A semaphore telegraph is an early system of conveying information by means of visual signals, using towers with pivoting shutters known as blades or paddles. Information is encoded by the position of the mechanical elements; the most used system was invented in 1792 in France by Claude Chappe, was popular in the late eighteenth to early nineteenth centuries. Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5–20 miles. Operators at each tower would watch the neighboring tower through a spyglass, when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower; this system was much faster than post riders for conveying a message over long distances, had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century and would be cheaper and more private; the line-of-sight distance between relay stations was limited by geography and weather, prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station.
Modern derivatives of the semaphore system include the heliograph. The word semaphore was coined in 1801 by the French inventor of the semaphore line itself, Claude Chappe, he composed it from the Greek elements σῆμα. Chappe coined the word tachygraph, meaning "fast writer". However, the French Army preferred to call Chappe's semaphore system the telegraph, meaning "far writer", coined by French statesman André François Miot de Mélito; the word semaphoric was first printed in English in 1808: "The newly constructed Semaphoric telegraphs", referring to the destruction of telegraphs in France. The word semaphore was first printed in English in 1816: "The improved Semaphore has been erected on the top of the Admiralty", referring to the installation of a simpler telegraph invented by Sir Home Popham. Semaphore telegraphs are called "optical telegraphs", "shutter telegraph chains", "Chappe telegraphs" or "Napoleonic semaphore". Optical telegraphy dates from ancient times, in the form of hydraulic telegraphs and smoke signals.
Modern design of semaphores was first foreseen by the British polymath Robert Hooke, who gave a vivid and comprehensive outline of visual telegraphy to the Royal Society in a 1684 submission in which he outlined many practical details. The system was never put into practice. One of the first experiments of optical signalling was carried out by the Anglo-Irish landowner and inventor, Sir Richard Lovell Edgeworth in 1767, he placed a bet with his friend, the horse racing gambler Lord March, that he could transmit knowledge of the outcome of the race in just one hour. Using a network of signalling sections erected on high ground, the signal would be observed from one station to the next by means of a telescope; the signal itself consisted of a large pointer that could be placed into eight possible positions in 45 degree increments. A series of two such signals gave a total 64 code elements and a third signal took it up to 512, he returned to his idea after hearing of Chappe's system. Credit for the first successful optical telegraph goes to the French engineer Claude Chappe and his brothers in 1792, who succeeded in covering France with a network of 556 stations stretching a total distance of 4,800 kilometres.
Le système Chappe was used for national communications until the 1850s. During 1790–1795, at the height of the French Revolution, France needed a swift and reliable communication system to thwart the war efforts of its enemies. France was surrounded by the forces of Britain, the Netherlands, Prussia and Spain, the cities of Marseille and Lyon were in revolt, the British Fleet held Toulon; the only advantage France held was the lack of cooperation between the allied forces due to their inadequate lines of communication. In the summer of 1790, the Chappe brothers set about devising a system of communication that would allow the central government to receive intelligence and to transmit orders in the shortest possible time. On 2 March 1791 at 11am, they sent the message “si vous réussissez, vous serez bientôt couverts de gloire” between Brulon and Parce, a distance of 16 kilometres; the first means used a combination of black and white panels, clocks and codebooks to send their message. The Chappes carried out experiments during the next two years, on two occasions their apparatus at Place de l'Étoile, Paris was destroyed by mobs who thought they were communicating with royalist forces.
However, in the summer of 1792 Claude was appointed Ingénieur-Télégraphiste and charged with establishing a line of stations between Paris and Lille, a distance of 230 kilometres. It was used to carry dispatches for the war between Austria. In 1794, it brought news of a French capture of Condé-sur-l'Escaut from the Austrians less than an hour after it occurred; the first symbol of a message to Lille would pass through 15 stations in only nine minutes. The speed of the line varied with the weather, but the line to Lille transferred 36 symbols, a complete message, in about 32 minutes. Another line of 50 stations was completed in 1798, covering 488 km betwe
History of radio
The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed. Radio development began as "wireless telegraphy". Radio history involves matters of broadcasting; the idea of wireless communication predates the discovery of "radio" with experiments in "wireless telegraphy" via inductive and capacitive induction and transmission through the ground and train tracks from the 1830s on. James Clerk Maxwell showed in theoretical and mathematical form in 1864 that electromagnetic waves could propagate through free space, it is that the first intentional transmission of a signal by means of electromagnetic waves was performed in an experiment by David Edward Hughes around 1880, although this was considered to be induction at the time. In 1888 Heinrich Rudolf Hertz was able to conclusively prove transmitted airborne electromagnetic waves in an experiment confirming Maxwell's theory of electromagnetism.
