Amateur Radio Station with multiple Receivers and Transceivers

Radio Portal

Radio is the wireless transmission of signals, 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. It does not require a medium of transport. Information is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude or their frequency. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.
Radio is a medium of wireless communication. ... Image File history File links NX1Z_Radio. ... Image File history File links NX1Z_Radio. ... Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... Image File history File links Radio_icon. ... For the use of the term in networking, see Wireless networking. ... In telecommunications, modulation is the process of varying a periodic waveform, i. ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... For other uses, see Frequency (disambiguation). ... For other uses, see Light (disambiguation). ... Radio propagation is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. ... In telecommunications, modulation is the process of varying a periodic waveform, i. ... Demodulation is the act of removing the modulation from an analog signal. ...

Although Nikola Tesla first demonstrated the feasibility of wireless communications in 1893, Guglielmo Marconi, an Italian inventor, was the first to develop workable radio communication. He sent and received his first radio signal in Italy in 1895.
Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ...

The word 'radio' is used to describe this phenomenon, and radio transmissions are classed as radio frequency emissions.

Etymology

Originally, radio or radioteleography was called 'wireless telegraphy', which was shortened to 'wireless'. The prefix radio- in the sense of wireless transmission was first recorded in the word radioconductor, coined by the French physicist Edouard Branly in 1897 and based on the verb to radiate (in Latin "radius" means "spoke of a wheel, beam of light, ray"). 'Radio' as a noun is said to have been coined by advertising expert Waldo Warren (White 1944). The word appears in a 1907 article by Lee de Forest, was adopted by the United States Navy in 1912 and became common by the time of the first commercial broadcasts in the United States in the 1920s. (The noun 'broadcasting' itself came from an agricultural term, meaning 'scattering seeds'.) The term was then adopted by other languages in Europe and Asia, although British Commonwealth countries retained the term 'wireless' until the mid-20th century. In Japanese, the term 'wireless' is the basis for the term 'radio wave' although the term for the device that listens to radio waves is literally 'device for receiving sounds'. Eugène Édouard Désiré Branly (23 October 1844 - 24 March 1940) was a French physicist. ... Lee De Forest, (August 26, 1873 – June 30, 1961) was an American inventor with over 300 patents to his credit. ... USN redirects here. ...

In recent years the term 'wireless' has gained renewed popularity through the rapid growth of short range networking, e.g., WLAN ('Wireless Local Area Network'), WiFi and Bluetooth as well as mobile telephony, e.g., GSM and UMTS. Today, the term 'radio' often refers to the actual transceiver device or chip, whereas 'wireless' refers to the system and/or method used for radio communication. Hence one talks about radio transceivers and Radio Frequency Identification (RFID), but about wireless devices and wireless sensor networks. Wikipedia does not yet have an article with this exact name. ... Wi-Fi (or Wi-fi, WiFi, Wifi, wifi), short for Wireless Fidelity, is a set of standards for wireless local area networks (WLAN) currently based on the IEEE 802. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... Global System for Mobile communications (GSM: originally from Groupe Spécial Mobile) is the most popular standard for mobile phones in the world. ... Universal Mobile Telecommunications System (UMTS) is one of the third-generation (3G) mobile phone technologies. ... An EPC RFID tag used for Wal-Mart Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. ...

Invention

Further information: Invention of radio

Although invention was long attributed to Guglielmo Marconi, the identity of the original inventor of radio, at the time called wireless telegraphy, is contentious[1]. Development from a laboratory demonstration to commercial utility spanned several decades and required the efforts of many practitioners. The controversy over who invented the radio, with the benefit of hindsight, can be broken down as follows: // Within the timeline of radio, many people were involved in the invention of radio transmission of information as we know it today. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ... // Within the timeline of radio, many people were involved in the invention of radio transmission of information as we know it today. ... Wireless telegraphy is the practice of remote writing (see telegraphy) without the wires normally involved in an electrical telegraph. ...

• In 1887, David E. Hughes transmitted Morse code by radio at and below the Super low frequency range (via a clockwork transmitter).

• In 1888, Heinrich Hertz produced and measured the Ultra High Frequency range (via a sparkgap transmitter).

• In 1891, Nikola Tesla began wireless research. He developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and transmitted long-distance signals.

• Between 1893 and 1894, Roberto Landell de Moura, a Brazilian priest and scientist, conducted experiments. He did not publicise his achievement until 1900 but later obtained Brazilian patent.

• In 1894 in Kolkata (Calcutta), Sir Jagdish Chandra Bose (J. C. Bose) invented the mercury coherer, together with the telephone receiver.

• Alexander Stepanovich Popov, in 1894, built his first radio receiver, which contained a coherer but actually coherer was first demonstrated by J.C. Bose. Popov demonstrated the coherer, further refined as a lightning detector, to the Russian Physical and Chemical Society on May 7, 1895.

• In 1894, Guglielmo Marconi read about Hertz's and Tesla's work on wireless telegraphy, and began his own experiments.

• In December of 1901 Guglielmo Marconi used J.C. Bose's inventions to receive the radio signal in his first transatlantic radio communication over a distance of 2000 miles from Poldhu, UK, to St. Johns, Newfoundland. Marconi was celebrated worldwide for this achievement. Soon after the patent was given to Marconi. He even received the Nobel Prize.

• In early 1900s Reginald Fessenden _[2] and Lee de Forest invented amplitude-modulated (AM) radio) allowing an audio signal to be sent over the air.

• In 1935 Edwin H. Armstrong invented frequency-modulated (FM) radio, so that an audio signal can avoid "static," that is, interference from electrical equipment and atmospherics.

