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Clear Channel

Clear channel

:This article is about the class of AM radio stations that are called clear channel stations based on their technical parameters, not their owner. For the company named Clear Channel, which owns radio stations most of which are not in this class, please see Clear Channel Communications. Clear channel stations are AM radio stations that are designated as such so that only one or two 50,000 watt powerhouses operate at night on each designated frequency, covering a wide area via sky wave propagation. Non-clear channel stations transmitting on these frequencies are (or were) required to shut down at night, leading them to be known as daytimers. In North America, some frequencies were designated by the North American Radio Broadcasting Agreement (NARBA) (to which the U.S., Canada, and Mexico are signatory) as clear channels. These are considered by the FCC and CRTC to be class A (formerly class 1-A or I-A) stations. Daytimers are in class D. For the U.S., clear channels first appeared in 1922 when the Commerce Department moved stations which had all used two frequencies (one for entertainment stations, one for news) onto 52 frequencies. Two were used for all low-power stations and the large stations each got their own frequency. A few frequencies were used on both the East and West Coast, which were considered far enough apart to limit interference. At this time large stations were limited to 1000 watts. Later in 1928, the AM band was reorganized with local, regional and clear channels (and a few reserved for Canada) by the new Federal Radio Commission. Gradually maximum power was increased to 50,000 watts. This system was continued in the 1941 NARBA system although almost all stations shifted broadcast frequencies. Recently however, the FCC has authorized nighttime operation by lower-powered stations on these frequencies, thus limiting the non-interference range of the primary licensees. Stations are still required to reduce power or reconfigure their transmitters at night. Regional class stations have been allowed to increase their power to the same 50,000 watts as clear channel stations. In 1987 the rules were changed so that no new stations would have daytime-only licenses. Clear Channel Communications, a San Antonio, Texas-based company which owns a large number of U.S. radio stations, was originally formed to purchase one of these stations, WOAI; the company now owns more than a dozen.

Clear channels in North America

The following two tables show all of the class-A stations in North America. Stations in Alaska are shown separately due to their unique status. WOWO was previously a class-A station and is called out in the treaties as such. However, in the 1990s WOWO was downgraded to a class B allotment by reducing its night power to 9.8 kW, and thus no longer has a secondary service area. CHUC applied for and was granted 1580 at Cobourg, Ontario with 10 kW, but chose instead to move to FM. This channel was originally allocated to CBJ in Chicoutimi, Quebec. CHUC is notified to the U.S. as an existing station on 1580.

External links

- [http://www.fcc.gov/mb/audio/amclasses.html AM Station Classes - Clear, Regional, and Local Channels] (FCC Website)
- [http://www.ac6v.com/clearam.htm Big USA, Mexico, and Canadian AM radio stations] Category:United States communications regulation Category:Canadian media regulation Category:Radio
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Clear Channel Communications

:This article is about the company. Radio stations owned by Clear Channel should not be confused with clear channel radio stations, which are AM radio stations with certain technical parameters. Clear Channel Communications is a media company based in the United States of America. Clear Channel, founded in 1972 by Lowry Mays and Red McCombs, wields considerable influence in radio broadcasting, concert promotion and hosting, and fixed advertising in the United States through its subsidiaries. The company owns over 1,200 high-power AM, FM, and shortwave radio stations and more than 30 television stations in the United States, among other media outlets in other countries. The present head of the company is Mark Mays and its headquarters is located in San Antonio, Texas. The term "clear channel" comes from AM broadcasting, referring to a channel (frequency) on which only one station transmits. In U.S. and Canadian broadcasting history, "clear channel" (or class I-A) stations had exclusive rights to their frequencies throughout most of the continent at night, when AM stations travel very far due to skywave. WOAI in San Antonio was such a station. (The term is now becoming obsolete, not because of the company's choice of name, but because the exclusive rights of such stations have been trimmed back significantly.)

History

Clear Channel Communications purchased its first FM station in San Antonio in 1972. They purchased the second "clear channel" AM station WOAI in 1975. In 1986, the company purchased its first stations outside of San Antonio. In 1992, the US Congress relaxed radio ownership rules slightly, allowing the company to acquire more than 2 stations per market. By 1995, they owned 43 radio stations and 16 television stations. In 1996, the Telecommunications Act of 1996 became law. This act deregulated media ownership, allowing a company to own more stations than previously. Clear Channel went on a buying spree, purchasing more than 70 other media companies, plus individual stations. In a few cases, following purchase of a competitor, Clear Channel was forced to divest some of their stations, as they were above the legal thresholds in some cities.

Businesses

Clear Channel has purchased interest in, or outright acquired companies in a number of media or advertising related industries. This is not an exhaustive list.

Radio

Clear Channel has purchased stations from or acquired the following radio companies:
- The Ackerley Group
- AMFM
- Apex
- Chancellor
- Clark Broadcasting
- Dame Media
- Eastern Radio Assets
- Gulfstar
- Jacor
- Nationwide Communications
- Quad City
- Roberts
- Taylor Broadcasting
- Trumper Communications

Outdoor advertising

Trumper Communications
- Bought Eller Media, Universal Outdoor, and More Group Plc, giving Clear Channel outdoor advertising space in 25 countries.
- Owns part of Italian street furniture company, Jolly Pubblicita S.p.A.
- Owns BBH Exhibits, Yellow Checker Star Cab Displays, Dauphin, Taxi Tops, Donrey Media and Ackerley Media. Also owns an outdoor advertising company in Switzerland and Poland and a major outdoor advertising firm in Chile.

TV

First TV station purchased was WPMI-TV in Mobile, Alabama in 1988. They now own more than 30 additional stations, a few of these are independent (no-network affiliates).

Live events

- Clear Channel owns SFX Entertainment, now known as Clear Channel Entertainment, providing venue and artist management. It owns, operates and/or exclusively books 135 live entertainment venues, including 28 in Europe, along with producing high profile events such as Super Bowl halftime shows. It also represents major music artists and sports stars.
- US Touring Productions of Broadway Shows The Lion King and Mamma Mia
- Owns USHRA (United States Hot Rod Association), a promoter of tractor pulls and monster truck races.
- Produces sporting events: 84 Lumber Classic of Pennsylvania; Legg Mason Tennis Classic; ADT Skills Challenge; American Century Golf Championship; THQ World Supercross GP; National Arenacross Series; IFMA Freestyle Motocross; and IHRA Drag Racing
- Produces concerts and festivals: Ozzfest, Jagermeister Music Tour, Lollapalooza and Music Midtown (Atlanta)

News and information

- Operates Clear Channel News Network and local news networks in Kentucky, Virginia, Ohio, Oklahoma, Alabama, Tennessee, Georgia and Florida
- Premiere Radio Networks
- FOX Sports Radio Network
- Acquired Agri Broadcast Network (ABN), a farm programming provider in Ohio
- Publishes Inside Radio magazine
- Clear Channel Traffic reports on road and traffic conditions nationwide, and in Mexico City, Mexico

Worldwide

- Owns part of radio groups in New Zealand, Mexico, Norway, and Australia.
- Owns outdoor advertising companies in Switzerland, Poland, Chile, Brazil, and Italy
- Owns L & C Outdoor Comunicacao Visual Ltda., of Brazil.
- Acquired Italian music promoters Milano Concerti and Trident Agency.
- Owns Clear Channel Entertainment do Brasil Ltda, a Brazilian music promotion and production company
- Owns the only airport advertising contract in South America.
- In the UK, owns:
- Large numbers of billboards (through a takeover of Adshel)
- A controlling stake in Mean Fiddler, and thus interests in:
- Several music festivals festivals, including Glastonbury Festival, V Festival, Reading and Leeds Festivals, Homelands Festivaland Download Festival
- The majority of medium-sized London music venues, including Brixton Academy and the Mean Fiddler.
- A concert promotion business which promotes large outdoor concerts in Hyde Park, London, as well as numerous small and medium concert venues across the country.
- See Clear Channel UK

Controversy

As a large company operating in many different states, with numerous employees, Clear Channel has been involved in a number of highly visible controversies.

