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107-486: The AWS band uses microwave frequencies in several segments: from 1695 to 2200 MHz. The service is intended to be used by mobile devices such as wireless phones for mobile voice, data, and messaging services. Most manufacturers of smartphone mobile handsets provide versions of their phones that include radios that can communicate using the AWS spectrum. Though initially limited, device support for AWS has steadily improved

214-647: A band being used for Milstar . Global Navigation Satellite Systems (GNSS) including the Chinese Beidou , the American Global Positioning System (introduced in 1978) and the Russian GLONASS broadcast navigational signals in various bands between about 1.2 GHz and 1.6 GHz. Radar is a radiolocation technique in which a beam of radio waves emitted by a transmitter bounces off an object and returns to

321-591: A natural monopoly . The FCC controlled telephone rates and imposed other restrictions under Title II to limit the profits of AT&T and ensure nondiscriminatory pricing. In the 1960s, the FCC began allowing other long-distance companies, namely MCI, to offer specialized services. In the 1970s, the FCC allowed other companies to expand offerings to the public. A lawsuit in 1982 led by the Justice Department after AT&T underpriced other companies, resulted in

428-516: A standing wave is present, they may also be used to measure the distance between the nodes , which is equal to half the wavelength. The precision of this method is limited by the determination of the nodal locations. Microwaves are non-ionizing radiation, which means that microwave photons do not contain sufficient energy to ionize molecules or break chemical bonds, or cause DNA damage, as ionizing radiation such as x-rays or ultraviolet can. The word "radiation" refers to energy radiating from

535-604: A "chief" that is appointed by the chair of the commission. Bureaus process applications for licenses and other filings, analyze complaints, conduct investigations, develop and implement regulations, and participate in hearings . The FCC has twelve staff offices. The FCC's offices provide support services to the bureaus. The FCC leases space in the Sentinel Square III building in northeast Washington, D.C. Prior to moving to its new headquarters in October 2020,

642-458: A . Microwaves travel solely by line-of-sight paths; unlike lower frequency radio waves, they do not travel as ground waves which follow the contour of the Earth, or reflect off the ionosphere ( skywaves ). Although at the low end of the band they can pass through building walls enough for useful reception, usually rights of way cleared to the first Fresnel zone are required. Therefore, on

749-431: A computer-controlled array of antennas that produces a beam that can be electronically steered in different directions. At microwave frequencies, the transmission lines which are used to carry lower frequency radio waves to and from antennas, such as coaxial cable and parallel wire lines , have excessive power losses, so when low attenuation is required, microwaves are carried by metal pipes called waveguides . Due to

856-468: A coupled electric field and magnetic field could travel through space as an electromagnetic wave , and proposed that light consisted of electromagnetic waves of short wavelength. In 1888, German physicist Heinrich Hertz was the first to demonstrate the existence of electromagnetic waves, generating radio waves using a primitive spark gap radio transmitter . Federal Communications Commission The Federal Communications Commission ( FCC )

963-535: A frequency near 2.45 GHz (12 cm) through food, causing dielectric heating primarily by absorption of the energy in water. Microwave ovens became common kitchen appliances in Western countries in the late 1970s, following the development of less expensive cavity magnetrons . Water in the liquid state possesses many molecular interactions that broaden the absorption peak. In the vapor phase, isolated water molecules absorb at around 22 GHz, almost ten times

1070-422: A harmonic generator and a mixer. The accuracy of the measurement is limited by the accuracy and stability of the reference source. Mechanical methods require a tunable resonator such as an absorption wavemeter , which has a known relation between a physical dimension and frequency. In a laboratory setting, Lecher lines can be used to directly measure the wavelength on a transmission line made of parallel wires,

1177-432: A network could demand any time it wanted from a Network affiliate . The second concerned artist bureaus. The networks served as both agents and employers of artists, which was a conflict of interest the report rectified. In assigning television stations to various cities after World War II , the FCC found that it placed many stations too close to each other, resulting in interference. At the same time, it became clear that

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1284-705: A new Federal Communications Commission, including in it also the telecommunications jurisdiction previously handled by the Interstate Commerce Commission. Title II of the Communications Act focused on telecommunications using many concepts borrowed from railroad legislation and Title III contained provisions very similar to the Radio Act of 1927 . The initial organization of the FCC was effected July 17, 1934, in three divisions, Broadcasting, Telegraph, and Telephone. Each division

1391-530: A place in the electromagnetic spectrum with frequency above ordinary radio waves , and below infrared light: In descriptions of the electromagnetic spectrum , some sources classify microwaves as radio waves, a subset of the radio wave band, while others classify microwaves and radio waves as distinct types of radiation. This is an arbitrary distinction. Bands of frequencies in the microwave spectrum are designated by letters. Unfortunately, there are several incompatible band designation systems, and even within

1498-515: A receiver, allowing the location, range, speed, and other characteristics of the object to be determined. The short wavelength of microwaves causes large reflections from objects the size of motor vehicles, ships and aircraft. Also, at these wavelengths, the high gain antennas such as parabolic antennas which are required to produce the narrow beamwidths needed to accurately locate objects are conveniently small, allowing them to be rapidly turned to scan for objects. Therefore, microwave frequencies are