After the discovery of these "Hertzian waves" many scientists and inventors experimented with wireless transmission, some trying to develop a system of communication, some intentionally using these new Hertzian waves, some not. Maxwell's theory showing that light and Hertzian electromagnetic waves were the same phenomenon at different wavelengths led "Maxwellian" scientist such as John Perry, Frederick Thomas Trouton and Alexander Trotter to assume they would be analogous to optical signaling and the Serbian American engineer Nikola Tesla to consider them useless for communication since "light" could not transmit further than line of sight. In 1892 the physicist William Crookes wrote on the possibilities of wireless telegraphy based on Hertzian waves and in 1893 Tesla proposed a system for transmitting intelligence and wireless power using the earth as the medium. Others, such as Amos Dolbear, Sir Oliver Lodge, Reginald Fessenden, Alexander Popov were involved in the development of components and theory involved with the transmission and reception of airborne electromagnetic waves for their own theoretical work or as a potential means of communication.
Over several years starting in 1894 the Italian inventor Guglielmo Marconi built the first complete, commercially successful wireless telegraphy system based on airborne Hertzian waves. Marconi demonstrated the application of radio in military and marine communications and started a company for the development and propagation of radio communication services and equipment; the meaning and usage of the word "radio" has developed in parallel with developments within the field of communications and can be seen to have three distinct phases: electromagnetic waves and experimentation. In an 1864 presentation, published in 1865, James Clerk Maxwell proposed theories of electromagnetism, with mathematical proofs, that showed that light and predicted that radio and x-rays were all types of electromagnetic waves propagating through free space. In 1886–88 Heinrich Rudolf Hertz conducted a series of experiments that proved the existence of Maxwell's electromagnetic waves, using a frequency in what would be called the radio spectrum.
Many individuals—inventors, engineers and businessmen—constructed systems based on their own understanding of these and other phenomena, some predating Maxwell and Hertz's discoveries. Thus "wireless telegraphy" and radio wave-based systems can be attributed to multiple "inventors". Development from a laboratory demonstration to a commercial entity spanned several decades and required the efforts of many practitioners. 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 could detect signals over a few hundred yards. He demonstrated his discovery to the Royal Society in 1880, but was told it was induction, therefore abandoned further research. Thomas Edison came across the electromagnetic phenomenon while experimenting with a telegraph at Menlo Park, he noted an unexplained transmission effect while experimenting with a telegraph. He referred to this as etheric force in an announcement on November 28, 1875.
Elihu Thomson published his findings on Edison's new "force", again attributing it to induction, an explanation that Edison accepted. Edison would go on the next year to take out U. S. Patent 465,971 on a system of electrical wireless communication between ships based on electrostatic coupling using the water and elevated terminals. Although this was not a radio system, Edison would sell his patent rights to his friend Guglielmo Marconi at the Marconi Company in 1903, rather than another interested party who might end up working against Marconi's interests. Between 1886 and 1888 Heinrich Rudolf Hertz published the results of his experiments wherein he was able to transmit electromagnetic waves through the air, proving Maxwell's electromagnetic theory. Thus, given Hertz comprehensive discoveries, radio waves were referred to as "Hertzian waves". Between 1890 and 1892 physicists such as John Perry, Frederick Thomas Trouton and William Crookes proposed electromagnetic or Hertzian waves as a navigation aid or means of communication, with Crookes writing on the possibilities of wireless telegraphy based on Hertzian waves in 1892.
