Timeline of radio
Encyclopedia
The timeline of radio lists within the history of radio
, the technology
and events that produced instruments that use radio
waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history
.
, at the time called wireless telegraphy
, is contentious. 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 Nikola Tesla
, Guglielmo Marconi
, and Alexander Popov.
. Marconi equipped ships with life saving wireless communications and established the first transatlantic radio service. Tesla developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and transmitted long distant signals.
s, the company called "British Marconi
" was established and began communication between coast radio station
s 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 own 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. Around the turn of the century, the Slaby-Arco wireless system was developed by Adolf Slaby
and Georg von Arco
(later incorporated into Telefunken
).
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.
History of 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. Radio development began as "wireless telegraphy"...
, the technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
and events that produced instruments that use radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history
History
History is the discovery, collection, organization, and presentation of information about past events. History can also mean the period of time after writing was invented. Scholars who write about history are called historians...
.
Origins and developments
The identity of the original inventor of radioInvention Of Radio
Within the history of radio, several people were involved in the invention of radio and there were many key inventions in what became the modern systems of wireless. Radio development began as "wireless telegraphy"...
, at the time called wireless telegraphy
Wireless telegraphy
Wireless telegraphy is a historical term used today to apply to early radio telegraph communications techniques and practices, particularly those used during the first three decades of radio before the term radio came into use....
, is contentious. The key invention for the beginning of "wireless transmission of data using the entire frequency spectrum", known as the spark-gap transmitter
Spark-gap transmitter
A spark-gap transmitter is a device for generating radio frequency electromagnetic waves using a spark gap.These devices served as the transmitters for most wireless telegraphy systems for the first three decades of radio and the first demonstrations of practical radio were carried out using them...
, has been attributed to Nikola Tesla
Nikola Tesla
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...
, Guglielmo Marconi
Guglielmo Marconi
Guglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
, and Alexander Popov.
Radio's prehistory (19th century)
- 1820: Hans Christian ØrstedHans Christian ØrstedHans Christian Ørsted was a Danish physicist and chemist who discovered that electric currents create magnetic fields, an important aspect of electromagnetism...
discovered the relationship between electricityElectricityElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
and magnetismMagnetismMagnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...
in a very simple experimentExperimentAn experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
. He demonstrated that a wire carrying a current was able to deflect a magnetized compassCompassA compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...
needle. - 1831: Michael FaradayMichael FaradayMichael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....
began a series of experiments in which he discovered electromagnetic inductionElectromagnetic inductionElectromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids....
. The relation was mathematically modeled by Faraday's lawFaraday's law of inductionFaraday's law of induction dates from the 1830s, and is a basic law of electromagnetism relating to the operating principles of transformers, inductors, and many types of electrical motors and generators...
, which subsequently became one of the four Maxwell equationsMaxwell's equationsMaxwell's equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electrodynamics, classical optics, and electric circuits. These fields in turn underlie modern electrical and communications technologies.Maxwell's equations...
. Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal. - 1861 to 1865: James Clerk MaxwellJames Clerk MaxwellJames Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...
made experiments with electromagnetic waves. - July 30, 1872: Mahlon LoomisMahlon LoomisMahlon Loomis was an early wireless telegraph experimenter.-Early history:...
was issued . - 1873: Maxwell, as a result of experiments, first described the theoretical basis of the propagation of electromagnetic waves in his paper to the Royal SocietyRoyal SocietyThe Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
A Dynamical Theory of the Electromagnetic Field. - 28 November 1875: Thomas EdisonThomas EdisonThomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...
announced to the press that while experimenting with the telegraph, he had noted a phenomenon that he termed "etheric forceEtheric forceEtheric force, a term coined by Thomas Edison to describe a phenomenon that was later to be understood as high frequency electromagnetic waves, effectively, radio...
". He abandoned this research when Elihu ThomsonElihu ThomsonElihu Thomson was an American engineer and inventor who was instrumental in the founding of major electrical companies in the United States, the United Kingdom and France.-Early life:...