• In 1943, the U.S. Supreme Court acknowledged that Marconi's work wasn't original, and the patent ownership is given back to Nikola Tesla. However, Tesla died shortly before the decision was announced.^[1]

David E. Hughes David Edward Hughes (16 May 1831 – 22 January 1900) was an accomplished musician and a professor of music as well as chair of natural philosophy at a ladies seminary in Bardstown, Kentucky. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Heinrich Rudolf Hertz (February 22, 1857 - January 1, 1894) was the German physicist and mechanician for whom the hertz, an SI unit, is named. ... This article is about the radio frequency. ... The Spark-gap transmitter is a device for generating radio frequency electromagnetic waves. ... Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... A TRIBUTE TO FATHER ROBERTO LANDELL DE MOURA Father Landell de Moura Surely, we all admire the great men and women who left an indelible and positive mark for humanity, in every manifestation of human wisdom. ... , “Calcutta” redirects here. ... Sir Jagadish Chandra Bose (Bengali: জগদীশ চন্দ্র বসু Jôgdish Chôndro Boshu) (November 30, 1858 – November 23, 1937) was a Bengali physicist from undivided India, who pioneered the investigation of radio and microwave optics. ... This article is about the element. ... The coherer was the first device used to detect radio signals in wireless telegraphy. ... For other uses, see Telephone (disambiguation). ... Alexander Popov (1859-1905) Alexander Stepanovich Popov (Russian: Александр Степанович Попов) (March 4/16 1859 - January 13/December 31 1905/6) was a Russian physicist who publicly demonstrated the transmission of radio waves (but did not apply for a patent for this invention). ... The coherer was the first device used to detect radio signals in wireless telegraphy. ... is the 127th day of the year (128th in leap years) in the Gregorian calendar. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ... Reginald Fessenden (October 6, 1866 – July 22, 1932) was a Canadian inventor, best known for his work in early radio. ... Lee De Forest, (August 26, 1873 – June 30, 1961) was an American inventor with over 300 patents to his credit. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... Mediumwave radio transmissions (sometimes called Medium frequency or MF) are those between the frequencies of 300 kHz and 3000 kHz. ... Edwin Howard Armstrong (December 18, 1890 – January 31, 1954) was an American electrical engineer and inventor. ... In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity sound over broadcast radio. ...

History

For more details on this topic, see History of radio.

Tesla demonstrating wireless transmissions during his high frequency and potential lecture of 1891. After continued research, Tesla gave the fundamentals of radio in 1893.

In 1893, in St. Louis, Missouri, Nikola Tesla made devices for his experiments with electricity. Addressing the Franklin Institute in Philadelphia and the National Electric Light Association, he described and demonstrated in detail the principles of his wireless work. [3] The descriptions contained all the elements that were later incorporated into radio systems before the development of the vacuum tube. He initially experimented with magnetic receivers, unlike the coherers (detecting devices consisting of tubes filled with iron filings which had been invented by Temistocle Calzecchi-Onesti at Fermo in Italy in 1884) used by Guglielmo Marconi and other early experimenters. [4]. For the controversy about who invented radio, see Invention of radio. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Nickname: Location in the state of Missouri Coordinates: , Country State County Independent City Government  - Mayor Francis G. Slay (D) Area  - City  66. ... This article is about the U.S. state. ... Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... Franklin Institute Front steps as seen from the adjacent Moore College This article is about the science museum in Philadelphia. ... For other uses, see Philadelphia (disambiguation) and Philly. ... The National Electric Light Association (NELA) was a national trade association including the operators of central power generation stations and interested individuals. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... The coherer was the first device used to detect radio signals in wireless telegraphy. ... For other uses, see Iron (disambiguation). ... Temistocle Calzecchi Onesti (b. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ...

In 1894 Alexander Stepanovich Popov built his first radio receiver, which contained a coherer. Further refined as a lightning detector, it was presented to the Russian Physical and Chemical Society on May 7, 1895. 1894 (MDCCCXCIV) was a common year starting on Monday (see link for calendar). ... Alexander Popov (1859-1905) Alexander Stepanovich Popov (Russian: Александр Степанович Попов) (March 4/16 1859 - January 13/December 31 1905/6) was a Russian physicist who publicly demonstrated the transmission of radio waves (but did not apply for a patent for this invention). ... For the device which is a tuner (radio) and a amplifier and/or loudspeaker, see receiver (home stereo). ... The coherer was the first device used to detect radio signals in wireless telegraphy. ... Lightning detector at the Kennedy Space Center in Florida. ... is the 127th day of the year (128th in leap years) in the Gregorian calendar. ... Year 1895 (MDCCCXCV) was a common year starting on Tuesday (link will display full calendar) of the Gregorian calendar (or a common year starting on Sunday of the 12-day-slower Julian calendar). ...

The first public demonstration of wireless telegraphy took place in the lecture theatre of the Oxford University Museum of Natural History on August 14, 1894, carried out by Professor Oliver Lodge and Alexander Muirhead. During the demonstration a radio signal was sent from the neighbouring Clarendon laboratory building, and received by apparatus in the lecture theatre. Vanity Fair cartoon. ... Alexander Muirhead (1848-1920) Born Saltoun, East Lothian, Scotland was an electrical engineer specialising in wireless telegraphy. ...

In 1896, Marconi was awarded the British patent 12039, Improvements in transmitting electrical impulses and signals and in apparatus there-for, for radio. In 1897 he established the world's first radio station on the Isle of Wight, England. Marconi opened the world's first "wireless" factory in Hall Street, Chelmsford, England in 1898, employing around 50 people. Year 1896 (MDCCCXCVI) was a leap year starting on Wednesday (link will display calendar). ... For other uses, see Patent (disambiguation). ... For other uses, see Isle of Wight (disambiguation). ... For other uses, see England (disambiguation). ... Arms of Chelmsford Borough Council This article is about the town of Chelmsford in Essex. ...