After learning of Hertz' demonstrations of wireless transmission, inventor Nikola Tesla began developing his own systems based on Hertz' and Maxwell's ideas working toward a means o
A telephone number is a sequence of digits assigned to a fixed-line telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network or other public and private networks. A telephone number serves as an address for switching telephone calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange; the exchange completes the call either to another locally connected subscriber or via the PSTN to the called party. Telephone numbers are assigned within the framework of a national or regional telephone numbering plan to subscribers by telephone service operators, which may be commercial entities, state-controlled administrations, or other telecommunication industry associations.
Telephone numbers were first used in 1879 in Lowell, when they replaced the request for subscriber names by callers connecting to the switchboard operator. Over the course of telephone history, telephone numbers had various lengths and formats, included most letters of the alphabet in leading positions when telephone exchange names were in common use until the 1960s. Telephone numbers are dialed in conjunction with other signaling code sequences, such as vertical service codes, to invoke special telephone service features; when telephone numbers were first used they were short, from one to three digits, were communicated orally to a switchboard operator when initiating a call. As telephone systems have grown and interconnected to encompass worldwide communication, telephone numbers have become longer. In addition to telephones, they have been used to access other devices, such as computer modems and fax machines. With landlines and pagers falling out of use in favor of all-digital always-connected broadband Internet and mobile phones, telephone numbers are now used by data-only cellular devices, such as some tablet computers, digital televisions, video game controllers, mobile hotspots, on which it is not possible to make or accept a call.
The number contains the information necessary to identify uniquely the intended endpoint for the telephone call. Each such endpoint must have a unique number within the public switched telephone network. Most countries use fixed-length numbers and therefore the number of endpoints determines the necessary length of the telephone number, it is possible for each subscriber to have a set of shorter numbers for the endpoints most used. These "shorthand" or "speed calling" numbers are automatically translated to unique telephone numbers before the call can be connected; some special services have their own short numbers The dialing plan in some areas permits dialing numbers in the local calling area without using area code or city code prefixes. For example, a telephone number in North America consists of a three-digit area code, a three-digit central office code, four digits for the line number. If the area has no area code overlays or if the provider allows it, seven-digit dialing may be permissible for calls within the area, but some areas have implemented mandatory ten-digit dialing.
Other special phone numbers are used for high-capacity numbers with several telephone circuits a request line to a radio station where dozens or hundreds of callers may be trying to call in at once, such as for a contest. For each large metro area, all of these lines will share the same prefix, the last digits corresponding to the station's frequency, callsign, or moniker. In the international telephone network, the format of telephone numbers is standardized by ITU-T recommendation E.164. This code specifies that the entire number should be 15 digits or shorter, begin with a country prefix. For most countries, this is followed by an area code or city code and the subscriber number, which might consist of the code for a particular telephone exchange. ITU-T recommendation E.123 describes how to represent an international telephone number in writing or print, starting with a plus sign and the country code. When calling an international number from a landline phone, the + must be replaced with the international call prefix chosen by the country the call is being made from.
Many mobile phones allow the + to be entered directly, by pressing and holding the "0" for GSM phones, or sometimes "*" for CDMA phones. The format and allocation of local phone numbers are controlled by each nation's respective government, either directly or by sponsored organizations. In the United States, each state's public service commission regulates, as does the Federal Communications Commission. In Canada, which shares the same country code with the U. S. regulation is through the Canadian Radio-television and Telecommunications Commission. Local number portability allows a subscriber to requ
A teleprinter is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. They were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering; the machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could be used to create punched tape for data storage and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media; these included a simple pair of wires. A teleprinter attached to a modem could communicate through standard switched public telephone lines; this latter configuration was used to connect teleprinters to remote computers in time-sharing environments. Teleprinters have been replaced by electronic computer terminals which have a computer monitor instead of a printer.
Teleprinters are still used in the aviation industry, variations called Telecommunications Devices for the Deaf are used by the hearing impaired for typed communications over ordinary telephone lines. The teleprinter evolved through a series of inventions by a number of engineers, including Samuel Morse, Alexander Bain, Royal Earl House, David Edward Hughes, Emile Baudot, Donald Murray, Charles L. Krum, Edward Kleinschmidt and Frederick G. Creed. Teleprinters were invented in order to send and receive messages without the need for operators trained in the use of Morse code. A system of two teleprinters, with one operator trained to use a keyboard, replaced two trained Morse code operators; the teleprinter system improved message speed and delivery time, making it possible for messages to be flashed across a country with little manual intervention. There were a number of parallel developments on both sides of the Atlantic Ocean. In 1835 Samuel Morse devised a recording telegraph, Morse code was born.