, among others, ridiculed the idea. - 1878: David E. HughesDavid E. HughesDavid Edward Hughes , was a British scientist and musician. Hughes was co-inventor of the microphone, a harpist and a professor of music.-Biography:...
was the first to transmit and receive radio waves when he noticed that his induction balanceMetal detectorA metal detector is a device which responds to metal that may not be readily apparent.The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field...
caused noise in the receiver of his homemade telephoneTelephoneThe telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
. - 1880: David Hughes demonstrated his discovery to the Royal Society, but was told it was merely inductionElectromagnetic inductionElectromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids....
. - 1884: Temistocle Calzecchi-OnestiTemistocle Calzecchi-Onesti-References:* at radiomarconi.com* at browsebiography.com...
at FermoFermoFermo is a town and comune of the Marche, Italy, in the Province of Fermo.Fermo is located on a hill, the Sabulo with a fine view, on a branch from Porto San Giorgio on the Adriatic coast railway....
in Italy invented a tube filled with ironIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
filings, called a "cohererCohererThe coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the twentieth century. Invented around 1890 by French scientist Édouard Branly, it consisted of a tube or capsule containing two electrodes spaced a...
". - 1884 to 1886: Edouard BranlyEdouard BranlyÉdouard Eugène Désiré Branly was a French inventor, physicist and professor at the Institut Catholique de Paris. He is primarily known for his early involvement in wireless telegraphy and his invention of the Branly coherer around 1890.-Biography:The coherer was the first widely used detector for...
of France produced an improved version of the coherer. - 1885: Edison took out a patent on a system of radio communication between ships, which he then sold to Guglielmo MarconiGuglielmo MarconiGuglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
.
- 1886 to 1888: Heinrich Rudolf HertzHeinrich Rudolf HertzHeinrich Rudolf Hertz was a German physicist who clarified and expanded the electromagnetic theory of light that had been put forth by Maxwell...
validated Maxwell's theory through experiment. He demonstrated that radio radiation had all the properties of waves (now called Hertzian wavesTransverse waveA transverse wave is a moving wave that consists of oscillations occurring perpendicular to the direction of energy transfer...
), and discovered that the electromagnetic equations could be reformulated into a partial differential equationPartial differential equationIn mathematics, partial differential equations are a type of differential equation, i.e., a relation involving an unknown function of several independent variables and their partial derivatives with respect to those variables...
called the wave equationWave equationThe wave equation is an important second-order linear partial differential equation for the description of waves – as they occur in physics – such as sound waves, light waves and water waves. It arises in fields like acoustics, electromagnetics, and fluid dynamics...
. - 1885 to 1892: Claims have been made that Murray, KentuckyMurray, KentuckyMurray is a city in Calloway County, Kentucky, United States. The population was 17,741 at the 2010 census and has a micropolitan area population of 37,191. It is the 22nd largest city in Kentucky...
farmer Nathan StubblefieldNathan StubblefieldNathan B. Stubblefield was an American inventor and Kentucky melon farmer. It has been claimed that Stubblefield invented the radio before either Nikola Tesla or Guglielmo Marconi, but his devices seem to have worked by audio frequency induction or, later, audio frequency earth conduction rather...
invented radio, but his devices seem to have worked by induction transmission rather than radio transmission. - 1893 to 1894: Roberto Landell de Moura, a Brazilian priest and scientist, conducted experiments. He did not publicize his achievement until 1900.
Wireless beginnings
In the history of radio and development of "wireless telegraphy", there are multiple claims to the invention of radioInvention Of Radio
Within the history of radio, several people were involved in the invention of radio and there were many key inventions in what became the modern systems of wireless. Radio development began as "wireless telegraphy"...
. Marconi equipped ships with life saving wireless communications and established the first transatlantic radio service. Tesla developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and transmitted long distant signals.
- 1893: At St. LouisSt. Louis, MissouriSt. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
, MissouriMissouriMissouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
, TeslaNikola TeslaNikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...
gave a public demonstration of "wirelessWirelessWireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
" radio communication. Addressing the Franklin InstituteFranklin InstituteThe Franklin Institute is a museum in Philadelphia, Pennsylvania, and one of the oldest centers of science education and development in the United States, dating to 1824. The Institute also houses the Benjamin Franklin National Memorial.-History:On February 5, 1824, Samuel Vaughn Merrick and...
in Philadelphia and the National Electric Light AssociationNational Electric Light AssociationThe National Electric Light Association was a national United States trade association including the operators of central power generation stations and interested individuals. Founded in 1885 by G. S. Bowen Terry and Charles A. Brown, it represented the interests of various private companies...