Market share

In the late 1990s and early 2000s the company became an object of persistent criticism. Critics claim that it has abused its market position and has operated in an unethical manner. FCC regulations were relaxed following the Telecommunications Act of 1996, allowing companies to own far more radio signals than before. After spending about $30 billion, Clear Channel owned over 1200 stations nationwide, including as many as 7 stations in certain markets. Competitors and listeners complained, but so far the company has been able to hold on to all of its stations after divesting a few following the acquisition of AMFM.

September 11, 2001

Following the September 11, 2001 attacks on New York and Washington, D.C., a list of songs apparently recommended to be removed from airplay as inappropriate during a time of national mourning was generated and circulated (See List of songs deemed inappropriate by Clear Channel following the September 11, 2001 attacks). A small list was initially generated by the Clear Channel office, though individual program directors added many of their own songs. A list containing about 150 songs was soon circulating on the Internet. The criteria for choosing the songs seemed to be unreasonable to many. A number of songs were apparently placed on the list because they had specific words such as "plane", "fly", and "falling" in their titles. Many people found it particularly ludicrous that John Lennon's "Imagine" was one of the songs listed. Clear Channel denies that this was a list of "banned" songs, claiming it was a list of titles that should be played only after great thought. Many individual stations did play songs from the list. Not only did many individual stations play songs from the alleged lists, Clear Channel's Classic Rock station, near its Radio Headquaters in Cincinnati, played many of those "banned" songs shortly after 9/11 and after the salon.com story about the list. Songs that were played included Tom Petty's Free Falling and John Lennon's Imagine.

Pro Freedom Rallies

In the build up to the second Iraq War Clear Channel organized and paid for a counterpoint to anti-war demonstrations, supporters of war in Iraq have descended on cities from Fort Wayne to Cleveland, and Atlanta to Philadelphia. Waving flags, messages of support for the troops - and also banners attacking liberals, excoriating the UN, and in one case, advising: "Bomb France Now." Clear Channel paid for the advertising costs and for the hire of musicians for the rallies. Clear Channel said the rallies were "patriotic", not "pro-war".

Banning music and political ramifications

In March of 2003, the lead singer of the Dixie Chicks said to an English concert audience, "Just so you know, we're ashamed the President of the United States is from Texas," upsetting many music fans and politicians in the United States. Thinking the Dixie Chicks were now a pariah and thus unmarketable, all of the country music stations owned by Cumulus Media were told to stop playing their music. There is specualtion that Clear Channel also may have directed their stations to do so, but the company states this was solely the work of local station managers, DJ’s, and angry fans. Some critics of Clear Channel, including the editors of Rock and Rap Confidential, claim otherwise. They claim that Clear Channel executives, in a bid to gain support for various policies they were pushing in Washington, instigated the boycott among its country music stations themselves to send a message to other musicians that criticizing President George Bush's administration could hurt your career (through reduced airplay, etc.) Clear Channel denies these accusations. Clear Channel stations were not the only radio stations to ban their music; another large media company, Atlanta-based Cox Radio, did the same. See Dixie Chicks.

Live music recordings

In 2004, Clear Channel acquired a key patent in the process of producing "instant live recordings", in which a live performance is recorded directly from the sound engineer's console during the show, and then rapidly burned on CD so that audience members can buy copies of the show as they are leaving the venue. This is intended to provide additional revenue to the artist, venue, and promoter, as well as stifle the demand for unauthorized bootleg concert recordings made by audience members for profit. However, some media critics, as well as smaller business rivals, believe that Clear Channel is using the patent (on the process of adding cues to the beginning and ending of tracks during recording, so that the concert is not burned as a single enormous track) to drive competitors out of business or force them to pay licensing fees, even if they do not use precisely the same process. [http://www.rollingstone.com/news/story/_/rnd/1085518316199/pageid/rs.Home/has-player/true/pageregion/single1/id/6066617?rnd=1102422965968&has-player=true&version=6.0.11.847]

Indecency zero tolerance

During the nationwide crackdown on indecent material following the 2004 Super Bowl, Clear Channel launched a "self-policing" effort, and declared that there would be no "indecent" material allowed on the air. This led to the company's dismissal of several of their own employees, including popular and high-profile hosts in a number of cities. Free-speech advocates cried foul. During this same period, Howard Stern was dropped from six Clear Channel owned stations in Florida, California, Pennsylvania, New York and Kentucky. By mid-year, rival Viacom brought Stern's show back to those six markets. In June, 2004, Viacom/Infinity Broadcasting Inc./One Twelve Inc. filed a $10 million lawsuit against Clear Channel for breaking of contracts and non-payment of licensing fees due to the dropping of Stern's show. Viacom is Howard Stern's employer. In the following July, Clear Channel filed a countersuit of $3 million.

Concerts and promotions

Clear Channel has settled a lawsuit with a Denver, Colorado concert promoter, Nobody In Particular Presents (NIPP). In the lawsuit, NIPP alleged that Clear Channel halted airplay on its local stations for NIPP clients, and that Clear Channel would not allow NIPP to publicize its concerts on the air. The lawsuit was settled in 2004 with no monetary consideration, but Clear Channel has new rules regarding local concert promotion in Denver. In 2002, Clear Channel was sued by the US Justice Department for not allowing people with diabetes to bring medically necessary supplies, including syringes used for insulin, into concert venues. Clear Channel changed their policy shortly afterward. In 2004, Clear Channel was sued by a San Francisco, California man for charging a mandatory parking fee on every ticket sold for a venue, whether the person purchasing the ticket was driving alone, car-pooling, or using public transportation. This is still unresolved.

