Invention of radio
In the
history of radio and development of "
wireless telegraphy", there are multiple claims to the
invention of radio. The most commonly accepted claims to the
invention of
radio are those of
Alexander Stepanovich Popov,
Nikola Tesla and
Guglielmo Marconi. Marconi equipped ships with life saving wireless communications and established the first transatlantic radio service. Tesla developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and transmitted long distant signals.
In the late 1800s, it was clear to various scientists and experimenters that wireless communication was possible. Various theoretical and experimental innovations lead to the development of radio and the communication system we know today. Some early work was done by
local effects and
experiments of
electromagnetic induction. Many understood that there was nothing similar to the "
ethereal telegraphy"
["Wireless telegraphy". Scientific American, June 19, 1897, page 386. Uses the term to connote "aether's conduction".]["The Slaby system of wireless duplex telegraphy". Scientific American, March 9, 1901, pages 146-147. Uses the term to connote "aether's conduction".] and
telegraphy by induction; the phenomena being wholly distinct. Wireless telegraphy was beginning to take hold and the practice of transmitting messages without wires was being developed. Many people worked on developing the devices and improvements.
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Timeline of the early radio |
Alexander Popov
Alexander Stepanovich Popov was the first to demonstrate the practical application of electromagnetic waves
(but did not apply for a patent for this invention). He would describe his findings concerning the wireless arts in a paper published in 1895. The article was based on a public demonstration of reception of electromagnetic waves accomplished by Popov on May, 7th 1895. Popov died in 1905 and his claim was not pressed by the Russian government until 40 years later.Popov's early experiments were transmissions of only 600 yards.
["Russia's Popov: Did he "invent" radio?". The First Electronic Church of America.] Popov's public demonstration of the transmission of radio waves, between different campus buildings, to the
Saint Petersburg Physical Society (around March, 1896) was before the public demonstration of the Marconi system (around September, 1896). In 1900, Popov stated (in front of the
Congress of Russian Electrical Engineers), : "[...]
the emission and reception of signals by Marconi by means of electric oscillations [was]
nothing new. In America, the famous engineer Nikola Tesla carried the same experiments in 1893."
["The Guglielmo Marconi Case Who is the True Inventor of Radio".]Popov would also experiment with ship-to-shore communication.
["The Electronic Era; When? Where? Who? How? Why?". First Electronic Church Of America.] These 1898 experiments were at a distance of 6 miles. The experiments in 1899 were transmitted to a distance of 30 miles.
Marconi
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Guglielmo Marconi : Italian-Irish electrical engineer and Nobel laureate known for the development of a practical wireless telegraphy system. |
After the 1880s Hertz experiments,
Guglielmo Marconi's proponents state that he read about the work while on vacation in 1894 (which was the same year
Hertz died). Marconi wondered if radio waves could be used for wireless communications.
[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.)] Marconi's early apparatus was a development of Hertz's laboratory apparatus into a system designed for communications purposes. At first he 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 over larger distances. He replaced Hertz's vertical dipoles by a vertical wire topped by a metal sheet, together with an opposing terminal that had a ground connection. The Marconi antenna was a vertical quarterwave monopole conductor, with no loading coil nor capacitive top load, and base driven by a regular power supply with a suitable matching section. Marconi replaced the spark gap in his receiver by the metal powder
coherer, a detector developed by
Edouard Branly and other experimenters. Marconi transmitted radio signals a distance of about a mile at the end of 1895.
[Marconi's Three; Transatlantic Radio Stations In Cape Breton.]Marconi's reputation is based, in large measure, on this accomplishments in radio communications and the 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 and his company were not alone in the field; his principal competition came from German scientists whose work would become the basis for the
Telefunken company (which Nikola Tesla assisted in building).
Marconi's (July 13, 1897) (and the reissued ) 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"
[Marconi, "Wireless Telegraphic Communication: Nobel Lecture, December 11, 1909." Nobel Lectures. Physics 1901-1921. Amsterdam: Elsevier Publishing Company, 1967: 196-222.]). 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.