Morse's instrument used a current to displace an electromagnet, which moved a marker, therefore recording the breaks in the current. Cooke & Wheatstone received a British patent covering telegraphy in 1837 and a second one in 1840 which described a type-printing telegraph with steel type fixed at the tips of petals of a rotating brass daisy-wheel, struck by an “electric hammer” to print Roman letters through carbon paper onto a moving paper tape. In 1841 Alexander Bain devised an electromagnetic printing telegraph machine, it used pulses of electricity created by rotating a dial over contact points to release and stop a type-wheel turned by weight-driven clockwork. The critical issue was to have the sending and receiving elements working synchronously. Bain attempted to achieve this using centrifugal governors to regulate the speed of the clockwork, it was patented, along with other devices, on April 21, 1841. By 1846, the Morse telegraph service was operational between Washington, D. C. and New York.
Royal Earl House patented his printing telegraph that same year. He linked two 28-key piano-style keyboards by wire; each piano key represented a letter of the alphabet and when pressed caused the corresponding letter to print at the receiving end. A "shift" key gave each main key two optional values. A 56-character typewheel at the sending end was synchronised to coincide with a similar wheel at the receiving end. If the key corresponding to a particular character was pressed at the home station, it actuated the typewheel at the distant station just as the same character moved into the printing position, in a way similar to the daisy wheel printer, it was thus an example of a synchronous data transmission system. House's equipment could transmit around 40 readable words per minute, but was difficult to manufacture in bulk; the printer could print out up to 2,000 words per hour. This invention was first put in operation and exhibited at the Mechanics Institute in New York in 1844. Landline teleprinter operations began in 1849, when a circuit was put in service between Philadelphia and New York City.
In 1855, David Edward Hughes introduced an improved machine built on the work of Royal Earl House. In less than two years, a number of small telegraph companies, including Western Union in early stages of development, united to form one large corporation – Western Union Telegraph Co. – to carry on the business of telegraphy on the Hughes system. In France, Émile Baudot designed in 1874 a system using a five-unit code, which began to be used extensively in that country from 1877; the British Post Office adopted the Baudot system for use on a simplex circuit between London and Paris in 1897, subsequently made considerable use of duplex Baudot systems on their Inland Telegraph Services. During 1901, Baudot's code was modified by Donald Murray, prompted by his development of a typewriter-like keyboard; the Murray system employed an intermediate step, a keyboard perforator, which allowed an operator to punch a paper tape, a tape transmitter for sending the message from the punched tape. At the receiving end of the line, a printing mechanism would
Telecommunication is the transmission of signs, messages, writings and sounds or information of any nature by wire, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology, it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is used in its plural form because it involves many different technologies. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, optical heliographs. Other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, loud whistles. 20th- and 21st-century technologies for long-distance communication involve electrical and electromagnetic technologies, such as telegraph and teleprinter, radio, microwave transmission, fiber optics, communications satellites.
A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse, Alexander Graham Bell, Edwin Armstrong and Lee de Forest, as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth; the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, the Latin communicare, meaning to share. Its modern use is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié. Communication was first used as an English word in the late 14th century, it comes from Old French comunicacion, from Latin communicationem, noun of action from past participle stem of communicare "to share, divide out.
Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots, was used by the Romans to aid their military. Frontinus said; the Greeks conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Sumatra, and in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, chains of beacons were used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London. In 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris.
However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres. As a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. On 25 July 1837 the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke, English scientist Sir Charles Wheatstone. Both inventors viewed their device as "an improvement to the electromagnetic telegraph" not as a new device. Samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837, his code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was completed on 27 July 1866, allowing transatlantic telecommunication for the first time; the conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849.