The next great invention was the vacuum tube detector, invented by Westinghouse engineers. On Christmas Eve, 1906, Reginald Fessenden used a synchronous rotary-spark transmitter for the first radio program 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. The first radio news program was broadcast August 31, 1920 by station 8MK in Detroit, Michigan. The first college radio station began broadcasting on October 14, 1920, from Union College, Schenectady, New York under the personal call letters of Wendell King, an African-American student at the school.[5] That month 2ADD, later renamed WRUC in 1940, aired what is believed to be the first public entertainment broadcast in the United States, a series of Thursday night concerts initially heard within a 100 mile radius and later for a 1,000 mile radius. In November 1920, it aired the first broadcast of a sporting event.[6],[7] At 9 pm on August 27, 1920, Sociedad Radio Argentina aired a live performance of Richard Wagner's Parsifal opera from the Coliseo Theater in downtown Buenos Aires, only about twenty homes in the city had a receiver to tune in. Meanwhile, Regular entertainment broadcasts commenced in 1922 from the Marconi Research Centre at Writtle, near Chelmsford, England. Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... Westinghouse logo (designed by Paul Rand) The Westinghouse Electric Company, headquartered in Monroeville, Pennsylvania, is an organization founded by George Westinghouse in 1886. ... The Christmas Eve (1904-05), watercolor painting by the Swedish painter Carl Larsson (1853-1919) Christmas Eve, the evening of December 24th, the preceding day or vigil before Christmas Day, is treated to a greater or a lesser extent in most Christian societies as part of the Christmas season. ... Reginald Fessenden (October 6, 1866 – July 22, 1932) was a Canadian inventor, best known for his work in early radio. ... Ocean Bluff and Brant Rock are villages located in the town of Marshfield in Plymouth County, Massachusetts. ... O Holy Night (Cantique de Noël) is a well-known Christmas carol composed by Adolphe Adam in 1847 to the French poem Minuit, chrétiens by Placide Cappeau (1808-1877), an accomplished amateur. ... For the Anne Rice novel, see Violin (novel). ... This Gutenberg Bible is displayed by the United States Library. ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 1920 (MCMXX) was a leap year starting on Thursday (link will display 1920) of the Gregorian calendar. ... Detroit redirects here. ... is the 287th day of the year (288th in leap years) in the Gregorian calendar. ... This article is about the Union College in New York. ... Schenectady is a city located in Schenectady County, New York, of which it is the county seat. ... This article is about the state. ... WRUC, 89. ... For the inventor of radio,Marconi see the competing claims in history of radio and the invention of radio. ... Statistics Population: Ordnance Survey OS grid reference: TL679063 Administration District: Chelmsford Shire county: Essex Region: East of England Constituent country: England Sovereign state: United Kingdom Other Ceremonial county: Essex Historic county: Essex Services Police force: Essex Police Ambulance service: East of England Post office and telephone Post town: CHELMSFORD Postal... Arms of Chelmsford Borough Council This article is about the town of Chelmsford in Essex. ...

One of the first developments in the early 20th century (1900-1959) was that aircraft used commercial AM radio stations for navigation. This continued until the early 1960s when VOR systems finally became widespread (though AM stations are still marked on U.S. aviation charts). In the early 1930s, single sideband and frequency modulation were invented by amateur radio operators. By the end of the decade, they were established commercial modes. Radio was used to transmit pictures visible as television as early as the 1920s. Commercial television transmissions started in North America and Europe in the 1940s. In 1954, Regency introduced a pocket transistor radio, the TR-1, powered by a "standard 22.5 V Battery". Flying machine redirects here. ... D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ... Aviation encompasses all the activities relating to airborne devices created by human ingenuity, generally known as aircraft. ... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ... In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. ... The Regency TR-4 shown here is similar in appearance to the original Regency TR-1 model, but the TR-1 has a gold tuning knob and lettering. ...

In 1960, Sony introduced its first transistorized radio, small enough to fit in a vest pocket, and able to be powered by a small battery. It was durable, because there were no tubes to burn out. Over the next 20 years, transistors replaced tubes almost completely except for very high-power uses. By 1963 color television was being regularly transmitted commercially, and the first (radio) communication satellite, TELSTAR, was launched. In the late 1960s, the U.S. long-distance telephone network began to convert to a digital network, employing digital radios for many of its links. In the 1970s, LORAN became the premier radio navigation system. Soon, the U.S. Navy experimented with satellite navigation, culminating in the invention and launch of the GPS constellation in 1987. In the early 1990s, amateur radio experimenters began to use personal computers with audio cards to process radio signals. In 1994, the U.S. Army and DARPA launched an aggressive, successful project to construct a software radio that could become a different radio on the fly by changing software. Digital transmissions began to be applied to broadcasting in the late 1990s. Year 1960 (MCMLX) was a leap year starting on Friday (link will display full calendar) of the Gregorian calendar. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... U.S. military MILSTAR communications satellite A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications using radio at microwave frequencies. ... This article needs to be cleaned up to conform to a higher standard of quality. ... LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from three or more stations to determine the position of a ship or aircraft. ... Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ... GPS redirects here. ... Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development of new technology for use by the military. ... A software-defined radio (SDR) system is a radio communication system which uses software for the modulation and demodulation of radio signals. ...

Uses of radio

Early uses were maritime, for sending telegraphic messages using Morse code between ships and land. The earliest users included the Japanese Navy scouting the Russian fleet during the Battle of Tsushima in 1905. One of the most memorable uses of marine telegraphy was during the sinking of the RMS Titanic in 1912, including communications between operators on the sinking ship and nearby vessels, and communications to shore stations listing the survivors. The first radio couldn't transmit sound or speech and was called the "wireless telegraph" 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ... Combatants Empire of Japan Russian Empire Commanders Heihachiro Togo Zinovi Rozhdestvenski # Nikolai Nebogatov Strength 4 battleships 27 cruisers destroyers and auxiliary vessels 8 battleships 3 coastal battleships 8 cruisers Casualties 117 dead 583 injured 3 torpedo boats sunk 4,380 dead 5,917 captured 21 ships sunk 7 captured 6... For other uses, see Titanic (disambiguation). ...

Radio was used to pass on orders and communications between armies and navies on both sides in World War I; Germany used radio communications for diplomatic messages once its submarine cables were cut by the British. The United States passed on President Woodrow Wilson's Fourteen Points to Germany via radio during the war. Broadcasting began from San Jose in 1909[8], and became feasible in the 1920s, with the widespread introduction of radio receivers, particularly in Europe and the United States. Besides broadcasting, point-to-point broadcasting, including telephone messages and relays of radio programs, became widespread in the 1920s and 1930s. Another use of radio in the pre-war years was the development of detecting and locating aircraft and ships by the use of radar (RAdio Detection And Ranging). “The Great War ” redirects here. ... Thomas Woodrow Wilson (December 28, 1856–February 3, 1924), was the twenty-eighth President of the United States. ... United States President Woodrow Wilson listed the Fourteen Points in a speech that he delivered to the United States Congress on January 8, 1918. ... For other uses, see San José. Nickname: Location of San Jose within Santa Clara County, California. ... For other uses, see Radar (disambiguation). ...