In 1901, Marconi claimed to have received daytime transatlantic radio short wave (HF) frequency signals at a
wavelength of 366 metres (820 kHz).
[Henry M. Bradford, "Marconi in Newfoundland: The 1901 Transatlantic Radio Experiment".] [Henry M. Bradford, "Did Marconi Receive Transatlantic Radio Signals in 1901? - Part 1". Wolfville, N.S..] [Henry M. Bradford, "Did Marconi Receive Transatlantic Radio Signals in 1901? Part 2, Conclusion: The Trans-Atlantic Experiments". Wolfville, N.S..] The early spark transmitters
may have been broadly tuned and the Poldhu transmitter
may have radiated sufficient energy in that part of the spectrum for a transatlantic transmission,
if Marconi was using an untuned receiver when he claimed to have received the transatlantic signal at Newfoundland in 1901. When he used a tuned receiver aboard the SS Philadelphia in 1902, he could only receive a daytime signal from Poldhu, a distance of 700 miles,
less than half the distance from Poldhu to Newfoundland. At night the signals were reported to have been received several times further, and his successful transatlantic transmissions from Glace Bay, Nova Scotia in 1902 were made at night. Marconi would later found the
Marconi Company and would jointly receive the 1909
Nobel Prize in Physics with
Karl Ferdinand Braun.
Case against Marconi
By 1895, Marconi introduces 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.
[ P.J.Papadopoulos, "Nikola Tesla; The Guglielmo Marconi Case, Who is the True Inventor of Radio?"] Marconi's later practical four tuned system was predated by N. Tesla, O. 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
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, a distance of around a mile. In comparison, this was small when put against Tesla's early-1895 transmissions of up to 50 miles. Also of note is that Marconi's 1901 Poldhu - Newfoundland transmission claim has been doubted.
[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, (PDF file; ed. accessed April 14, 2006)] Critics have stated that it is more likely that Marconi received
stray atmospheric noise from
atmospheric electricity in the 1901 experiment.
[ "Marconi's Error: The First Transatlantic Wireless Telegraphy in 1901"] The transmitting station in Poldhu, Cornwall used a spark-gap transmitter that, at best, could produce a signal just below the medium frequncy and with high power levels (a maximum time-averaged power of 35 kilowatts, but with a peak pulse power of megawatts). The message reportedly received was three dots. Dr Jack Belrose has recently contested this, however, based on theoretical work as well as an actual reenactment of the experiment; he believes that Marconi heard only random atmospheric noise and mistook it for the signal. There are engineers which agree with Jack Belrose that the 1901 bridging of the Atlantic never took place.
Tesla
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Nikola Tesla : Serbian-American inventor, physicist, mechanical engineer and electrical engineer which is regarded as one of the most important inventors in history. |
Nikola Tesla initially held the rights to radio. He had ,
"Apparatus for Transmission of Electrical Energy" (May 15, 1900; filed Feb. 19, 1900), division of
"System of Transmission of Electrical Energy", March 20, 1900 (March 20, 1900; filed Sept. 2, 1897). 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. 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 [...]".
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US645576 Transmitter
Vertical high aspect-ratio quarterwave helical resonator, possessing a large capacitive top load, which was driven at the base by a regular power supply and suitable matching section. This image is from one of Tesla's patent. |
Tesla's
aerial parameters consisted of a small (as to distribution of height) vertical high aspect-ratio quarterwave helical resonator, possessing a large capacitive top load, which was driven at the base by a regular power supply and suitable matching section. The aerial's opposing terminal was grounded. Tesla's vertical structure could radiate as a common "hertzian" antenna, if driven in a certain fashion, but would resonate, though, if the driving circuitry was arranged properly. Some of the roughly hemispherical shaped conductors that Tesla used had a capacitance comparable to that of a large radio antenna. The applied voltage caused an oscillating current to flow between the earth and the elevated conductor, as it does in a conventional low frequency radio transmitter with a vertical radio antenna and ground.
