User:Anthony Appleyard/Radio priority controversy
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There has been controversy about who invented radio.
There was a long dispute, including a court action, between Guglielmo Marconi and Nikola Tesla as to who "invented radio" and therefore had the rights to the founding patents of radio transmission of messages. Their work and discoveries are described at length in Tesla's role in the history of radio and Marconi's role in the history of radio.
The other main claimant is Alexander Stepanovich Popov: see History of radio#Alexander Popov.
The general history of the discovery of radio, including about other people who are claimed as inventors of radio, is in History of radio.
[edit] Tesla's early work
Tesla's work started in or before March 1891. In March 1981 he patented a "Method of Operating Arc-Lamps", which from available description seems to have reliably emitted radio waves, but seems not to have been intended to do that.
Around July 1891 Tesla established his laboratory in New York. See Tesla's role in the history of radio#Tesla's work in New York for more information.
[edit] Maroni's early work and patent
Marconi started his work in or before January 1896. (Some say that in 1894 he read about Hertz's work.) Marconi developed and commercialized his work into a practical communications system, which Tesla did not. He got his patent U.S. Patent 586193 in 13 July 1897. See Marconi's role in the history of radio#Marconi's patent.
[edit] Case against Marconi: priority
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. [1] Marconi's later practical four tuned system was pre-dated by N. Tesla, Oliver Lodge, and J. S. Stone. 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 Bruan, but not excluding others) from which many of Marconi's devices and methods were derived. Marconi's U.S. Patent 676332 Apparatus for wireless telegraphy [1901], in which a more developed system was disclosed than in his earlier patents, was well after contributions made by other investigators.
Marconi’s late-1895 transmission of signals was for around a mile. This was small when put against Tesla's early-1895 transmissions of up to 50 miles.
[edit] Tesla's first two radio patents
Nikola Tesla initially held the rights to radio. Later these patents were withdrawn. See Tesla's role in the history of radio#Tesla's first two radio patents.
[edit] The Poldhu experiment
In 1901, Marconi in Newfoundland claimed to have received daytime transatlantic radio short wave (HF) frequency signals at a wavelength of 366 metres (820 kHz) transmitted at Poldhu in Cornwall in England, but some say that he merely detected natural static that resembled the signal. For more information, see Marconi's role in the history of radio#The Poldhu experiment.
[edit] Tesla's patents withdrawn
Shortly after the turn of the 20th century, the US Patent Office reversed its decision on the priority of radio and awarded Marconi the patent for radio. Tesla fought to re-acquire his radio patent, but failed.
[edit] Court decision
In 1943 a lawsuit regarding Marconi's numerous other radio patents was resolved by the U.S. Supreme Court, who overturned most of these. 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 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 (such as U.S. Patent 763772 ) stemmed. 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." [2]
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." [3]
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." [4]
[edit] Case for Marconi
Marconi supporters have stated that Marconi was not aware of the works of Nikola Tesla in the United States. See Tesla's role in the history of radio#Whether Marconi knew of Tesla's work.
[edit] Case for Tesla
Tesla's system can produce a variety of wave propagations, pending the driving apparatus. See Tesla's role in the history of radio#Tesla's type of transmission.
[edit] Case against Tesla
Tesla never completed his "worldwide wireless system", primarily because of financial difficulties. See Tesla's role in the history of radio#Tesla's work unfinished.
[edit] Music group album
The band named "Tesla" has an album, The Great Radio Controversy, which is titled after this controversy of the identity of the inventor of radio. The album inner sleeve recounts the story where the Serbian-American engineer Tesla (who the band is named after) is the true inventor of radio, while the Italian Marconi took the credit and is widely regarded with the title.
[edit] Footnotes and citations
- ^ P.J.Papadopoulos, "Nikola Tesla; The Guglielmo Marconi Case, Who is the True Inventor of Radio?"
- ^ 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.
- ^ Wireless Telegraph co. of America v. United States.
- ^ Wireless Telegraph co. of America v. United States.
