Radio broadcasting is transmission by radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both; the signal types can be digital audio. The earliest radio stations did not carry audio. For audio broadcasts to be possible, electronic detection and amplification devices had to be incorporated; the thermionic valve was invented in 1904 by the English physicist John Ambrose Fleming. He developed a device he called an "oscillation valve"; the heated filament, or cathode, was capable of thermionic emission of electrons that would flow to the plate when it was at a higher voltage. Electrons, could not pass in the reverse direction because the plate was not heated and thus not capable of thermionic emission of electrons. Known as the Fleming valve, it could be used as a rectifier of alternating current and as a radio wave detector; this improved the crystal set which rectified the radio signal using an early solid-state diode based on a crystal and a so-called cat's whisker.
However, what was still required was an amplifier. The triode was patented on March 4, 1906, by the Austrian Robert von Lieben independent from that, on October 25, 1906, Lee De Forest patented his three-element Audion, it wasn't put to practical use until 1912 when its amplifying ability became recognized by researchers. By about 1920, valve technology had matured to the point where radio broadcasting was becoming viable. However, an early audio transmission that could be termed a broadcast may have occurred on Christmas Eve in 1906 by Reginald Fessenden, although this is disputed. While many early experimenters attempted to create systems similar to radiotelephone devices by which only two parties were meant to communicate, there were others who intended to transmit to larger audiences. Charles Herrold started broadcasting in California in 1909 and was carrying audio by the next year.. In The Hague, the Netherlands, PCGG started broadcasting on November 6, 1919, making it, arguably the first commercial broadcasting station.
In 1916, Frank Conrad, an electrical engineer employed at the Westinghouse Electric Corporation, began broadcasting from his Wilkinsburg, Pennsylvania garage with the call letters 8XK. The station was moved to the top of the Westinghouse factory building in East Pittsburgh, Pennsylvania. Westinghouse relaunched the station as KDKA on November 2, 1920, as the first commercially licensed radio station in America; the commercial broadcasting designation came from the type of broadcast license. The first licensed broadcast in the United States came from KDKA itself: the results of the Harding/Cox Presidential Election; the Montreal station that became CFCF began broadcast programming on May 20, 1920, the Detroit station that became WWJ began program broadcasts beginning on August 20, 1920, although neither held a license at the time. In 1920, wireless broadcasts for entertainment began in the UK from the Marconi Research Centre 2MT at Writtle near Chelmsford, England. A famous broadcast from Marconi's New Street Works factory in Chelmsford was made by the famous soprano Dame Nellie Melba on 15 June 1920, where she sang two arias and her famous trill.
She was the first artist of international renown to participate in direct radio broadcasts. The 2MT station began to broadcast regular entertainment in 1922; the BBC was amalgamated in 1922 and received a Royal Charter in 1926, making it the first national broadcaster in the world, followed by Czech Radio and other European broadcasters in 1923. Radio Argentina began scheduled transmissions from the Teatro Coliseo in Buenos Aires on August 27, 1920, making its own priority claim; the station got its license on November 19, 1923. The delay was due to the lack of official Argentine licensing procedures before that date; this station continued regular broadcasting of entertainment and cultural fare for several decades. Radio in education soon followed and colleges across the U. S. began adding radio broadcasting courses to their curricula. Curry College in Milton, Massachusetts introduced one of the first broadcasting majors in 1932 when the college teamed up with WLOE in Boston to have students broadcast programs.