Tesla's structure could also inject a large alternating current into the earth via the ground terminal. Tesla's,
not Marconi's, discovery of great importance was of the "
groundwave" method. The method to produce surface waves was the consequence of adding a ground connection to the transmitter. Tesla stated, in 1893, that,
"One of the terminals of the source would be connected to Earth [as a
electric ground connection ...]
the other to an insulated body of large surface.
["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.]This method led to longer transmission ranges. Many AM stations use this same principle to boost reception of their signals.
["Why AM Radio Stations Must Reduce Power, Change Operations, or Cease Operations at Night". fcc.gov.]It has also been noted that Tesla was one of the first to patent a means to reliably produce radio frequencies. Tesla's ,
"Method of Operating Arc-Lamps" (March 10, 1891), describes an
alternator that produces high-frequency current for that time period, around 10,000 cycles per second (later to be known as
hertz). Though his
patentable innovation was to suppress the disagreeable sound of power-frequency harmonics produced by arc lamps operating on frequencies within the range of human hearing, the frequency produced by the device was in the
longwave broadcasting range (
VLF band). Around July of 1891, after becoming a naturalized citizen of the United States, he established his
New York laboratory and constructed various apparatus that produced between 15,000 to 18,000 cycles per second. At this location, he also lit vacuum tubes wirelessly (thus providing hard evidence for the potential of wireless transmissions).
In the beginning of 1895, Tesla was able to detect signals from the transmissions of his New York lab at
West Point (a distance of 50 miles).
[PBS: Marconi and Tesla: Who invented radio? (ed. this is noted as having been accomplished in Leland's book concerning Tesla's "Work with Alternating Currents" [see general information section])] By early 1896, he attained devices that produced
undamped (or continous) waves around 50,000 cycles per second[Covered in Leland's book concerning Tesla's "Work with Alternating Currents".] and, between 1895 and 1898, Tesla continued his research into wireless transmission principles. After travelling to Colorado Springs (around 1899), Telsa lit a bank of incandescent bulbs wirelessly at very long distances during his experiments with the
magnifying transmitter.
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. A lawsuit regarding Marconi's numerous other radio patents was resolved by the U.S. Supreme Court, who overturned most of these (1943). 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 ) 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."
[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.] 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."
[Wireless Telegraph co. of America v. United States.] 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."
[Wireless Telegraph co. of America v. United States.] Transmission and radiation of radio frequency energy was a feature exhibited in the experiments by Tesla and was noted early on to be used for the
telecommunication of
information.
["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.]["Experiments with Alternating Currents of High Potential and High Frequency". Delivered before the Institution of Electrical Engineers, London, February 1892.] In 1892, Tesla delivered a widely reported presentation before the Institution of Electrical Engineers of London in which he noted, among other things, that intelligence would 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".
["Nikola Tesla, 1856 - 1943". IEEE History Center, IEEE, 2003.]Marconi supporters have stated that Marconi was not aware of the works of Nikola Tesla in the United States. It is unlikely, though, that Marconi was unaware of Tesla's presentations. Both
"On Light and Other High Frequency Phenomena" (Philadelphia/St. Louis; Franklin Institute in 1893) and
"Experiments with Alternating Currents of High Potential and High Frequency" (London; 1892) were reported on internationally. Tesla's 1893 presentation at the Franklin Institute was reported across America (such as in the
Century Magazine) and throughout Europe.
[Ljubo Vujovi, "Tesla Biography; Nikola Tesla, The genius who lit the world". Teslasociety.com.] Tesla also did perform public demonstrations of actual and related work, such as the remote-controlled boat in
1898 (of which was protected under ). The remote-controlled boat contained "rotating coherers" that allowed secure communication between transmitter and receiver.
Tesla's system can produce a variety of waves propagation, pending the driving apparatus. Tesla believed that his wireless system would be better than most other radio systems because
transverse electromagnetic waves (whose behavior depends on its wavelength) would decay as they travelled from the transmitter, making the signals uselessly weak at long distances. Tesla advanced that
longitudinal electromagnetic waves (such as those that occur in
waves in plasmas) through the medium would be used, as he theorized that they would be practically lossless. His devices can be driven to produce either transverse or longitudinal waves.
