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Encyclopedia > FM broadcasting in the USA

FM broadcasting in the U.S. began in the 1930s. The use of FM radio has been associated with higher sound quality in music radio. Face The 1930s (years from 1930–1939) were described as an abrupt shift to more radical and conservative lifestyles, as countries were struggling to find a solution to the Great Depression, also known in Europe as the World Depression. ... FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity sound over broadcast radio. ...

Contents

History of FM radio in the U.S.

Main article: History of radio, FM radio. The pre-history and early history of radio is the history of technology that produced instruments that use radio waves. ...


In the United States FM radio stations broadcast at frequencies of 87.8–108 MHz. FM radio, and later stereo FM radio, were both developed in the United States primarily by Edwin Armstrong. A radio station is an audio (sound) broadcasting service, traditionally broadcast through the air as radio waves (a form of electromagnetic radiation) from a transmitter to an antenna and a thus to a receiving device. ... Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... MHZ redirects here. ... Edwin Howard Armstrong (December 18, 1890 – January 31, 1954) was an American electrical engineer and inventor. ...


W1XOJ was the first FM radio station, granted a construction permit by the FCC in 1937. On January 5, 1940 FM radio was demonstrated to the FCC for the first time. FM radio was assigned the 42 to 50 MHz band of the spectrum in 1940. WAAF 107. ... The FCCs official seal. ... Year 1937 (MCMXXXVII) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar. ... is the 5th day of the year in the Gregorian calendar. ... Year 1940 (MCMXL) was a leap year starting on Monday (link will display the full 1940 calendar) of the Gregorian calendar. ...


After World War II, the FCC moved FM to the frequencies between 88 and 106 MHz on June 27, 1945.The change in frequency was said to be for avoiding possible interference problems between stations in nearby cities and to make "room" for more FM radio channels. However, it has been alleged that the FCC was influenced by RCA chairman David Sarnoff, and that the change had the covert goal of disrupting the successful FM network that Edwin Armstrong had established on the old band. Radios built for the original FM radio band could be retrofitted with converters, but many were just replaced. The greater expense was to the radio stations themselves that had to rebuild their stations for the new FM radio band. The move of the FM band, an organized campaign of misinformation by RCA (a company that competed with FM radio by focusing on AM radio and the emerging technology of television), and adverse rulings by the FCC severely set back the development of FM radio. On March 1, 1945 W47NV began operations in Nashville, Tennessee, becoming the first modern commercial FM radio station. However, FM radio did not recover from the setback until the upsurge in high fidelity equipment in the late 1950s. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... David Sarnoff (February 27, 1891–December 12, 1971) was the Pioneer of American Television and founder of the [National Broadcasting Corporation][1], NBC. Throughout most of his career he led the Radio Corporation of America (RCA) in various capacities shortly after its founding in 1919 to his retirement in 1970. ... is the 60th day of the year (61st in leap years) in the Gregorian calendar. ... Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... WSM-FM is a Nashville, Tennessee FM radio station. ... Nickname: Location in Davidson County and the state of Tennessee Coordinates: , Country United States State Tennessee Counties Davidson County Founded: 1779 Incorporated: 1806 Government  - Mayor Bill Purcell (D) Area  - City  526. ... Official language(s) English Capital Nashville Largest city Memphis Largest metro area Nashville Area  Ranked 36th  - Total 42,169 sq mi (109,247 km²)  - Width 120 miles (195 km)  - Length 440 miles (710 km)  - % water 2. ... This does not cite any references or sources. ...


During the 1970s, FM radio experienced a golden age of integrity programming, with disc jockeys playing what they wanted, including album cuts not designated as "singles" and lengthy prog rock tracks. The film FM (1978) portrays a fictional group of Los Angeles "maverick" FM disc jockeys reacting against the new formatting changes at their station. The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... Computer programming (often simply programming) is the craft of implementing one or more interrelated abstract algorithms using a particular programming language to produce a concrete computer program. ... For other meanings of DJ, see DJ (disambiguation). ... A collection of various CD singles In music, a single is a short recording of one or more separate tracks. ... The progressive rock band Yes performing in 1977. ... FM was a 1978 movie directed by John A. Alonzo, and starring Michael Brandon, Eileen Brennan, Alex Karras and others. ... Year 1978 (MCMLXXVIII) was a common year starting on Sunday (link displays the 1978 Gregorian calendar). ... Flag Seal Nickname: City of Angels Location Location within Los Angeles County in the state of California Coordinates , Government State County California Los Angeles County Mayor Antonio Villaraigosa (D) Geographical characteristics Area     City 1,290. ...