However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. Starting in 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using the newly discovered phenomenon of radio waves, showing by 1901 that they could be transmitted across the Atlantic Ocean; this was the start of wireless telegraphy by radio. Voice and music had little early success. World War I accelerated the development of radio for military communications. After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated development of radio for the wartime purposes of aircraft and land communication, radio navigation and radar. Development of stereo FM broadcasting of radio
The smoke signal is one of the oldest forms of long-distance communication. It is a form of visual communication used over long distance. In general smoke signals are used to transmit news, signal danger, or gather people to a common area. In ancient China, soldiers stationed along the Great Wall would alert each other of impending enemy attack by signaling from tower to tower. In this way, they were able to transmit a message as far away as 750 kilometres in just a few hours. Misuse of the smoke signal is known to have contributed to the fall of the Western Zhou Dynasty in the 8th century BCE. King You of Zhou had a habit of fooling his warlords with false warning beacons in order to amuse Bao Si, his concubine. Polybius, a Greek historian, devised a more complex system of alphabetical smoke signals around 150 BCE, which converted Greek alphabetic characters into numeric characters, it enabled messages to be signaled by holding sets of torches in pairs. This idea, known as the "Polybius square" lends itself to cryptography and steganography.
This cryptographic concept has been used with Japanese Hiragana and the Germans in the years of the First World War. The North American indigenous peoples communicated via smoke signal; each tribe had understanding. A signaler started a fire on an elevation using damp grass, which would cause a column of smoke to rise; the grass would be taken off as it dried and another bundle would be placed on the fire. Reputedly the location of the smoke along the incline conveyed a meaning. If it came from halfway up the hill, this would signify all was well, but from the top of the hill it would signify danger. Smoke signals remain in use today. In Rome, the College of Cardinals uses smoke signals to indicate the selection of a new Pope during a papal conclave. Eligible cardinals conduct a secret ballot; the ballots are burned after each vote. Black smoke indicates a failed ballot. Colored smoke grenades are used by military forces to mark positions during calls for artillery or air support. Smoke signals may refer to smoke-producing devices used to send distress signals.
Lewis and Clark's journals cite several occasions when they adopted the Native American method of setting the plains on fire to communicate the presence of their party or their desire to meet with local tribes. Yámanas of South America used fire to send messages by smoke signals, for instance if a whale drifted ashore; the large amount of meat required notification of many people. They might have used smoke signals on other occasions, thus it is possible that Magellan saw such fires but he may have seen the smoke or lights of natural phenomena; the Cape Town Noon Gun the smoke its firing generates, was used to set marine chronometers in Table Bay. Aboriginal Australians throughout Australia would send up smoke signals for various purposes. Sometimes to notify others of their presence when entering lands which were not their own. Sometimes used to describe visiting whites, smoke signals were the fastest way. Smoke signals were sometimes to notify of incursions by hostile tribes, or to arrange meetings between hunting parties of the same tribe.
This signal could be from a fixed lookout on a ridge of from a mobile band of tribesman. "Putting up a smoke" would result in nearby individuals or groups replying with their own signals. To carry information, the colour of the smoke was varied, sometimes black, white or blue depending on whether the material being burnt was wet grass, dry grass, reeds or other, the shape of the smoke could be a column, ball or smoke ring; this message could include the names of individual tribesmen. Like other means of communication, signals could be misinterpreted. In one recorded instance, a smoke signal reply translated as "we are coming" was misinterpreted as joining a war party for protection of the tribe when it was hunting parties coming together after a successful hunt. Modern avionics has made skywriting possible. Gusinde, Martin. Nordwind—Südwind. Mythen und Märchen der Feuerlandindianer. Kassel: E. Röth. Itsz, Rudolf. "A kihunyt tüzek földje". Napköve. Néprajzi elbeszélések. Budapest: Móra Könyvkiadó. Pp. 93–112.
