^ a b "Nikola Tesla, 1856 - 1943". IEEE History Center, IEEE, 2003.
  12. ^ Martin, T. C., & Tesla, N. (1894). The inventions, researches and writings of Nikola Tesla, with special reference to his work in polyphase currents and high potential lighting. New York: The Electrical Engineer.
  13. ^ The True Wireless, Electrical Experimenter, May 1919, pages 28-30, 61-63, 87.
  14. ^ "Jagadish Chandra Bose". ieee-virtual-museum.org.
  15. ^ "The Work of Jagdish Chandra Bose: 100 years of mm-wave research". tuc.nrao.edu.
  16. ^ "Jagadish Chandra Bose", ieee-virtual-museum.org.
  17. ^ Bondyopadhyay, Probir K., "Sir J. C. Bose's Diode Detector Received Marconi's First Transatlantic Wireless Signal Of December 1901 (The "Italian Navy Coherer" Scandal Revisited)". Proc. IEEE, Vol. 86, No. 1, January 1988.
  18. ^ tesla2006
  19. ^ Johnson, R., & Brown, J. H. (1904). "Nikola Tesla", The twentieth century biographical dictionary of notable Americans. Boston: Biographical Society. (cf., He was called the father of wireless telegraphy, which theory he first described in a lecture before the National Electric Light association at St. Louis, Mo., March, 1893; his ideas being given practical demonstration by Marconi in 1902.)
  20. ^ U.S. patent 454,622, June 23, 1891 (ed., This patent is cited in Maver's Wireless Telegraphy by William Maver on Page 165.)
  21. ^ "The True Wireless"
  22. ^ D.T. Emerson, "The work of Jagadis Chandra Bose: 100 years of mm-wave research". National Radio Astronomy Observatory, February 1998.
  23. ^ Gunston, D. (1965). Guglielmo Marconi, father of radio. London: Weidenfeld & Nicolson.
  24. ^ Henry M. Bradford, "Marconi's Three; Transatlantic Radio Stations In Cape Breton". Read before the Royal Nova Scotia Historical Society, 31 January 1996. (ed. the site is reproduced with permission from the Royal Nova Scotia Historical Society Journal, Volume 1, 1998.)
  25. ^ Marconi's Three; Transatlantic Radio Stations In Cape Breton.
  26. ^ P.J.Papadopoulos, "Nikola Tesla; The Guglielmo Marconi Case, Who is the True Inventor of Radio?" Originally at http://www.mercury.gr/tesla/marcen.html
  27. ^ Tesla was the first, though, to expound the principles of the four-tuned system. The earlier two-tuned systems were not practical for commercial activity (as found in the United States court case). In addition, other prior work was conducted by others (such as by Hertz and Braun, but not excluding others) from which many of Marconi's devices and methods were derived. Marconi's U.S. patent 676,332 Apparatus for wireless telegraphy [1901], in which a more intricate system was disclosed than in his earlier patents, was filed after contributions made by other investigators.
  28. ^ This was small when put against Tesla's transmissions below 50 miles.
  29. ^ Marconi, "Wireless Telegraphic Communication: Nobel Lecture, December 11, 1909." Nobel Lectures. Physics 1901–1921. Amsterdam: Elsevier Publishing Company, 1967: 196–222.
  30. ^ Henry M. Bradford, "Marconi in Newfoundland: The 1901 Transatlantic Radio Experiment".
  31. ^ Henry M. Bradford, "Did Marconi Receive Transatlantic Radio Signals in 1901? - Part 1". Wolfville, N.S..
  32. ^ Henry M. Bradford, "Did Marconi Receive Transatlantic Radio Signals in 1901? Part 2, Conclusion: The Trans-Atlantic Experiments". Wolfville, N.S..
  33. ^ a b John S. Belrose, "Fessenden and Marconi; Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century" International Conference on 100 Years of Radio, 5-7 September, 1995. Accessed 2008-08-09
  34. ^ "Marconi's Error: The First Transatlantic Wireless Telegraphy in 1901"
  35. ^ A maximum time-averaged power of 35 kilowatts, but with a peak pulse power of megawatts.
  36. ^ In addition to being bolstered by Tesla supporters.