, he described in detail the principles of radio communication. The apparatus that he used contained all the elements that were incorporated into radio systems before the development of the "oscillation valve", the early vacuum tubeVacuum tubeIn electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
. Tesla was the first to apply the mechanism of electrical conduction to wireless practices. Also, he initially used sensitive electromagneticElectromagnetic radiationElectromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
receivers , that were unlike the less responsive cohererCohererThe coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the twentieth century. Invented around 1890 by French scientist Édouard Branly, it consisted of a tube or capsule containing two electrodes spaced a...
s later used by Marconi and other early experimenters. Afterwards, the principle of radio communication (sending signals through space to receivers) was publicized widely. Various scientists, inventors, and experimenters begin to investigate wireless methods. - 1894: Heinrich Rudolf HertzHeinrich Rudolf HertzHeinrich Rudolf Hertz was a German physicist who clarified and expanded the electromagnetic theory of light that had been put forth by Maxwell...
died. - 19 August 1894: British physicist Sir Oliver Lodge demonstrated the reception of Morse code signaling using radio waves using a "coherer".
- November 1894: The Indian physicist, Jagdish Chandra BoseJagdish Chandra BoseAcharya Sir Jagadish Chandra Bose, CSI, CIE, FRS was a Bengali polymath: a physicist, biologist, botanist, archaeologist, as well as an early writer of science fiction...
, demonstrated publicly the use of radio waves in Calcutta, but he was not interested in patenting his work.Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves, proving that communication signals can be sent without using wires. - 1894: The Russian physicist Alexander Popov built a cohererCohererThe coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the twentieth century. Invented around 1890 by French scientist Édouard Branly, it consisted of a tube or capsule containing two electrodes spaced a...
. - 1896: Marconi was awarded a patent for radio with BritishUnited KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
PatentPatentA patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
12039, Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-for. This is the initial patent for 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 is widely researched. - 1896: Bose went to London on a lecture tour and met Marconi, who was conducting wireless experiments for the British post office.
- 1897: Marconi established the radio station on the Isle of WightIsle of WightThe Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
, EnglandEnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. In the U.S. during 1897, Tesla applied for two key radio patents. Those two patents were issued in early 1900. - 1898: Marconi opened the first radio factory, on Hall Street, Chelmsford, England, employing around 50 people.
- 1899: Bose announced his invention of the "iron-mercury-iron coherer with telephone detector" in a paper presented at Royal Society, London.
- 1900: Reginald FessendenReginald FessendenReginald Aubrey Fessenden , a naturalized American citizen born in Canada, was an inventor who performed pioneering experiments in radio, including early—and possibly the first—radio transmissions of voice and music...
made a weak transmission of voice over the airwaves. - Around 1900: Tesla opened the Wardenclyffe TowerWardenclyffe TowerWardenclyffe Tower also known as the Tesla Tower, was an early wireless telecommunications tower designed by Nikola Tesla and intended for commercial trans-Atlantic wireless telephony, broadcasting, and to demonstrate the transmission of power without interconnecting wires...
facility and advertised services. - 1901: MarconiGuglielmo MarconiGuglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
claims to have received in St. John'sSignal Hill, Newfoundland and LabradorSignal Hill is a hill which overlooks the city of St. John's, Newfoundland and Labrador, Canada.Due to its strategic placement overlooking the harbour, fortifications have been placed on the hill since the mid 17th century.-History:...
, Newfoundland a radio signal transmitted from PoldhuPoldhuPoldhu is a small area in south Cornwall, England, UK, situated on the Lizard Peninsula; it comprises Poldhu Point and Poldhu Cove. It lies on the coast west of Goonhilly Downs, with Mullion to the south and Porthleven to the north...
in CornwallCornwallCornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
(UK), but this is disputed. The claims of Marconi's signal and case against it are still discussed. - 1904: The U.S. Patent OfficeUnited States Patent and Trademark OfficeThe United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...
