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History of Radio

For the controversy about who invented radio, see Invention of radio. For the programming of early radio stations, see Old-time radio.
The early history of radio is the history of technology that produced radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio.[1] Radio development began as "wireless telegraphy".[1] Later radio history increasingly involves matters of programming and content.
In the history of radio and development of "wireless telegraphy", several people are claimed to have "invented the radio" leading to a great radio controversy. The most commonly accepted claims are:
  • Jagadish Chandra Bose
  • Guglielmo Marconi, who equipped ships with life-saving wireless communications, conducted a reported transatlantic radio communications experiments in 1901 and established the first commercial transatlantic radio service in 1907.
  • Alexander Stepanovich Popov
  • Nikola Tesla, who developed means to produce radio frequency currents, publicly demonstrated the principles of radio, and transmitted long distance signals.
Radio technology is a product of many different discoveries and developments.
Various scientists proposed that electricity and magnetism, both capable of causing attraction and repulsion of objects, were linked. In 1802 Gian Domenico Romagnosi suggested the relationship between electric current and magnetism, but his reports went unnoticed. In 1820 Hans Christian Ørsted performed a widely known experiment on man-made electric current and magnetism. He demonstrated that a wire carrying a current could deflect a magnetized compass needle. Ørsted's experiments discovered the relationship between electricity and magnetism in a very simple experiment. Ørsted's work influenced André-Marie Ampère to produce a theory of electromagnetism. During its early development and long after wide use of the technology, disputes persisted as to who could claim sole credit for this obvious boon to mankind. Closely related, radio was developed along with two other key inventions, the telegraph and the telephone.[1]

Contents

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[edit] Wireless experiments of the 19th century

In the late 19th century it was clear to various scientists and experimenters that wireless communication was possible. Various theoretical and experimental innovations led 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" [2][3] 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.

[edit] Faraday

James Clerk Maxwell, a theoretical physicist who developed a set of equations describing electromagnetic waves. These later later became known as Maxwell's equations.
In 1831, Michael Faraday 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. Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal.

[edit] Maxwell

Between 1861 and 1865, based on the earlier experimental work of Faraday and other scientists, James Clerk Maxwell 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, "A Dynamical Theory of the Electromagnetic Field."

[edit] William Henry Ward

In April 1872 William Henry Ward received U.S. Patent 126,356 for radio development. However, this patent did not refer to any known scientific theory of electromagnetism and could never have received and transmitted radio waves.

[edit] Mahlon Loomis

A few months after Ward received his patent, Mahlon Loomis of West Virginia received U.S. Patent 129,971 for a "wireless telegraph" in July 1872. This claimed to utilize atmospheric electricity 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. It is substantially similar to William Henry Ward's patent and could not have transmitted and received radio waves.

[edit] Edison (1875)

Towards the end of 1875, while experimenting with the telegraph, Thomas Edison 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. The idea was not based on the electromagnetic waves described by Maxwell.

[edit] David E. Hughes

In 1878, David E. Hughes noticed that sparks could be heard in a telephone receiver when experimenting with his carbon microphone. He developed this carbon-based detector further and eventually could detect signals over a few hundred yards. He demonstrated his discovery to the Royal Society in 1880, but was told it was merely induction, and therefore abandoned further research.

[edit] Calzecchi-Onesti

In 1884, Temistocle Calzecchi-Onesti at Fermo in Italy invented a primitive device that responded to radio waves. It consisted of a tube filled with iron filings, called a "coherer". This device was a critical discovery because it would later be developed to become the first practical radio detector.

[edit] Edouard Branly

Between 1884 and 1886, Edouard Branly of France produced an improved version of the coherer.

[edit] Edison (1885)

In 1885, Edison took out U.S. Patent 465,971 on a system of radio communication between ships (which later he sold to Marconi). The patent, however, was not based on the transmission and reception of electromagnetic waves.

[edit] Hertz

Between 1886 and 1888, Heinrich Rudolf Hertz studied Maxwell's theory and validated it through experiment. He demonstrated the transmission and reception of the electromagnetic waves predicted by Maxwell and thus was the first person to intentionally transmit and receive radio. He discovered that the electromagnetic equations could be reformulated into a partial differential equation called the wave equation. Famously, he saw no practical use for his discovery. For more information see Hertz' radio work at Invention of radio.

[edit] Stubblefield

Claims have been made that Murray, Kentucky farmer Nathan Stubblefield developed radio between 1885 and 1892, before either Tesla or Marconi, but his devices seemed to have worked by induction transmission rather than radio transmission.