  37. ^ Fleming, J. A. (1908). The principles of electric wave telegraphy. London: New York and. (cf., [...] researches of Professor J. C. Bose are of particular interest. He states that the sensitiveness of any form of contact cymoscope consisting of conducting particles depends upon the proper adjustment of the pressure between the particles and the value of the external electromotive force which is in waiting, so to speak, to send or increase the current through the contacts.) See J. C. Bose, Proc. Soy. Soc. Land., 1899, vol. G5, p. 166 ; or Science Abstracts, vol. ii. No. 1716.
  38. ^ Institution of Electrical Engineers, Physical Society (Great Britain), American Physical Society, American Institute of Electrical Engineers, Electrochemical Society, & Associazione elettrotecnica italiana. (1898). Science abstracts. [London]: Institution of Electrical Engineers. Page 963
  39. ^ Prof Rajesh Kochhar, J.C. BOSE: The Inventor Who Wouldn’t Patent. Science Reporter, Feb 2000
  40. ^ The life and work of Sir Jagadis C. Bose on page 62
  41. ^ In 1896, the Daily Chronicle of England reported on his UHF experiments: "The inventor (J.C. Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable application of this new theoretical marvel."
  42. ^ Jagadis Chandra Bose and His Pioneering Research on Microwave
  43. ^ jcbose, calcuttaweb.com
  44. ^ "Jagadish Chandra Bose", ieee-virtual-museum.org
  45. ^ Geddes, P. (1920). The life and work of Sir Jagadis C. Bose. London: Longmans, Green.
  46. ^ De Forest, L. (1950). Father of radio: the autobiography of Lee de Forest. Chicago: Wilcox & Follett.
  47. ^ Lee de Forest. pbs.org
  48. ^ Fritz E. Froehlich, Allen Kent, (1992). The Froehlich/Kent Encyclopedia of Telecommunications: Volume 4 - Communications Human Factors to Cryptology. CRC Press. Page 285. ISBN 082472903X
  49. ^ Fleming, J. A. (1908). The principles of electric wave telegraphy. London: New York and Co. (cf., Joseph Henry, in the United States, between 1842 and 1850, explored many of the puzzling facts connected with this subject, and only obtained a clue to the anomalies when he realized that the discharge of a condenser through a low resistance circuit is oscillatory in nature. Amongst other things, Henry noticed the power of condenser discharges to induce secondary currents which could magnetize steel needles even when a great distance separated the primary and secondary circuits.)
  50. ^ See "The Scientific Writings" of Joseph Henry, vol. i. pp. 203, 20:-i ; also Proceedings of tltc American Assoc. fur Advancement of Science, 1850, vol. iv. pp. 877, 378, Joseph Henry, "On the Phenomena of the Leyden Jar." The effect of the oscillatory discharge on a magnetized needle is clearly described in this paper.
  51. ^ Ames, J. S., Henry, J., & Faraday, M. (1900). The discovery of induced electric currents. New York: American book. (cf. On moving to Princeton, in 1832, [...] investigated also the discharge of a Leyden jar, proved that it was oscillatory in character, and showed that its inductive effects could be detected at a distance of two hundred feet, thus clearly establishing the existence of electro-magnetic waves.)
  52. ^ Eugenii Katz, "Joseph Henry". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics.
  53. ^ Timeline of the First Thirty Years of Radio
  54. ^ Ames, J. S., Henry, J., & Faraday, M. (1900). The discovery of induced electric currents. New York: American book (cf., [...] experiment was performed in August 1829.)
  55. ^ Researches of Prof. D. E. Hughes (1899)
  56. ^ http://tenwatts.blogspot.com/2006/03/bio-david-e-hughes.html
  57. ^ a b c Darrel T. Emerson, The Stage Is Set: Developments before 1900 Leading to Practical Wireless Communication
  58. ^ Eugenii Katz, "David Edward Hughes". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics.
  59. ^ Peter Rowlands (ed.) and J. Patrick Wilson (ed.) "Oliver Lodge and the Invention of Radio" ISBN 1-873694-02-4
  60. ^ OTB - Oliver Lodge: Almost the Father of Radio. antiquewireless.org.
  61. ^ Guglielmo Marconi -- Britannica Online Encyclopedia
  62. ^ BBC Wales, "Marconi's Waves"
  63. ^ Marconi's Achievement (1902)
  64. ^ http://www.ieee.ca/millennium/radio/radio_differences.html
  65. ^ Marconi's Wellfleet (Cape Cod) Wireless. Stormfax.