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 EdisonThomas EdisonThomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...
and Andrew CarnegieAndrew CarnegieAndrew Carnegie was a Scottish-American industrialist, businessman, and entrepreneur who led the enormous expansion of the American steel industry in the late 19th century...
. 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.
Spark-gap telegraphy
Using various patentPatent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
s, the company called "British Marconi
Marconi Company
The Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as The Wireless Telegraph & Signal Company...
" was established and began communication between coast radio station
Coast radio station
A coast radio station is an on-shore maritime radio station which monitors radio distress frequencies and relays ship-to-ship and ship-to-land communications.-See also:* Marconi Station* Utility station...
s 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 own 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. Around the turn of the century, the Slaby-Arco wireless system was developed by Adolf Slaby
Adolf Slaby
Adolf Karl Heinrich Slaby was a German wireless pioneer and the first Professor of electro-technology at the Technical University of Berlin .-Education:Slaby was born in Berlin, the son of a bookbinder...
and Georg von Arco
Georg von Arco
Georg Wilhelm Alexander Hans Graf von Arco was a German physicist, radio pioneer, and one of the joint founders of the "Society for Wireless Telegraphy" which became the Telefunken company. He was an engineer and the technical director of Telefunken...
(later incorporated into Telefunken
Telefunken
Telefunken is a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft...
).
- 24 December 1906: Reginald FessendenReginald FessendenReginald Aubrey Fessenden , a naturalized American citizen born in Canada, was an inventor who performed pioneering experiments in radio, including early—and possibly the first—radio transmissions of voice and music...
used an Alexanderson alternatorAlexanderson alternatorAn Alexanderson alternator is a rotating machine invented by Ernst Alexanderson in 1904 for the generation of high frequency alternating current up to 100 kHz, for use as a radio transmitter...
and rotary spark-gap transmitterSpark-gap transmitterA spark-gap transmitter is a device for generating radio frequency electromagnetic waves using a spark gap.These devices served as the transmitters for most wireless telegraphy systems for the first three decades of radio and the first demonstrations of practical radio were carried out using them...
to make the first radio audio broadcast, from Brant Rock, MassachusettsOcean Bluff-Brant Rock, MassachusettsOcean Bluff-Brant Rock is a census-designated place in Plymouth County, Massachusetts, United States, composed of the villages of Ocean Bluff and Brant Rock in the town of Marshfield...
. Ships at sea heard a broadcast that included Fessenden playing O Holy NightO Holy Night"O Holy Night" is a well-known Christmas carol composed by Adolphe Adam in 1847 to the French poem "Minuit, chrétiens" by Placide Cappeau , a wine merchant and poet, who had been asked by a parish priest to write a Christmas poem...
on the violinViolinThe violin is a string instrument, usually with four strings tuned in perfect fifths. It is the smallest, highest-pitched member of the violin family of string instruments, which includes the viola and cello....
and reading a passage from the BibleBibleThe Bible refers to any one of the collections of the primary religious texts of Judaism and Christianity. There is no common version of the Bible, as the individual books , their contents and their order vary among denominations...
. - 1907: Marconi established the first permanent transatlantic wireless service from ClifdenClifdenClifden is a town on the coast of County Galway, Ireland and being Connemara's largest town, it is often referred to as "the Capital of Connemara". It is located on the Owenglen River where it flows into Clifden Bay...
, Ireland to Glace Bay, Nova Scotia. - 1909: Marconi and Karl Ferdinand BraunKarl Ferdinand BraunKarl Ferdinand Braun was a German inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of the radio and television technology: he shared with Guglielmo Marconi the 1909 Nobel Prize in Physics.-Biography:Braun was born in Fulda, Germany, and...
were awarded the Nobel Prize in PhysicsNobel Prize in PhysicsThe Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
for "contributions to the development of wireless telegraphy". - April 1909: Charles David Herrold, an electronics instructor in San Jose, CaliforniaSan Jose, CaliforniaSan Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...
constructed a broadcasting station. It used spark gapSpark gapA spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the voltage difference between the conductors exceeds the gap's breakdown voltage, a spark forms,...