Stations on "Auto-pilot"

Clear Channel, like other broadcasters both large and small, utilizes technology (known as Prophet) that allows a DJ from anywhere in the country to sound as if he or she is broadcasting from anywhere else in the country, on any other station. A technological outgrowth of earlier, tape-based automation systems dating back to the nineteen-sixties, this is called voice-tracking, and some smaller market stations are partially staffed by these "cyber-jocks", who may have never visited the town they are broadcasting in. A side-effect of this trend to automate radio stations, as opposed to signing off overnight, is that no one is there to warn people when disaster strikes. Clear Channel was criticized for an incident that occurred in Minot, North Dakota, when a Canadian Pacific Railway train filled with toxic anhydrous ammonia derailed early on the morning of January 18, 2002. City officials had improperly programmed the EAS (Emergency Alert System) equipment that was supposed to allow them to automatically broadcast information over local radio stations, including the six stations (of nine in Minot) owned by Clear Channel. No personnel answered the phone during the overnight hours when city officials attempted to reach the stations by telephone. The incident has been cited repeatedly in subsequent years by opponents of media consolidation. Clear Channel maintains that the issue was a failure of the EAS system and says it has subsequently worked to improve emergency contact procedures at its stations.

Rejection of anti-war billboard

In 2004, Project Billboard, a non-profit Democratic political advocacy group, filed a breach of contract suit against Clear Channel for the rejection by its outdoor advertising division of a billboard ad against the war in Iraq. The ad, intended for a 40-foot billboard Clear Channel manages in Times Square, was to have the slogan, "Democracy is best taught by example, not by war," along with a red, white and blue cartoon image of a bomb. Clear Channel's contract with Project Billboard only allowed the company to reject ads that were illegal or contrary to public morals; Clear Channel claimed that the image of the bomb was insensitive in New York City, the site of the most devastating of the 9/11 terrorist attacks. Project Billboard claimed that Clear Channel's rejection was instead for purely political reasons. Clear Channel settled the suit by agreeing to an alternative featuring an image of a peace dove instead of a bomb.

Censorship

Clear Channel has been criticized for censoring opinions critical of George W. Bush and other Republicans. Clear-Channel-owned KTVX was the only local television station which refused to air the paid political message of Cindy Sheehan against the war in Iraq [http://www.sltrib.com/ci_2960205?rss]. Some Utahns consider this to be another act of censorship of grass-roots free speech. Though this also goes against the fact that Clear Channel changed many of its AM talk/music stations to the progressive talk format (featuring the Air America Radio network]]) format which is highly critical of President Bush.

ClearChannelSucks.net and musician boycotts

As well as the website http://www.ClearChannelSucks.net spawned from RadioAid's battle for the ownership of the ClearChannelSucks domain [http://www.austinchronicle.com/issues/dispatch/2005-04-01/pols_feature6.html], there are a notable amount of bands, and radio hosts, including Howard Stern that actively boycott Clear Channel. The most widely known of these are The Locust, as well as Conor Oberst, the leading figure behind Bright Eyes, who openly and continuously advocate the boycotting of all Clear Channel events, venues, advertising area and radio stations. The Locust are so attached to this boycotting that it is affecting their April 2005 tour with the Mike Patton side project Fantômas. Another outspoken detractor of Clear Channel is veteran rocker Neil Young, who has criticized the company in numerous interviews. After having refused to perform in Clear Channel-owned venues for several years, Young was finally forced to do so on his 2000 "CSNY2K" tour with Crosby, Stills and Nash. In 2003, on an even more extensive tour showcasing his Greendale song-story, Young turned his shows into theatrical productions in which images lampooning Clear Channel were prominently displayed.

Official Response to Controversy

Clear Channel officially denies most of these allegations. An article titled [http://www.clearchannel.com/Corporate/PressRelease.aspx?PressReleaseID=1167&p=hidden Know the Facts] on its corporate website addresses many of these concerns.

Corporate governance

Current members of the board of directors of Clear Channel Communications are: Alan Feld, Perry Lewis, Lowry Mays, B.J. McCombs, Phyllis Riggins, Theodore Strauss, J.C. Watts, and John H. Williams. Former members of the board of directors of the corporation are: Tom Hicks and Vernon Jordan.

Top executives

- Lowry Mays - company founder, chairman
- Mark Mays - son of Lowry Mays, chief executive officer, president and chief operating officer; named CEO after serving as interim CEO since his father underwent surgery to treat a blood clot and bleeding in his brain
- Randall Mays - son of Lowry Mays, executive vice president and chief financial officer
- John Hogan - president and chief operating officer, Clear Channel Radio
- Tom Hicks, Clear Channel's former vice-chairman, is a past donor to Bush's political campaigning. The two were at the centre of a scandal when Mr Bush was governor and when Mr Hicks chaired a University of Texas investment board that awarded large investment-management contracts to several companies close to the Bush family - including the Carlyle Group, on whose payroll Mr Bush had been until weeks previously.

Program hosts (through its Premiere Radio Networks subsidiary)

- Rush Limbaugh
- Dr. Laura
- Phil Hendrie
- Jim Rome
- Bob and Tom
- Carson Daly
- Leeza Gibbons
- Rick Dees
- John Boy and Billy
- Casey Kasem
- Delilah
- Ryan Seacrest
- Donald Trump
- Jesse Jackson
- Glenn Beck

Famous people managed by Clear Channel or subsidiaries

Sports: David Beckham, Michael Jordan, Andre Agassi, Brandi Chastain, Pedro Martinez, Prince Naseem Hamed, Jason Giambi, Gary Lineker, Miguel Tejada, Roger Clemens, Greg Norman, Nomar Garciaparra, Jerry Rice, Kobe Bryant, Warrick Dunn, Al Michaels, Trent Green, Dick Vermeil, Gail Devers, Michael Owen, Nasser Hussain, Michael Atherton, and Alan Shearer. Music promoted by Clear Channel or subsidiaries: U2, System of a Down, Anthony and the Johnsons, Mötley Crüe, David Gray, LCD soundsystem, The Prodigy, Rod Stewart, Duran Duran, Feeder, Depeche Mode, David Gray, Bullet For My Valentine

Former hosts

- Bubba the Love Sponge was fired from a Clear Channel station on 24 February 2004, following a large FCC fine.
- Howard Stern, while not a Clear Channel employee, was permanently removed from all Clear Channel stations on 8 April 2004, following a large FCC fine.

External links and references

- [http://www.clearchannel.com/ Clear Channel Communications]
- [http://www.cjr.org/tools/owners/clearchannel.asp List of Clear Channel owned radio and TV stations by state]
- Eric Boehlert, [http://dir.salon.com/ent/feature/2001/04/30/clear_channel/index.html Radio's big bully], salon.com, April 30, 2001
- Eric Boehlert, [http://dir.salon.com/ent/feature/2001/05/30/clear_channel_employees/index.html Tough company], salon.com, May 30, 2001
- A Open Directory Project web directory related to [http://dmoz.org/Society/Issues/Business/Allegedly_Unethical_Firms/Clear_Channel_Communications/?tc=1 Clear Channel Communications]
- [http://www.corpwatch.org/issues/PID.jsp?articleid=8728 CorpWatch.org article on Clear Channel]
- [http://www.projectcensored.org/publications/2004/17.html Project Censored article on Clear Channel]
- [http://www.cnn.com/2004/LAW/07/12/billboard.lawsuit/index.html Group sues over anti-war billboard, CNN, July 12, 2004]
- [http://www.salon.com/ent/clear_channel/ Salon.com article on Clear Channel]
- [http://www.clearchannelsucks.net ClearChannelSucks.net] Category:Clear Channel Communications Category:Companies based in Texas Clear Channel Clear Channel Category:San Antonio, Texas