1605-410: A situation he found "perplexing". These efforts later were documented in a 2015 Harvard Case Study. In 2017, Christine Calvosa replaced Bray as the acting CIO of FCC. On January 4, 2023, the FCC voted unanimously to create a newly formed Space Bureau and Office of International Affairs within the agency, replacing the existing International Bureau. FCC chairwoman Jessica Rosenworcel explained that

1712-449: A source and not to radioactivity . The main effect of absorption of microwaves is to heat materials; the electromagnetic fields cause polar molecules to vibrate. It has not been shown conclusively that microwaves (or other non-ionizing electromagnetic radiation) have significant adverse biological effects at low levels. Some, but not all, studies suggest that long-term exposure may have a carcinogenic effect. During World War II , it

1819-574: A system the frequency ranges corresponding to some of the letters vary somewhat between different application fields. The letter system had its origin in World War 2 in a top-secret U.S. classification of bands used in radar sets; this is the origin of the oldest letter system, the IEEE radar bands. One set of microwave frequency bands designations by the Radio Society of Great Britain (RSGB),

1926-492: A vacuum under the influence of controlling electric or magnetic fields, and include the magnetron (used in microwave ovens ), klystron , traveling-wave tube (TWT), and gyrotron . These devices work in the density modulated mode, rather than the current modulated mode. This means that they work on the basis of clumps of electrons flying ballistically through them, rather than using a continuous stream of electrons. Low-power microwave sources use solid-state devices such as

2033-534: Is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequencies between 300 MHz and 300 GHz, broadly construed. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 30 cm and 3 mm), or between 1 and 3000 GHz (30 cm and 0.1 mm). The prefix micro- in microwave

2140-566: Is also more bandwidth in the microwave spectrum than in the rest of the radio spectrum; the usable bandwidth below 300 MHz is less than 300 MHz while many GHz can be used above 300 MHz. Typically, microwaves are used in remote broadcasting of news or sports events as the backhaul link to transmit a signal from a remote location to a television station from a specially equipped van. See broadcast auxiliary service (BAS), remote pickup unit (RPU), and studio/transmitter link (STL). Most satellite communications systems operate in

2247-416: Is also used to perform rotational spectroscopy and can be combined with electrochemistry as in microwave enhanced electrochemistry . Microwave frequency can be measured by either electronic or mechanical techniques. Frequency counters or high frequency heterodyne systems can be used. Here the unknown frequency is compared with harmonics of a known lower frequency by use of a low-frequency generator,

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2354-545: Is an independent agency of the United States government that regulates communications by radio , television , wire, satellite , and cable across the United States. The FCC maintains jurisdiction over the areas of broadband access , fair competition , radio frequency use, media responsibility, public safety, and homeland security . The FCC was formed by the Communications Act of 1934 to replace

2461-556: Is funded entirely by regulatory fees. It has an estimated fiscal-2022 budget of US $ 388 million. It has 1,482 federal employees as of July 2020. The FCC's mission, specified in Section One of the Communications Act of 1934 and amended by the Telecommunications Act of 1996 (amendment to 47 U.S.C. §151), is to "make available so far as possible, to all the people of the United States, without discrimination on

2568-555: Is inversely proportional to the transmitted frequency. Microwaves are used in spacecraft communication, and much of the world's data, TV, and telephone communications are transmitted long distances by microwaves between ground stations and communications satellites . Microwaves are also employed in microwave ovens and in radar technology. Before the advent of fiber-optic transmission, most long-distance telephone calls were carried via networks of microwave radio relay links run by carriers such as AT&T Long Lines . Starting in

2675-424: Is limited to a few kilometers. A spectral band structure causes absorption peaks at specific frequencies (see graph at right). Above 100 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so effective that it is in effect opaque , until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges. In a microwave beam directed at an angle into

2782-425: Is not meant to suggest a wavelength in the micrometer range; rather, it indicates that microwaves are small (having shorter wavelengths), compared to the radio waves used in prior radio technology . The boundaries between far infrared , terahertz radiation , microwaves, and ultra-high-frequency (UHF) are fairly arbitrary and are used variously between different fields of study. In all cases, microwaves include

2889-432: Is tabulated below: Other definitions exist. The term P band is sometimes used for UHF frequencies below the L band but is now obsolete per IEEE Std 521. When radars were first developed at K band during World War 2, it was not known that there was a nearby absorption band (due to water vapor and oxygen in the atmosphere). To avoid this problem, the original K band was split into a lower band, K u , and upper band, K

2996-616: The Big Bang , and is one of the few sources of information about conditions in the early universe. Due to the expansion and thus cooling of the Universe, the originally high-energy radiation has been shifted into the microwave region of the radio spectrum. Sufficiently sensitive radio telescopes can detect the CMBR as a faint signal that is not associated with any star, galaxy, or other object. A microwave oven passes microwave radiation at

3103-711: The Broadcast Decency Enforcement Act of 2005 sponsored by then-Senator Sam Brownback , a former broadcaster himself, and endorsed by Congressman Fred Upton of Michigan who authored a similar bill in the United States House of Representatives . The new law stiffens the penalties for each violation of the Act. The Federal Communications Commission will be able to impose fines in the amount of $ 325,000 for each violation by each station that violates decency standards. The legislation raised