technology, but modulated the carrier frequency with the human voice, and later music. The station "San Jose Calling" (there were no call letters), continued in an unbroken lineage to eventually become today's KCBSKCBS (AM)KCBS is an all-news radio station in San Francisco, California, that is a key West Coast flagship radio station of the CBS Radio Network and Westwood One. Its transmitter is located in Novato, California. KCBS currently has studios on Battery Street, where it shares the location with co-owned KPIX...
in San Francisco. Herrold, the son of a Santa Clara ValleySanta Clara ValleyThe Santa Clara Valley is a valley just south of the San Francisco Bay in Northern California in the United States. Much of Santa Clara County and its county seat, San José, are in the Santa Clara Valley. The valley was originally known as the Valley of Heart’s Delight for its high concentration...
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 omnidirectional antennaOmnidirectional antennaIn radio communication, an omnidirectional antenna is an antenna which radiates radio wave power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna's axis. This radiation pattern is often...
s, which he mounted on the rooftops of various buildings in San Jose. Herrold also claims to be the first broadcaster to accept advertisingAdvertisingAdvertising is a form of communication used to persuade an audience to take some action with respect to products, ideas, or services. Most commonly, the desired result is to drive consumer behavior with respect to a commercial offering, although political and ideological advertising is also common...
, although advertising generally involves paid announcements. He exchanged publicity for a local record store for records to play on his station. - 1910: The Wireless Ship ActWireless Ship Act of 1910The Wireless Ship Act was passed by the United States Congress in 1910, requiring all ships of the United States traveling over two-hundred miles off the coast and carrying over fifty passengers to be equipped with wireless radio equipment with a range of one-hundred miles...
was passed by the United States CongressUnited States CongressThe United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
, requiring all ships of the United States traveling over two-hundred miles off the coast and carrying over fifty passengers to be equipped with wireless radio equipment with a range of one-hundred miles. The legislation was prompted by a shipping accident in 1909, where a single wireless operator saved the lives of 1200 people. - 1912: The RMS Titanic sank. While in distress, it contacted several other ships via wireless. After this, wireless telegraphy using spark-gap transmitters quickly became universal on large ships. The Radio Act of 1912Radio Act of 1912The Radio Act of 1912 is a United States federal law that mandated that all radio stations in the US be licensed by the federal government, as well as mandating that seagoing vessels continuously monitor distress frequencies....
required all seafaring vessels to maintain 24-hour radio watch and keep in contact with nearby ships and coastal radio stations. - 1913: MarconiMarconi CompanyThe Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as The Wireless Telegraph & Signal Company...
initiated duplex transatlantic wireless communication between North America and Europe for the first time, using receiver stations in LetterfrackLetterfrackLetterfrack or Letterfrac is a small village in the Connemara area of County Galway, Ireland. It was founded by the Quakers in the mid-19th century. The village is 15 km north-east of Clifden on Barnaderg Bay and lies at the head of Ballinakill harbour...
Ireland, and Louisbourg, Nova ScotiaLouisbourg, Nova ScotiaLouisbourg is a community in Nova Scotia's Cape Breton Regional Municipality.-History:The town's name was given by French military forces who founded the Fortress of Louisbourg and its fortified seaport on the southwest part of the harbour, in honour of Louis XV...
. - 1913: The International Convention for the Safety of Life at SeaInternational Convention for the Safety of Life at SeaThe International Convention for the Safety of Life at Sea is an international maritime safety treaty. The SOLAS Convention in its successive forms is generally regarded as the most important of all international treaties concerning the safety of merchant ships.- History :The first version of the...
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 to a foot wide, driven by about 2000 voltVoltThe volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
s DC. As the gaps made and broke contact, the radio wave was audible as a tone in a crystal set. 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.
Audio broadcasting (1915 to 1950s)
- 1916: First regular broadcasts on 9XM (now WHAWHA (AM)-External links:*Jeff Miller . *Randall Davidson. PortalWisconsin.org...
) - Wisconsin state weather, delivered in Morse Code - 1919: First clear transmission of human speech, (on 9XM) after experiments with voice (1918) and music (1917).
- 1920: Regular wireless broadcasts for entertainment began in ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, pioneered by the group around Enrique Telémaco SusiniEnrique Telémaco SusiniEnrique Telémaco Susini was an Argentine entrepreneur and media pioneer.In 1920, Susini led the effort for the first radio broadcast in Argentina, and subsequently established one of the earliest regular radio stations in the world...