  66. ^ "Wireless Telegraph and Signal Company" was formed on 20 July 1897 after granting of a British patent
  67. ^ a b Collins, A. F. (1913). Manual of wireless telegraphy and telephony. New York: J. Wiley. Page 177 - 209
  68. ^ http://home.luna.nl/~arjan-muil/radio/marconi/marconi-system.html
  69. ^ Beauchamp, K. G. (2001). History of telegraphy. London: Institution of Electrical Engineers. Page 206
  70. ^ American Institute of Electrical Engineers. (1884). Transactions of the American Institute of Electrical Engineers. New York: American Institute of Electrical Engineers. Page 120
  71. ^ "Guglielmo Marconi: The Nobel Prize in Physics 1909"
  72. ^ "Marconi Wireless Tel. Co. v. United States, 320 U.S. 1 (U.S. 1943)", 320 U.S. 1, 63 S. Ct. 1393, 87 L. Ed. 1731 Argued April 9,12, 1943. Decided June 21, 1943. http://caselaw.lp.findlaw.com/scripts/printer_friendly.pl?page=us/320/1.html (cf., But it is now held that in the important advance upon his basic patent Marconi did nothing that had not already been seen and disclosed.)
  73. ^ "Electromagnetism, Maxwell’s Equations, and Microwaves". IEEE Virtual Museum (2008). Retrieved on 2008-06-02.
  74. ^ James Clerk Maxwell, A Dynamical Theory of the Electromagnetic Field, Philosophical Transactions of the Royal Society of London 155, 459-512 (1865).
  75. ^ Estabrooks, M. (1995). Electronic technology, corporate strategy, and world transformation. Westport, Conn: Quorum Books. Page 27. (cf., [...] Maxwell did not prove that these waves actually existed [...])
  76. ^ "Early Radio Transmission Recognized as Milestone". IEEE. Retrieved on July 16, 2006.
  77. ^ Eugenii Katz, "Alexander Stepanovich Popov ". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics.
  78. ^ By 1895, Tesla stated that he had the ability to transmit signals under 50 miles
  79. ^ U.S. patent 447,920
  80. ^ Tesla's presentation at the Franklin Institute was reported across America (such as in The Century Magazine) and throughout Europe.
  81. ^ "Nikola Tesla, 1856 - 1943". IEEE History Center, IEEE, 2003. (cf., In 1891 he lectured on his high-frequency devices to the American Institute of Electrical Engineers, and this lecture, coupled with a spectacular demonstration of these apparatuses, made him famous. He [later in 1892] repeated his performance in Europe, to great acclaim, and enjoyed international celebrity.)
  82. ^ "On Light and Other High Frequency Phenomena". Delivered before the Franklin Institute, Philadelphia, February 1893, and before the National Electric Light Association, St. Louis, March 1893.
  83. ^ "Experiments with Alternating Currents of High Potential and High Frequency". Delivered before the Institution of Electrical Engineers, London, February 1892.
  84. ^ Tesla; Man Out of Time By Margaret Cheney. Page 144.
  85. ^ Ljubo Vujovi, "Tesla Biography; Nikola Tesla, The genius who lit the world". Teslasociety.com.
  86. ^ "Nikola Tesla, 1856 - 1943". IEEE History Center, IEEE, 2003. (cf., In a lecture-demonstration given in St. Louis in [1893] - two years before Marconi's first experiments - Tesla also predicted wireless communication; the apparatus that he employed contained all the elements of spark and continuous wave that were incorporated into radio transmitters before the advent of the vacuum tube.)
  87. ^ Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power : An Extended Interview. Chapter IV ISBN 1-893817-01-6 (cf., [Counsel] What form of device did you use, and where did you use it, for noting the generation of these oscillations or waves in the antenna?
    [Tesla] [...] With such an instrument, I operated, for instance, in West Point — I received signals from my laboratory on Houston Street in West Point.
    [Counsel] This was then the machine that you used when working with West Point?
    [Tesla] I operated once or twice with it at that distance, but usually as I was investigating in the city. [...]")
  88. ^ Tesla, N., & Childress, D. H. (2000). The Tesla papers. Kempton, Ill: Adventures Unlimited. Page 136.
  89. ^ Who Invented Radio? (cf., By early 1895, Tesla was ready to transmit a signal 50 miles to West Point, New York ... But in that same year, disaster struck. A building fire consumed Tesla's lab, destroying his work.)