Translation of the original: Итс, Р.Ф.. Камень солнца. Ленинград: Detskaya Literatura. Title means: “Stone of sun”. Myers, Fred. Pintupi Country, Pintupi Self. USA: Smithsonian Institution
Edwin Howard Armstrong
Edwin Howard Armstrong was an American electrical engineer and inventor, best known for developing FM radio and the superheterodyne receiver system. He held 42 patents and received numerous awards, including the first Medal of Honor awarded by the Institute of Radio Engineers, the French Legion of Honor, the 1941 Franklin Medal and the 1942 Edison Medal, he was inducted into the National Inventors Hall of Fame and included in the International Telecommunication Union's roster of great inventors. Armstrong was born in the Chelsea district of New York City, the oldest of John and Emily Armstrong's three children, his father began working at a young age at the American branch of the Oxford University Press, which published bibles and standard classical works advancing to the position of vice president. His parents first met at the North Presbyterian Church, located at Ninth Avenue, his mother's family had strong ties to Chelsea, an active role in church functions. When the church moved north, the Smiths and Armstrongs followed, in 1895 the Armstrong family moved from their brownstone row house at 347 West 29th Street to a similar house at 26 West 97th Street in the Upper West Side.
The family was comfortably middle class. At the age of eight, Armstrong contracted Sydenham's chorea, an infrequent but serious neurological disorder precipitated by rheumatic fever. For the rest of his life, Armstrong was afflicted with a physical tic exacerbated by excitement or stress. Due to this illness, he was home-tutored for two years. To improve his health, the Armstrong family moved to a house overlooking the Hudson River, at 1032 Warburton Avenue in Yonkers; the Smith family subsequently moved next door. Armstrong's tic and the time missed from school led him to become withdrawn. From an early age, Armstrong showed an interest in electrical and mechanical devices trains, he loved heights and constructed a makeshift backyard antenna tower that included a bosun's chair for hoisting himself up and down its length, to the concern of neighbors. Much of his early research was conducted in the attic of his parent's house. In 1909, Armstrong enrolled at Columbia University in New York City, where he became a member of the Epsilon Chapter of the Theta Xi engineering fraternity, studied under Professor Michael Pupin at the Hartley Laboratories, a separate research unit at Columbia.
Another of his instructors, Professor John H. Morecroft remembered Armstrong as being intensely focused on the topics that interested him, but somewhat indifferent to the rest of his studies, he was known for challenging conventional wisdom and being quick to question the opinions of both professors and peers. In one case, he recounted how he tricked an instructor he disliked into receiving a severe electrical shock, he stressed the practical over the theoretical, stating that progress was more the product of experimentation and work based on physical reasoning than on mathematical calculation and formulae. Armstrong graduated from Columbia in 1913. During World War I, Armstrong served in the Signal Corps as a captain and a major. In 1934, he filled the vacancy left by John H. Morecroft's death, receiving an appointment as a Professor of Electrical Engineering at Columbia, a position he held the remainder of his life. Following college graduation, he received a $600 one-year appointment as a laboratory assistant at Columbia, after which he nominally worked as a research assistant, for a salary of $1 a year, under Professor Pupin.
Unlike most engineers, Armstrong never became a corporate employee. He set up a self-financed independent research and development laboratory at Columbia, owned his patents outright. Armstrong began working on his first major invention. In late 1906, Lee de Forest had invented the three-element "grid Audion" vacuum-tube. How vacuum tubes worked was not understood at the time. De Forest's initial Audions did not have a high vacuum and developed a blue glow at modest plate voltages. By 1912, how vacuum tubes worked was understood, the advantages of high vacuum tubes were appreciated. While growing up Armstrong had experimented with the early, temperamental, "gassy" Audions. Spurred by the discoveries, he developed a keen interest in gaining a detailed scientific understanding of how vacuum-tubes worked. In conjunction with Professor Morecroft he used an oscillograph to conduct comprehensive studies, his breakthrough discovery was determining that employing positive feedback produced amplification hundreds of times greater than attained, with the amplified signals now strong enough so that receivers could use loudspeakers instead of headphones.
Further investigation revealed that when the feedback was increased beyond a certain level a vacuum-tube would go into oscillation, thus could be used as a continuous-wave radio transmitter. Beginning in 1913 Armstrong prepared a series of comprehensive demonstrations and papers that documented his research, in late 1913 applied for patent protection covering the regenerative circuit. On October 6, 1914, U. S. patent 1,113,149 was issued for his discovery. Although Lee de Forest discounted Armstrong's findings, beginning in 1915 de Forest filed a series of competing patent applications that copied Armstrong's claims, now stating that he had discovered regeneration first, based on August 6, 1912 notebook entry, while working for the Federal Telegraph company, prior to the