Besides his intention to transmit wireless signals of intelligence, he proposed to transmit
electric power via
electrical conduction through the Earth and the upper atmosphere, as well as in between them both (in the Earth-ionosphere region which is now known as a
resonant cavity). This power transmission was to be done not by "hertzian waves", but through
standing surface waves. Tesla's proposed wireless transmitter utilized a resonant transformer to apply a very high voltage of high frequency between the earth and a large elevated conductor, as discussed earlier.
Case against Tesla
It is a
popular belief, or a
misconception, that Tesla had a small influence on the development of radio. Tesla never did complete his "worldwide wireless system", primarily because of financial difficulties. Cost overruns prevented him from completing the
wireless station tower that he built in the early 1900s on Long Island, New York. Many
modern Marconi supporters dispute the relevancy of his demonstrations of the remote-controlled boat (with its internal rotating coherer) as well as his public lecture demonstrations.
Many scientists and
inventors contributed to the invention of wireless telegraphy and radio. Individuals that helped to further the science include, among others:-
*
Georg von Arco: European pioneer.
*
Edouard Branly: invention of the Branly coherer around 1890.
*
Temistocle Calzecchi-Onesti: constructed a tuning "tube".
*
Amos Dolbear: Earth transmission, .
*
Thomas Alva Edison: "Etheric Force" experiments 1875; , 1891.
*
Michael Faraday: discovered
electromagnetic induction.
*
Reginald Fessenden: advanced "continuous" wave transmission.
*
Hans Christian Ørsted: discovered that a magnetic field surrounds a wire carrying current.
*
Joseph Henry: transmitted radiant energy from a capacitor through a coil and detected it 100 feet away, Dec. 1840.
*
Charles Herrold: advanced radio broadcasting.
*
David E. Hughes: early experiments with transmission and reception.
*
James Clerk Maxwell: developed a set of
equations expressing the basic laws of electricity and magnetism.
*
Jozef Murgaš: extensive work in the late 1890s.
*
William Henry Preece: early experiments in electromagnetism and wireless telephony.
*
Augusto Righi: continued Hertz's experiments.
*
Harry Shoemaker: 1901 to 1905; 40 patents.
*
Adolphus Slaby: European pioneer.
*
John Stone Stone: 1901 to 1904; 70 patents.
*
Nathan Stubblefield: wireless telephony demonstrations around 1902; , 1908.Below are more investigators that reportedly have claims to the invention of radio.
Jagdish Chandra Bose
Another pioneer of wireless communication was Prof
Jagdish Bose. In 1894, Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves, replicating 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." In Russia, Popov was performing closely related experiments but had recorded, in December 1895, that he was hoping for distant signalling with radio waves
[ D.T. Emerson, "The work of Jagadis Chandra Bose: 100 years of mm-wave research". National Radio Astronomy Observatory, February 1998.] The wireless signalling experiment by Marconi on Salisbury Plain in England was not until May 1897. The 1895 public demonstration by Bose in Calcutta predates this experiment.
["The Work of Jagdish Chandra Bose: 100 years of mm-wave research". tuc.nrao.edu.] ["Jagadish Chandra Bose", ieee-virtual-museum.org.] Both of Bose's experiments, though, was well after Tesla's demonstration of radio communication in 1892 and 1893.
Bose, it has been noted, was not interested in the commercial applications of the experiment's transmitter. He did not attempt 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 Royal Society, London.
[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.] Later, he received ,
"Detector for electrical distrubances" (1904), for a specific electromagntic receiver. While he is not known for greatly contributing to the development of commercial radio communication and did not file any patents for transmission, this doesn't discount that he does deserves recognition for contributing to the development of radio.
Heinrich Hertz
In his classic
UHF experiments,
Heinrich Hertz had verified that the properties of radio waves were consistent with Maxwell's electromagnetic theory. Of the three basic forms of wireless aerial launching structures common at the time, the Hertz antenna was a vertical dipole, center fed, half wavelength structure. No ground connection was used. Hertz's source and detector of radio waves might be regarded as a type of primitive radio transmitter and receiver good for true
free space transmission (but the transmitter was
not very good for actual use at the low frequency
space waves that most early wireless systems used as it had
no ground or Earthing element).