[edit] Landell de Moura

Between 1893 and 1894, Roberto Landell de Moura, a Brazilian priest and scientist, conducted experiments in wireless transmissions. He did not publicize his achievement until 1900, when he held a public demonstration of a wireless transmission of voice in São Paulo, Brazil on June 3.

[edit] Beginnings of radio

Nikola Tesla developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and transmitted long distant signals.
There are varying disputed claims about who invented radio, which in the beginning was called "wireless telegraphy". The key invention for the beginning of "wireless transmission of data using the entire frequency spectrum", known as the spark-gap transmitter, has been attributed to various men. Marconi equipped ships with lifesaving wireless communications and established the first transatlantic radio service. Tesla developed means to reliably produce radio frequency electrical currents, publicly demonstrated the principles of radio, and transmitted long distance signals.

[edit] Nikola Tesla

In 1891 Tesla began his research into radio. He later published an article, "The True Wireless", concerning this research.[4] In 1892 he gave a lecture called "Experiments with Alternate Currents of High Potential and High Frequency", in London (Available at Project Gutenberg).[5] In 1893, at St. Louis, Missouri, Tesla gave a public demonstration of "wireless" radio communication. Addressing the Franklin Institute in Philadelphia and the National Electric Light Association, he described in detail the principles of radio communication.[6]
The apparatus that Tesla used contained all the elements that were incorporated into radio systems before the development of the "oscillation valve", the early vacuum tube. Tesla initially used sensitive electromagnetic receivers,[7] that were unlike the less responsive coherers later used by Marconi and other early experimenters.
Afterward, the principle of radio communication (sending signals through space to receivers) was publicized widely from Tesla's experiments and demonstrations. Various scientists, inventors, and experimenters began to investigate wireless methods. For more information see Tesla's wireless work.

[edit] Oliver Lodge

Oliver Lodge transmitted radio signals on August 14, 1894 (one year after Tesla, five years after Heinrich Hertz and one year before Marconi) at a meeting of the British Association for the Advancement of Science at Oxford University.[8] (In 1995, the Royal Society recognized this scientific breakthrough at a special ceremony at Oxford University. For more information, see Past Years: An Autobiography, New York: Charles Scribner's Sons, p231.)
On 19 August 1894 Lodge demonstrated the reception of Morse code signalling via radio waves using a "coherer". He improved Edouard Branly's coherer radio wave detector by adding a "trembler" which dislodged clumped filings, thus restoring the device's sensitivity. [9] In August 1898 he got U.S. Patent 609,154, "Electric Telegraphy", that made wireless signals using Ruhmkorff coils or Tesla coils for the transmitter and a Branly coherer for the detector. This was key to the "syntonic" tuning concept. In 1912 Lodge sold the patent to Marconi.

[edit] Jagdish Chandra Bose

In November 1894, the Indian physicist, Jagdish Chandra Bose, demonstrated publicly the use of radio waves in Calcutta, but he was not interested in patenting his work.[10] Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves, proving that communication signals can be sent without using wires. He was thus the first to send and receive radio waves over a significant distance but did not commercially exploit this achievement.
The 1895 public demonstration by Bose in Calcutta was before Marconi's wireless signalling experiment on Salisbury Plain in England in May 1897.[11][12] 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."

[edit] Alexander Popov

Popov was the first man to demonstrate the practical applications of radio waves.
In 1895, the Russian physicist Alexander Popov built a coherer. On May 7, 1895, Popov performed a public demonstration of transmission and reception of radio waves used for communication at the Russian Physical and Chemical Society, using his coherer:[13] this day has since been celebrated in Russia as "Radio Day". He did not apply for a patent for this invention. Popov's early experiments were transmissions of only 600 yards (550 m). Popov was the first to develop a practical communication system based on the coherer, and is usually considered by the Russians to have been the inventor of radio.[14][15]
Around March 1896 Popov demonstrated in public the transmission of radio waves, between different campus buildings, to the Saint Petersburg Physical Society. (This was before the public demonstration of the Marconi system around September 1896.) Per other accounts, however, Popov achieved these results only in December 1897—that is, after publication of Marconi's patent.[16] In 1898 his signal was received 6 miles (9.7 km) away, and in 1899 30 miles away. In 1900, Popov stated at the Congress of Russian Electrical Engineers that,
"the emission and reception of signals by Marconi by means of electric oscillations was nothing new, as in America Nikola Tesla did the same experiments in 1893."[17][18]
Later Popov experimented with ship-to-shore communication. Popov died in 1905 and his claim was not pressed by the Russian government until 1945.