Broadcasting service is – according to Article 1.38 of the International Telecommunication Union´s Radio Regulations – defined as «A radiocommunication service in which the transmission are intended for direct reception by the general public. This service may include sound transmissions, television transmissions or other types of transmission.» Definitions identical to those contained in the Annexes to the Constitution and Convention of the International Telecommunication Union are marked "" or "" respectively. A radio broadcasting station is associated with wireless transmission, though in practice broadcasting transmission take place using both wires and radio waves; the point of this is that anyone with the appropriate receiving technology can receive the broadcast. In line to ITU Radio Regulations each broadcasting station shall be classified by the service in which it operates permanently or temporarily. Broadcasting by radio takes several forms; these include FM stations. There are several subtypes, namely commercial broadcasting, non-commercial educational public broadcasting and non-profit varieties as well as community radio, student-run campus radio stations, and
Richmond is the capital of the Commonwealth of Virginia in the United States. It is the center of the Greater Richmond Region. Richmond was incorporated in 1742 and has been an independent city since 1871; as of the 2010 census, the city's population was 204,214. The Richmond Metropolitan Area has a population of 1,260,029, the third-most populous metro in the state. Richmond is located at the fall line of the James River, 44 miles west of Williamsburg, 66 miles east of Charlottesville, 100 miles east of Lynchburg and 90 miles south of Washington, D. C. Surrounded by Henrico and Chesterfield counties, the city is located at the intersections of Interstate 95 and Interstate 64, encircled by Interstate 295, Virginia State Route 150 and Virginia State Route 288. Major suburbs include Midlothian to the southwest, Chesterfield to the south, Varina to the southeast, Sandston to the east, Glen Allen to the north and west, Short Pump to the west and Mechanicsville to the northeast; the site of Richmond had been an important village of the Powhatan Confederacy, was settled by English colonists from Jamestown in 1609, in 1610–1611.
The present city of Richmond was founded in 1737. It became Dominion of Virginia in 1780, replacing Williamsburg. During the Revolutionary War period, several notable events occurred in the city, including Patrick Henry's "Give me liberty or give me death" speech in 1775 at St. John's Church, the passage of the Virginia Statute for Religious Freedom written by Thomas Jefferson. During the American Civil War, Richmond served as the second and permanent capital of the Confederate States of America; the city entered the 20th century with one of the world's first successful electric streetcar systems. The Jackson Ward neighborhood is a national hub of African-American culture. Richmond's economy is driven by law and government, with federal and local governmental agencies, as well as notable legal and banking firms, located in the downtown area; the city is home to both the United States Court of Appeals for the Fourth Circuit, one of 13 United States courts of appeals, the Federal Reserve Bank of Richmond, one of 12 Federal Reserve Banks.
Dominion Energy and WestRock, Fortune 500 companies, are headquartered in the city, with others in the metropolitan area. After the first permanent English-speaking settlement was established in April 1607, at Jamestown, Captain Christopher Newport led explorers northwest up the James River, to an area, inhabited by Powhatan Native Americans; the earliest European settlement in the Central Virginia area was in 1611 at Henricus, where the Falling Creek empties into the James River. In 1619, early Virginia Company settlers struggling to establish viable moneymaking industries established the Falling Creek Ironworks. After decades of territorial conflicts with native tribes, the Falls of the James became more to white settlement in the late 1600s and early 1700s. In 1737, planter William Byrd II commissioned Major William Mayo to lay out the original town grid. Byrd named the city "Richmond" after the English town of Richmond near London, because the view of the James River was strikingly similar to the view of the River Thames from Richmond Hill in England, where he had spent time during his youth.
The settlement was laid out in April 1737, was incorporated as a town in 1742. In 1775, Patrick Henry delivered his famous "Give me Liberty or Give me Death" speech in St. John's Church in Richmond, crucial for deciding Virginia's participation in the First Continental Congress and setting the course for revolution and independence. On April 18, 1780, the state capital was moved from the colonial capital of Williamsburg to Richmond, to provide a more centralized location for Virginia's increasing westerly population, as well as to isolate the capital from British attack; the latter motive proved to be in vain, in 1781, under the command of Benedict Arnold, Richmond was burned by British troops, causing Governor Thomas Jefferson to flee as the Virginia militia, led by Sampson Mathews, defended the city. Richmond recovered from the war, by 1782 was once again a thriving city. In 1786, the Virginia Statute for Religious Freedom was passed at the temporary capitol in Richmond, providing the basis for the separation of church and state, a key element in the development of the freedom of religion in the United States.