[ Gary L. Peterson, "Comparing the Hertz-wave and Tesla wireless system". Feed Line No. 9 Article][Hertz wave] Hertz used the damped oscillating currents in a dipole antenna, triggered by a high voltage electrical 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 the detection of the radio wave. When he added cylindrical reflectors behind his dipole antennas, Hertz was able to detect radio waves about 20 metres from the transmitter in his laboratory. He did not try to extend this distance further because he was motivated by verifying electromagnetic theory, not by developing wireless communications. Hertz did not understand 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."
[ Eugenii Katz, "Heinrich Rudolf Hertz". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics.]Asked about the ramifications of his discoveries, Hertz replied, :
"Nothing, I guess." His discoveries would later be more fully understood by others. In Marconi's 1895 experiments, he followed Hertz's work (among others) by using a spark source in what became known as a
spark-gap transmitter.
Oliver Lodge
Oliver Lodge transmitted radio signals one year before Marconi but one year after Tesla. Lodge transmitted radio signals on August 14,
1894 at a meeting of the British Association for the Advancement of Science at Oxford University.
[ Sir Oliver Lodge Invented Radio - Not Marconi". ] [ In 1995 the Royal Society recognized this scientific break through at a special ceremony at Oxford University. For more, see "Past Years: An Autobiography''". New York: Charles Scribner's Sons, p231.] Lodge also improved the
Edouard Branly's coherer radio wave detector by adding a "trembler" which dislodged clumped filings, thus restoring the device's sensitivity.
[ Peter Rowlands (ed.) and J. Patrick Wilson (ed.) "Oliver Lodge and the Invention of Radio" ISBN 1873694024 ] He would later attain , "Electric Telegraphy" (August, 1898), that would produced wireless signals using Ruhmkorff or Tesla coils for the transmitter and a Branly coherer for the detector. This was key to the "
syntonic" tuning concept. Lodge would later sell the patent to Marconi in 1912.
M. Loomis and W. H. Ward
Mahlon Loomis of
West Virginia has the oldest and most documented claim of inventing radio. Loomis received for a "wireless telegraph" in 1872. This patent utilizes
atmospheric electricity to eliminate the overhead wire used by the existing telegraph systems. It did not contain diagrams or specific methods. It is substantially similar to received three months earlier by
William Henry Ward.
Ernest Rutherford
The New Zealander
Ernest Rutherford, 1st Baron Rutherford of Nelson was instrumental in the development of radio. In 1895 he was awarded an
Exhibition of 1851 Science Research Scholarship to Cambridge. He arrived in England with a reputation as an innovator and inventor, and distinguished himself in several fields, initially by working out the electrical properties of solids and then using wireless waves as a method of signalling. Rutherford was encouraged in his work by
Sir Robert Ball, who had been scientific adviser to the body maintaining lighthouses on the Irish coast; he wished to solve the difficult problem of a ship's inability to detect a lighthouse in fog. Sensing fame and fortune, Rutherford increased the sensitivity of his apparatus until he could detect electromagnetic waves over a distance of several hundred metres. The commercial development, though, of wireless technology was left for others, as Rutherford continued purely scientific research.
The invention of amplitude-modulated (AM) radio, so that more than one station can send signals (as opposed to spark-gap radio, where one transmitter covers the entire bandwidth of the spectrum) is attributed to
Reginald Fessenden and
Lee de Forest. The invention of frequency-modulated (FM) radio, where audio signals can avoid "static" or interference from electrical equipment and atmospherics, is attributed to
Edwin H. Armstrong.
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.
General information and overview articles
;Early Radio History US 1897 to 1927
*
Thomas H. White,
"Pioneering U.S. Radio Activities (1897-1917)", United States Early Radio History.
* Donald McNicol,
"The Early Days of Radio in America". The Electrical Experimenter, April, 1917, pages 893, 911.
