The invention of radio communication was preceded by many decades of establishing theoretical underpinnings, discovery and experimental investigation of radio waves, and engineering and technical developments related to their transmission and detection. These developments allowed Guglielmo Marconi to turn radio waves into a

wireless communication Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...

system. The idea that the wires needed for

electrical telegraph Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...

could be eliminated, creating a

wireless telegraph Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental technologies for t ...

, had been around for a while before the establishment of radio-based communication. Inventors attempted to build systems based on

electric conduction An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving ...

, electromagnetic induction, or on other theoretical ideas. Several inventors/experimenters came across the phenomenon of radio waves before its existence was proven; it was written off as electromagnetic induction at the time. The discovery of electromagnetic waves, including

radio waves Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...

, by Heinrich Rudolf Hertz in the 1880s came after theoretical development on the connection between

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

and magnetism that started in the early 1800s. This work culminated in a theory of

electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) li ...

developed by

James Clerk Maxwell James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and li ...

by 1873, which Hertz demonstrated experimentally. Hertz considered electromagnetic waves to be of little practical value. Other experimenters, such as

Oliver Lodge Sir Oliver Joseph Lodge, (12 June 1851 – 22 August 1940) was a British physicist and writer involved in the development of, and holder of key patents for, radio. He identified electromagnetic radiation independent of Hertz's proof and at his ...

and Jagadish Chandra Bose, explored the physical properties of electromagnetic waves, and they developed electric devices and methods to improve the transmission and detection of electromagnetic waves. But they did not apparently see the value in developing a communication system based on electromagnetic waves. In the mid 1890s, building on techniques physicists were using to study electromagnetic waves, Guglielmo Marconi developed the first apparatus for long-distance radio communication. On 23 December 1900, the Canadian inventor Reginald A. Fessenden became the first person to send audio (

wireless telephony Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...

) by means of electromagnetic waves, successfully transmitting over a distance of about a mile (1.6 kilometers,) and six years later on Christmas Eve 1906 he became the first person to make a public wireless broadcast. By 1910, these various wireless systems had come to be called "radio".

Wireless communication theories and methods previous to radio

Before the discovery of electromagnetic waves and the development of radio communication there were many wireless telegraph systems proposed and tested. In April 1872

William Henry Ward William Henry Ward on 30 April 1872 was granted a USA patent for "Improvement for collecting electricity for telegraphing" (). He theorized that an "electrical layer in the atmosphere" could carry signals like a telegraph wire, and thus is sometimes ...

received for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire. A few months after Ward received his patent,

Mahlon Loomis Mahlon Loomis (21 July 1826 – 13 October 1886) was an American dentist and inventor known for proposing a wireless communication and electric power generating system based on his idea that there were electrically charged layers in the earth's ...

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the B ...

received for a similar "wireless telegraph" in July 1872.Sterling, Christopher H. (ed.) (2003) ''Encyclopedia of Radio'' ( Volume 1
Page 831
/ref> The patented system claimed to utilize

atmospheric electricity Atmospheric electricity is the study of electrical charges in the Earth's atmosphere (or that of another planet). The movement of charge between the Earth's surface, the atmosphere, and the ionosphere is known as the global atmospheric electr ...

to eliminate the overhead wire used by the existing telegraph systems. It did not contain diagrams or specific methods and it did not refer to or incorporate any known scientific theory. Pat465971

In the United States,

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...

, in the mid-1880s, patented an electromagnetic induction system he called "grasshopper telegraphy", which allowed telegraphic signals to jump the short distance between a running train and telegraph wires running parallel to the tracks. In the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

William Preece Sir William Henry Preece (15 February 1834 – 6 November 1913) was a Welsh electrical engineer and inventor. Preece relied on experiments and physical reasoning in his life's work. Upon his retirement from the Post Office in 1899, Preece was m ...

was able to develop an electromagnetic induction telegraph system that, with antenna wires many kilometers long, could transmit across gaps of about . Inventor

Nathan Stubblefield Nathan Beverly Stubblefield (November 22, 1860 – March 28, 1928) was an American inventor best known for his wireless telephone work. Self-described as a "practical farmer, fruit grower and electrician",

, between 1885 and 1892, also worked on an induction transmission system. A form of

is recorded in four patents for the

photophone The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 ...

, invented jointly by Alexander Graham Bell and Charles Sumner Tainter in 1880. The photophone allowed for the transmission of sound on a beam of

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

, and on June 3, 1880 Bell and Tainter transmitted the world's first wireless telephone message on their newly invented form of light

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

.Carson, Mary Kay (2007
''Alexander Graham Bell: Giving Voice To The World''
Sterling Biographies, New York: Sterling Publishing Co., Inc., pp. 76–78. . In the early 1890s

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

Instead of using radio waves, Tesla's efforts were focused towards building a conduction based power distribution system, although he noted in 1893 that his system could also incorporate communication. His laboratory work and later large scale experiments at Colorado Springs led him to the conclusion that he could build a conduction based worldwide wireless system that would use the Earth itself (via injecting very large amounts of electric current into the ground) as the means to conduct the signal very long distances (across the Earth), overcoming the perceived limitations of other systems. He went on to try to implement his ideas of power transmission and wireless telecommunication in his very large but unsuccessful

Wardenclyffe Tower Wardenclyffe Tower (1901–1917), also known as the Tesla Tower, was an early experimental wireless transmission station designed and built by Nikola Tesla on Long Island in 1901–1902, located in the village of Shoreham, New York. Tesla inte ...

project.

Development of electromagnetism

Various scientists proposed that electricity and magnetism were linked. Around 1800 Alessandro Volta developed the first means of producing an electric current. In 1802

Gian Domenico Romagnosi Gian Domenico Romagnosi (; 11 December 1761 – 8 June 1835) was an Italian philosopher, economist and jurist. Biography Gian Domenico Romagnosi was born in Salsomaggiore Terme. He studied law at the University of Parma from 1782 to 1786. I ...

may have suggested a relationship between electricity and magnetism but his reports went unnoticed. In 1820 Hans Christian Ørsted performed a simple and today widely known experiment on electric current and magnetism. He demonstrated that a wire carrying a current could deflect a magnetized

compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...

needle. Ørsted's work influenced André-Marie Ampère to produce a theory of electromagnetism. Several scientists speculated that light might be connected with electricity or magnetism. In 1831,

Michael Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic inducti ...

began a series of experiments in which he discovered electromagnetic induction. The relation was mathematically modelled by Faraday's law, which subsequently became one of the four

Maxwell equations Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. T ...

. Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal. In 1846 Michael Faraday speculated that light was a wave disturbance in a "force field". Expanding upon a series of experiments by Felix Savary, between 1842 and 1850 Joseph Henry performed experiments detecting inductive magnetic effects over a distance of .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.)Se
''The Scientific Writings of Joseph Henry''
vol. i. pp. 203, 20:-i ; als
"Analysis of the Dynamic Phenomena of the Leyden Jar"
''Proceedings of the American Association for the Advancement of Science'', 1850, vol. iv. pp. 377–78, Joseph Henry. The effect of the oscillatory discharge on a magnetized needle is summarized in this review.Ames, J. S., Henry, J., & Faraday, M. (1900)
''The Discovery of Induced Electric Currents''
New York: American book. (cf. Page 107: "On moving to Princeton, in 1832, enry ..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.") He was the first (1838–42) to produce high frequency AC electrical oscillations, and to point out and experimentally demonstrate that the discharge of a capacitor under certain conditions is oscillatory, or, as he puts it, consists "''of a principal discharge in one direction and then several reflex actions backward and forward, each more feeble than the preceding until equilibrium is attained''". This view was also later adopted by Helmholtz, the mathematical demonstration of this fact was first given by Lord Kelvin in his paper on " Transient Electric Currents".Fessenden, Reginald (1908)
"Wireless Telephony"
''Transactions of the American Institute of Electrical Engineers'' (volume 27, part 1), June 29, 1908, pp. 553–630

Maxwell and the theoretical prediction of electromagnetic waves

Between 1861 and 1865, based on the earlier experimental work of Faraday and other scientists and on his own modification to Ampere's law,

developed his theory of electromagnetism, which predicted the existence of electromagnetic waves. In 1873 Maxwell described the theoretical basis of the propagation of electromagnetic waves in his paper to the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

, "''

A Dynamical Theory of the Electromagnetic Field "A Dynamical Theory of the Electromagnetic Field" is a paper by James Clerk Maxwell on electromagnetism, published in 1865. ''(Paper read at a meeting of the Royal Society on 8 December 1864).'' In the paper, Maxwell derives an electromagnetic wav ...

''." This theory united all previously unrelated observations, experiments and equations of electricity, magnetism, and optics into a consistent theory. His set of equations—

Maxwell's equations Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. ...

—demonstrated that electricity, magnetism, and light are all manifestations of the same phenomenon, the electromagnetic field. Subsequently, all other classic laws or equations of these disciplines were special cases of Maxwell's equations. Maxwell's work in electromagnetism has been called the "second great unification in physics", after Newton's unification of gravity in the 17th century.

Oliver Heaviside Oliver Heaviside FRS (; 18 May 1850 – 3 February 1925) was an English self-taught mathematician and physicist who invented a new technique for solving differential equations (equivalent to the Laplace transform), independently developed ...

, later reformulated Maxwell's original equations into the set of four vector equations that are generally known today as Maxwell's equations. Neither Maxwell nor Heaviside transmitted or received radio waves; however, their equations for electromagnetic fields established principles for radio design, and remain the standard expression of classical electromagnetism. Of Maxwell's work,

Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...

wrote:

"Imagine axwell'sfeelings when the differential equations he had formulated proved to him that electromagnetic fields spread in the form of polarised waves, and at the speed of light! To few men in the world has such an experience been vouchsafed... it took physicists some decades to grasp the full significance of Maxwell's discovery, so bold was the leap that his genius forced upon the conceptions of his fellow-workers."

Other physicists were equally impressed with Maxwell's work, such as

Richard Feynman Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfl ...

who commented:

"From a long view of the history of the world—seen from, say, ten thousand years from now—there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the laws of electromagnetism. The American Civil War will pale into provincial insignificance in comparison with this important scientific event of the same decade."

Experiments and proposals

Berend Wilhelm Feddersen Berend Wilhelm Feddersen (26 March 1832 in Schleswig – 1 July 1918 in Leipzig) was a German physicist. Biography Feddersen studied chemistry and physics at the University of Göttingen, where he became member of Burschenschaft Hannovera ( ...

, a German physicist, in 1859, as a private scholar in

Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as ...

, succeeded in experiments with the Leyden jar to prove that electric sparks were composed of damped oscillations. In 1870 the German physicist Wilhelm von Bezold discovered and demonstrated the fact that the advancing and reflected oscillations produced in conductors by a capacitor discharge gave rise to interference phenomena. Professors Elihu Thomson and E. J. Houston in 1876 made a number of experiments and observations on high frequency oscillatory discharges. In 1883 George Francis FitzGerald, George FitzGerald suggested at a British Association meeting that electromagnetic waves could be generated by the discharge of a capacitor, but the suggestion was not followed up, possibly because no means was known for detecting the waves.

Hertz experimentally verifies Maxwell's theory

When German physicist Heinrich Rudolf Hertz was looking for a subject for his doctoral dissertation in 1879, instructor Hermann von Helmholtz suggested he try to prove Maxwell's theory of electromagnetism. Hertz initially couldn't see any way to test the theory but his observation, in the autumn of 1886, of discharging a Leyden jar into a large coil and producing a spark in an adjacent coil gave him the idea of how to build a test apparatus.Huurdeman, Anton A. (2003) ''The Worldwide History of Telecommunications''. Wiley. . p. 202 Using a Ruhmkorff coil to create sparks across a gap (a spark gap transmitter) and observing the sparks created between the gap in a nearby metal loop Antenna (radio), antenna, between 1886 and 1888 Hertz would conduct a series of scientific experiments that would validate Maxwell's theory. Hertz published his results in a series of papers between 1887 and 1890, and again in complete book form in 1893. The first of the papers published, "''On Very Rapid Electric Oscillations''", gives an account of the chronological course of his investigation, as far as it was carried out up to the end of the year 1886 and the beginning of 1887. For the first time, electromagnetic

("Hertzian waves") were intentionally and unequivocally proven to have been transmitted through free space by a spark-gap device, and detected over a short distance. Hertz schematic0

Hertz was able to have some control over the frequencies of his radiated waves by altering the inductance and capacitance of his transmitting and receiving Antenna (radio), antennas. He focused the electromagnetic waves using a corner reflector and a parabolic reflector, to demonstrate that radio behaved the same as light, as Maxwell's electromagnetic theory had predicted more than 20 years earlier. Hertz did not devise a system for practical utilization of electromagnetic waves, nor did he describe any potential applications of the technology. Hertz was asked by his students at the University of Bonn what use there might be for these waves. He replied, "''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.''" Hertz died in 1894, and the art of radio wave communication was left to others to implement into a practical form. After Hertz's experiments, Sir William Crookes published an article in February 1892 in ''The Fortnightly Review'' on 'Some possibilities of electricity' with his thoughts on possibility of wireless communication based on the research of Lodge and Hertz, and the American physicist Amos Dolbear, Amos Emerson Dolbear brought similar attention to the idea.