Today, radio takes many forms, including wireless networks and mobile communications of all types, as well as radio broadcasting. Before the advent of television, commercial radio broadcasts included not only news and music, but dramas, comedies, variety shows, and many other forms of entertainment. Radio was unique among methods of dramatic presentation in that it used only sound. For more, see radio programming. While the term wireless network may technically be used to refer to any type of network that is wireless, the term is most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a computer network (which is a... Mobile phones from various years Several mobile phones A mobile or cellular telephone is a long-range, portable electronic device for personal telecommunications over long distances. ... Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. ... Radio broadcasts have been a popular entertainment since the 1910s, though popularity has declined a little in some countries since television became widespread. ...

Audio

A Fisher 500 AM/FM hi-fi receiver from 1959.

AM broadcast radio sends music and voice in the Medium Frequency (MF—0.300 MHz to 3 MHz) radio spectrum. AM radio uses amplitude modulation, in which the amplitude of the transmitted signal is made proportional to the sound amplitude captured (transduced) by the microphone while the transmitted frequency remains unchanged. Transmissions are affected by static and interference because lightning and other sources of radio that are transmitting at the same frequency add their amplitudes to the original transmitted amplitude. The most wattage an AM radio station in the United States is allowed to use is 50,000 watts and the majority of stations that emit signals this powerful were grandfathered in; these include WGN (AM), WJR, and CKLW. In 1986 KTNN received the last granted 50,000 watt license. Image File history File links Download high-resolution version (3472x2261, 1413 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Radio ... Image File history File links Download high-resolution version (3472x2261, 1413 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Radio ... AM broadcasting is radio broadcasting using Amplitude Modulation. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... WGN-AM is a radio station on 720 kHz in Chicago, co-owned with WGN-TV. WGN-AMs transmitter is located in Elk Grove Village, Illinois. ... WJR is a radio station in Detroit, Michigan, United States. ... CKLW is a 50,000 watt AM radio station broadcasting at 800 kHz located in Windsor, Ontario. ... KTNN is a Navajo Language AM radio station, broadcasting from Window Rock, Arizona, the seat of the government of the Navajo Nation. ...

FM broadcast radio sends music and voice with higher fidelity than AM radio. In frequency modulation, amplitude variation at the microphone causes the transmitter frequency to fluctuate. Because the audio signal modulates the frequency and not the amplitude, an FM signal is not subject to static and interference in the same way as AM signals. FM is transmitted in the Very High Frequency (VHF—30 MHz to 300 MHz) radio spectrum. VHF radio waves act more like light, traveling in straight lines, hence the reception range is generally limited to about 50-100 miles. During unusual upper atmospheric conditions, FM signals are occasionally reflected back towards the Earth by the ionosphere, resulting in Long distance FM reception. FM receivers are subject to the capture effect, which causes the radio to only receive the strongest signal when multiple signals appear on the same frequency. FM receivers are relatively immune to lightning and spark interference. FM broadcasting is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation (FM) to provide high-fidelity sound over broadcast radio. ... In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... Microphones redirects here. ... Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ... TV DX and FM DX are two terms, customarily grouped together, that mean distant reception of TV and FM radio stations, respectively. ... In telecommunication, a capture effect is a phenomenon, associated with FM reception, in which only the stronger of two signals at or near the same frequency will be demodulated. ...

High power is useful in penetrating buildings, diffracting around hills, and refracting for some distance beyond the horizon. Consequently, 100,000 watt FM stations can regularly be heard up to 100 miles (160 km) away, and farther (e.g., 150 miles, 240 km) if there are no competing signals.

A few old "grandfathered" stations do not conform to these power rules. WBCT-FM (93.7) in Grand Rapids, Michigan, runs 320,000 watts ERP, and can increase to 500,000 watts ERP by the terms of its original license. This huge power level does not usually help to increase range as much as one might expect, because VHF frequencies travel in nearly straight lines over the horizon and off into space. Nevertheless, when there were fewer FM stations competing, this station could be heard near Bloomington, Illinois, almost 300 miles (500 km) distant. WBCT also known as B-93 is a radio station in Grand Rapids, Michigan with a country music format. ... Grand Rapids redirects here. ... This article is about the U.S. State. ... Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. ...

FM Sub-carrier services are secondary signals transmitted "piggyback" along with the main program. Special receivers are required to utilize these services. Analog channels may contain alternative programming, such as reading services for the blind, background music or stereo sound signals. In some extremely crowded metropolitan areas, the sub-channel program might be an alternate foreign language radio program for various ethnic groups. Sub-carriers can also transmit digital data, such as station identification, the current song's name, web addresses, or stock quotes. In some countries, FM radios automatically re-tune themselves to the same channel in a different district by using sub-bands. A multiple piggyback. ...

Aviation voice radios use VHF AM. AM is used so that multiple stations on the same channel can be received. (Use of FM would result in stronger stations blocking out reception of weaker stations due to FM's capture effect). Aircraft fly high enough that their transmitters can be received hundreds of miles (or kilometres) away, even though they are using VHF. VHF radio is radio transmission in the 30-300 MHz frequency range, as a means of short-range, line-of-sight verbal communication. ... In telecommunication, a capture effect is a phenomenon, associated with FM reception, in which only the stronger of two signals at or near the same frequency will be demodulated. ...

Marine voice radios can use AM in the shortwave High Frequency (HF—3 MHz to 30 MHz) radio spectrum for very long ranges or narrowband FM in the VHF spectrum for much shorter ranges. Government, police, fire and commercial voice services use narrowband FM on special frequencies. Fidelity is sacrificed to use a smaller range of radio frequencies, usually five kHz of deviation, rather than the 75 kHz used by FM broadcasts and 25 kHz used by TV sound. Portable VHF radio set Marine VHF radio is installed on all large ships and most motorized small craft. ... This article is about the SI unit of frequency. ...

Civil and military HF (high frequency) voice services use shortwave radio to contact ships at sea, aircraft and isolated settlements. Most use single sideband voice (SSB), which uses less bandwidth than AM. On an AM radio SSB sounds like ducks quacking. Viewed as a graph of frequency versus power, an AM signal shows power where the frequencies of the voice add and subtract with the main radio frequency. SSB cuts the bandwidth in half by suppressing the carrier and (usually) lower sideband. This also makes the transmitter about three times more powerful, because it doesn't need to transmit the unused carrier and sideband. A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ...