. - 1920: Spark-gap telegraphy stopped.
- 20 August 1920: E.W. Scripps's WWJWWJ (AM)WWJ is Detroit, Michigan's only 24-hour all-news radio station. Broadcasting at 950 kHz, the station is owned and operated by CBS Corporation subsidiary CBS Radio. The station first went on the air on August 20, 1920 with the call sign 8MK...
in Detroit received its commercial broadcasting license and started broadcasting. It has carried a regular schedule of programming to the present. Broadcasting was not yet supported by advertisingAdvertisingAdvertising is a form of communication used to persuade an audience to take some action with respect to products, ideas, or services. Most commonly, the desired result is to drive consumer behavior with respect to a commercial offering, although political and ideological advertising is also common...
. The stations owned by manufacturers and department stores were established to sell radios and those owned by newspapers to sell papers and express the opinions of the owners. - 31 August 1920: The first known radio news program was broadcast by station 8MK, the unlicensed predecessor of WWJ (AM)WWJ (AM)WWJ is Detroit, Michigan's only 24-hour all-news radio station. Broadcasting at 950 kHz, the station is owned and operated by CBS Corporation subsidiary CBS Radio. The station first went on the air on August 20, 1920 with the call sign 8MK...
in Detroit, MichiganDetroit, MichiganDetroit is the major city among the primary cultural, financial, and transportation centers in the Metro Detroit area, a region of 5.2 million people. As the seat of Wayne County, the city of Detroit is the largest city in the U.S. state of Michigan and serves as a major port on the Detroit River...
. - October 1920: Westinghouse in Pittsburgh, PennsylvaniaPittsburgh, PennsylvaniaPittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...
became the first US commercial broadcasting station to be licensed when it was granted call letters KDKAKDKA (AM)KDKA is a radio station licensed to Pittsburgh, Pennsylvania, USA. Created by the Westinghouse Electric Corporation on November 2, 1920, it is one of the world's first modern radio stations , a distinction that has also been challenged by other stations, although it has claimed to be the first in...
. (Their engineer Frank ConradFrank ConradFrank Conrad was a radio broadcasting pioneer who worked as the Assistant Chief Engineer for the Westinghouse Electric Corporation in Pittsburgh, Pennsylvania,...
had been broadcasting from his own station since 1916.) - 1922: Regular wireless broadcasts for entertainment began in the UK from the MarconiGuglielmo MarconiGuglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
Research Centre at WrittleWrittleThe village of Writtle lies a mile west of Chelmsford, Essex, England, it has a traditional village green, complete with duck pond and a Norman church; and was once described as: 'one of the loveliest villages in England, with a ravishing variety of ancient cottages'...
near Chelmsford, England. Early radios ran the entire power of the transmitter through a carbon microphone. - Mid 1920s:
- AmplifyingAmplifierGenerally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
vacuum tubeVacuum tubeIn electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s revolutionized radio receivers and transmitterTransmitterIn electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
s; Westinghouse engineers improved them. (Before that, the commonest type of receiver was the crystal setCrystal radio receiverthumb|Boy listening to a modern crystal radioA crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no battery or power source and runs on the power received from radio waves by a long wire antenna...
, although some early radios used some type of amplification through electric current or battery.) - Inventions of the triode amplifier, generatorElectrical generatorIn electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
, and detector enabled audio radio. - FessendenReginald FessendenReginald Aubrey Fessenden , a naturalized American citizen born in Canada, was an inventor who performed pioneering experiments in radio, including early—and possibly the first—radio transmissions of voice and music...
and Lee de ForestLee De ForestLee De Forest was an American inventor with over 180 patents to his credit. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the "electronic age", as the Audion helped to usher in the widespread use...
pioneered the invention of amplitude-modulatedAmplitude modulationAmplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...
radio (AM radio), so more than one station can send signals (as opposed to spark-gap radio, where one transmitter covers the entire bandwidth of spectra). WestinghouseWestinghouse Electric (1886)Westinghouse Electric was an American manufacturing company. It was founded in 1886 as Westinghouse Electric Company and later renamed Westinghouse Electric Corporation by George Westinghouse. The company purchased CBS in 1995 and became CBS Corporation in 1997...
bought DeForestLee De ForestLee De Forest was an American inventor with over 180 patents to his credit. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the "electronic age", as the Audion helped to usher in the widespread use...