Pre-Hertz radio wave detection

During 1789–91, Luigi Galvani noticed that a spark generated nearby caused a convulsion in a frog's leg being touched by a scalpel."Wireless before Marconi" by L. V. Lindell (2006), included in ''History of Wireless'' by T. K. Sarkar, Robert Mailloux, Arthur A. Oliner, M. Salazar-Palma, Dipak L. Sengupta, John Wiley & Sons, pp. 258–61 In different experiments, he noticed contractions in frogs' legs caused by lightning and a luminous discharge from a charged Leyden jar that disappeared over time and was renewed whenever a spark occurred nearby. Joseph Henry observed magnetised needles from lightning in the early 1840s. In 1852 Samuel Alfred Varley noticed a remarkable fall in the resistance of masses of metallic filings under the action of atmospheric electrical discharges. David Edward Hughes

Towards the end of 1875, while experimenting with the telegraph,

noted a phenomenon that he termed "etheric force", announcing it to the press on November 28. He abandoned this research when Elihu Thomson, among others, ridiculed the idea, claiming it was electromagnetic induction. In 1879 the experimenter and inventor David Edward Hughes, working in London, discovered that a bad contact in a Bell telephone he was using in his experiments seemed to be sparking when he worked on a nearby induction balance (an early form of metal detector).Walters, Rob (2005) ''Spread Spectrum: Hedy Lamarr and the Mobile Phone'', Satin, page 16''The Electrician'', Volume 43
"Notes"
(May 5, 1899, p. 35)
"Prof. D. E. Hughes's Researches in Wireless Telegraphy"
by J. J. Fahie (May 5, 1899, pp. 40–41)
"The National Telephone Company's Staff Dinner"
(Hughes remarks), (May 12, 1899, pp. 93–94) He developed an improved detector to pick up this unknown "extra current" based on his new microphone design (similar to later detectors known as coherers or crystal detectors) and developed a way to interrupt his induction balance to produce a series of sparks. By trial and error experiments he eventually found he could pick up these "aerial waves" as he carried his telephone device down the street out to a range of . On February 20, 1880, he demonstrated his experiment to representatives of the

including Thomas Henry Huxley, Sir George Gabriel Stokes, and William Spottiswoode, then president of the Society. Stokes was convinced the phenomenon Hughes was demonstrating was merely electromagnetic induction, not a type of conduction through the air. Hughes was not a physicist and seems to have accepted Stokes observations and did not pursue the experiments any further. His work may have been mentioned in William Crookes' 1892 ''Fortnightly Review'' review of 'Some possibilities of electricity' article as an unnamed individual whose experiment Crookes participate in.Crookes, William (February 1, 1892
"Some Possibilities of Electricity"
''The Fortnightly Review'', pp. 173–81

Development of radio waves

The Branly detector

In 1890, Édouard Branly demonstrated what he later called the "radio-conductor," which Lodge in 1893 named the coherer, the first sensitive device for detecting radio waves. Shortly after the experiments of Hertz, Branly discovered that loose metal filings, which in a normal state have a high electrical resistance, lose this resistance in the presence of electric oscillations and become practically conductors of electricity. This Branly showed by placing metal filings in a glass box or tube, and making them part of an ordinary electric circuit. According to the common explanation, when electric waves are set up in the neighborhood of this circuit, electromotive forces are generated in it which appear to bring the filings more closely together, that is, to cohere, and thus their electrical resistance decreases, from which cause this piece of apparatus was termed by Sir Oliver Lodge a coherer. Hence the receiving instrument, which may be a telegraph relay, that normally would not indicate any sign of current from the small battery, can be operated when electric oscillations are set up.Maver, William Jr. (1904
''Maver's Wireless Telegraphy: Theory and Practice''
/ref> Branly further found that when the filings had once cohered they retained their low resistance until shaken apart, for instance, by tapping on the tube. The coherer, however, was not sensitive enough to be used reliably as radio developed.

Lodge's demonstrations

British physicist and writer Sir

came close to being the first to prove the existence of Maxwell's electromagnetic waves. In a series of spring 1888 experiments conducted with a Leyden jar connected to a length of wire with spaced spark gaps he noticed he was getting different size sparks and a glow pattern along the wire that seemed to be a function of wavelength.James P. Rybak
Oliver Lodge: Almost the Father of Radio
page 4, from Antique Wireless Before he could present his own findings he learned of Hertz' series of proofs on the same subject. On 1 June 1894, at a meeting of the British Association for the Advancement of Science at Oxford University, Lodge gave a memorial lecture on the work of Hertz (recently deceased) and the German physicist's proof of the existence of electromagnetic waves 6 years earlier. Lodge set up a demonstration on the quasi-optical nature of "Hertzian waves" (radio waves) and demonstrated their similarity to light and vision including reflection and transmission.Sungook Hong, Wireless: From Marconi's Black-box to the Audion, MIT Press, 2001, pp. 30–32 Later in June and on 14 August 1894 he did similar experiments, increasing the distance of transmission up to 55 meters. In these lectures Lodge demonstrated a detector that would become standard in radio work, an improved version of Branly's detector which Lodge dubbed the ''coherer''. It consisted of a glass tube containing metal filings between two electrodes. When the small electrical charge from waves from an antenna were applied to the electrodes, the metal particles would cling together or "wikt:cohere, cohere" causing the device to become conductive allowing the current from a battery to pass through it. In Lodge's setup the slight impulses from the coherer were picked up by a mirror galvanometer which would deflect a beam of light being projected on it, giving a visual signal that the impulse was received. After receiving a signal the metal filings in the coherer were broken apart or "decohered" by a manually operated vibrator or by the vibrations of a bell placed on the table near by that rang every time a transmission was received. Lodge also demonstrated tuning using a pair of Leyden jars that could be brought into resonance.W.A. Atherton, From Compass to Computer: History of Electrical and Electronics Engineering, Macmillan International Higher Education, 1984, p. 185 Lodge's lectures were widely publicized and his techniques influenced and were expanded on by other radio pioneers including Augusto Righi and his student Guglielmo Marconi, Alexander Stepanovich Popov, Alexander Popov, Lee de Forest, and Jagadish Chandra Bose. Lodge at the time seemed to see no value in using radio waves for signalling or wireless telegraphy and there is debate as to whether he even bothered to demonstrate communication during his lectures. Physicist John Ambrose Fleming, pointed out that Lodge's lecture was a physics experiment, not a demonstration of telegraphic signaling.Sungook Hong, Wireless: From Marconi's Black-box to the Audion, MIT Press, 2001, page 48 After radio communication was developed Lodge's lecture would become the focus of priority disputes over who invented wireless telegraphy (radio). His early demonstration and later development of radio tuning (his 1898 Syntonic Tuner (radio), tuning patent) would lead to patent disputes with the Marconi Company. When Lodge's syntonic patent was extended in 1911 for another seven years Marconi agreed to settle the patent dispute and purchase the patent.