  90. ^ Leland I. Anderson (ed.), "John Stone Stone, Nikola Tesla's Priority in Radio and Continuous-Wave Radiofrequency Apparatus". The Antique Wireless Review, Vol. 1. 1986. 24 pages, illustrated. (ed., available at Twenty First Century Books)
  91. ^ Marshall Cavendish Corporation. (2008). Inventors and inventions. New York: Marshall Cavendish. Page 1395
  92. ^ U.S. Supreme Court, "Marconi Wireless Telegraph co. of America v. United States". 320 U.S. 1. Nos. 369, 373. Argued April 9-12, 1943. Decided June 21, 1943. (cf. The Tesla patent No. 645,576, applied for September 2, 1897, [...] disclosed a four-circuit system, having two circuits each at transmitter and receiver, and recommended that all four circuits be tuned to the same frequency. [... the apparatus could be] used for wireless communication, which is dependent upon the transmission of electrical energy.)
  93. ^ "System of Transmission of Electrical Energy", (March 20, 1900; filed Sept. 2, 1897)
  94. ^ "Apparatus for Transmission of Electrical Energy" (May 15, 1900; filed February 19, 1900)
  95. ^ Tesla, N., & Anderson, L. I. (1998). Nikola Tesla: guided weapons & computer technology. Tesla presents series, pt. 3. Breckenridge, Colo: Twenty First Century Books.
  96. ^ Tesla, N., & Anderson, L. I. (2002). Nikola Tesla on his work with alternating currents and their application to wireless telegraphy, telephony, and transmission of power: an extended interview. Tesla presents series, pt. 1. Breckenridge, Colo: Twenty-First Century Books.
  97. ^ The schematics are illustrated in U.S. patent 613,809 and describes "rotating coherers".
  98. ^ Wardenclyffe - A Forfeited Dream
  99. ^ Tesla, Nikola (1891). "Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination".
  100. ^ The True Wireless. Electrical Experimenter, May 1919, pages 28-30, 61-63, 87. (cf., The popular impression is that my wireless work was begun in 1893, but as a matter of fact I spent the two preceding years in investigations, employing forms of apparatus, some of which were almost like those of today.)
  101. ^ earlyradiohistory Fakes, Frauds, and Cranks (1866-1922)
  102. ^ The patent called for construction so as to collect, hold, distribute, and utilize aerial currents of natural electricity for telegraphic and other purposes.
  103. ^ Specification forming part of Letters Patent No. 126,356, dated April 30, 1872.
  104. ^ a b Margaret Cheney (2001). Tesla: Man Out of Time. Simon and Schuster. ISBN 0743215362.
  105. ^ 320 U.S. 1. Marconi Wireless Telegraph co. of America v. United States
  106. ^ Cheney, M., Uth, R., & Glenn, J. (1999). Tesla, Master of Lightning. New York: Barnes & Noble Books. Page 71.
  107. ^ U.S. Supreme Court, "Marconi Wireless Telegraph co. of America v. United States". 320 U.S. 1. Nos. 369, 373. Argued April 9-12, 1943. Decided June 21, 1943.
  108. ^ Wireless Telegraph co. of America v. United States.
  109. ^ Wireless Telegraph co. of America v. United States.

General Information

Offline
  • Anderson, L.I., "Priority in the Invention of Radio: Tesla vs. Marconi", Antique Wireless Association Monograph No. 4, March, 1980.
  • Anderson, L.I., "John Stone Stone on Nikola Tesla's Priority in Radio and Continuous-Wave Radiofrequency Apparatus", The A.W.A. (Antique Wireless Association) Review, Vol. 1, 1986, pp. 18-41.
Weblinks
The album, The Great Radio Controversy, is titled after the controversy about the identity of the inventor of radio. It is posed that Serbian engineer Nikola Tesla (whom the band is named after) is the true inventor of radio, while the Italian Guglielmo Marconi took the credit and is widely regarded as having the title. The album's inner sleeve recounts this story.

See also

People
Edwin Howard Armstrong, John Stone Stone, Ernst Alexanderson, Reginald Fessenden, Oliver Lodge
Radio
Radio communication system, Timeline of radio, Oldest radio station, Birth of public radio broadcasting, Crystal radio
Categories
Radio People, Radio Pioneers, Discovery and invention controversies
Other
List of persons considered father or mother of a field, Radiotelegraph and Spark-Gap Transmitters, The Great Radio Controversy, Induction coil, Ruhmkorff coil, Poldhu, Alexanderson alternator, De Forest tube
Retrieved from "https://en.wikipedia.org/w/index.php?title=Invention_of_radio&oldid=238495119"