TETRA, Terrestrial Trunked Radio is a digital cell phone system for military, police and ambulances. Commercial services such as XM, WorldSpace and Sirius offer encrypted digital Satellite radio. The TETRA logo TErrestrial Trunked RAdio (TETRA) (formerly known as Trans European Trunked RAdio) is a specialist Professional Mobile Radio and walkie talkie standard used by police departments, fire departments, ambulance services and the military. ... XM Satellite Radio (NASDAQ: XMSR) is a satellite radio service in the United States based in Washington, DC and controlled by News Corporations DirecTV, General Motors, American Honda, Hughes Electronics, and several private investment groups. ... WorldSpaces AfriStar control center in Washington, D.C. WorldSpace is the worlds first digital satellite radio network. ... Sirius Satellite Radio NASDAQ: SIRI is one of two satellite radio (SDARS) services operating in the United States and Canada, along with XM Satellite Radio. ... // A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals. ...

Telephony

Mobile phones transmit to a local cell site (transmitter/receiver) that ultimately connects to the public switched telephone network (PSTN) through an optic fiber or microwave radio and other network elements. When the mobile phone nears the edge of the cell site's radio coverage area, the central computer switches the phone to a new cell. Cell phones originally used FM, but now most use various digital modulation schemes. Recent developments in Sweden (such as DROPme) allow for the instant downloading of digitial material from a radio broadcast (such as a song) to a mobile phone.

Satellite phones use satellites rather than cell towers to communicate. They come in two types: INMARSAT and Iridium. Both types provide world-wide coverage. INMARSAT uses geosynchronous satellites, with aimed high-gain antennas on the vehicles. Iridium uses 66 Low Earth Orbit satellites as the cells. A cleverly mounted base station on top of an Electricity pylon. ... The public switched telephone network (PSTN) is the network of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the network of the worlds public IP-based packet-switched networks. ... Inmarsat is an international telecommunications company founded in 1979, originally as an intergovernmental organization. ... An Iridium phone (without the aerial) The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ...

Video

Television sends the picture as AM and the sound as FM, with the sound carrier a fixed frequency (4.5 MHz in the NTSC system) away from the video carrier. Analog television also uses a vestigial sideband on the video carrier to reduce the bandwidth required. NTSC is the analog television system in use in Canada, Japan, Mexico, the Philippines, South Korea, Taiwan, the United States, and some other countries, mostly in the Americas (see map). ... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ...

Digital television uses 8VSB modulation in North America (under the ATSC digital television standard), and COFDM modulation elsewhere in the world (using the DVB-T standard). A Reed-Solomon error correction code adds redundant correction codes and allows reliable reception during moderate data loss. Although many current and future codecs can be sent in the MPEG-2 transport stream container format, as of 2006 most systems use a standard-definition format almost identical to DVD: MPEG-2 video in Anamorphic widescreen and MPEG layer 2 (MP2) audio. High-definition television is possible simply by using a higher-resolution picture, but H.264/AVC is being considered as a replacement video codec in some regions for its improved compression. With the compression and improved modulation involved, a single "channel" can contain a high-definition program and several standard-definition programs. 8VSB is the 8-level vestigial sideband modulation method adopted for terrestrial broadcast of the ATSC digital television standard in the United States and Canada. ... Established in 1982, the Advanced Television Systems Committee (ATSC) is the group that developed the ATSC digital television standard for the United States, also adopted by Canada, Mexico, South Korea, and recently Honduras and is being considered by other countries. ... Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... Reed-Solomon error correction is a coding scheme which works by first constructing a polynomial from the data symbols to be transmitted and then sending an over-sampled plot of the polynomial instead of the original symbols themselves. ... Streaming media are media that are consumed (read, heard, viewed) while it is being delivered. ... A container format is a computer file format that can contain various types of data, compressed by means of standardized codecs. ... DVD (also known as Digital Versatile Disc or Digital Video Disc) is a popular optical disc storage media format. ... MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... For the film format, see anamorphic format. ... MPEG-1 Audio Layer II (MP2, sometimes Musicam) is an audio codec defined by ISO/IEC 11172-3. ... High-definition television (HDTV) is a digital television broadcasting system with greater resolution than traditional television systems (NTSC, SECAM, PAL). ... H.264 is a standard for video compression. ...

Navigation

All satellite navigation systems use satellites with precision clocks. The satellite transmits its position, and the time of the transmission. The receiver listens to four satellites, and can figure its position as being on a line that is tangent to a spherical shell around each satellite, determined by the time-of-flight of the radio signals from the satellite. A computer in the receiver does the math. Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ...

Radio direction-finding is the oldest form of radio navigation. Before 1960 navigators used movable loop antennas to locate commercial AM stations near cities. In some cases they used marine radiolocation beacons, which share a range of frequencies just above AM radio with amateur radio operators. Loran systems also used time-of-flight radio signals, but from radio stations on the ground. VOR (Very High Frequency Omnidirectional Range), systems (used by aircraft), have an antenna array that transmits two signals simultaneously. A directional signal rotates like a lighthouse at a fixed rate. When the directional signal is facing north, an omnidirectional signal pulses. By measuring the difference in phase of these two signals, an aircraft can determine its bearing or radial from the station, thus establishing a line of position. An aircraft can get readings from two VORs and locate its position at the intersection of the two radials, known as a "fix." When the VOR station is collocated with DME (Distance Measuring Equipment), the aircraft can determine its bearing and range from the station, thus providing a fix from only one ground station. Such stations are called VOR/DMEs. The military operates a similar system of navaids, called TACANs, which are often built into VOR stations. Such stations are called VORTACs. Because TACANs include distance measuring equipment, VOR/DME and VORTAC stations are identical in navigation potential to civil aircraft. LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from three or more stations to determine the position of a ship or aircraft. ... D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ... D-VOR/DME ground station DME by itself Distance Measuring Equipment (DME) is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals. ...