J. C. Bose

In November 1894, the Indian physicist, Jagadish Chandra Bose, demonstrated publicly the use of radio waves in Kolkata, Calcutta, but he was not interested in patenting his work. Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves, confirming that communication signals can be sent without using wires. He sent and received radio waves over distance but did not commercially exploit this achievement. Bose demonstrated the ability of the signal to travel from the lecture room, and through an intervening room and passage, to a third room distant from the radiator, thus passing through three solid walls on the way, as well as the body of the chairman (who happened to be the Lieutenant-Governor). The receiver at this distance still had energy enough to make a contact which set a bell ringing, discharged a pistol, and exploded a miniature mine. To get this result from his small radiator, Bose set up an apparatus which curiously anticipated the lofty 'antennae' of modern wireless telegraphy—a circular metal plate at the top of a pole, high, being put in connection with the radiator and a similar one with the receiving apparatus.Geddes, Sir Patrick (1920
''The life and work of Sir Jagadis C. Bose''
Longmans, Green, pp. 61–65. The form of 'Coherer' devised by Professor Bose, and described by him at the end of his paper ':s:On A New Electro-Polariscope, On a new Electro Polariscope' allowed for the sensibility and range to appear to leave little to be desired at the time. In 1896, the British, Daily Chronicle (United Kingdom), Daily Chronicle 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.''" After Bose's Friday Evening Discourses at the Royal Institution, The Electric Engineer expressed 'surprise that no secret was at any time made as to its construction, so that it has been open to all the world to adopt it for practical and possibly money-making purposes.' Bose was sometimes criticised as unpractical for making no profit from his inventions. In 1899, Bose announced the development of an "''iron-mercury-iron coherer with telephone detector''" in a paper presented at the

, London. Later he received , "''Detector for electrical disturbances''" (1904), for a specific electromagnetic receiver. Bose would continue with his research and made other contributions to the development of radio.

Adaptations of radio waves

Popov's lightning detector

In 1894–95 the Russian physicist Alexander Popov (physicist), Alexander Stepanovich Popov conducted experiments developing a radio receiver, an improved version of coherer-based design by

. His design with coherer auto-tapping mechanism was designed as a lightning detector to help the forest service track lightning strikes that could start fires. His receiver proved to be able to sense lightning strikes at distances of up to 30 km. Popov built a version of the receiver that was capable of automatically recording lightning strikes on paper rolls. Popov presented his radio receiver to the Russian Physical and Chemical Society on May 7, 1895 — the day has been celebrated in the Russian Federation as "Radio Day" promoted in eastern European countries as the inventor of radio. 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. He did not apply for a patent for this invention.

Tesla's boat

In 1898

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

Tesla, N., & Anderson, L. I. (1998). ''Nikola Tesla: Guided Weapons & Computer Technology''. Tesla presents series, pt. 3. Breckenridge, Colo: Twenty-First Century Books. between transmitter and receiver, which he demonstrated in 1898. Tesla called his invention a "teleautomaton" and he hoped to sell it as a guided naval torpedo.

Radio based wireless telegraphy

Marconi

Guglielmo Marconi studied at the Livorno, Leghorn Technical School, and acquainted himself with the published writings of Professor Augusto Righi of the University of Bologna. In 1894, Sir William Preece delivered a paper to the Royal Institution in London on electric signalling without wires. In 1894 at the Royal Institution lectures, Lodge delivered "The Work of Hertz and Some of His Successors"."The Work of Hertz" by Oliver Lodge
''Proceedings'' (volume 14: 1893–95), Royal Institution of Great Britain, pp. 321–49 Marconi is said to have read, while on vacation in 1894, about the experiments that Hertz did in the 1880s. Marconi also read about Tesla's work. It was at this time that Marconi began to understand that radio waves could be used for wireless communications. 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 at the end of 1895. Marconi was awarded a patent for radio with United Kingdom Intellectual Property Office, British patent]
No. 12,039
''Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-for''. The complete specification was filed March 2, 1897. This was Marconi's initial patent for the radio, though it used various earlier techniques of various other experimenters and resembled the instrument demonstrated by others (including Popov). During this time spark-gap wireless telegraphy was widely researched. In July, 1896, Marconi got his invention and new method of telegraphy to the attention of Preece, then engineer-in-chief to the British Government Postal, telegraph and telephone service, Telegraph Service, who had for the previous twelve years interested himself in the development of wireless telegraphy by the inductive-conductive method. On June 4, 1897, he delivered "Signalling through Space without Wires". Preece devoted considerable time to exhibiting and explaining the Marconi apparatus at the Royal Institution in London, stating that Marconi invented a new relay which had high sensitiveness and delicacy. Coherer Rcvr