3210-504: The United States Senate for five-year terms, except when filling an unexpired term. The U.S. president designates one of the commissioners to serve as chairman. No more than three commissioners may be members of the same political party . None of them may have a financial interest in any FCC-related business. Commissioners may continue serving until the appointment of their replacements. However, they may not serve beyond

3317-494: The breakup of the Bell System from AT&T. Beginning in 1984, the FCC implemented a new goal that all long-distance companies had equal access to the local phone companies' customers. Effective January 1, 1984, the Bell System's many member-companies were variously merged into seven independent "Regional Holding Companies", also known as Regional Bell Operating Companies (RBOCs), or "Baby Bells". This divestiture reduced

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3424-577: The field-effect transistor (at least at lower frequencies), tunnel diodes , Gunn diodes , and IMPATT diodes . Low-power sources are available as benchtop instruments, rackmount instruments, embeddable modules and in card-level formats. A maser is a solid-state device which amplifies microwaves using similar principles to the laser , which amplifies higher frequency light waves. All warm objects emit low level microwave black-body radiation , depending on their temperature , so in meteorology and remote sensing , microwave radiometers are used to measure

3531-457: The 1960s All-Channel Receiver Act ), to make UHF viable against entrenched VHF stations. In markets where there were no VHF stations and UHF was the only TV service available, UHF survived. In other markets, which were too small to financially support a television station, too close to VHF outlets in nearby cities, or where UHF was forced to compete with more than one well-established VHF station, UHF had little chance for success. Denver had been

3638-438: The 2.3 GHz, 2.5 GHz, 3.5 GHz and 5.8 GHz ranges. Mobile Broadband Wireless Access (MBWA) protocols based on standards specifications such as IEEE 802.20 or ATIS/ANSI HC-SDMA (such as iBurst ) operate between 1.6 and 2.3 GHz to give mobility and in-building penetration characteristics similar to mobile phones but with vastly greater spectral efficiency. Some mobile phone networks, like GSM , use

3745-425: The 5 GHz range. Licensed long-range (up to about 25 km) Wireless Internet Access services have been used for almost a decade in many countries in the 3.5–4.0 GHz range. The FCC recently carved out spectrum for carriers that wish to offer services in this range in the U.S. — with emphasis on 3.65 GHz. Dozens of service providers across the country are securing or have already received licenses from

3852-689: The 95 GHz focused beam heats the skin to a temperature of 54 °C (129 °F) at a depth of 0.4 millimetres ( 1 ⁄ 64  in). The United States Air Force and Marines are currently using this type of active denial system in fixed installations. Microwave radiation is used in electron paramagnetic resonance (EPR or ESR) spectroscopy, typically in the X-band region (~9 GHz) in conjunction typically with magnetic fields of 0.3 T. This technique provides information on unpaired electrons in chemical systems, such as free radicals or transition metal ions such as Cu(II). Microwave radiation

3959-565: The AWS spectrum. Since for downlink AWS uses a subset of UMTS frequency band I (2100 MHz) some UMTS2100 capable handsets do detect AWS networks but cannot register on them due to the difference in uplink frequencies (1710–1755 MHz for AWS versus 1920–1980 MHz for UMTS2100). Though initially limited, device support for AWS has steadily improved the longer the frequency has been in general use, with most high-end and many mid-range handsets supporting it over HSPA , LTE , or both. In Canada, almost all available LTE handsets support AWS as it

4066-437: The C, X, K a , or K u bands of the microwave spectrum. These frequencies allow large bandwidth while avoiding the crowded UHF frequencies and staying below the atmospheric absorption of EHF frequencies. Satellite TV either operates in the C band for the traditional large dish fixed satellite service or K u band for direct-broadcast satellite . Military communications run primarily over X or K u -band links, with K

4173-762: The Cable Communications Policy Act of 1984, and made substantial modifications to Title VI in the Cable Television and Consumer Protection and Competition Act of 1992. Further modifications to promote cross-modal competition (telephone, video, etc.) were made in the Telecommunications Act of 1996, leading to the current regulatory structure. Broadcast television and radio stations are subject to FCC regulations including restrictions against indecency or obscenity. The Supreme Court has repeatedly held, beginning soon after

4280-522: The FCC a legal basis for imposing net neutrality rules (see below), after earlier attempts to impose such rules on an "information service" had been overturned in court. In 2005, the FCC formally established the following principles: To encourage broadband deployment and preserve and promote the open and interconnected nature of the public Internet, Consumers are entitled to access the lawful Internet content of their choice; Consumers are entitled to run applications and use services of their choice, subject to

4387-587: The FCC in the newly created post of associate general counsel/chief diversity officer. Numerous controversies have surrounded the city of license concept as the internet has made it possible to broadcast a single signal to every owned station in the nation at once, particularly when Clear Channel, now IHeartMedia , became the largest FM broadcasting corporation in the US after the Telecommunications Act of 1996 became law - owning over 1,200 stations at its peak. As part of its license to buy more radio stations, Clear Channel