[edit] 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 meters. The commercial development, though, of wireless technology was left for others, as Rutherford continued purely scientific research. Thomson quickly realised that Rutherford was a researcher of exceptional ability and invited him to join in a study of the electrical conduction of gases.

[edit] Guglielmo Marconi

Guglielmo Marconi was an electrical engineer and Nobel laureate known for the development of a practical wireless telegraphy system.
In 1896, Guglielmo Marconi was awarded a patent for radio with British Patent 12039, Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-for. This was the initial patent for the radio, though it used various earlier techniques of various other experimenters (primarily Tesla) and resembled the instrument demonstrated by others (including Popov). During this time spark-gap wireless telegraphy was widely researched.
In 1896, Bose went to London on a lecture tour and met Marconi, who was conducting wireless experiments for the British post office. In 1897, Marconi established the radio station at Niton, Isle of Wight, England. In 1897, Tesla applied for two key radio patents in the USA. Those two patents were issued in early 1900. In 1898, Marconi opened a radio factory in Hall Street, Chelmsford, England, employing around 50 people. In 1899, Bose announced his invention of the "iron-mercury-iron coherer with telephone detector" in a paper presented at Royal Society, London.

[edit] Julio Cervera Baviera

Julio Cervera Baviera
Recent studies in Spain credit Julio Cervera Baviera as the inventor of the radio (in 1902).[19] [20] Cervera Baviera obtained patents in England, Germany, Belgium, and Spain. In May-June 1899, Cervera had, with the blessing of the Spanish Army, visited Marconi's radiotelegraphic installations on the English Channel, and worked to develop his own system. He began collaborating with Marconi on resolving the problem of a wireless communication system, obtaining some patents by the end of 1899. Cervera, who had worked with Marconi and his assistant George Kemp in 1899, resolved the difficulties of wireless telegraph and obtained his first patents prior to the end of that year. On March 22, 1902, Cervera founded the Spanish Wireless Telegraph and Telephone Corporation and brought to his corporation the patents he had obtained in Spain, Belgium, Germany and England.[21] He established the second and third regular radiotelegraph service in the history of the world in 1901 and 1902 by maintaining regular transmissions between Tarifa and Ceuta for three consecutive months, and between Javea (Cabo de la Nao) and Ibiza (Cabo Pelado). This is after Marconi established the radiotelegraphic service between the Isle of Wight and Bournemouth in 1898. In 1906, Domenico Mazzotto wrote: "In Spain the Minister of War has applied the system perfected by the commander of military engineering, Julio Cervera Baviera (English patent No. 20084 (1899))."[22] Cervera thus achieved some success in this field, but his radiotelegraphic activities ceased suddenly, the reasons for which are unclear to this day.[23]

[edit] Turn of the century

Around the turn of the century, the Slaby-Arco wireless system was developed by Adolf Slaby and Georg von Arco. In 1900, Reginald Fessenden made a weak transmission of voice over the airwaves. Around 1900, Tesla opened the Wardenclyffe Tower facility and advertised services. In 1901, Marconi conducted the first successful transatlantic experimental radio communications. In 1903, Wardenclyffe Tower neared completion. Various theories exist on how Tesla intended to achieve the goals of this wireless system (reportedly, a 200 kW system). Tesla claimed that Wardenclyffe, as part of a World System of transmitters, would have allowed secure multichannel transceiving of information, universal navigation, time synchronization, and a global location system.
In 1904, The U.S. Patent Office reversed its decision, awarding Marconi a patent for the invention of radio, possibly influenced by Marconi's financial backers in the States, who included Thomas Edison and Andrew Carnegie. This also allowed the U.S. government (among others) to avoid having to pay the royalties that were being claimed by Tesla for use of his patents. For more information see Marconi's radio work. In 1907, Marconi established the first commercial transatlantic radio communications service, between Clifden, Ireland and Glace Bay, Newfoundland.

[edit] Early radio telegraphy and telephony

Donald Manson working as an employee of the Marconi Company (England, 1906)

[edit] British Marconi

Using various patents, the company called British Marconi was established in 1897 and began communication between coast radio stations and ships at sea. This company along with its subsidiary American Marconi, had a stranglehold on ship to shore communication. It operated much the way American Telephone and Telegraph operated until 1983, owning all of its equipment and refusing to communicate with non-Marconi equipped ships. Many inventions improved the quality of radio, and amateurs experimented with uses of radio, thus the first seeds of broadcasting were planted.

[edit] Telefunken

The company Telefunken was founded on May 27, 1903 as "Telefunken society for wireless telefon" of Siemens & Halske (S & H) and the Allgemeine Elektrizitäts-Gesellschaft (General Electricity Company) as joint undertakings for radio engineering in Berlin. It continued as a joint venture of AEG and Siemens AG, until Siemens left in 1941. In 1911, Kaiser Wilhelm II sent Telefunken engineers to West Sayville, New York to erect three 600-foot (180-m) radio towers there. Nikola Tesla assisted in the construction. A similar station was erected in Nauen, creating the only wireless communication between North America and Europe.

[edit] Reginald Fessenden

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. On Christmas Eve 1906, Reginald Fessenden used an Alexanderson alternator and rotary spark-gap transmitter to make the first radio audio broadcast, from Brant Rock, Massachusetts. Ships at sea heard a broadcast that included Fessenden playing O Holy Night on the violin and reading a passage from the Bible.

[edit] Ferdinand Braun

In 1909, Marconi and Karl Ferdinand Braun were awarded the Nobel Prize in Physics for "contributions to the development of wireless telegraphy".

[edit] Charles David Herrold

In April 1909 Charles David Herrold, an electronics instructor in San Jose, California constructed a broadcasting station. It used spark gap technology, but modulated the carrier frequency with the human voice, and later music. The station "San Jose Calling" (there were no call letters), continued to eventually become today's KCBS in San Francisco. Herrold, the son of a Santa Clara Valley farmer, coined the terms "narrowcasting" and "broadcasting", respectively to identify transmissions destined for a single receiver such as that on board a ship, and those transmissions destined for a general audience. (The term "broadcasting" had been used in farming to define the tossing of seed in all directions.) Charles Herrold did not claim to be the first to transmit the human voice, but he claimed to be the first to conduct "broadcasting". To help the radio signal to spread in all directions, he designed some omnidirectional antennas, which he mounted on the rooftops of various buildings in San Jose. Herrold also claims to be the first broadcaster to accept advertising (he exchanged publicity for a local record store for records to play on his station), though this dubious honour usually is foisted on WEAF (1922).
RMS Titanic (April 2, 1912).
In 1912, the RMS Titanic sank in the northern Atlantic Ocean. After this, wireless telegraphy using spark-gap transmitters quickly became universal on large ships. In 1913, the International Convention for the Safety of Life at Sea was convened and produced a treaty requiring shipboard radio stations to be manned 24 hours a day. A typical high-power spark gap was a rotating commutator with six to twelve contacts per wheel, nine inches (229 mm) to a foot wide, driven by about 2000 volts DC. As the gaps made and broke contact, the radio wave was audible as a tone in a Magnetic detector at a remote location. The telegraph key often directly made and broke the 2000 volt supply. One side of the spark gap was directly connected to the antenna. Receivers with thermionic valves became commonplace before spark-gap transmitters were replaced by continuous wave transmitters.

[edit] Harold J. Power

On March 8, 1916, Harold Power with his radio company American Radio and Research Company (AMRAD), broadcast the first continuous broadcast in the world from Tufts University under the call sign 1XE (it lasted 3 hours). The company later became the first to broadcast on a daily schedule, and the first to broadcast radio dance programs, university professor lectures, the weather, and bedtime stories [24].

[edit] Edwin Armstrong

Inventor Edwin Howard Armstrong is credited with developing many of the features of radio as it is known today. Armstrong patented three important inventions that made today's radio possible. Regeneration, the superheterodyne circuit and wide-band frequency modulation or FM. Regeneration or the use of positive feedback greatly increased the amplitude of received radio signals to the point where they could be heard without headphones. The superhet simplified radio receivers by doing away with the need for several tuning controls. It made radios more sensitive and selective as well. FM gave listeners a static-free experience with better sound quality and fidelity than AM.

[edit] Other innovators

Many scientists and inventors contributed to the invention of wireless telegraphy and telephony. Individuals that helped to further the science include, among others:

[edit] Audio broadcasting (1919 to 1950s)

See also: Old-time radio

[edit] Crystal sets

In the 1920s, the United States government publication, "Construction and Operation of a Simple Homemade Radio Receiving Outfit", showed how almost any person handy with simple tools could a build an effective crystal radio receiver.
The most common type of receiver before vacuum tubes was the crystal set, although some early radios used some type of amplification through electric current or battery. Inventions of the triode amplifier, motor-generator, and detector enabled audio radio. The use of amplitude modulation (AM), with which more than one station can simultaneously send signals (as opposed to spark-gap radio, where one transmitter covers the entire bandwidth of spectra) was pioneered by Fessenden and Lee de Forest.
To this day there is a small but avid base of fans of this technology who study and practice the art and science of designing and making crystal sets as a hobby; the Boy Scouts of America have often undertaken such craft projects to introduce boys to electronics and radio, and quite a number of them having grown up remain staunch fans of a radio that 'runs on nothing, forever'. As the only energy available is that gathered by the antenna system, there are inherent limitations on how much sound even an ideal set could produce, but with only moderately decent antenna systems remarkable performance is possible with a superior set.

[edit] The first vacuum tubes

During the mid 1920s, amplifying vacuum tubes (or thermionic valves in the UK) revolutionized radio receivers and transmitters. John Ambrose Fleming developed an earlier tube known as an "oscillation valve" (it was a diode). Lee De Forest placed a screen, the "grid" electrode, between the filament and plate electrode, creating the triode. The Dutch engineer Hanso Schotanus à Steringa Idzerda made the first regular wireless broadcast for entertainment from his home in The Hague on 6 November 1919. He broadcast his popular program four nights per week until 1924 when he ran into financial troubles.
On 27 August 1920, regular wireless broadcasts for entertainment began in Argentina, pioneered by the group around Enrique Telémaco Susini, and spark gap telegraphy stopped. On 31 August 1920 the first known radio news program was broadcast by station 8MK, the unlicensed predecessor of WWJ (AM) in Detroit, Michigan. In 1922 regular wireless broadcasts for entertainment began in the UK from the Marconi Research Centre 2MT at Writtle near Chelmsford, England. Early radios ran the entire power of the transmitter through a carbon microphone. In the 1920s, the Westinghouse company bought Lee De Forest's and Edwin Armstrong's patent. During the mid 1920s, Amplifying vacuum tubes (US)/thermionic valves (UK) revolutionized radio receivers and transmitters. Westinghouse engineers developed a more modern vacuum tube.

[edit] Licensed commercial public radio stations

The question of the 'first' publicly-targeted licensed radio station in the U.S. has more than one answer and depends on semantics. Settlement of this 'first' question may hang largely upon what constitutes 'regular' programming.
  • It is commonly attributed to KDKA in Pittsburgh, Pennsylvania, which in October 1920 received its license and went on the air as the first US licensed commercial broadcasting station. (Their engineer Frank Conrad had been broadcasting from his own station since 1916.) Technically, KDKA was the first of several already-extant stations to receive a 'limited commercial' license.
  • On February 17, 1919, station 9XM at the University of Wisconsin in Madison broadcast human speech to the public at large. 9XM was first experimentally licensed in 1914, began regular Morse code transmissions in 1916, and its first music broadcast in 1917. Regularly scheduled broadcasts of voice and music began in January 1921. That station is still on the air today as WHA.
  • On August 20, 1920, at least two months before KDKA, E.W. Scripps's WBL (now WWJ) in Detroit started broadcasting. It has carried a regular schedule of programming to the present.
  • There is the history noted above of Charles David Herrold's radio services (eventually KCBS) going back to 1909.
Broadcasting was not yet supported by advertising or listener sponsorship. The stations owned by manufacturers and department stores were established to sell radios and those owned by newspapers to sell newspapers and express the opinions of the owners. In the 1920s, radio was first used to transmit pictures visible as television. During the early 1930s, single sideband (SSB) and frequency modulation (FM) were invented by amateur radio operators. By 1940, they were established commercial modes.
Westinghouse was brought into the patent allies group, General Electric, American Telephone and Telegraph, and Radio Corporation of America, and became a part owner of RCA. All radios made by GE and Westinghouse were sold under the RCA label 60% GE and 40% Westinghouse. ATT's Western Electric would build radio transmitters. The patent allies attempted to set up a monopoly, but they failed due to successful competition. Much to the dismay of the patent allies, several of the contracts for inventor's patents held clauses protecting "amateurs" and allowing them to use the patents. Whether the competing manufacturers were really amateurs was ignored by these competitors.
These features arose:
http://en.wikipedia.org/wiki/Radio_history
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