Radio station

A radio station is a sound broadcasting service. Traditionally, radio stations have broadcast through the air via radio waves (a form of electromagnetic radiation), sent through a transmitter and antenna. Today, many if not most stations broadcast via cable FM, local wire networks, satellite, or the Internet as well as (or instead of) atmospheric broadcasting. Stations can be linked in radio networks to broadcast a common program, either in syndication or simulcast, or both. Broadcasting program material in real time is known as live broadcasting. As technology for sound recording improved, an increasing proportion of broadcast programming used pre-recorded material. A current trend is the automation of radio stations. Some stations now operate without direct human intervention by using entirely pre-recorded material sequenced by computer control (see Voice-tracking). Radio stations are of several types. The best known are the AM and FM stations, including both commercial and public or nonprofit varieties. Non-commercial college and university radio stations are found throughout the developed world. The earliest radio stations were simply radio telegraph systems, and did not carry audio. The first known audio transmission that could be called a broadcast occurred on Christmas Eve in 1906, and was made by Reginald Fessenden. While many early experimenters attempted to create systems similar to radiotelephone devices where 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. For the next decade, radio tinkerers had to build their own radio receivers. KDKA AM of Pittsburgh, Pennsylvania (owned by Westinghouse) started broadcasting as the first "commercial" radio station on November 2, 1920. The commercial sense of the station came from the type of license—they didn't start airing advertisements until a few years later. The first broadcast was the results of the U.S. presidential election, 1920. Many historians base KDKA's status as "first" on the fact that commercially-produced radio receivers weren't available until that time. However, by that standard, many believe that other stations should count, as at least one smaller manufacturer with their own station was making radios by the time KDKA was licensed. AM stations were developed first. AM refers to amplitude modulation, a mode of broadcasting radio waves, and occurs on North American airwaves in the mediumwave frequency range of 530 to 1700 kHz (known as the "standard broadcast band"). The band was expanded in the 1990s by adding nine channels from 1620 to 1700 kHz. Channels are spaced every 10 kHz in the Americas, and generally every 9 kHz everywhere else. Europe also uses the longwave band. FM refers to frequency modulation, and occurs on VHF airwaves everywhere (except Japan) in the frequency range of 88 to 108 MHz. Japan uses the 74 to 90 MHz band. FM stations are much more popular in economically developed regions, such as Europe and the United States, especially since higher sound fidelity and stereo broadcasting became common in this format. The digital radio stations are now emerging, first in Europe (the U.K. and Germany), and later in the United States. The European system is named DAB, for Digital Audio Broadcasting, and uses the public domain EUREKA 147 system. In the United States, the IBOC system is named HD Radio and owned by a private company, a consortium called iBiquity. It is expected that for the next 10 to 20 years, all these systems will co-exist, while by 2015 to 2020 digital radio may predominate, at least in the developed countries. Many other non-broadcast types of radio stations exist. These include:
- base stations for police, fire and ambulance networks
- military base stations
- dispatch base stations for taxis, trucks, and couriers
- emergency broadcast systems
- amateur radio stations

External links

- [http://search.fcc.gov/query.html?qt=radio+station&col=fccall+edocs+digest&ht=0&qp=&qs=&qc=&pw=100%25&ws=0&la=en&qm=0&st=1&nh=10&lk=1&rf=0&oq=&rq=0&si=0&Submit+search+request.x=8&Submit+search+request.y=9 In the United States, See FCC]
- category:broadcast engineering ja:ラジオ放送局

Watt

:For other uses, see: Watt (disambig) The watt (symbol: W) is the SI derived unit of power.
Definition
One watt is one joule of energy per second. : 1 W = 1 J/s = 1 newton meter per second
Origin
The watt is named after James Watt for his contributions to the development of the steam engine, and was adopted by the Second Congress of the British Association for the Advancement of Science in 1889 and by the 11th Conférence Générale des Poids et Mesures in 1960.
SI multiples

Conversions

- 1 watt ≈ 3.41214163 BTU/h
- 1 horsepower ≈ 745.700 W
- 1 horsepower (electrical British) = 746 W
- 1 horsepower (electrical European) = 736 W
- 1 horsepower ("metric") = 735.498 75 W
Derived and qualified units for power distribution
A watt is a unit of power or the amount of energy per unit time.
Kilowatt-hour, MWd
When paired with a unit of time the term watt is used for expressing energy consumption. For example, a kilowatt hour, is the amount of energy expended by a one kilowatt device over the course of one hour; it equals 3.6 megajoules (1 hour = 3600 seconds). A megawatt day (MWd or MW·d) is equal to 86.4 GJ (1 day = 86400 seconds). These units are often used in the context of power plants and home energy bills. For the use of watts as a measurement of transmitter power in radio, see effective radiated power and nominal power.
MWe, MWt
Watt electrical (abbreviation: We) is a term that refers to power produced as electricity. SI prefixes can be used, for example megawatt electrical (MWe) and gigawatt electrical (GWe). Watt thermal (abbreviation: Wt). This is a term that refers to thermal power produced. SI prefixes can be used, for example megawatt thermal (MWt) and gigawatt thermal (GWt). For example, a nuclear power plant might use a fission reactor to generate heat (thermal output) which creates steam to drive a turbine to generate electricity. See nuclear proliferation for discussion of a reactor that generates 200 MWt (50 MWe), and another reactor that generates 800 MWt (200 MWe).
See also

- SI
- Kilowatt hour (kW·h)
- Watt balance
- Conversion of units
- Orders of magnitude (power)
- James Watt
- RMS
- Back to the Future
External links

- Nelson, Robert A., "[http://www.aticourses.com/international_system_units.htm The International System of Units] Its History and Use in Science and Industry". Via Satellite, February 2000. Category:SI derived units Category:Units of power ko:와트 ja:ワット simple:Watt

Frequency

: Frequency is the measurement of the number of times that a repeated event occurs per unit time. It is also defined as the rate of change of phase of a sinusoidal waveform.

Measurement

To calculate the frequency of an event, the number of occurrences of the event within a fixed time interval are counted, and then divided by the length of the time interval. In SI units, the result is measured in hertz (Hz), named after the German physicist Heinrich Rudolf Hertz. 1 Hz means that an event repeats once per second, 2 Hz is twice per second, and so on. This unit was originally called a cycle per second (cps), which is still used sometimes. Other units that are used to measure frequency include revolutions per minute (rpm) and radians per second (rad/s). Heart rate and musical tempo are measured in beats per minute (BPM). An alternative method to calculate frequency is to measure the time between two consecutive occurrences of the event (the period) and then compute the frequency as the reciprocal of this time: :

f = \frac

where T is the period. A more accurate measurement takes many cycles into account and averages the period between each.