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4494-437: The FCC indicated that the public largely believed that the severe consolidation of media ownership had resulted in harm to diversity, localism, and competition in media, and was harmful to the public interest. David A. Bray joined the commission in 2013 as chief information officer and quickly announced goals of modernizing the FCC's legacy information technology (IT) systems, citing 200 different systems for only 1750 people

4601-563: The FCC leased space in the Portals building in southwest Washington, D.C. Construction of the Portals building was scheduled to begin on March 1, 1996. In January 1996, the General Services Administration signed a lease with the building's owners, agreeing to let the FCC lease 450,000 sq ft (42,000 m ) of space in Portals for 20 years, at a cost of $ 17.3 million per year in 1996 dollars. Prior to

4708-403: The FCC said that nearly 55 million Americans did not have access to broadband capable of delivering high-quality voice, data, graphics and video offerings. On February 26, 2015, the FCC reclassified broadband Internet access as a telecommunications service, thus subjecting it to Title II regulation, although several exemptions were also created. The reclassification was done in order to give

4815-408: The FCC to operate in this band. The WIMAX service offerings that can be carried on the 3.65 GHz band will give business customers another option for connectivity. Metropolitan area network (MAN) protocols, such as WiMAX (Worldwide Interoperability for Microwave Access) are based on standards such as IEEE 802.16 , designed to operate between 2 and 11 GHz. Commercial implementations are in

4922-459: The FCC's re-allocation map of stations did not come until April 1952, with July 1, 1952, as the official beginning of licensing new stations. Other FCC actions hurt the fledgling DuMont and ABC networks. American Telephone and Telegraph (AT&T) forced television coaxial cable users to rent additional radio long lines , discriminating against DuMont, which had no radio network operation. DuMont and ABC protested AT&T's television policies to

5029-514: The FCC, which regulated AT&T's long-line charges, but the commission took no action. The result was that financially marginal DuMont was spending as much in long-line charge as CBS or NBC while using only about 10 to 15 percent of the time and mileage of either larger network. The FCC's "Sixth Report & Order" ended the Freeze. It took five years for the US to grow from 108 stations to more than 550. New stations came on line slowly, only five by

5136-504: The FCC. Bidding for this new spectrum started on August 9, 2006 and the majority of the frequency blocks were sold to T-Mobile USA to deploy their 3G wireless network in the United States. This move effectively killed the former MMDS and/or Wireless Cable service in the United States. The following mobile network operators are known to use AWS. Indicated in the list are the launch dates and city. Primary network (UMTS) UMTS and LTE LTE only Microwave Microwave

5243-460: The Internet, cable services and wireless services has raised questions whether new legislative initiatives are needed as to competition in what has come to be called 'broadband' services. Congress has monitored developments but as of 2009 has not undertaken a major revision of applicable regulation. The Local Community Radio Act in the 111th Congress has gotten out of committee and will go before

5350-567: The Portals, the FCC had space in six buildings at and around 19th Street NW and M Street NW. The FCC first solicited bids for a new headquarters complex in 1989. In 1991 the GSA selected the Portals site. The FCC had wanted to move into a more expensive area along Pennsylvania Avenue . In 1934, Congress passed the Communications Act , which abolished the Federal Radio Commission and transferred jurisdiction over radio licensing to

5457-492: The United States accelerated an already ongoing shift in the FCC towards a decidedly more market-oriented stance. A number of regulations felt to be outdated were removed, most controversially the Fairness Doctrine in 1987. In terms of indecency fines, there was no action taken by the FCC on the case FCC v. Pacifica until 1987, about ten years after the landmark United States Supreme Court decision that defined

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5564-508: The United States, the service is administered by the Federal Communications Commission . The licenses were broken up into 6 blocks (A-F). Block A consisted of 734 Cellular Market Areas (CMA). Blocks B and C were each divided into 176 Economic Areas (EA), sometimes referred to as BEA by the FCC. Blocks D, E, and F were each broken up into 12 Regional Economic Area Groupings (REAG), sometimes referred to as REA by

5671-422: The basis of race, color, religion, national origin, or sex, rapid, efficient, nationwide, and world-wide wire and radio communication services with adequate facilities at reasonable charges." The act furthermore provides that the FCC was created "for the purpose of the national defense" and "for the purpose of promoting safety of life and property through the use of wire and radio communications." Consistent with

5778-490: The body. The lens and cornea of the eye are especially vulnerable because they contain no blood vessels that can carry away heat. Exposure to microwave radiation can produce cataracts by this mechanism, because the microwave heating denatures proteins in the crystalline lens of the eye (in the same way that heat turns egg whites white and opaque). Exposure to heavy doses of microwave radiation (as from an oven that has been tampered with to allow operation even with

5885-572: The book value of AT&T by approximately 70%. The FCC initially exempted "information services" such as broadband Internet access from regulation under Title II. The FCC held that information services were distinct from telecommunications services that are subject to common carrier regulation. However, Section 706 of the Telecommunications Act of 1996 required the FCC to help accelerate deployment of "advanced telecommunications capability" which included high-quality voice, data, graphics, and video, and to regularly assess its availability. In August 2015,