A permanent home for the new government, the Greek Revival style of the Virginia State Capitol building, was designed by Thomas Jefferson with the assistance of Charles-Louis Clérisseau, was completed in 1788. After the American Revolutionary War, Richmond emerged as an important industrial center. To facilitate the transfer of cargo from the flat-bottomed James River bateaux above the fall line to the ocean-faring ships below, an enterprising George Washington helped design the James River and Kanawha Canal from Westham east to Richmond, in the 18th century to bypass Richmond's rapids on the upper James River with the intent of providing a water route across the Appalachian Mountains to the Kanawha River flowing westward into the Ohio eventually to the Mississippi River; the legacy of the canal boatmen is represented by the figure in the center of the city flag. As a result of this and ample access to hydropower due to the falls, Richmond became home to some of the largest manufacturing facilities in the country, including iron works and flour mills, the largest facilities of their kind in The South.
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Howard Allan Stern is an American radio and television personality, author and photographer. He is best known for his radio show The Howard Stern Show, which gained popularity when it was nationally syndicated on terrestrial radio from 1986 to 2005. Stern has broadcast on Sirius XM Satellite Radio since 2006. Stern landed his first radio jobs while at Boston University. From 1976 to 1982, Stern developed his on-air personality through morning positions at WRNW in Briarcliff Manor, New York, WCCC in Hartford, Connecticut, WWWW in Detroit, WWDC in Washington, D. C. Stern worked afternoons at WNBC in New York City from 1982 until his firing in 1985. In 1985, he began a 20-year run at WXRK in New York City. Stern won numerous industry awards, including Billboard’s Nationally Syndicated Air Personality of the Year eight consecutive times, is the first to have the number one morning show in New York City and Los Angeles simultaneously, he became the most fined radio host when the Federal Communications Commission issued fines totaling $2.5 million to station owners for content it deemed indecent.
Stern became one of the highest paid radio figures after signing a five-year deal with Sirius in 2004 worth $500 million. In recent years, Stern's photography has been featured in WHIRL magazines. From 2012 to 2015, he served as a judge on America's Got Talent. Stern has described himself as King of All Media since 1992 for his successes outside radio, he hosted and produced numerous late night television shows, pay-per-view events, home videos. His two books, Private Parts and Miss America, entered The New York Times Best Seller list at number one and sold over one million copies; the former was made into a biographical comedy film in 1997 that had Stern and his radio show staff star as themselves. It grossed $41.2 million domestically. Stern performs on its soundtrack, which charted the Billboard 200 at number one and was certified platinum for one million copies sold. Stern's third book, Howard Stern Comes Again, will be released in May 2019. Howard Allan Stern was born on January 12, 1954, the second child of Ben and Ray Stern who lived in the Jackson Heights neighborhood of Queens in New York City.
Stern's parents are Jewish, their families are from Poland and Austria-Hungary. Ray was an office clerk in New York City before she became a homemaker and took up work as an inhalation therapist. Ben served in the U. S. Army on Long Island and in California during the war, he worked as a radio engineer at WHOM in Manhattan and as a co-owner and operator at Aura Recording Inc. a Manhattan recording studio where cartoons and commercials were cut. Stern described his older sister Ellen as the "complete opposite" of himself and "very quiet."In 1955, the family moved to Roosevelt, New York, on Long Island where Stern attended Washington-Rose Elementary School followed by Roosevelt Junior-Senior High School. Stern attended Hebrew school where he was given the name Tzvi; as a youngster Stern took five years of piano lessons and took an interest in marionettes, using them to entertain his friends with explicit shows. He formed a band with the Electric Comicbook, on vocals and keyboards. From the age of nine to his second year at university, Stern spent his summers at Camp Wel-Met, a youth camp in Narrowsburg, New York where he worked camper and counselor duties.