Frequency of waves

Measuring the frequency of sound, electromagnetic waves (such as radio or light), electrical signals, or other waves, the frequency in hertz is the number of cycles of the repetitive waveform per second. If the wave is a sound, frequency is what mainly characterizes its pitch. Frequency has an inverse relationship to the concept of wavelength. The frequency f is equal to the speed v of the wave divided by the wavelength λ (lambda) of the wave: :

f = \frac

In the special case of electromagnetic waves moving through a vacuum, then v = c, where c is the speed of light in a vacuum, and this expression becomes: :

f = \frac

NOTE: When waves travel from one medium to another, their frequency remains exactly the same - only their wavelength and/or speed changes.

Invariance

Apart from its being modified by Doppler effect, frequency is an invariant quantity in the universe. That is, it cannot be changed by any physical process unlike velocity of propagation or wavelength.

Examples

- The frequency of the standard pitch A above middle C is usually defined as 440 Hz, that is, 440 cycles per second () and known as concert pitch, to which an orchestra tunes.
- A baby can hear tones with oscillations up to approximately 20,000 Hz, but these frequencies become more difficult to hear as people age.
- In Europe, the frequency of the alternating current in mains is 50 Hz (close to the tone G).
- In North America, the frequency of the alternating current is 60 Hz (close to the tone B flat — that is, a minor third above the European frequency). The frequency of the 'hum' in an audio recording can show where the recording was made — in Europe or in America.

External links

- [http://www.sengpielaudio.com/calculator-wavelength.htm Conversion: frequency to wavelength and back]
- [http://www.sengpielaudio.com/calculator-period.htm Conversion: period, cycle duration, periodic time to frequency] Category:Physical quantity Category:Sound Category:Wave mechanics ko:진동수 ja:周波数 th:ความถี่

Sky wave

Skywave is the propagation of radio waves by the refraction caused by the Earth's highly charged ionosphere. A skywave is a radio wave from a distant radio station (or rarely, a TV station) that is refracted in the ionosphere. It brings in distant stations at night as clear as local stations. Low to mid frequencies below approximately 10 MHz (longer than 30 meters) including broadcasts in the mediumwave and shortwave bands (and to some extent longwave), travel most efficiently this way at night, acting more like the Earth's natural electrical field than other higher frequencies above 10 MHz (shorter than 30 Meters) which have properties more akin to light and travel better during the day. Frequencies Lower than 30 kHz have a wavelength longer than the distance between the Earth and the Ionosphere. The Ionosphere, though refracting, can usually bend radio waves enough so they come back to the surface of the Earth.The Ionosphere has been called a natural radio "mirror". Because the solar wind "blows" the ionosphere toward the earth on the day side, and away from it on the night side, the refractive layer of the ionosphere is much higher above the surface at night. The amount of ionisation and the distance of the higher charge in the ionosphere affect the amount of refraction.

Propagation

The word propagation can mean:
- Multiplication or increase, as by natural reproduction. In artificial reproduction see propagation of schema.
- In genetics, propagation is another term for the elongation part of transcription.
- In agriculture and horticulture, propagation is the production of increased numbers of plants, by seeds, cuttings, grafting or other methods.
- In religion, propagation is a term often used for winning new converts to the particular religion.
- In physics, propagation is the motion of waves through or along a medium.
- In chemistry, propagation describes the catalytically-driven process of polymer elongation.
- In Psychological Operations, propagation is some degree of success in the spread of propaganda.
- In digital circuits, propagation delay is the time between input and output of logic gates. Note: For electromagnetic waves, propagation may occur in a vacuum as well as in a material transmission medium. See also: photon, waveguide, polarization, antenna theory

NARBA

NARBA has several meanings:
- the 1941 North American Radio Broadcasting Agreement treaty [http://www.bostonradio.org/radio/narba.html]
- the North American Rare Bird Alert program [http://www.narba.org]

United States

:For alternative meanings, see the disambiguation page for US, USA, United States, or American. The United States of America is a federal democratic republic situated primarily in central North America. It comprises 50 states and one federal district, and has several territories. It is also referred to, with varying formality, as the United States, the U.S., the U.S.A., the States, or simply and most commonly, America. The official founding date of the United States is July 4, 1776, when the Second Continental Congress—representing thirteen British colonies—adopted the Declaration of Independence. However, the structure of the government was profoundly changed in 1788, when the states replaced the Articles of Confederation with the United States Constitution. The date on which each of the fifty states adopted the Constitution is typically regarded as the date that state "entered the Union" (became part of the United States). Since the mid-20th century, following World War II, the United States has emerged as a dominant global influence in economic, political, military, scientific, technological, and cultural affairs.

Geography and climate

The United States shares land borders with Canada (to the north) and Mexico (to the south), and territorial water boundaries with Canada, Russia, the Bahamas, and numerous smaller nations. It is otherwise bounded by the Pacific Ocean and the Bering Sea, in the west; the Arctic Ocean, in the northernmost areas; and the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea, in the eastern and southeastern areas. Forty-eight of the states are in the single region between Canada and Mexico; this group is referred to, with varying precision and formality, as the continental or contiguous United States, sometimes abbreviated CONUS, and as the Lower 48. Alaska, which is not included in the term contiguous United States, is at the northwestern end of North America, separated from the Lower 48 by Canada. The archipelago of Hawaii is in the Pacific Ocean. The capital city, Washington, District of Columbia is a federal district located on land donated by the state of Maryland. (Virginia also donated land, but it was returned in 1847.) The United States also has overseas territories with varying levels of independence and organization. When inland water is included in the total area, only Russia and Canada are larger than the United States; if inland water is excluded, China ranks third and the U.S. ranks fourth. The United States' total area is 3,718,711 square miles (9,631,418 km²), of which land makes up 3,537,438 square miles (9,161,923 km²) and water makes up 181,273 square miles (469,495 km²). The United States' landscape is one of the most varied among those of the world's nations: among its many features are temperate forestland and rolling hills, on the east coast; mangrove, in Florida; the Great Plains, in the center of the country; the Mississippi–Missouri river system; the Great Lakes, four of the five of which are shared with Canada; the Rocky Mountains, west of the Great Plains; deserts and temperate coastal zones, west of the Rocky Mountains; and temperate rain forests, in the Pacific northwest. Alaska's tundra, and the volcanic, tropical islands of Hawaii add to the geographic diversity. Hawaii The climate varies along with the landscape, from tropical in Hawaii and southern Florida to tundra in Alaska and atop some of the highest mountains. Most of the North and East experience a temperate continental climate, with warm summers and cold winters. Most of the South experiences a subtropical humid climate with mild winters and long, hot, humid summers. Rainfall decreases markedly from the humid forests of the Eastern Great Plains to the semi-arid shortgrass prairies on the high plains abutting the Rocky Mountains. Arid deserts, including the Mojave, extend through the lowlands and valleys of the southwest, from westernmost Texas to California and northward throughout much of Nevada. Some parts of California have a Mediterranean climate. Rainforests line the windward mountains of the Pacific Northwest from Oregon to Alaska.