FM radio channel assignments in the U.S.

In the United States, frequency-modulated broadcasting stations operate in a frequency band extending from 87.8 MHz to 108.0 MHz, for a total of 20.2 MHz. It is divided into 101 channels, each 0.2 MHz wide, designated "channel 200" through "channel 300." In actual practice, no one (except the FCC) uses these channel numbers; the frequencies are used instead.


To receive a station, an FM receiver is tuned to the center frequency of the station's channel. The lowest channel, channel 200, extends from 87.8 MHz to 88.0 MHz; thus its center frequency is 87.9 MHz. Channel 201 has a center frequency of 88.1 MHz, and so on, up to channel 300, which extends from 107.8 to 108.0 MHz and has a center frequency of 107.9 MHz. In most of the world, the FM broadcast band, used for broadcasting FM radio stations, goes from 87. ...


Because each channel is 0.2 MHz wide, the center frequencies of adjacent channels differ by 0.2 MHz. Because the lowest channel is centered on 87.9 MHz, the tenths digit (in MHz) of the center frequency of any FM station in the United States is always an odd number. FM audio for television channel 6 is broadcast at a carrier frequency of 87.75 MHz, and many radios can tune down this low; a few low-power television stations licensed for channel 6 are operated solely for their right to use this frequency and broadcast only nominal video programming. For the same reason, assignment restrictions between TV stations on channel 6 and nearby FM stations are stringent: there are only two stations in the United States (KSFH and translator K200AA) licensed to operate on 87.9 MHz, both due to being forced off of another channel. Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... In broadcasting, a translator is an FM radio station or a TV station which acts as a full-duplex repeater. ... KAWZ is an FM radio station in Twin Falls, Idaho operating on a frequency of 89. ...


Originally, FM stations in a market were generally spaced four channels (800 kHz) apart. This spacing was developed in response to problems perceived on the original FM band, mostly due to deficiencies in receiver technology of the time. With modern equipment, this is widely understood to be unnecessary, and in many countries shorter spacings are used. Other spacing restrictions relate to mixing products with nearby television, air-traffic control, and two-way radio systems as well as other FM broadcast stations. The most significant such taboo restricts the allocation of stations 10.6 and 10.8 MHz apart, to protect against mixing products which will interfere with an FM receiver's standard 10.7 MHz intermediate frequency stage. An intermediate frequency (IF) is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. ...


Commercial broadcasting is licensed only on channels 221 through 300 (the upper 80 channels, frequencies between 92 and 108 MHz), with 200 through 220 (the lower 21 channels, frequencies between 88 and 92 MHz) being reserved for noncommercial educational (NCE) broadcasting. In some "twin city" markets close to the Canadian or Mexican border, such as Detroit, Michigan and Windsor, Ontario, or San Diego, California and Tijuana, Baja California, commercial stations operating from those countries target U.S. audiences on "reserved band" channels, as neither Canada nor Mexico has such a reservation. Because of this necessary sharing, the FCC reserves a few other channels for such NCE stations. The term Twin city or twin town may be applied to one of the following notions. ... “Detroit” redirects here. ... Official language(s) None (English, de-facto) Capital Lansing Largest city Detroit Largest metro area Metro Detroit Area  Ranked 11th  - Total 97,990 sq mi (253,793 km²)  - Width 239 miles (385 km)  - Length 491 miles (790 km)  - % water 41. ... Nickname: Motto: The river and the land sustain us. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Capital Toronto Largest city Toronto Official languages English Government - Lieutenant-Governor James K. Bartleman - Premier Dalton McGuinty (Liberal) Federal representation in Canadian Parliament - House seats 106 - Senate seats 24 Confederation July 1, 1867 (1st) Area [1] Ranked... “San Diego” redirects here. ... Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area  Ranked 3rd  - Total 158,302 sq mi (410,000 km²)  - Width 250 miles (400 km)  - Length 770 miles (1,240 km)  - % water 4. ... Tijuana (Spanish [tixwana], English usually [ËŒtiːəˈwÉ‘nÉ™]), is the largest city in the Mexican state of Baja California and the seat of the municipality of Tijuana. ... Baja California (literally lower California in Spanish) is the northernmost state of Mexico. ...