He recalled his time there as "the greatest experience." Stern wished to be in radio at the age of five. He was an infrequent listener in his youth, but names talk personalities Bob Grant and Brad Crandall as early influences, his father set up a microphone, tape machine and turntable in the basement of his home which Stern used to record his make-believe radio shows, incorporating different characters and pre-recorded prank calls and commercials. He made several visits to his father's recording studio and witnessed "some of the great voice guys" work with him, including Don Adams and Larry Storch voice Tennessee Tuxedo and His Tales, which began his desire to be on the air and "do a show," rather than play records. In the late 1960s, Roosevelt became a predominantly black area. In June 1969, the family moved to nearby Rockville Centre, Stern, at age fifteen, transferred to South Side High School where he became "a total introvert." He graduated from the school in 1972. In 1972, Stern declined a place at Elmira College to instead pursue a Communications degree at Boston University, but his average high school grades caused him to spend the first two years in its College of Basic Studies.
In his second year, he started work at the campus radio station WTBU, where he played records, read the news, hosted interview programs. He co-hosted a weekly comedy show with three fellow students named The King Schmaltz Bagel Hour, canceled during its first broadcast for a racial sketch named "Godzilla Goes to Harlem". Stern took cannabis, LSD during his studies, but quit after he experienced a difficult trip on too much LSD. In 1974, he gained admission to the university's School of Public Communications, he studied for a diploma at the Radio Engineering Institute of Electronics in Fredericksburg, Virginia in July 1975 which earned him a first-class radio-telephone operator license, a required certificate for all radio broadcasters at the time, issued by the Federal Communications
Frequency is the number of occurrences of a repeating event per unit of time. It is referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency; the period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency. For example: if a newborn baby's heart beats at a frequency of 120 times a minute, its period—the time interval between beats—is half a second. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals, radio waves, light. For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics and radio, frequency is denoted by a Latin letter f or by the Greek letter ν or ν; the relation between the frequency and the period T of a repeating event or oscillation is given by f = 1 T.
The SI derived unit of frequency is the hertz, named after the German physicist Heinrich Hertz. One hertz means. If a TV has a refresh rate of 1 hertz the TV's screen will change its picture once a second. A previous name for this unit was cycles per second; the SI unit for period is the second. A traditional unit of measure used with rotating mechanical devices is revolutions per minute, abbreviated r/min or rpm. 60 rpm equals one hertz. As a matter of convenience and slower waves, such as ocean surface waves, tend to be described by wave period rather than frequency. Short and fast waves, like audio and radio, are described by their frequency instead of period; these used conversions are listed below: Angular frequency denoted by the Greek letter ω, is defined as the rate of change of angular displacement, θ, or the rate of change of the phase of a sinusoidal waveform, or as the rate of change of the argument to the sine function: y = sin = sin = sin d θ d t = ω = 2 π f Angular frequency is measured in radians per second but, for discrete-time signals, can be expressed as radians per sampling interval, a dimensionless quantity.
Angular frequency is larger than regular frequency by a factor of 2π. Spatial frequency is analogous to temporal frequency, but the time axis is replaced by one or more spatial displacement axes. E.g.: y = sin = sin d θ d x = k Wavenumber, k, is the spatial frequency analogue of angular temporal frequency and is measured in radians per meter. In the case of more than one spatial dimension, wavenumber is a vector quantity. For periodic waves in nondispersive media, frequency has an inverse relationship to the wavelength, λ. In dispersive media, the frequency f of a sinusoidal wave is equal to the phase velocity v of the wave divided by the wavelength λ of the wave: f = v λ. In the special case of electromagnetic waves moving through a vacuum v = c, where c is the speed of light in a vacuum, this expression becomes: f = c λ; when waves from a monochrome source travel from one medium to another, their frequency remains the same—only their wavelength and speed change. Measurement of frequency can done in the following ways, Calculating the frequency of a repeating event is accomplished by counting the number of times that event occurs within a specific time period dividing the count by the length of the time period.