5992-444: The commission in 1934 comprised the following seven members: The complete list of commissioners is available on the FCC website. Frieda B. Hennock (D-NY) was the first female commissioner of the FCC in 1948. The FCC regulates broadcast stations, repeater stations as well as commercial broadcasting operators who operate and repair certain radiotelephone , radio and television stations. Broadcast licenses are to be renewed if

6099-414: The conversion, Congress established a federally sponsored DTV Converter Box Coupon Program for two free converters per household. The FCC regulates telecommunications services under Title II of the Communications Act of 1934. Title II imposes common carrier regulation under which carriers offering their services to the general public must provide services to all customers and may not discriminate based on

6206-427: The designated VHF channels, 2 through 13, were inadequate for nationwide television service. As a result, the FCC stopped giving out construction permits for new licenses in October 1948, under the direction of Chairman Rosel H. Hyde . Most expected this "Freeze" to last six months, but as the allocation of channels to the emerging UHF technology and the eagerly awaited possibilities of color television were debated,

6313-508: The door open) can produce heat damage in other tissues as well, up to and including serious burns that may not be immediately evident because of the tendency for microwaves to heat deeper tissues with higher moisture content. Microwaves were first generated in the 1890s in some of the earliest radio wave experiments by physicists who thought of them as a form of "invisible light". James Clerk Maxwell in his 1873 theory of electromagnetism , now called Maxwell's equations , had predicted that

6420-516: The early 1950s, frequency-division multiplexing was used to send up to 5,400 telephone channels on each microwave radio channel, with as many as ten radio channels combined into one antenna for the hop to the next site, up to 70 km away. Wireless LAN protocols , such as Bluetooth and the IEEE 802.11 specifications used for Wi-Fi, also use microwaves in the 2.4 GHz ISM band , although 802.11a uses ISM band and U-NII frequencies in

6527-819: The earth's surface as ground waves , or reflect from the ionosphere , so terrestrial microwave communication links are limited by the visual horizon to about 40 miles (64 km). At the high end of the band, they are absorbed by gases in the atmosphere, limiting practical communication distances to around a kilometer. Microwaves are widely used in modern technology, for example in point-to-point communication links, wireless networks , microwave radio relay networks, radar , satellite and spacecraft communication , medical diathermy and cancer treatment, remote sensing , radio astronomy , particle accelerators , spectroscopy , industrial heating, collision avoidance systems , garage door openers and keyless entry systems , and for cooking food in microwave ovens . Microwaves occupy

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6634-421: The end of November 1952. The Sixth Report and Order required some existing television stations to change channels, but only a few existing VHF stations were required to move to UHF, and a handful of VHF channels were deleted altogether in smaller media markets like Peoria , Fresno , Bakersfield and Fort Wayne, Indiana to create markets which were UHF "islands." The report also set aside a number of channels for

6741-413: The end of the next session of Congress following term expiration. In practice, this means that commissioners may serve up to 1 + 1 ⁄ 2 years beyond the official term expiration listed above if no replacement is appointed. This would end on the date that Congress adjourns its annual session, generally no later than noon on January 3. The FCC is organized into seven bureaus, each headed by

6848-489: The end of the digital television transition. After delaying the original deadlines of 2006, 2008, and eventually February 17, 2009, on concerns about elderly and rural folk, on June 12, 2009, all full-power analog terrestrial TV licenses in the U.S. were terminated as part of the DTV transition , leaving terrestrial television available only from digital channels and a few low-power LPTV stations. To help U.S. consumers through

6955-528: The entire super high frequency (SHF) band (3 to 30 GHz, or 10 to 1 cm) at minimum. A broader definition includes UHF and extremely high frequency (EHF) ( millimeter wave ; 30 to 300 GHz) bands as well. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S , C , X , K u , K , or K a band , or by similar NATO or EU designations. Microwaves travel by line-of-sight ; unlike lower frequency radio waves , they do not diffract around hills, follow

7062-423: The fine ten times over the previous maximum of $ 32,500 per violation. The FCC has established rules limiting the national share of media ownership of broadcast radio or television stations. It has also established cross-ownership rules limiting ownership of a newspaper and broadcast station in the same market, in order to ensure a diversity of viewpoints in each market and serve the needs of each local market. In

7169-598: The first post-Freeze construction permits. KFEL (now KWGN-TV )'s first regular telecast was on July 21, 1952. In 1996, Congress enacted the Telecommunications Act of 1996 , in the wake of the breakup of AT&T resulting from the U.S. Department of Justice's antitrust suit against AT&T. The legislation attempted to create more competition in local telephone service by requiring Incumbent Local Exchange Carriers to provide access to their facilities for Competitive Local Exchange Carriers . This policy has thus far had limited success and much criticism. The development of

7276-414: The frequency can then be calculated. A similar technique is to use a slotted waveguide or slotted coaxial line to directly measure the wavelength. These devices consist of a probe introduced into the line through a longitudinal slot so that the probe is free to travel up and down the line. Slotted lines are primarily intended for measurement of the voltage standing wave ratio on the line. However, provided