's and Armstrong's patent.
- Amplifying
- 1920s: Radio was first used to transmit pictures visible as televisionTelevisionTelevision is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
. - Early 1930s: Single sideband (SSB) and frequency modulationFrequency modulationIn telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...
(FM) were invented by amateur radio operators. By 1940, they were established commercial modes.
Westinghouse was brought into the patent allies group, General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
, 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.
| United States United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... ) or governmental (Europe Europe Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting... ) station networks Federal Radio Commission The Federal Radio Commission was a government body that regulated radio use in the United States from its creation in 1926 until its replacement by the Federal Communications Commission in 1934... Federal Communications Commission The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the... Soap opera A soap opera, sometimes called "soap" for short, is an ongoing, episodic work of dramatic fiction presented in serial format on radio or as television programming. The name soap opera stems from the original dramatic serials broadcast on radio that had soap manufacturers, such as Procter & Gamble,... Edwin Armstrong Edwin Howard Armstrong was an American electrical engineer and inventor. Armstrong was the inventor of modern frequency modulation radio.... invented it. FM uses frequency modulation Frequency modulation In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant... of the radio wave to minimize static White noise White noise is a random signal with a flat power spectral density. In other words, the signal contains equal power within a fixed bandwidth at any center frequency... and interference from electrical equipment and the atmosphere, in the audio program. Federal Communications Commission The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the... (FCC). Supreme Court of the United States The Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases... shortly after Tesla's death, because prior art Prior art Prior art , in most systems of patent law, constitutes all information that has been made available to the public in any form before a given date that might be relevant to a patent's claims of originality... existed before Marconi's patent was established. Ignoring Tesla's prior art Prior art Prior art , in most systems of patent law, constitutes all information that has been made available to the public in any form before a given date that might be relevant to a patent's claims of originality... , the decision may have let the U.S. government avoid paying damages that the Marconi Company was claiming for use of its patents during World War I World War I World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918... ; it is speculated that the U.S. government initially refused to grant Marconi the patent right, to nullify any claims Tesla had for compensation. World War II World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis... : The FM radio broadcast was introduced in Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate... . Europe Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting... at a meeting in Copenhagen Copenhagen Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region... . Because of the recent war, Germany (which was not even invited) was only given a few medium-wave frequencies, which are not very good for broadcasting. For this reason Germany began broadcasting on USW, "ultra short wave" (nowadays called VHF). After some amplitude modulation Amplitude modulation Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent... experience with VHF, it was realized that FM radio was a much better alternative for VHF radio than AM. Later 20th century developments
Telex on radioTelegraphyTelegraphy Telegraphy is the long-distance transmission of messages via some form of signalling technology. Telegraphy requires messages to be converted to a code which is known to both sender and receiver... did not go away on radio. Instead, the degree of automation increased. On land-lines in the 1930s, Teletypewriters automated encoding, and were adapted to pulse-code dialing to automate routing, a service called telex Teleprinter A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the... . For thirty years, telex was the absolute cheapest form of long-distance communication, because up to 25 telex channels could occupy the same bandwidth as one voice channel. For business and government, it was an advantage that telex directly produced written documents. Telex systems were adapted to short-wave radio by sending tones over single sideband. CCITT ITU-T The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications.... R.44 (the most advanced pure-telex standard) incorporated character-level error detection and retransmission as well as automated encoding and routing. For many years, telex-on-radio (TOR) was the only reliable way to reach some third-world countries. TOR remains reliable, though less-expensive forms of e-mail are displacing it. Many national telecom companies historically ran nearly pure telex networks for their governments, and they ran many of these links over short wave radio. Internet radioInternet radioInternet radio Internet radio is an audio service transmitted via the Internet... consists of sending radio-style audio programming over streaming Internet Internet The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide... connections: no radio transmitters need be involved at any point in the process. See also
External links
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