For example, if 71 events occur within 15 seconds the frequency is: f = 71 15 s ≈ 4.73 Hz If the number of counts is not large, it is more accurate to measure the time interval for a predetermined number of occurrences, rather than the number of occurrences within a specified time. The latter method introduces a random error into the count of between zero and one count, so on average half a count; this is called gating error and causes an average error in the calculated frequency of Δ f = 1 2 T
HD Radio is a trademarked term for Xperi's in-band on-channel digital radio technology used by AM and FM radio stations to transmit audio and data by using a digital signal embedded "on-frequency" above and below a station's standard analog signal, providing the means to listen to the same program in either HD or as a standard broadcast. The HD format provides the means for a single radio station to broadcast one or more different programs in addition to the program being transmitted on the radio station's analog channel, it was developed by iBiquity. In September 2015 iBiquity was acquired by DTS bringing the HD Radio technology under the same banner as DTS' eponymous theater surround sound systems.. It was acquired by Xperi in 2016, it was selected by the U. S. Federal Communications Commission in 2002 as a digital audio broadcasting method for the United States, is the only digital system approved by the FCC for digital AM/FM broadcasts in the United States, it is known as NRSC-5, with the latest version being NRSC-5-D.
Other digital radio systems include FMeXtra, Digital Audio Broadcasting, Digital Radio Mondiale, Compatible AM-Digital. While HD Radio does allow for an all-digital mode, this system is used by some AM and FM radio stations to simulcast both digital and analog audio within the same channel as well as to add new FM channels and text information. Although HD Radio broadcasting's content is free-to-air, listeners must purchase new receivers in order to receive the digital portion of the signal. By May 2018, HD Radio technology was claimed to be used by more than 3500 individual services in the United States; this compares with more than 2200 services operating with the DAB system. HD Radio increases the bandwidth required in the FM band to 400 kHz for the analog/digital hybrid version; this makes adoption outside the United States problematic. In the United States the FM broadcast band channels have a spacing of 200 kHz, as opposed to the 100 kHz, normal elsewhere; the 200 kHz spacing means that in practice, stations having concurrent or adjacent coverage areas will not be spaced at less than 400 kHz in order to respect protection ratios which would not be met with 200 kHz spacing.
This leaves space for the digital sidebands. Outside the US, spacing can be 300 kHz; the FCC has not indicated any intent to force off analog radio broadcasts as it has with analog television broadcasts, as it would not result in the recovery of any radio spectrum rights which could be sold. Thus, there is no deadline. In addition, there are many more analog AM/FM radio receivers than there were analog televisions, many of these are car stereos or portable units that cannot be upgraded. Digital information is transmitted using OFDM with an audio compression algorithm called HDC.. HD Radio equipped stations pay a one-time licensing fee for converting their primary audio channel to iBiquity's HD Radio technology, 3% of incremental net revenues for any additional digital subchannels; the cost of converting a radio station can run between $100,000 and $200,000. Receiver manufacturers pay a royalty. If the primary digital signal is lost the HD Radio receiver will revert to the analog signal, thereby providing seamless operation between the newer and older transmission methods.
The extra HD-2 and HD-3 streams are not simulcast on analog, causing the sound to drop-out or "skip" when digital reception degrades. Alternatively the HD Radio signal can revert to a more-robust 20 kilobit per second stream, though the sound is reduced to AM-like quality. Datacasting is possible, with metadata providing song titles or artist information. IBiquity Digital claims that the system approaches CD quality audio and offers reduction of both interference and static. Sending pure digital data through the 20 kilohertz AM channel is equivalent to sending data through two 33 kbit/s analog telephone lines, thus limiting the maximum throughput possible. By using spectral band replication the HDC+SBR codec is able to simulate the recreation of sounds up to 15,000 Hz, thus achieving moderate quality on the bandwidth-tight AM band; the HD Radio AM hybrid mode offers two options which can carry 40 or 60 kbit/s of data, but most AM digital stations default to the more-robust 40 kbit/s mode which features redundancy.