7383-406: The frequency of the microwave oven. Microwave heating is used in industrial processes for drying and curing products. Many semiconductor processing techniques use microwaves to generate plasma for such purposes as reactive ion etching and plasma-enhanced chemical vapor deposition (PECVD). Microwaves are used in stellarators and tokamak experimental fusion reactors to help break down

7490-458: The gas into a plasma and heat it to very high temperatures. The frequency is tuned to the cyclotron resonance of the electrons in the magnetic field, anywhere between 2–200 GHz, hence it is often referred to as Electron Cyclotron Resonance Heating (ECRH). The upcoming ITER thermonuclear reactor will use up to 20 MW of 170 GHz microwaves. Microwaves can be used to transmit power over long distances, and post- World War 2 research

7597-459: The high cost and maintenance requirements of waveguide runs, in many microwave antennas the output stage of the transmitter or the RF front end of the receiver is located at the antenna. The term microwave also has a more technical meaning in electromagnetics and circuit theory . Apparatus and techniques may be described qualitatively as "microwave" when the wavelengths of signals are roughly

7704-435: The house floor with bi-partisan support, and unanimous support of the FCC. By passing the Telecommunications Act of 1996, Congress also eliminated the cap on the number of radio stations any one entity could own nationwide and also substantially loosened local radio station ownership restrictions. Substantial radio consolidation followed. Restrictions on ownership of television stations were also loosened. Public comments to

7811-446: The identity of the customer or the content of the communication. This is similar to and adapted from the regulation of transportation providers (railroad, airline, shipping, etc.) and some public utilities. Wireless carriers providing telecommunications services are also generally subject to Title II regulation except as exempted by the FCC. The FCC regulates interstate telephone services under Title II. The Telecommunications Act of 1996

7918-527: The largest U.S. city without a TV station by 1952. Senator Edwin Johnson (D-Colorado), chair of the Senate's Interstate and Foreign Commerce Committee , had made it his personal mission to make Denver the first post-Freeze station. The senator had pressured the FCC, and proved ultimately successful as the first new station (a VHF station) came on-line a remarkable ten days after the commission formally announced

8025-538: The latter company acquired Mobilicity in 2015. Quebecor licensed AWS spectrum throughout the province of Quebec and began offering service with its Vidéotron Mobile brand on September 9, 2010. Shaw Communications licensed AWS spectrum in western Canada and northern Ontario, began to build some infrastructure for providing wireless phone service, but subsequently decided to cancel further development and did not launch this service. The licenses were eventually sold to Rogers, with some transferred to Wind. Shaw re-entered

8132-565: The longer the band has been in general use, with most high-end and many mid-range handsets supporting it over UMTS , LTE and 5G NR . The AWS band defined in 2002 (AWS-1), used microwave frequencies in two segments, from 1710 to 1755 MHz for uplink, and from 2110 to 2155 MHz for downlink. The service is intended to be used by mobile devices such as wireless phones for mobile voice, data, and messaging services. Most manufacturers of smartphone mobile handsets provide versions of their phones that include radios that can communicate using

8239-577: The low-microwave/high-UHF frequencies around 1.8 and 1.9 GHz in the Americas and elsewhere, respectively. DVB-SH and S-DMB use 1.452 to 1.492 GHz, while proprietary/incompatible satellite radio in the U.S. uses around 2.3 GHz for DARS . Microwave radio is used in point-to-point telecommunications transmissions because, due to their short wavelength, highly directional antennas are smaller and therefore more practical than they would be at longer wavelengths (lower frequencies). There

8346-759: The main frequencies used in radar. Microwave radar is widely used for applications such as air traffic control , weather forecasting, navigation of ships, and speed limit enforcement . Long-distance radars use the lower microwave frequencies since at the upper end of the band atmospheric absorption limits the range, but millimeter waves are used for short-range radar such as collision avoidance systems . Microwaves emitted by astronomical radio sources ; planets, stars, galaxies , and nebulas are studied in radio astronomy with large dish antennas called radio telescopes . In addition to receiving naturally occurring microwave radiation, radio telescopes have been used in active radar experiments to bounce microwaves off planets in

8453-868: The mobile services market when it acquired Wind Mobile in 2016. Halifax-based EastLink obtained licenses in eastern Canada, with a small amount of spectrum bought in Ontario and Alberta, and is currently building up infrastructure to launch mobile phone and data services in Nova Scotia and PEI in 2012. This Service has since launched and is available in numerous markets around Atlantic Canada with roaming through Rogers and Bell. Rogers Wireless , Bell Mobility , Telus Mobility , SaskTel , and Manitoba Telecom Services (MTS) all received licenses for AWS spectrum, which they are now using for their LTE networks. Freedom Mobile has subsequently refarmed some spectrum in their UMTS network and deployed LTE on bands 4, and 66. In

8560-492: The move was done to improve the FCC's "coordination across the federal government" and to "support the 21st-century satellite industry." The decision to establish the Space Bureau was reportedly done to improve the agency's capacity to regulate Satellite Internet access . The new bureau officially launched on April 11, 2023. The commissioners of the FCC are: The initial group of FCC commissioners after establishment of