The Marconi Company Ltd. was founded by Marconi in 1897, known as the Wireless Telegraph Trading Signal Company. Also in 1897, Marconi established the radio station at Niton, Isle of Wight, England. Marconi's wireless telegraphy was inspected by the Post Office Telegraph authorities; they made a series of experiments with Marconi's system of telegraphy without connecting wires, in the Bristol Channel. The October wireless signals of 1897 were sent from Salisbury Plain to Bath, England, Bath, a distance of . Around 1900 Marconi developed an empirical law that, for simple vertical sending and receiving antennas of equal height, the maximum working telegraphic distance varied as the square of the height of the antenna. This became known as Marconi's law. Other experimental stations were established at Lavernock Point, near Penarth; on the Flat Holmes, an island in mid-channel, and at Brean Down, a promontory on the Somerset side. Signals were obtained between the first and last-named points, a distance of, approximately, . The receiving instrument used was a Morse inkwriter of the Post Office pattern. In 1898, Marconi opened a radio factory in Hall Street, Chelmsford, England, employing around 50 people. In 1899, Marconi announced his invention of the "iron-mercury-iron coherer with telephone detector" in a paper presented at Royal Society, London. In May, 1898, communication was established for the Lloyd's of London, Corporation of Lloyds between Ballycastle, County Antrim, Ballycastle and the Lighthouse on Rathlin Island in the north of Ireland. In July 1898, the Marconi telegraphy was employed to report the results of yacht races at the Kingstown Regatta for the Daily Express (Dublin), Dublin Express newspaper. A set of instruments were fitted up in a room at Kingstown, and another on board a steamer, the Flying Huntress. The aerial conductor on shore was a strip of wire netting attached to a mast high, and several hundred messages were sent and correctly received during the progress of the races. At this time His Majesty King Edward VII, then Prince of Wales, had the misfortune to injure his knee, and was confined on board the royal yacht Osltorm in Cowes Bay. Marconi fitted up his apparatus on board the royal yacht by request, and also at Osborne House, Isle of Wight, and kept up wireless communication for three weeks between these stations. The distances covered were small; but as the yacht moved about, on some occasions high hills were interposed so that the aerial wires were overtopped by hundreds of feet, yet this was no obstacle to communication. These demonstrations led the Corporation of Trinity House to afford an opportunity for testing the system in practice between the South Foreland Lighthouse, near Dover, and the East Goodwin Lightship, on the Goodwin Sands. This installation was set in operation on December 24, 1898, and proved to be of value. It was shown that when once the apparatus was set up it could be worked by ordinary seamen with very little training. At the end of 1898 electric wave telegraphy established by Marconi had demonstrated its utility, especially for communication between ship and ship and ship and shore.A summary of his work on wireless telegraphy up to the beginning of 1899 is given in a paper read by Marconi to the Institution of Electrical Engineers on March 2, 1899.
"Wireless Telegraphy"
by G. Marconi, ''Journal of the Institution of Electrical Engineers'', 1899 (volume 28), pp. 273–91) The Haven Hotel station and Wireless Telegraph Mast was where much of Marconi's research work on wireless telegraphy was carried out after 1898.Fleming (1908
pp. 431–32
/ref> In 1899, he transmitted messages across the English Channel. Also in 1899, Marconi delivered "''Wireless Telegraphy''" to the Institution of Electrical Engineers. In addition, in 1899, W. H. Preece delivered "Aetheric Telegraphy", stating that the experimental stage in wireless telegraphy had been passed in 1894 and inventors were then entering the commercial stage. Preece, continuing in the lecture, details the work of Marconi and other British inventors. In April 1899, Marconi's experiments were repeated for the first time in the United States, by Jerome Green at the University of Notre Dame. In October, 1899, the progress of the America's Cup, yachts in the international race between the Columbia and Shamrock was successfully reported by aerial telegraphy, as many as 4,000 words having been (as is said) despatched from the two ship stations to the shore stations. Immediately afterward the apparatus was placed by request at the service of the United States Navy Board, and some highly interesting experiments followed under Marconi's personal supervision. The Marconi Company was renamed Marconi's Wireless Telegraph Company in 1900. Marconi at newfoundland

In 1901, Marconi claimed to have received daytime transatlantic radio frequency signals at a medium frequency, wavelength of 366 metres (820 kHz).Bradford, Henry M.
"Did Marconi Receive Transatlantic Radio Signals in 1901? – Part 1"
Antique Wireless Association (antiquewireless.org)Bradford, Henry M.
"Did Marconi Receive Transatlantic Radio Signals in 1901? Part 2 (conclusion): The Trans-Atlantic Experiments
Antique Wireless Association (antiquewireless.org) Marconi established a wireless transmitting station at Marconi House, Rosslare Strand, Co. Wexford in 1901 to act as a link between Poldhu in Cornwall and Clifden in Co. Galway. His announcement on 12 December 1901, using a kite-supported antenna for reception, stated that the message was received at Signal Hill (Newfoundland and Labrador), Signal Hill in St. John's, Newfoundland and Labrador, St John's, Newfoundland and Labrador, Newfoundland (now part of Canada) via signals transmitted by the company's new high-power station at Poldhu, Cornwall. The message received had been prearranged and was known to Marconi, consisting of the Morse letter 'S' – three dots. Bradford has recently contested the reported success, however, based on theoretical work as well as a reenactment of the experiment. It is now well known that long-distance transmission at a wavelength of 366 meters is not possible during the daytime, because the skywave is heavily absorbed by the ionosphere. It is possible that what was heard was only random atmospheric noise, which was mistaken for a signal, or that Marconi may have heard a shortwave harmonic of the signal. The distance between the two points was about . The Poldhu to Colony of Newfoundland, Newfoundland transmission claim has been criticized.Belrose, John S.
"Fessenden and Marconi; Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century"
International Conference on 100 Years of Radio, September 5–7, 1995. Retrieved 2018-02-05. There are various science historians, such as Belrose and Bradford, who have cast doubt that the Atlantic was bridged in 1901, but other science historians have taken the position that this was the first transatlantic radio transmission. Critics have claimed that it is more likely that Marconi received stray atmospheric Signal noise, noise from

in this experiment. The transmitting station in Poldhu, Cornwall used a spark-gap transmitter that could produce a signal in the medium frequency range and with high power levels. Marconi transmitted from England to Canada and the United States. In this period, a particular electromagnetic receiver, called the ''Marconi magnetic detector'' or ''hysteresis magnetic detector'',"Hertzian Wave Telegraphy: Lecture III", delivered by J. A. Fleming on March 16, 1903, Society of Arts (Great Britain), ''Journal of the Society of Arts'' (volume 51), August 7, 1903
p. 761
/ref> was developed further by Marconi and was successfully used in his early transatlantic work (1902) and in many of the smaller stations for a number of years. In 1902, a Marconi station was established in the village of Crookhaven, County Cork, Ireland to provide marine radio communications to ships arriving from the Americas. A ship's master could contact shipping line agents ashore to enquire which port was to receive their cargo without the need to come ashore at what was the first port of landfall. Ireland was also, due to its western location, to play a key role in early efforts to send trans-Atlantic messages. Marconi transmitted from his station in Glace Bay, Nova Scotia, Canada across the Atlantic, and on 18 January 1903 a Marconi station sent a message of greetings from Theodore Roosevelt, the President of the United States, to the King of the United Kingdom, marking the first transatlantic radio transmission originating in the United States.

In 1904, Marconi inaugurated an ocean daily newspaper, the ''Cunard Daily Bulletin'', on the Royal Mail Ship, R.M.S. "RMS Campania, Campania." At the start, passing events were printed in a little pamphlet of four pages called the ''Cunard Bulletin''. The title would read Cunard Daily Bulletin, with subheads for "''wikt:Marconigrams, Marconigrams Direct to the Ship''." All the passenger ships of the Cunard Company were fitted with Marconi's system of wireless telegraphy, by means of which constant communication was kept up, either with other ships or with land stations on the eastern or western hemisphere. The RMS Lucania, in October 1903, with Marconi on board, was the first vessel to hold communications with both sides of the Atlantic. The ''Cunard Daily Bulletin'', a thirty-two page illustrated paper published on board these boats recorded news received by wireless telegraphy, and was the first ocean newspaper. In August 1903, an agreement was made with the British Government by which the Cunard Co. were to build two Steam ship, steamers, to be, with all other Cunard ships, at the disposal of the British Admiralty for hire or purchase whenever they might be required, the Government lending the company £2,600,000 to build the ships and granting them a subsidy of £150,000 a year. One was the RMS Lusitania and another was the RMS Mauretania (1906), RMS Mauritania. Marconi was awarded the 1909 Nobel Prize in Physics with Karl Ferdinand Braun for contributions to radio sciences. Marconi's demonstrations of the use of radio for wireless communications, equipping ships with life saving wireless communications, establishing the first transatlantic radio service,In December 1902, he established wireless telegraphic communication between Cape Breton, Canada and England, the first message inaugurating the system being transmitted from the Governor General of Canada to King Edward VII, and a few weeks later a message inaugurating wireless connection between America (Cape Cod, Massachusetts) and Cornwall, England was transmitted from the President of the United States to the King of England.
"Wireless telegraphy"
''Encyclopaedia of Ships and Shipping'' edited by Herbert B. Mason. The Shipping Encyclopaedia, 1908, pp. 686–88.) and building the first stations for the British shortwave service, have marked his place in history. In June and July 1923, Marconi's shortwave transmissions took place at night on 97 meters from Poldhu, Poldhu Wireless Station, Cornwall, to his yacht Elettra (ship), Elettra in the Cape Verde, Cape Verde Islands. In September 1924, Marconi transmitted during daytime and nighttime on 32 meters from Poldhu to his yacht in Beirut. In July 1924, Marconi entered into contracts with the British General Post Office (GPO) to install telegraphy circuits from London to Australia, India, South Africa and Canada as the main element of the Imperial Wireless Chain. The UK-to-Canada shortwave "''Beam Wireless Service''" went into commercial operation on 25 October 1926. Beam Wireless Services from the UK to Australia, South Africa and India went into service in 1927. Electronic components for the system were built at Marconi's New Street wireless factory in Chelmsford.

Braun

Ferdinand Braun's major contributions were the introduction of a closed tuned circuit in the generating part of the transmitter, and its separation from the radiating part (the antenna) by means of inductive coupling, and later on the usage of crystals for receiving purposes. Braun experimented at first at the University of Strasbourg. Braun had written extensively on wireless subjects and was well known through his many contributions to the Electrician and other scientific journals."Dr. Braun, Famous German Scientist, Dead"
''The Wireless Age'' (volume 5), June 1918, pp. 709–10 In 1899, he would apply for the patents, ''Electro telegraphy by means of condensers and induction coils'' and ''Wireless electro transmission of signals over surfaces''. Pioneers working on wireless devices eventually came to a limit of distance they could cover. Connecting the antenna directly to the spark gap produced only a heavily damped pulse train. There were only a few cycles before oscillations ceased. Braun's circuit afforded a much longer sustained oscillation because the energy encountered less loss swinging between coil and Leyden Jars. Also, by means of inductive antenna coupling the radiator was matched to the generator. In spring 1899 Braun, accompanied by his colleagues Cantor and Zenneck, went to Cuxhaven to continue their experiments at the North Sea. On February 6, 1899, he would apply for the United States Patent, . Not before long he bridged a distance of 42 km to the city of Mutzing. On 24 September 1900 radio telegraphy signals were exchanged regularly with the island of Heligoland over a distance of 62 km. Lightvessels in the river Elbe and a coast station at Cuxhaven commenced a regular radio telegraph service. On August 6, 1901, he would apply for . By 1904, the closed circuit system of wireless telegraphy, connected with the name of Braun, was well known and generally adopted in principle. The results of Braun's experiments, published in the Electrician, possess interest, apart from the method employed. Braun showed how the problem could be satisfactorily and economically solved."Increasing the Transmitter Energy"
''The Electrical Magazine'' edited by Theodore Feilden (volume 1), May 26, 1904, p. 506 The closed circuit oscillator has the advantage, as was known, of being able to draw upon the kinetic energy in the oscillator circuit, and thus, because such a circuit can be given a much greater capacity than can be obtained with a radiating aerial alone, much more energy can be stored up and radiated by its employment. The emission is also prolonged, both results tending towards the attainment of the much desired train of undamped waves. The energy available, though greater than with the open system, was still inconsiderable unless very high potentials, with the attendant drawbacks, were used. Braun avoided the use of extremely high potentials for charging the gap and also makes use of a less wasteful gap by sub-dividing it. The chief point in his new arrangement, however, is not the sub-division of the gap merely but their arrangement, by which they are charged in parallel, at low voltages, and discharge in series. The Nobel Prize awarded to Braun in 1909 depicts this design.

Stone Stone

John Stone Stone labored as an early Telecommunications engineering, telephone engineer and was influential in developing

technology, and obtained dozens of key patents in the field of "space telegraphy". Patents of Stone for radio, together with their equivalents in other countries, form a very voluminous contribution to the patent literature of the subject. More than seventy United States patents have been granted to this patentee alone. In many cases these specifications are learned contributions to the literature of the subject, filled with valuable references to other sources of information.Fleming (1908
p. 520
/ref> Stone has had issued to him a large number of patents embracing a method for impressing oscillations on a radiator system and emitting the energy in the form of waves of predetermined length whatever may be the electrical dimensions of the oscillator.Collins, A. Frederick (1905) ''Wireless Telegraphy: Its History, Theory and Practice''
p. 164
/ref> On February 8, 1900, he filed for a selective system in . In this system, two simple circuits are associated inductively, each having an independent degree of freedom, and in which the restoration of electric oscillations to zero potential the currents are superimposed, giving rise to compound harmonic currents which permit the resonator system to be syntonized with precision to the oscillator. Stone's system, as stated in , developed free or unguided simple harmonic electromagnetic signal waves of a definite frequency to the exclusion of the energy of signal waves of other frequencies, and an elevated conductor and means for developing therein forced simple electric vibrations of corresponding frequency.Maver (1904
p. 126
/ref> In these patents Stone devised a multiple inductive oscillation circuit with the object of forcing on the antenna circuit a single oscillation of definite frequency. In the system for receiving the energy of free or unguided simple harmonic electromagnetic signal waves of a definite frequency to the exclusion of the energy of signal waves of other frequencies, he claimed an elevated conductor and a resonant circuit associated with said conductor and attuned to the frequency of the waves, the energy of which is to be received. A coherer made on what is called the ''Stone system''Stanley, Rupert (1919) ''Text-book on Wireless Telegraphy'', Longmans, Green
p. 300
/ref> was employed in some of the Portable radio, portable wireless outfits of the United States Army. The Stone Coherer has two small steel plugs between which are placed loosely packed carbon granules. This is a ''self-decohering'' device; though not as sensitive as other forms of detectors it is well suited to the rough usage of portable outfits.