HD Radio provides a pure digital mode, which lacks an analog signal for fallback and instead reverts to a 20 kbit/s signal during times of poor reception. The pure digital mode transmissions will stay within the AM station's channel instead of spilling into the channels next to the station transmitting "HD radio" as the hybrid stations do; the AM version of HD Radio technology uses the 20 kHz channel, overlaps 5 kHz into the opposite sideband of the adjacent channel on both sides. When operating in pure digital mode, the AM HD Radio signal fits inside a standard 20 kHz channel or an extended 30 kHz channel, at the discretion of the station manager; as AM radio stations are spaced at 9 kHz or 10 kHz intervals, much of the digital information overlaps adjacent channels when in hybrid mode. Some nigh
In electronics and telecommunications, a transmitter or radio transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, applied to the antenna; when excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary component parts of all electronic devices that communicate by radio, such as radio and television broadcasting stations, cell phones, walkie-talkies, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, spacecraft, radar sets and navigational beacons; the term transmitter is limited to equipment that generates radio waves for communication purposes. Generators of radio waves for heating or industrial purposes, such as microwave ovens or diathermy equipment, are not called transmitters though they have similar circuits; the term is popularly used more to refer to a broadcast transmitter, a transmitter used in broadcasting, as in FM radio transmitter or television transmitter.
This usage includes both the transmitter proper, the antenna, the building it is housed in. A transmitter can be a separate piece of electronic equipment, or an electrical circuit within another electronic device. A transmitter and a receiver combined in one unit is called a transceiver; the term transmitter is abbreviated "XMTR" or "TX" in technical documents. The purpose of most transmitters is radio communication of information over a distance; the information is provided to the transmitter in the form of an electronic signal, such as an audio signal from a microphone, a video signal from a video camera, or in wireless networking devices, a digital signal from a computer. The transmitter combines the information signal to be carried with the radio frequency signal which generates the radio waves, called the carrier signal; this process is called modulation. The information can be added to the carrier in several different ways, in different types of transmitters. In an amplitude modulation transmitter, the information is added to the radio signal by varying its amplitude.
In a frequency modulation transmitter, it is added by varying the radio signal's frequency slightly. Many other types of modulation are used; the radio signal from the transmitter is applied to the antenna, which radiates the energy as radio waves. The antenna may be enclosed inside the case or attached to the outside of the transmitter, as in portable devices such as cell phones, walkie-talkies, garage door openers. In more powerful transmitters, the antenna may be located on top of a building or on a separate tower, connected to the transmitter by a feed line, a transmission line. Electromagnetic waves are radiated by electric charges undergoing acceleration. Radio waves, electromagnetic waves of radio frequency, are generated by time-varying electric currents, consisting of electrons flowing through a metal conductor called an antenna which are changing their velocity or direction and thus accelerating. An alternating current flowing back and forth in an antenna will create an oscillating magnetic field around the conductor.
The alternating voltage will charge the ends of the conductor alternately positive and negative, creating an oscillating electric field around the conductor. If the frequency of the oscillations is high enough, in the radio frequency range above about 20 kHz, the oscillating coupled electric and magnetic fields will radiate away from the antenna into space as an electromagnetic wave, a radio wave. A radio transmitter is an electronic circuit which transforms electric power from a power source into a radio frequency alternating current to apply to the antenna, the antenna radiates the energy from this current as radio waves; the transmitter impresses information such as an audio or video signal onto the radio frequency current to be carried by the radio waves. When they strike the antenna of a radio receiver, the waves excite similar radio frequency currents in it; the radio receiver extracts the information from the received waves. A practical radio transmitter consists of these parts: A power supply circuit to transform the input electrical power to the higher voltages needed to produce the required power output.
An electronic oscillator circuit to generate the radio frequency signal. This generates a sine wave of constant amplitude called the carrier wave, because it serves to "carry" the information through space. In most modern transmitters, this is a crystal oscillator in which the frequency is controlled by the vibrations of a quartz crystal; the frequency of the carrier wave is considered the frequency of the transmitter. A modulator circuit to add the information to be transmitted to the carrier wave produced by the oscillator; this is done by varying some aspect of the carrier wave. The information is provided to the transmitter either in the form of an audio signal, which represents sound, a video signal which represents moving images, or for data in the form of a binary digital signal which represents a sequence of bits, a bitstream. Different types of transmitters use different modulation methods to transmit information: In an AM transmitter the amplitude of the carrier wave is varied in proportion to the modulation signal.
In an FM transmitter the frequency of the carrier is varied by the modulation signal. In an FSK transmitter, which transmits digital data, the frequency of the carrier is shifted between two frequencies which represent the two binary digits, 0 and 1. Many oth