History

American history started with the migration of people from Asia across the Bering land bridge approximately 12,000 years ago following large animals that they hunted into the Americas. These Native Americans left evidence of their presence in petroglyphs, burial mounds, and other artifacts. It is estimated that 2-9 million people lived in the territory now occupied by the U.S. before European contact, and the subsequent introduction of foreign diseases such as small pox that greatly diminished the native populations. Some advanced societies were the Anasazi of the southwest, who inhabited Chaco Canyon, and the Woodland Indians, who built Cahokia, located near present-day St Louis, a city with a population of 40,000 at its peak in AD 1200. Vikings first visited North America around 1000, but did not settle permanently. Following the discovery voyages of Christopher Columbus around 1492, other Europeans began to explore and settle there. During the 1500s and 1600s, the Spanish settled parts of the present-day Southwest and Florida, founding St. Augustine, Florida in 1565 and Santa Fe (in what is now New Mexico) in 1607. The first successful English settlement was at Jamestown, Virginia, also in 1607. Within the next two decades, several Dutch settlements, including New Amsterdam (the predecessor to New York City), were established in what are now the states of New York and New Jersey. In 1637, Sweden established a colony at Fort Christina (in what is now Delaware), but lost the settlement to the Dutch in 1655. This was followed by extensive British settlement of the east coast. The British colonists remained relatively undisturbed by their home country until after the French and Indian War, when France ceded Canada and the Great Lakes region to Britain. Britain then imposed taxes on the 13 colonies, widely regarded by the colonists as unfair because they were denied representation in the British Parliament. Tensions between Britain and the colonists increased, and the thirteen colonies eventually rebelled against British rule. British Parliament, George Washington (1789-1797).]] In 1776, the 13 colonies split from Great Britain and formed the United States, the world's first constitutional and democratic federal republic, after their Declaration of Independence of that year, and the Revolutionary War (1775 to 1783). The original political structure was a confederation in 1777, ratified in 1781 as the Articles of Confederation. After long debate, this was supplanted by the Constitution in 1789, forming a more centralized federal government. Prior to all these was the Albany Congress in 1754, in which a union was first seriously proposed. From early colonial times, there was a shortage of labor, which encouraged unfree labor, particularly indentured servitude and slavery. In the mid-19th century, a major division occurred in the United States over the issue of states' rights and the expansion of slavery. The northern states had become opposed to slavery, while the southern states saw it as necessary for the continued success of southern agriculture and wanted it expanded to the territories. Several federal laws were passed in an attempt to settle the dispute, including the Missouri Compromise and the Compromise of 1850. The dispute reached a crisis in 1861, when seven southern states seceded¹ from the Union and formed the Confederate States of America, leading to the Civil War. Soon after the war began, four more southern states seceded. During the war, Abraham Lincoln issued the Emancipation Proclamation, mandating the freedom of all slaves in states in rebellion, though full emancipation did not take place until after the end of the war in 1865, the dissolution of the Confederacy, and the Thirteenth Amendment took effect. The Civil War effectively ended the question of a state's right to secede, and is widely accepted as a major turning point after which the federal government became more powerful than state governments. Thirteenth Amendment). The title of the painting, from a 1726 poem by Bishop Berkeley, was a phrase often quoted in the era of Manifest Destiny, expressing a widely held belief that civilization had steadily moved westward throughout history. [http://americanart.si.edu/t2go/1lw/1931.6.1.html (more)] ]] During the 19th century, many new states were added to the original 13 as the nation expanded across the continent. Manifest Destiny was a philosophy that encouraged westward expansion in the United States. As the population of the Eastern states grew and as a steady increase of immigrants entered the country, settlers moved steadily westward across North America. In the process, the U.S. displaced most American Indian nations. This displacement of American Indians continues to be a matter of contention in the U.S. with many tribes attempting to assert their original claims to various lands. In some areas American Indian populations were reduced by foreign diseases contracted through contact with European settlers, and US settlers acquired those emptied lands. In other instances American Indians were removed from their traditional lands by force. Though some would say the U.S. was not a colonial power until the Spanish-American War when it acquired Puerto Rico, Guam and the Philippines, the dominion exercised over land in North America the United States claimed is essentially colonial. The Philippines became independent in 1946. During this period, the nation also became an industrial power. This continued into the 20th century, which has been termed "the American Century" because of the nation's overriding influence on the world. The US became a center for innovation and technological development; major technologies that America either developed or was greatly involved in improving include the telephone, television, computer, the Internet, nuclear weapons, nuclear power, aviation, and aeronautics. In addition to the Civil War, another major traumatic experience for the nation was the Great Depression (1929 to 1939). The nation has also taken part in several major foreign wars, including World War I and World War II (in both of which the US later joined the Allies). During the Cold War, the US was a major player in the Korean War and Vietnam War, and, along with the Soviet Union, was considered one of the world's two "superpowers". With the collapse of the Soviet Union, the US emerged as the world's leading economic and military power. Beginning in the 1990s, the United States became very involved in police actions and peacekeeping, including actions in Kosovo, Haiti, Somalia and Liberia, and the first Persian Gulf War driving Iraq out of Kuwait. After attacks on the World Trade Center and the Pentagon on September 11, 2001, the United States and other allied nations found themselves involved in what has come to be called the "War on Terrorism," which has primarily encompassed military actions in both Afghanistan and Iraq.

Government

Iraq of the United States.]]

Republic and suffrage

The United States is an example of a constitutional republic, with a government composed of and operating through a set of limited powers imposed by its design and enumerated in the United States Constitution. Specifically, the nation operates as a presidential democracy. There are three levels of government: federal, state, and local. Officials of each of these levels are either elected by eligible voters via secret ballot or appointed by other elected officials. Americans enjoy almost universal suffrage from the age of 18 regardless of race, sex, or wealth. There are some limits, however: felons are disenfranchised and in some states former felons are likewise. Furthermore, the national representation of territories and the federal district of Washington, DC in Congress is limited: residents of the District of Columbia are subject to federal laws and federal taxes but their only Congressional representative is a non-voting delegate.

Federal government

The federal government is the national government, comprising the Legislative Branch (led by Congress), the Executive Branch (led by the President), and the Judicial Branch (led by the Supreme Court). These three branches were designed to apply checks and balances on each other. The Constitution limits the powers of the federal government to defense, foreign affairs, the issuing and management of currency, the management of trade and relations between the states, and the protection of human rights. In addition to these explicitly stated powers, the federal government—with the assistance of the Supreme Court—has gradually extended these powers into such areas as welfare and education, on the basis of the "necessary and proper" clause of the Constitution.

The Congress

necessary and proper The Congress of the United States is the legislative branch of the federal government of the United States. It is bicameral, comprising the House of Representatives and the Senate. The House of Representatives consists of 435 members, each of whom represents a congressional district and serves for a two-year term. House seats are apportioned among the states by population; in contrast, each state has two Senators, regardless of population. There are a total of 100 senators, who serve six-year terms. The powers of Congress are limited to those enumerated in the Constitution; all other powers are reserved to the states and the people. The Constitution also includes the necessary-and-proper clause, which grants Congress the power to "make all laws which shall be necessary and proper for carrying into execution the foregoing powers."