Radar

Radar (Radio Detection And Ranging) detects objects at a distance by bouncing radio waves off them. The delay caused by the echo measures the distance. The direction of the beam determines the direction of the reflection. The polarization and frequency of the return can sense the type of surface. Navigational radars scan a wide area two to four times per minute. They use very short waves that reflect from earth and stone. They are common on commercial ships and long-distance commercial aircraft For other uses, see Radar (disambiguation). ...

General purpose radars generally use navigational radar frequencies, but modulate and polarize the pulse so the receiver can determine the type of surface of the reflector. The best general-purpose radars distinguish the rain of heavy storms, as well as land and vehicles. Some can superimpose sonar data and map data from GPS position. GPS redirects here. ...

Search radars scan a wide area with pulses of short radio waves. They usually scan the area two to four times a minute. Sometimes search radars use the doppler effect to separate moving vehicles from clutter. Targeting radars use the same principle as search radar but scan a much smaller area far more often, usually several times a second or more. Weather radars resemble search radars, but use radio waves with circular polarization and a wavelength to reflect from water droplets. Some weather radar use the doppler to measure wind speeds. A source of waves moving to the left. ... A source of waves moving to the left. ...

Data (digital radio)

Most new radio systems are digital, see also: Digital TV, Satellite Radio, Digital Audio Broadcasting. The oldest form of digital broadcast was spark gap telegraphy, used by pioneers such as Marconi. By pressing the key, the operator could send messages in Morse code by energizing a rotating commutating spark gap. The rotating commutator produced a tone in the receiver, where a simple spark gap would produce a hiss, indistinguishable from static. Spark gap transmitters are now illegal, because their transmissions span several hundred megahertz. This is very wasteful of both radio frequencies and power. Digital television (DTV) uses digital modulation and compression to broadcast video, audio and data signals to television sets. ... // A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ... Telegraph and Telegram redirect here. ... 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ...

The next advance was continuous wave telegraphy, or CW (Continuous Wave), in which a pure radio frequency, produced by a vacuum tube electronic oscillator was switched on and off by a key. A receiver with a local oscillator would "heterodyne" with the pure radio frequency, creating a whistle-like audio tone. CW uses less than 100 Hz of bandwidth. CW is still used, these days primarily by amateur radio operators (hams). Strictly, on-off keying of a carrier should be known as "Interrupted Continuous Wave" or ICW or on-off keying (OOK). Telegraph and Telegram redirect here. ... A continuous wave (CW) is an electromagnetic wave of constant amplitude and frequency. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... Cross coupled LC oscillator with output on top An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave. ... In telecommunications, to heterodyne is to generate new frequencies by mixing two or more signals in a nonlinear device such as a vacuum tube, transistor, or diode mixer. ... Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... On-off keying (OOK) is a type of modulation that represents digital data as the presence or absence of a carrier wave. ...

Radio teletypes usually operate on short-wave (HF) and are much loved by the military because they create written information without a skilled operator. They send a bit as one of two tones. Groups of five or seven bits become a character printed by a teletype. From about 1925 to 1975, radio teletype was how most commercial messages were sent to less developed countries. These are still used by the military and weather services. RadioTeleType (RTTY) is a telecommunications system consisting of two teleprinters linked by a radio link. ...

Aircraft use a 1200 Baud radioteletype service over VHF to send their ID, altitude and position, and get gate and connecting-flight data. Microwave dishes on satellites, telephone exchanges and TV stations usually use quadrature amplitude modulation (QAM). QAM sends data by changing both the phase and the amplitude of the radio signal. Engineers like QAM because it packs the most bits into a radio signal when given an exclusive (non-shared) fixed narrowband frequency range. Usually the bits are sent in "frames" that repeat. A special bit pattern is used to locate the beginning of a frame. “QAM” redirects here. ...

Communication systems that limit themselves to a fixed narrowband frequency range are vulnerable to jamming. A variety of jamming-resistant spread spectrum techniques were initially developed for military use, most famously for Global Positioning System satellite transmissions. Commercial use of spread spectrum begin in the 1980s. Bluetooth, most cell phones, and the 802.11b version of Wi-Fi each use various forms of spread spectrum. The term Jamming can refer to several things: Jamming as an electronic warfare (EW) - a technique to limit the effectiveness of an opponents communications and/or detection equipment, like Radio Jamming and Radar Jamming E-Mail Jamming- used by electronic political activists or hackers to disable e-mail systems... Spread-spectrum telecommunications is a technique in which a signal is transmitted in a bandwidth considerably greater than the frequency content of the original information. ... GPS redirects here. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ...

Systems that need reliability, or that share their frequency with other services, may use "coded orthogonal frequency-division multiplexing" or COFDM. COFDM breaks a digital signal into as many as several hundred slower subchannels. The digital signal is often sent as QAM on the subchannels. Modern COFDM systems use a small computer to make and decode the signal with digital signal processing, which is more flexible and far less expensive than older systems that implemented separate electronic channels. COFDM resists fading and ghosting because the narrow-channel QAM signals can be sent slowly. An adaptive system, or one that sends error-correction codes can also resist interference, because most interference can affect only a few of the QAM channels. COFDM is used for WiFi, some cell phones, Digital Radio Mondiale, Eureka 147, and many other local area network, digital TV and radio standards. Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... Digital signal processing (DSP) is the study of signals in a digital representation and the processing methods of these signals. ... Wi-Fi (or Wi-fi, WiFi, Wifi, wifi), short for Wireless Fidelity, is a set of standards for wireless local area networks (WLAN) currently based on the IEEE 802. ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ... Digital Radio Mondiale (DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcast, particularly shortwave. ... Eureka 147 is a protocol for digital radio broadcasting originally developed in Europe, but now being deployed in many countries around the world. ...

Heating

Radio-frequency energy generated for heating of objects is generally not intended to radiate outside of the generating equipment, to prevent interference with other radio signals. Microwave ovens use intense radio waves to heat food. (Note: It is a common misconception that the radio waves are tuned to the resonant frequency of water molecules. The microwave frequencies used are actually about a factor of ten below the resonant frequency.) Diathermy equipment is used in surgery for sealing of blood vessels. Induction furnaces are used for melting metal for casting. Microwave oven A microwave oven, or microwave, is a kitchen appliance employing microwave radiation primarily to cook or heat food. ... In the natural sciences, the term diathermy means electrically-induced heat and is commonly used for muscle relaxation. ... A furnace is a device for heating air or any other fluid. ... This article is about the manufacturing process. ...

Amateur radio service

Amateur radio is a hobby in which enthusiasts purchase or build their own equipment and use radio for their own enjoyment. They may also provide an emergency and public-service radio service. This has been of great use, saving lives in many instances. Radio amateurs are licensed to use frequencies in a large number of narrow bands throughout the radio spectrum. They use all forms of encoding, including obsolete and experimental ones. Several forms of radio were pioneered by radio amateurs and later became commercially important including FM, single-sideband (SSB), AM, digital packet radio and satellite repeaters. Some amateur frequencies may be disrupted by power-line internet service. Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... The abbreviations FM, Fm, and fm may refer to: Electrical engineering Frequency modulation (FM) and its most common applications: FM broadcasting, used primarily to broadcast music and speech at VHF frequencies FM synthesis, a sound-generation technique popularized by early digital synthesizers Science Femtometre (fm), an SI measure of length...

Unlicensed radio services

Personal radio services such as Citizens' Band Radio, Family Radio Service, Multi-Use Radio Service and others exist in North America to provide simple, (usually) short range communication for individuals and small groups, without the overhead of licensing. Similar services exist in other parts of the world. These radio services involve the use of handheld units. The commonest form of unlicensed radio is known as Free or Pirate radio, the main differences being that a Free radio station does not advertise or make any money, while the Pirate station could not exist without adverts, payolas, etc. A typical CB base station. ... The Family Radio Service is an improved walkie talkie system authorized in the United States. ... The Multi-Use Radio Service (MURS) is a small two-way radio service consisting of five frequencies in the VHF spectrum. ...

Radio control (RC)

Radio remote controls use radio waves to transmit control data to a remote object as in some early forms of guided missile, some early TV remotes and a range of model boats, cars and airplanes. Large industrial remote-controlled equipment such as cranes and switching locomotives now usually use digital radio techniques to ensure safety and reliability. This radio control airplane is carrying a scale model of X-33 and is taking part in NASA research. ... It has been suggested that this article or section be merged into Missile. ... HPI E-Savage Tamiya Wild Willy Kyosho Mini-Z Monster Team Losi Micro-T A radio-controlled car (R/C car) is a powered model car driven from a distance using a radio control system. ... A modern crawler type derrick crane with outriggers. ... Great Western Railway No. ...

In Madison Square Garden, at the Electrical Exhibition of 1898, Nikola Tesla successfully demonstrated a radio-controlled boat.[9] He was awarded U.S. patent No. 613,809 for a "Method of and Apparatus for Controlling Mechanism of Moving Vessels or Vehicles." [10] Madison Square Garden, often abbreviated as MSG, known colloquially simply as The Garden, has been the name of four arenas in New York City, United States. ...

The electromagnetic spectrum

Radio waves are a form of electromagnetic radiation, created whenever a charged object (in normal radio transmission, an electron) accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum. In radio, this acceleration is caused by an alternating current in an antenna. Radio frequencies occupy the range from a few tens of hertz to three hundred gigahertz, although commercially important uses of radio use only a small part of this spectrum.^[2] Other types of electromagnetic radiation, with frequencies above the RF range, are microwave, infrared, visible light, ultraviolet, X-rays and gamma rays. Since the energy of an individual photon of radio frequency is too low to remove an electron from an atom, radio waves are classified as non-ionizing radiation. This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... For other uses, see Electron (disambiguation). ... Acceleration is the time rate of change of velocity, and at any point on a v_t graph, it is given by the gradient of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of velocity. ... It has been suggested that this article or section be merged with Radio waves. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... City lights viewed in a motion blurred exposure. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... This article is about the SI unit of frequency. ... This article is about the type of Electromagnetic radiation. ... For other uses, see Infrared (disambiguation). ... For other uses, see Light (disambiguation). ... For other uses, see Ultraviolet (disambiguation). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... This article is about electromagnetic radiation. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... For other uses, see Electron (disambiguation). ... Properties For other meanings of Atom, see Atom (disambiguation). ... Non-ionizing radiation (or, esp. ...

Other

Energy autarkic radio technology consists of a small radio transmitter powered by environmental energy (push of a button, temperature differences, light, vibrations, etc.). A number of schemes have been proposed for Wireless energy transfer. Various plans included transmitting power using microwaves, and the technique has been demonstrated. (See Microwave power transmission). These schemes include, for example, solar power stations in orbit beaming energy down to terrestrial users. An artists depiction of a solar satellite, which could send energy wirelessly to a space vessel or planetary surface. ... This article is about the type of Electromagnetic radiation. ... This article does not cite any references or sources. ... Ultraviolet image of the Sun. ... An artists depiction of a solar satellite, which could send energy wirelessly to a space vessel or planetary surface. ...

See also

Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... DIORA AGA RSZ-50 ca. ... The No. ... A Baygen clockwork radio with crank in winding position Radio receivers were originally operated by battery. ... Community radio is a type of radio service that caters to the interests of a certain area, broadcasting material that is popular to a local audience but is overlooked by more powerful broadcast groups. ... An example of a modern set created by VE6AB The crystal radio receiver (also known as a crystal set) is a passive radio receiver consisting of a variable LC tuned circuit, a diode detector, and audio transducer. ... Dead air is a phenomenon whereby a broadcast which normally carries audio or video unintentionally becomes silent or blank (also known as unmodulated carrier). ... FCC redirects here. ... This article is about the SI unit of frequency. ... Typical hospital radio studio Hospital radio stations provide radio entertainment to patients in UK hospitals. ... The concept of hot and cool media was developed by media theorist Marshall McLuhan. ... International broadcasting is broadcasting deliberately aimed at a foreign, rather than a domestic, audience. ... Internet radio (aka e-Radio) is an audio broadcasting service transmitted via the Internet. ... An Internet radio device is a hardware device that receives and plays audio from Internet radio stations or, optionally, a users PC. The devices which are currently on the market mainly support MP3 (MPEG1 Audio Layer 3) streaming, Windows Media Audio (WMA) and ASF , they all generally with sample... // Within the timeline of radio, many people were involved in the invention of radio transmission of information as we know it today. ... A radio network is a network system which distributes programming to multiple stations simultaneously, or slightly delayed, for the purpose of extending total coverage beyond the limits of a single broadcast signal. ... This is a list of Wikipedia articles on Internet streaming media resources. ... Starting in the autumn of 2004, radio stations began to investigate podcasting as suitable for delivering their programming, especially news and interview shows that were free of the complications of music licensing. ... This article does not cite any references or sources. ... Mediumwave radio transmissions serves as the most common band for broadcasting. ... This article does not cite any references or sources. ... Near Vertical Incidence Skywave , NVIS, is a radio antenna configuration that provides usable signals in the range between groundwave and skywave distances (usually 30 to 400 miles, or 50 to 650 km). ... Before television, radio was the dominant home entertainment medium. ... The term Pirate Radio usually refers to illegal or unregulated radio transmission. ... The Very Large Array, a radio interferometer in New Mexico, USA Radio astronomy is a subfield of astronomy that studies celestial objects in the radio frequency portion of the electromagnetic spectrum. ... A radio documentary or feature is a radio programme devoted to covering a particular topic in some depth, usually with a mixture of commentary and sound pictures. ... A radio commercial (often called an advert in the United Kingdom) is a form of advertising in which goods, services, organizations, ideas, etc. ... Radio broadcasts have been a popular entertainment since the 1910s, though popularity has declined a little in some countries since television became widespread. ... Radio propagation is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. ... Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ... Splicing and glueing magnetic tape is a thing of the past. ... In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signal for use as sound, pictures, navigational-position information, etc. ... // A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... A software-defined radio (SDR) system is a radio communication system which uses software for the modulation and demodulation of radio signals. ... TV DX and FM DX are two terms, customarily grouped together, that mean distant reception of TV and FM radio stations, respectively. ... Regency TR-1. ... A Sansui TU-X1 stereo FM tuner. ... The International Telecommunication Union uses a special system for classifying radio frequency signals. ... VFO is an acronym for Variable Frequency Oscillator. ...

Notes

• Online Radio Station 124radiostation online radio station as review says it is the "most easiest" to use website to listen songs.

Nikola Tesla with his invention, a wireless lightbulb powered by the electric field surrounding it. ...

References

• A História da Rádio em Datas (1819-1997) (in Portuguese) - notes on etymology
• Leigh White, Buck Fuller and the Dymaxion World (refers to Waldo Warren as the inventor of the word radio), in: The Saturday Evening Post, 14 October 1944, cited in: Joachim Krausse and Claude Lichtenstein (eds.), Your Private Sky, Lars Müller Publishers, Baden/Switzerland, 1999, page 132. ISBN 3-907044-88-6
• L. de Forest, article in Electrical World 22 June 1270/1 (1907), early use of word "radio".
• http://web.mit.edu/varun_ag/www/bose.html - It contains a proof that Sir Jagadish Chandra Bose invented the Mercury Coherer which was later used by Guglielmo Marconi and along with other patents.

is the 287th day of the year (288th in leap years) in the Gregorian calendar. ... is the 173rd day of the year (174th in leap years) in the Gregorian calendar. ...

Further reading

• Aitkin Hugh G. J. The Continuous Wave: Technology and the American Radio, 1900-1932 (Princeton University Press, 1985).
• Briggs Asa. The History of Broadcasting in the United Kingdom (Oxford University Press, 1961).
• Ewbank Henry and Lawton Sherman P. Broadcasting: Radio and Television (Harper & Brothers, 1952).
• Fisher, Marc Something In The Air: Radio, Rock, and the Revolution That Shaped A Generation (Random House, 2007).
• Maclaurin W. Rupert. Invention and Innovation in the Radio Industry (The Macmillan Company, 1949).
• Ray William B. FCC: The Ups and Downs of Radio-TV Regulation (Iowa State University Press, 1990).
• Scannell, Paddy, and Cardiff, David. A Social History of British Broadcasting, Volume One, 1922-1939 (Basil Blackwell, 1991).
• Schwoch James. The American Radio Industry and Its Latin American Activities, 1900-1939 (University of Illinois Press, 1990).
• Sterling Christopher H. Electronic Media, A Guide to Trends in Broadcasting and Newer Technologies 1920-1983 (Praeger, 1984).
• White Llewellyn. The American Radio (University of Chicago Press, 1947).

Primary sources

• De Forest, Lee. Father of Radio: The Autobiography of Lee de Forest (1950).

External links

Wikimedia Commons has media related to:

Radio

Look up radio in
Wiktionary, the free dictionary.

• Radio Frequency Chart
• Horzepa, Stan, "Surfin': Who Invented Radio?". Arrl.org. 10 October 2003.
• Online Radio
• IAteacher: Interactive Explanation of Radio Receiver Construction
• U.S. Supreme Court, "Marconi Wireless Telegraph co. of America v. United States". 320 U.S. 1. Nos. 369, 373. Argued 9 April-12, 1943. Decided 21 June 1943.
• 'A Day In Radio' from The University of Virginia's Department of American Studies
• Radio Announcer
• Steven Schoenherr's History of Radio
• The Broadcast Archive - Radio History on the Web!
• George H. Clark Radioana Collection, ca. 1880 - 1950 - Archives Center, National Museum of American History, Smithsonian Institution
• A gallery of Antiques from the 1920s to the 1960s
• United States Early Radio History
• Open Directory Project - Radio
• Books about Radios and RF field; schematics for radio transmitters and receivers
• VOR Basic Information
• How Stuff Works - Radio
• Early Canadian Radio Station Lists
• Canadian Communications Foundation - The History on Canadian Broadcasting.
• United States Early Radio History
• Historic Radios from Around the World at Kurrajong Radio Museum, Australia
• The British DX Club
• www.worldofradio.com Glen Houser's World Of Radio
• Radio Today Daily News and Information about radio
• Community Broadcasting Association of Australia
• Community Broadcasting Online (Australia)
• Radio Broadcasting from Ghana West Africa
• Internet Radio Broadcasting Directory

Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... is the 283rd day of the year (284th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... is the 99th day of the year (100th in leap years) in the Gregorian calendar. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 1943 (MCMXLIII) was a common year starting on Friday (the link will display full 1943 calendar) of the Gregorian calendar. ...