8667-503: The negative effects of media concentration and consolidation on racial-ethnic diversity in staffing and programming. At these Latino town hall meetings, the issue of the FCC's lax monitoring of obscene and pornographic material in Spanish-language radio and the lack of racial and national-origin diversity among Latino staff in Spanish-language television were other major themes. President Barack Obama appointed Mark Lloyd to

8774-482: The newly emerging field of educational television , which hindered struggling ABC and DuMont 's quest for affiliates in the more desirable markets where VHF channels were reserved for non-commercial use. The Sixth Report and Order also provided for the "intermixture" of VHF and UHF channels in most markets; UHF transmitters in the 1950s were not yet powerful enough, nor receivers sensitive enough (if they included UHF tuners at all - they were not formally required until

8881-473: The objectives of the act as well as the 1999 Government Performance and Results Act (GPRA), the FCC has identified four goals in its 2018–22 Strategic Plan. They are: Closing the Digital Divide, Promoting Innovation, Protecting Consumers & Public Safety, and Reforming the FCC's Processes. The FCC is directed by five commissioners appointed by the president of the United States and confirmed by

8988-520: The origin of the Universe . Microwave technology is extensively used for point-to-point telecommunications (i.e., non-broadcast uses). Microwaves are especially suitable for this use since they are more easily focused into narrower beams than radio waves, allowing frequency reuse ; their comparatively higher frequencies allow broad bandwidth and high data transmission rates , and antenna sizes are smaller than at lower frequencies because antenna size

9095-584: The passage of the Communications Act of 1934, that the inherent scarcity of radio spectrum allows the government to impose some types of content restrictions on broadcast license holders notwithstanding the First Amendment. Cable and satellite providers are also subject to some content regulations under Title VI of the Communications Act such as the prohibition on obscenity, although the limitations are not as restrictive compared to broadcast stations. The 1981 inauguration of Ronald Reagan as President of

9202-473: The power of the FCC over indecent material as applied to broadcasting. After the 1990s had passed, the FCC began to increase its censorship and enforcement of indecency regulations in the early 2000s to include a response to the Janet Jackson " wardrobe malfunction " that occurred during the halftime show of Super Bowl XXXVIII . Then on June 15, 2006, President George W. Bush signed into law

9309-425: The printed circuit inverted F antenna (PIFA) used in cell phones. Their short wavelength also allows narrow beams of microwaves to be produced by conveniently small high gain antennas from a half meter to 5 meters in diameter. Therefore, beams of microwaves are used for point-to-point communication links, and for radar . An advantage of narrow beams is that they do not interfere with nearby equipment using

9416-654: The radio regulation functions of the previous Federal Radio Commission . The FCC took over wire communication regulation from the Interstate Commerce Commission . The FCC's mandated jurisdiction covers the 50 states, the District of Columbia , and the territories of the United States . The FCC also provides varied degrees of cooperation, oversight, and leadership for similar communications bodies in other countries in North America. The FCC

9523-650: The report was the breakup of the National Broadcasting Company (NBC), which ultimately led to the creation of the American Broadcasting Company (ABC), but there were two other important points. One was network option time, the culprit here being the Columbia Broadcasting System (CBS). The report limited the amount of time during the day and at what times the networks may broadcast. Previously

9630-639: The same as the dimensions of the circuit, so that lumped-element circuit theory is inaccurate, and instead distributed circuit elements and transmission-line theory are more useful methods for design and analysis. As a consequence, practical microwave circuits tend to move away from the discrete resistors , capacitors , and inductors used with lower-frequency radio waves . Open-wire and coaxial transmission lines used at lower frequencies are replaced by waveguides and stripline , and lumped-element tuned circuits are replaced by cavity resonators or resonant stubs . In turn, at even higher frequencies, where

9737-406: The same frequency, allowing frequency reuse by nearby transmitters. Parabolic ("dish") antennas are the most widely used directive antennas at microwave frequencies, but horn antennas , slot antennas and lens antennas are also used. Flat microstrip antennas are being increasingly used in consumer devices. Another directive antenna practical at microwave frequencies is the phased array ,

9844-960: The second half of 2006, groups such as the National Hispanic Media Coalition, the National Latino Media Council, the National Association of Hispanic Journalists, the National Institute for Latino Policy , the League of United Latin American Citizens (LULAC) and others held town hall meetings in California, New York and Texas on media diversity as its effects Latinos and minority communities. They documented widespread and deeply felt community concerns about

9951-898: The sky, a small amount of the power will be randomly scattered as the beam passes through the troposphere . A sensitive receiver beyond the horizon with a high gain antenna focused on that area of the troposphere can pick up the signal. This technique has been used at frequencies between 0.45 and 5 GHz in tropospheric scatter (troposcatter) communication systems to communicate beyond the horizon, at distances up to 300 km. The short wavelengths of microwaves allow omnidirectional antennas for portable devices to be made very small, from 1 to 20 centimeters long, so microwave frequencies are widely used for wireless devices such as cell phones , cordless phones , and wireless LANs (Wi-Fi) access for laptops , and Bluetooth earphones. Antennas used include short whip antennas , rubber ducky antennas , sleeve dipoles , patch antennas , and increasingly

10058-651: The solar system, to determine the distance to the Moon or map the invisible surface of Venus through cloud cover. A recently completed microwave radio telescope is the Atacama Large Millimeter Array , located at more than 5,000 meters (16,597 ft) altitude in Chile, which observes the universe in the millimeter and submillimeter wavelength ranges. The world's largest ground-based astronomy project to date, it consists of more than 66 dishes and

10165-435: The station meets the "public interest, convenience, or necessity". The FCC's enforcement powers include fines and broadcast license revocation (see FCC MB Docket 04-232). Burden of proof would be on the complainant in a petition to deny. The FCC first promulgated rules for cable television in 1965, with cable and satellite television now regulated by the FCC under Title VI of the Communications Act. Congress added Title VI in

10272-433: The surface of the Earth, microwave communication links are limited by the visual horizon to about 30–40 miles (48–64 km). Microwaves are absorbed by moisture in the atmosphere, and the attenuation increases with frequency, becoming a significant factor ( rain fade ) at the high end of the band. Beginning at about 40 GHz, atmospheric gases also begin to absorb microwaves, so above this frequency microwave transmission

10379-464: The temperature of objects or terrain. The sun and other astronomical radio sources such as Cassiopeia A emit low level microwave radiation which carries information about their makeup, which is studied by radio astronomers using receivers called radio telescopes . The cosmic microwave background radiation (CMBR), for example, is a weak microwave noise filling empty space which is a major source of information on cosmology 's Big Bang theory of

10486-410: The wavelength of the electromagnetic waves becomes small in comparison to the size of the structures used to process them, microwave techniques become inadequate, and the methods of optics are used. High-power microwave sources use specialized vacuum tubes to generate microwaves. These devices operate on different principles from low-frequency vacuum tubes, using the ballistic motion of electrons in

10593-619: Was a proposal regarding the AWS-4 Block, which regulated use of 2000-2020 MHz and 2180-2200 MHz. These were initially proposed for use with the Mobile Satellite System (MSS), but later more uses were introduced In Canada, Industry Canada held the auction for AWS spectrum in 2008. Freedom Mobile (formerly Wind Mobile) had licensed AWS spectrum in every province, and began offering voice and data services on December 16, 2009. Its Saskatchewan and Manitoba spectrum

10700-416: Was built in an international collaboration by Europe, North America, East Asia and Chile. A major recent focus of microwave radio astronomy has been mapping the cosmic microwave background radiation (CMBR) discovered in 1964 by radio astronomers Arno Penzias and Robert Wilson . This faint background radiation, which fills the universe and is almost the same in all directions, is "relic radiation" from

10807-443: Was done to examine possibilities. NASA worked in the 1970s and early 1980s to research the possibilities of using solar power satellite (SPS) systems with large solar arrays that would beam power down to the Earth's surface via microwaves. Less-than-lethal weaponry exists that uses millimeter waves to heat a thin layer of human skin to an intolerable temperature so as to make the targeted person move away. A two-second burst of

10914-441: Was forced to divest all TV stations. To facilitate the adoption of digital television, the FCC issued a second digital TV (DTV) channel to each holder of an analog TV station license. All stations were required to buy and install all new equipment ( transmitters , TV antennas, and even entirely new broadcast towers ), and operate for years on both channels. Each licensee was required to return one of their two channels following

11021-515: Was later sold off to Sasktel and MTS, respectively. Freedom only operates in British Columbia, Alberta and Ontario, although they have roaming agreements with Rogers, Telus and Bell at extra cost. Mobilicity also used the AWS spectrum and began offering services in May 2010, operating in similar areas as Wind but with a smaller network footprint. Its AWS network was combined with Rogers when

11128-560: Was led by two of the seven commissioners, with the FCC chairman being a member of each division. The organizing meeting directed the divisions to meet on July 18, July 19, and July 20, respectively. In 1940, the Federal Communications Commission issued the "Report on Chain Broadcasting " which was led by new FCC chairman James Lawrence Fly (and Telford Taylor as general counsel). The major point in

11235-493: Was observed that individuals in the radiation path of radar installations experienced clicks and buzzing sounds in response to microwave radiation. Research by NASA in the 1970s has shown this to be caused by thermal expansion in parts of the inner ear. In 1955, Dr. James Lovelock was able to reanimate rats chilled to 0 and 1 °C (32 and 34 °F) using microwave diathermy. When injury from exposure to microwaves occurs, it usually results from dielectric heating induced in

11342-524: Was the first frequency over which LTE was offered there, and was still the most commonly supported frequency for LTE in Canada as of 2014-08-21. In 2012 the [FCC] released rules for the 'H' block (AWS-2), covering the frequencies 1915-1920 MHz and 1995-2000 MHz. In 2013 they regulated the AWS-3 Block, covering bands 1695-1710 MHz, 1755-1780 MHz and 2155-2180 MHz. In 2012 there

11449-471: Was the first major legislative reform since the 1934 act and took several steps to de-regulate the telephone market and promote competition in both the local and long-distance marketplace. The important relationship of the FCC and the American Telephone and Telegraph (AT&T) Company evolved over the decades. For many years, the FCC and state officials agreed to regulate the telephone system as

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