Naval wireless

Royal Navy

In 1897, recently promoted Royal Navy Captain Henry Jackson (Royal Navy officer), Henry Jackson became the first person to achieve ship-to-ship wireless communications and demonstrated continuous communication with another vessel up to three miles away. became the first British warship to have wireless telegraphy installed when she conducted the first trials of the new equipment for the Royal Navy. Starting in December 1899, HMS ''Hector'' and were outfitted with wireless equipment. On 25 January 1901, HMS ''Jaseur'' received signals from the ''Marconi transmitter'' on the Isle of Wight and from HMS ''Hector'' (25 January).

US Navy

In 1899 the United States Navy Board issued a report on the results of investigations of the Marconi system of wireless telegraphy. The report noted that the system was well adapted for use in squadron signalling, under conditions of rain, fog, darkness and motion of speed although dampness affected the performance."Wireless Telegraphy" by J. W. Reading, ''Locomotive Engineers Journal'' (volume 44)
p. 77
/ref> They also noted that when two stations were transmitting simultaneously both would be received and that the system had the potential to affect the compass. They reported ranges from for large ships with tall masts () to for smaller vessels. The board recommended that the system was given a trial by the United States Navy.

Wireless telephony

Fessenden

In late 1886, Reginald Fessenden began working directly for Thomas Edison at the inventor's new laboratory in West Orange, New Jersey. Fessenden quickly made major advances, especially in receiver design, as he worked to develop audio reception of signals. The United States Weather Bureau began, early in 1900, a systematic course of experimentation in wireless telegraphy, employing him as a specialist.Sewall (1904
pp. 66–71
/ref> Fessenden evolved the heterodyne principle here where two signals combined to produce a third signal. In 1900, construction began on a large radio transmitting alternator. Fessenden, experimenting with a high-frequency spark transmitter, successfully transmitted speech on December 23, 1900, over a distance of about , the ''first audio radio transmission''. Early in 1901 the Weather Bureau officially installed Fessenden at Wier's Point, Roanoke Island, North Carolina, and he made experimental transmissions across water to a station located about west of Cape Hatteras, the distance between the two stations being roughly . An alternator of 1 kW output at 10 kilohertz was built in 1902. The credit for the development of this machine is due to Charles Proteus Steinmetz, Caryl D. Haskins, Ernst Alexanderson, John T. H. Dempster, Henry Geisenhoner, Adam Stein, Jr., and F. P. Mansbendel. In a paper written by Fessenden in 1902, it was asserted that important advances had been made, one of which was overcoming largely the loss of energy experienced in other systems. In an interview with a ''New York Journal'' correspondent, Fessenden stated that in his early apparatus he did not use an air transformer at the sending end, nor a concentric cylinder for emitters and antennae, and had used capacity, but arranged in a manner entirely different from that in other systems, and that he ''did not'' employ a coherer or any form of imperfect contact. Fessenden asserted that he had paid particular attention to selective and multiplexing, multiplex systems, and was well satisfied with the results in that direction. On August 12, 1902, 13 patents were issued to Fessenden, covering various methods, devices, and systems for signaling without wires. These patents involved many new principles, the ''chef-d'oeuvre'' of which was a method for Distributed-element model, distributing capacity and inductance instead of localizing these coefficients of the oscillator as in previous systems. Brant rock radio tower 1910

By the summer of 1906, a machine producing Low frequency, 50 kilohertz was installed at the Brant Rock station, and in the fall of 1906, what was called an Alternator, electric alternating dynamo was working regularly at 75 kilohertz, with an output of 0.5 kW. Fessenden used this for wireless telephoning to Plymouth, Massachusetts, a distance of approximately . In the following year machines were constructed having a frequency of 96 kilohertz and outputs of 1 kW and 2 kW. Fessenden believed that the damped wave-coherer system was essentially and fundamentally incapable of development into a practical system. He would employ a two-phase electric power, two-phase high frequency ''alternator method'' and the Continuous wave, continuous production of waves with changing constants of sending circuit. Fessenden would also use duplex communication, duplex and multiplex communication, multiplex commutator methods. On December 11, 1906, operation of the wireless transmission in conjunction with the wire lines took place. In July 1907 the range was considerably extended and speech was successfully transmitted between Brant Rock and Jamaica, Queens, Jamaica, on Long Island, a distance of nearly , in daylight and mostly over land, the mast at Jamaica being approximately high.

Fleming

In November 1904, the English physicist John Ambrose Fleming invented the two-electrode vacuum-tube rectifier, which he called the ''Fleming oscillation valve''. for which he obtained GB patent 24850 and . This "Fleming Valve" was sensitive and reliable, and so it replaced the crystal diode used in receivers used for long-distance wireless communication. It had an advantage, that it could not be permanently injured or set out of adjustment by any exceptionally strong stray signal, such as those due to atmospheric electricity. Fleming earned a Hughes Medal in 1910 for his electronic achievements. Marconi used this device as a radio detector. The Supreme Court of the United States would eventually invalidate the US patent because of an improper disclaimer and, additionally, maintained the technology in the patent was known art when filed. This invention was the first vacuum tube. Fleming's diode was used in radio receivers for many decades afterward, until it was superseded by improved solid state (electronics), solid state electronic technology more than 50 years later.

De Forest

Lee De Forest had an interest in wireless telegraphy and he invented the Audion tube, Audion in 1906. He was president and secretary of the De Forest Radio Telephone and Telegraph Company (1913). The De Forest System was adopted by the United States Government, and had been demonstrated to other Governments including those of Great Britain, Denmark, Germany, Russia, and British Indies, all of which purchased De Forest apparatus previous to the Great War. De Forest is one of the fathers of the "electronic age", as the Audion helped to usher in the widespread use of electronics.Weiss, G., & Leonard, J. W. (1920
"De Forest Radio Telephone and Telegraph Company"
''America's Maritime Progress'', New York: New York marine news Co., p. 254. De Forest made the ''Audion tube'' from a vacuum tube. He also made the "''Oscillion''", an undamped wave transmitter. He developed the De Forest method of wireless telegraphy and founded the American De Forest Wireless Telegraph Company. De Forest was a distinguished electrical engineer and the foremost American contributor to the development of wireless telegraphy and telephony. The elements of his device takes relatively weak electrical signals and amplifies them. The ''Audion Detector'', ''Audion Amplifier'', and the "''Oscillion''" transmitter had furthered the radio art and the transmission of written or audible speech. In World War I, the De Forest system was a factor in the efficiency of the United States Signal Service, and was also installed by the United States Government in Alaska.

Radio invention timeline

Below is a brief selection of important events and individuals related to the development of radio, from 1860 to 1910.Hong, Sungook (2001) ''Wireless: From Marconi's Black-box to the Audion'', MIT Press, page 9 ImageSize = width:777 height:600 DateFormat = YYYY Period = from:1860 till:1910 PlotArea = width:716 height:550 left:40 bottom:20 TimeAxis = orientation:vertical order:reverse ScaleMajor = unit:year increment:10 start:1860 ScaleMinor = unit:year increment:1 start:1860 PlotData= at:1864 fontsize:S text:"Maxwell predicts electromagnetic (EM) waves. at:1879 fontsize:S text:"Hughes demonstrates transmission of signals over 460m." at:1887 fontsize:S text:"Hertz publishes research experiments confirming Maxwell's theory in the journal Annalen der Physik." at:1890 fontsize:S text:"Branly demonstrates the coherer as a radio wave detector." at:1892 fontsize:S text:"William Crookes suggests Hertzian waves could be used in wireless telegraphy" at:1893 fontsize:S text:"Tesla demonstrates his wireless power techniques at St. Louis, Missouri." at:1894 fontsize:S text:"Bose ignited gunpowder and rang a bell at a distance in Calcutta." at:1895 fontsize:S text:"Popov presents his radio receiver to the Russian Physical and Chemical Society. Marconi transmits radio signals for about 1.5 miles (2.4 km)" at:1897 fontsize:S text:"Marconi sends wireless signals from Salisbury Plain to Bath, a distance of 34 miles (55 km)." at:1899 fontsize:S text:"Braun transmits 42 km. Popov transmits 130 miles." at:1900 fontsize:S text:"Fessenden makes the first audio radio transmission." at:1901 fontsize:S text:"Marconi reports transatlantic transmission." at:1902 fontsize:S text:"Marconi station in Canada became the first radio message to cross the Atlantic from North America." at:1906 fontsize:S text:"Fessenden transmits audio (radio telephony) over a distance of approximately 11 miles (18 km)." at:1909 fontsize:S text:"Braun and Marconi receive Nobel Prize in physics, 'in recognition of their contributions to the development of wireless telegraphy'."

Footnotes

External links

;United States Court case *
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. ;Books and articles:''listed by date, earliest first''
Telegraphing across space, Electric wave method
The Electrical engineer. (1884). London: Biggs & Co. (ed., the article is broke up, it begins on p. 466 and continues o
p. 493
) * Fahie, J. J. (1900)
A history of wireless telegraphy, 1838–1899: including some bare-wire proposals for subaqueous telegraphs
Edinburgh: W. Blackwood and Sons. * Thompson, S. P., Homans, J. E., & Tesla, N. (1903). Polyphase electric currents and alternate-current motors.
Wireless Telegraphy
. The library of electrical science, v. 6. New York: P.F. Collier & Son. * Sewall, C. H. (1904)
Wireless telegraphy: its origins, development, inventions, and apparatus
New York: D. Van Nostrand. * Trevert, E. (1904)
The A.B.C. of wireless telegraphy; a plain treatise on Hertzian wave signaling; embracing theory, methods of operation, and how to build various pieces of the apparatus employed
Lynn, Mass: Bubier Pub. * Collins, A. F. (1905)
Wireless telegraphy; its history, theory and practice
New York: McGraw Pub. * Mazzotto, D., & Bottone, S. R. (1906)
Wireless telegraphy and telephony
London: Whittaker & Co. * Erskine-Murray, J. (1907)
A handbook of wireless telegraphy: Its theory and practice, for the use of electrical engineers, students, and operators
London: Crosby Lockwood and Son. (ed., also available in th
Van Nostrand (1909)
version). * Murray, J. E. (1907)
A handbook of wireless telegraphy
New York: D. Van Nostrand Co.; [etc.] * Simmons, H. H. (1908).
Wireless telegraphy

Outlines of electrical engineering
London: Cassell and Co. * Fleming, J. A. (1908)
The principles of electric wave telegraphy
London: New York and Co. * Twining, H. L. V., & Dubilier, W. (1909)
Wireless telegraphy and high frequency electricity; a manual containing detailed information for the construction of transformers, wireless telegraph and high frequency apparatus, with chapters on their theory and operation
Los Angeles, Cal: The author. * Bottone, S. R. (1910)
Wireless telegraphy and Hertzian waves
London: Whittaker & Co. * Bishop, L. W. (1911)
The wireless operators' pocketbook of information and diagrams.
Lynn, Mass: Bubier Pub. Co.; [etc., etc.]. * Massie, W. W., & Underhill, C. R. (1911)
Wireless telegraphy and telephony popularly explained
New York: D. Van Nostrand. * Ashley, C. G., & Hayward, C. B. (1912)
Wireless telegraphy and wireless telephony
an understandable presentation of the science of wireless transmission of intelligence. Chicago: American School of Correspondence. * Stanley, R. (1914)
Text book on wireless telegraphy
London: Longmans, Green. * Thompson, S. P. (1915)
Elementary lessons in electricity and magnetism
New York: Macmillan * Bucher, E. E. (1917)
Practical wireless telegraphy
A complete text book for students of radio communication. New York: Wireless Press, Inc. * American Institute of Electrical Engineers. (1919)
Transactions of the American Institute of Electrical Engineers
New York: American Institute of Electrical Engineers. (ed., Contains ''Radio Telephony'' — By E. B. Craft and E. H. Colpitts (Illustrated)
Page 305
* Stanley, R. (1919)
Text-book on wireless telegraphy
London: Longmans, Green. ;Encyclopedias * Chisholm, H. (1910). The encyclopædia britannica: A dictionary of arts, sciences, literature and general information. Cambridge, Eng: At the University press. "Telegraph",
Part II – Wireless Telegraphy
. * American Technical Society. (1914). Cyclopedia of applied electricity: A general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric light transmission, alternating-current machinery, telegraphy, etc
Volume 7Wireless Telegraphy and Telephony By C. G. Ashley Page 147
Chicago: American technical society. * Colby, F. M., Williams, T., & Wade, H. T. (1922).
Wireless Telegraphy

The New international encyclopaedia
New York: Dodd, Mead and Co. *
Wireless telegraphy

The Encyclopædia Britannica
(1922). London: Encyclopædia Britannica. ;Gutenberg project
''The New Physics and Its Evolution''. Chapter VII : A Chapter in the History of Science: Wireless telegraphy
by Lucien Poincaré, eBook #15207, released February 28, 2005. ;Websites
Tesla society

Early Radio History
* Howeth, Captain H.S
''History of Communications – Electronics in the United States Navy''
published 1963, GPO, 657 pages. Free online public domain US government published book. * Wunsch, A.D.,

" ''Antenna'', Volume 11 No. 1, November 1998, Society for the History of Technology * Katz, Randy H., "

'". History of Communications Infrastructures

* {{Telecommunications Discovery and invention controversies History of electronic engineering History of inventions, Radio History of radio Articles which contain graphical timelines