The President

necessary-and-proper clause At the top level of the executive branch is the President of the United States. The President and Vice-President are elected as 'running mates' for four-year terms by the Electoral College, for which each state, as well as the District of Columbia, is allocated a number of seats based on its representation (or ostensible representation, in the case of D. C.) in both houses of Congress (see U.S. Electoral College). The relationship between the President and the Congress reflects that between the English monarchy and parliament at the time of the framing of the United States Constitution. Congress can legislate to constrain the President's executive power, even with respect to his or her command of the armed forces; however, this power is used only very rarely—a notable example was the constraint placed on President Richard Nixon's strategy of bombing Cambodia during the Vietnam War. The President cannot directly propose legislation, and must rely on supporters in Congress to promote his or her legislative agenda. The President's signature is required to turn congressional bills into law; in this respect, the President has the power—only occasionally used—to veto congressional legislation. Congress can override a presidential veto with a two-thirds majority vote in both houses. The ultimate power of Congress over the President is that of impeachment or removal of the elected President through a House vote, a Senate trial, and a Senate vote. The threat of using this power has had major political ramifications in the cases of Presidents Andrew Johnson, Richard Nixon, and Bill Clinton. The President makes around 2,000 executive appointments, including members of the Cabinet and ambassadors, which must be approved by the Senate; the President can also issue executive orders and pardons, and has other Constitutional duties, among them the requirement to give a State of the Union address to Congress once a year. Although the President's constitutional role may appear to be constrained, in practice, the office carries enormous prestige that typically eclipses the power of Congress: the Presidency has justifiably been referred to as 'the most powerful office in the world'. The Vice President is first in the line of succession, and is the President of the Senate ex officio, with the ability to cast a tie-breaking vote. The members of the President's Cabinet are responsible for administering the various departments of state, including the Department of Defense, the Justice Department, and the State Department. These departments and department heads have considerable regulatory and political power, and it is they who are responsible for executing federal laws and regulations. George W. Bush is the 43rd President, currently serving his second term.

The Courts

George W. Bush The highest court is the Supreme Court, which consists of nine justices. The court deals with federal and constitutional matters, and can declare legislation made at any level of the government as unconstitutional, nullifying the law and creating precedent for future law and decisions. Below the Supreme Court are the courts of appeals, and below them in turn are the district courts, which are the general trial courts for federal law. Separate from, but not entirely independent of, this federal court system are the individual court systems of each state, each dealing with its own laws and having its own judicial rules and procedures. A case may be appealed from a state court to a federal court only if there is a federal question; the supreme court of each state is the final authority on the interpretation of that state's laws and constitution.

State and local governments

supreme court of each state. Note that Alaska and Hawaii are shown at different scales, and that the Aleutian Islands and the uninhabited Northwestern Hawaiian Islands are omitted from this map.]] The state governments have the greatest influence over people's daily lives. Each state has its own written constitution and has different laws. There are sometimes great differences in law and procedure between the different states, concerning issues such as property, crime, health, and education. The highest elected official of each state is the Governor. Each state also has an elected legislature (bicameral in every state except Nebraska), whose members represent the different parts of the state. Of note is the New Hampshire legislature, which is the third-largest legislative body in the English-speaking world, and has one representative for every 3,000 people. Each state maintains its own judiciary, with the lowest level typically being county courts, and culminating in each state supreme court, though sometimes named differently. In some states, supreme and lower court justices are elected by the people; in others, they are appointed, as they are in the federal system. The institutions that are responsible for local government are typically town, city, or county boards, making laws that affect their particular area. These laws concern issues such as traffic, the sale of alcohol, and keeping animals. The highest elected official of a town or city is usually the mayor. In New England, towns operate directly democratically, and in some states, such as Rhode Island and Connecticut, counties have little or no power, existing only as geographic distinctions. In other areas, county governments have more power, such as to collect taxes and maintain law enforcement agencies.

Political divisions

With the Declaration of Independence, the thirteen colonies proclaimed themselves to be nation states modeled after the European states of the time. Although considered as sovereigns initially, under the Articles of Confederation of 1781 they entered into a "Perpetual Union" and created a fully sovereign federal state, delegating certain powers to the national Congress, including the right to engage in diplomatic relations and to levy war, while each retaining their individual sovereignty, freedom and independence. But the national government proved too ineffective, so the administrative structure of the government was vastly reorganized with the United States Constitution of 1789. Under this new union, the continued status of the individual states as sovereign nation states fell into dispute in 1861, as several states attempted to secede from the union; in response, then-President Abraham Lincoln claimed that such secession was illegal, and the result was the American Civil War. Since the Union victory in 1865, the independent status of the individual states has not been broached again by any state, and the status of each state within the union has been deemed by mainstream officials and academics to be settled as being subordinate to the union as a whole. In subsequent years, the number of states grew steadily due to western expansion, the purchase of lands by the national government from other nation states, and the subdivision of existing states, resulting in the current total of 50. The states are generally divided into smaller administrative regions, including counties, cities and townships. The United States–Canadian border is the longest undefended political boundary in the world. The U.S. is divided into three distinct sections:
- the "continental United States," also known as "the Lower 48" and more accurately termed the conterminous, coterminous or contiguous United States
- Alaska, which is physically connected only to Canada
- the archipelago of Hawaii, in the central Pacific Ocean. The United States also holds several other territories, districts, and possessions, notably the federal district of the District of Columbia, which is the nation's capital, and several overseas insular areas, the most significant of which are American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Palmyra Atoll is the United States' only incorporated territory; it is unorganized and uninhabited. The United States Navy has held a base at a portion of Guantanamo Bay, Cuba, since 1898. The United States government possesses a lease to this land, which only mutual agreement or United States abandonment of the area can terminate. The present Cuban government of Fidel Castro disputes this arrangement, claiming Cuba was not truly sovereign at the time of the signing. The United States argues this point moot because Cuba apparently ratified the lease post-revolution, and with full sovereignty, when it cashed one rent check in accordance with the disputed treaty.

Foreign relations and military

sovereign] The immense military and economic dominance of the United States has made foreign relations an especially important topic in its politics, with considerable concern about the image of the United States throughout the world. Reactions towards the United States by other nationalities are often strong, ranging from uninhibited admiration and mimicking of all things American to anti-Americanism. US foreign policy has swung about several times over the course of its history between the poles of strict isolationism and imperialism and everywhere in between. Three of the nation's four military branches are administered by the Department of Defense: the Army, the Navy (including the Marine Corps), and the Air Force. The Coast Guard falls under the jurisdiction of the Department of Homeland Security in peacetime, but is placed under the Department of the Navy in time of war. The combined United States armed forces consist of 1.4 million active duty personnel, along with several hundred thousand each in the Reserves and the National Guard. Military conscription ended in 1973. The United States Armed forces are considered to be the most powerful military (of any sort) on Earth and their force projection capabilities are unrivaled by any other nation. The 2005 defense budget amounted to $401.7 billion, which is an increase of 4% over 2004 and of 35% since 2001. Over 50% of that number is spent in research & development. (For comparison, in 2004 the European Union (considered as the second-largest military force) had a combined total of 1.6 million troops, and a defense budget of €160 billion, with less than 10% of that being spent on R&D.)