FM stations in the U.S. are now assigned based on a table of separation distance values from currently licensed stations, based on station "class" (power output, antenna height, and geographical location). These regulations (see Docket 80-90) have resulted in approximately double the number of possible stations, and increases in allowable power levels, over the original bandplan scheme described above. All powers are specified as effective radiated power (ERP), which takes into account the magnifying effect (gain) of multiple antenna elements. A bandplan or band plan is a plan for utilizing a particular band of radio frequencies, that are a portion of the Electromagnetic spectrum . ... This article does not cite any references or sources. ... In electronics, gain is usually taken as the mean ratio of the signal output of a system to the signal input of the system. ...

FM broadcast zones in the U.S.
FM broadcast zones in the U.S.

The U.S. is divided into Zone I (roughly the northeastern quarter of the U.S. mainland, excluding the far northern areas), Zone I-A (California south of 40 degrees latitude, U.S. Virgin Islands, Puerto Rico), and Zone II (all other locations). The highest-power stations are class C in zone II, and class B in the others. There are no B stations in zone II, nor any C stations in the others. (See the list of broadcast station classes.) Canada is also divided in this manner, based on the most highly-populated regions. Image File history File links US_FM_broadcast_zones. ... Image File history File links US_FM_broadcast_zones. ... Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area  Ranked 3rd  - Total 158,302 sq mi (410,000 km²)  - Width 250 miles (400 km)  - Length 770 miles (1,240 km)  - % water 4. ... Latitude,usually denoted symbolically by the Greek letter phi, , gives the location of a place on Earth north or south of the equator. ... This is the list of broadcast station classes. ...


High power is useful in penetrating buildings, diffracting around hills, and refracting for some distance beyond the horizon. 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. ... Nickname: Location of Grand Rapids within Kent County, Michigan Coordinates: , Country United States State Michigan County Kent Founded 1826 Incorporation (city) 1850 Government  - Mayor (Part-time) George Heartwell Area  - City  45. ... Official language(s) None (English, de-facto) Capital Lansing Largest city Detroit Largest metro area Metro Detroit Area  Ranked 11th  - Total 97,990 sq mi (253,793 km²)  - Width 239 miles (385 km)  - Length 491 miles (790 km)  - % water 41. ... Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. ...


See also

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 most of the world, the FM broadcast band, used for broadcasting FM radio stations, goes from 87. ... 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... FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity sound over broadcast radio. ... Mediumwave radio transmissions (sometimes called Medium frequency or MF) are those between the frequencies of 300 kHz and 3000 kHz. ... AM stereo is any of a number of mutually-incompatible techniques for broadcasting two_channel audio in the mediumwave band in a manner that is compatible with receivers designed for standard amplitude modulation. ... This is the list of broadcast station classes. ... The pre-history and early history of radio is the history of technology that produced instruments that use radio waves. ... Radio Data System, or RDS, is a standard from the European Broadcasting Union for sending small amounts of digital information using conventional FM radio broadcasts. ... // The title of Oldest Radio Station is a controversial one, but can be assumed from several in Europe (particularly of England and Germany), and in the United States and Canada. ...

External links

Related websites

  • An Introduction to FM MPX
  • Some history of the FM multiplex system (search down the page for "pilot-tone multiplex system")
  • Stereo for Dummies Many graphs that show waveforms at different points in the FM Multiplex process
  • FM Transmitters

  Results from FactBites:
 
FM broadcasting: Information from Answers.com (2277 words)
The original FM broadcast band in the United States until 1946 was on 42 to 50 MHz with 0.2 MHz channel spacing.
FM started in Australia in 1947 but did not catch on and was shut down in 1961 to expand the television band.
FM transmitters have been used to construct miniature wireless microphones for espionage and surveillance purposes (covert listening devices or so-called "bugs"); the advantage to using the FM broadcast band for such operations is that the receiving equipment would not be considered particularly suspect.
  More results at FactBites »

 
 

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