*
"Notes and comments; Telegraphy without wires", Journal of the Franklin Institute, December, 1897, pages 463-464.
* "
John Stone Stone on Nikola Tesla's Priority in Radio and Continuous-Wave Radiofrequency Apparatus".
Twenty First Century Books, 2005.
Tesla
*Leland Anderson, "Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power", Sun Publishing Company, LC 92-60482, ISBN 0-9632652-0-2 (ed. excerpts available online)
* Aleksandar Marincic and Djuradj Budimir, "Tesla contribution to radio wave propagation". (PDF);Miscellaneous
*Sungook Hong,
"Wireless: from Marconi's Black-box to the Audion", Cambridge, MA: MIT Press, 2001, ISBN 0262082985
*
"A Comparison of the Tesla and Marconi Low-Frequency Wireless Systems ". Twenty First Century Books, Breckenridge, Co..
* A. David Wunsch,
"Misreading the Supreme Court: A Puzzling Chapter in the History of Radio". Mercurians.org.
Footnotes and citations
;Citations and notes
Readings
* Leland I. Anderson, Priority in the Invention of Radio — Tesla vs. Marconi, Antique Wireless Association monograph, 1980, examining the 1943 decision by the US Supreme Court holding the key Marconi patent invalid (9 pages). (21st Century Books)
* Weightman, Gavin, "Signor Marconi's magic box : the most remarkable invention of the 19th century & the amateur inventor whose genius sparked a revolution" 1st Da Capo Press ed., Cambridge, MA : Da Capo Press, 2003.
* Garratt, G. R. M., "The early history of radio : from Faraday to Marconi", London, Institution of Electrical Engineers in association with the Science Museum, History of technology series, 1994. ISBN 0852968450 LCCN gb 94011611
* Masini, Giancarlo. "Guglielmo Marconi". Turin: Turinese typographical-publishing union, 1975. LCCN 77472455 (ed. Contains 32 tables outside of the text)
* Geddes, Keith, "Guglielmo Marconi, 1874-1937". London : H.M.S.O., A Science Museum booklet, 1974. ISBN 0112901980 LCCN 75329825 (ed. Obtainable in the U.S.A. from Pendragon House Inc., Palo Alto, California.)
* Coe, Douglas and Kreigh Collins (ills), "Marconi, pioneer of radio". New York, J. Messner, Inc., 1943. LCCN 43010048
* Waldron, Richard Arthur, "Theory of guided electromagnetic waves". London, New York, Van Nostrand Reinhold, 1970. ISBN 0442091672 LCCN 69019848 //r86
* Marconi's Wireless Telegraph Company, "Year book of wireless telegraphy and telephony", London : Published for the Marconi Press Agency Ltd., by the St. Catherine Press / Wireless Press. LCCN 14017875 sn 86035439
* Hancock, Harry Edgar, "Wireless at sea; the first fifty years. A history of the progress and development of marine wireless communications written to commemorate the jubilee of the Marconi International Marine Communication Company limited". Chelmsford, Eng., Marconi International Marine Communication Co., 1950. LCCN 51040529 /L
;Websites
* Julian Rubin, "Guglielmo Marconi: The Invention of Radio". January 2006.
*" Guglielmo Marconi and Early Systems of Wireless Communication". Marconi.com. (PDF file)
* Katz, Randy H., "Look Ma, No Wires": Marconi and the Invention of Radio". History of Communications Infrastructures.
* Brazilian experimenter Roberto Landell de Moura
* J. L. Pimsleur, "Invention of Radio Celebrated in S.F.; 100th birthday exhibit this weekend ". San Francisco Chronicle, 1995.
* "The Invention of the Radio". Through the wires, a century of communication, library.thinkquest.org.
* "The Invention of Radio''". inventors.about.com.
* "Presentation of the Edison Medal to Nikola Tesla". Minutes of the Annual Metting of the American Institute of Electrical Engineers. Held at the Engeering Society Building, New Yaork City, Friday evening, May 18, 1917.