Largest cities

The United States has dozens of major cities, including 11 of the 55 global cities of all types — with three "alpha" global cities: New York City, Los Angeles, and Chicago. The figures expressed below are for populations within city limits. A different ranking is evident when considering U.S. metro area populations, although the top three would be unchanged. Note that some cities not listed (such as Atlanta, Boston, Las Vegas, Miami, Nashville, New Orleans, Seattle, and Washington, D.C.) are still considered important on the basis of other factors and issues, including culture, economics, heritage, and politics. The twenty largest cities, based on the United States Census Bureau's 2004 estimates, are as follows:

Economy

The United States has the largest single-country economy in the world, with a per-capita gross domestic product of $40,100. In this market-oriented economy, private individuals and business firms make most of the decisions, and the federal and state governments buy needed goods and services predominantly in the private marketplace. gross domestic product The largest industry of the U.S. is now service, which employs roughly three quarters of the U.S. work force. The United States has many natural resources, including oil and gas, metals, and such minerals as gold, soda ash, and zinc. In agriculture, the U.S. is a top producer of, among other crops, corn, soy beans, and wheat; the United States is a net exporter of food. The U.S. manufacturing sector produces goods such as, cars, airplanes, steel, and electronics, among many others. Economic activity varies greatly from one part of the country to another, with many industries being largely dependent on a certain city or region; New York City is the center of the American financial, publishing, broadcasting, and advertising industries; Silicon Valley is the country’s primary location for high-technology companies, while Los Angeles is the most important center for film production. The Midwest is known for its reliance on manufacturing and heavy industry, with Detroit, Michigan, serving as the center of the American automotive industry; the Great Plains are known as the "breadbasket" of America for their tremendous agricultural output; the intermountain region serves as a mining hub and natural gas resource; the Pacific Northwest for fish and timber, while Texas is largely associated with the oil industry; the Southeast is a major hub for both medical research and the textiles industry. Several countries continue to link their currency to the dollar or even use it as a currency (such as Ecuador), although this practice has subsided since the collapse of the Bretton Woods system. Many markets are also quoted in dollars, such as those of oil and gold. The dollar is also the predominant reserve currency in the world, and more than half of global reserves are in dollars. The largest trading partner of the United States is Canada (19%), followed by China (12%), Mexico (11%), and Japan (8%). More than 50% of total trade is with these four countries. In 2003, the United States was ranked as the third most visited tourist destination in the world; its 40,400,000 visitors ranked behind France's 75,000,000 and Spain's 52,500,000. Labor unions have existed since the 19th century, and grew large and powerful from the 1930s to the 1950s. See Labor history of the United States. Since 1970 they have shrunk in the private sector and now cover fewer than 8% of the workers. However union membership has grown rapidly in the public sector, especially among teachers, nurses, police, postal workers, and municipal clerks. There have been few strikes in recent years. The United States' imports exceed exports by 80%, leading to an annual trade deficit of $700,000,000,000, or 6% of gross domestic product. It is the largest debtor nation in the world, with total gross foreign debt of over $13,000,000,000,000 (2005 estimate); and it absorbs more than 50% of global savings annually. Since the 1980s, the U.S. has increased the use of neoliberal economic policies that reduce government intervention and reduce the size of the welfare state, backing away from the more interventionist Keynsian economic policies that had been in favor since the Great Depression. As a result, the United States provides fewer government-delivered social welfare services than most industrialized nations, choosing instead to keep its tax burden lower and relying more heavily on the free market and private charities. Sixteen states and the District of Columbia have minimum wages higher than the national level ($5.15 per-hour), including the highest, Washington State at $7.35. Twenty-six states are the same as the federal level; two--Ohio and Kansas--are below; and six do not have state laws. America's wealth is relatively highly concentrated. The average C.E.O. earns 500 times the typical amount a worker grosses, this is up from 25 times in the late 1970s. In terms of wealth the top 1% of Americans own 40% of all assets and 50.1% of the country's income goes to the top twenty percent of households. Average wages for the majority of employees have been largely stagnating since the 1970s. America's poverty line defined as a family of four earning less than $19,157 is at 12.7% of the general population. Approximately one out of every five children in the United States grows up below the official poverty line. Among racial groups; African Americans have the lowest median income while Asians had the highest. Regionally, the southern states had the lowest median incomes while the West Coast and New England had the highest. The current Federal Reserve Chairman Alan Greenspan remarked that the U.S.’s growing income inequality since the 1970s is, "not the type of thing which a democratic society - a capitalist democratic society - can really accept without addressing."[http://www.csmonitor.com/2005/0614/p01s03-usec.html?s=itm] However, Greenspan also noted, "...you can look at the system and say it's got a lot of problems to it, and sure it does. It always has. But you can't get around the fact that this is the most extraordinarily successful economy in history."

Transportation

Alan Greenspan ]] Because the United States is a relatively young nation, most of the development of U.S. cities has taken place since the invention of the automobile. To link its vast territory, the United States built a network of high-capacity, high-speed highways, of which the most important element is the Interstate Highway system, commissioned in the 1950s by President Dwight D. Eisenhower and modeled after the German Autobahn. The United States also has a transcontinental rail system, which is used for moving freight across the lower forty-eight states. Passenger rail service is provided by Amtrak, which serves forty-six of the lower forty-eight states. Many cities in the United States have extensive mass-transit systems. New York City operates one of the world's largest and most heavily used subway systems. The regional rail and bus networks that extend into Long Island, New Jersey, Upstate New York, and Connecticut are among the most heavily used in the world. Air travel is often preferred for destinations over 300 miles (500 kilometers) away. In terms of passengers, seventeen of the world's thirty busiest airports in 2004 were in the U.S., including the world's busiest, Hartsfield-Jackson Atlanta International Airport; in terms of cargo, in the same year, twelve of the world's thirty busiest airports were in the U.S., including the world's busiest, Memphis International Airport. There are several major seaports in the United States; the three busiest are the Port of Los Angeles, California; the Port of Long Beach, California; and the Port of New York and New Jersey. Others include Houston, Texas; Charleston, South Carolina; Savannah, Georgia; Miami, Florida; Portland, Oregon; San Francisco, California; Boston, Massachusetts; Philadelphia, Pennsylvania; and Seattle, Washington; plus, outside the contiguous forty-eight states, Anchorage, Alaska, and Honolulu, Hawaii.

Society

Demographics

Hawaii The mean center of the U.S. population continues to drift farther west and south. The fastest growing region is the western United States followed by the southern portion. According to Census 2000, the states that saw the greatest increases from 1990 were: Nevada (66.3%), Arizona (40%), Colorado (30.6%), Utah (29.6%), Idaho (28.5%), Georgia (26.4%), Florida (23.5%), Texas (22.8%), North Carolina (21.4%), and Washington (21.1%). [http: