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Business Band
In the United States, the business band is the colloquial name used by radio users who utilize, and scanner hobbyists who listen to, the Federal Communications Commission (FCC) Industrial/Business pool frequencies. The regulations listing frequencies in this pool are contained in Subpart C of Part 90, Title 47 of the CFR. Overview The pool describes a series of frequencies on the VHF and UHF two-way radio bands. They are reserved for use by companies and individuals operating commercial activities; educational, philanthropic, or ecclesiastical institutions; clergy activities or hospitals, clinics, or medical associations. In the United States, use of these frequencies requires a license issued by the U.S. FCC. The exceptions to this are five specific frequencies that are also part of the Multi-Use Radio Service (MURS), which permits unlicensed operation on these frequencies, provided the output power does not exceed 2 watts. Other frequency bands, such as citizens band ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citizens Band Radio
Citizens band radio (also known as CB radio), used in many countries, is a land mobile radio system, a system allowing short-distance person-to-many persons bidirectional voice communication among individuals, using two way radios operating on 40 channels near 27 MHz (11 m) in the high frequency (a.k.a. shortwave) band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service ( "ham" radio). In many countries, CB operation does not require a license, and (unlike amateur radio) it may be used for business or personal communications. Like many other land mobile radio services, multiple radios in a local area share a single frequency channel, but only one can transmit at a time. The radio is normally in receive mode to receive transmissions of other radios on the channel; when users want to talk they press a " push to talk" button on their radio, which turns on their transmitter. Users ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GMRS
The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-distance two-way communication and authorized under part 95 of 47 USC. It requires a license in the United States, but some GMRS compatible equipment can be used license-free in Canada. The US GMRS license is issued for a period of 10 years by the FCC. The United States permits use by adult individuals who possess a valid GMRS license, as well as their immediate family members.The FCC definition of “immediate family” includes the licensee’s spouse, children, stepchildren, parents, stepparents, siblings, grandparents, aunts, uncles, nephews, nieces, and in-laws. See . Immediate relatives of the GMRS system licensee are entitled to communicate among themselves for personal or business purposes, but employees of the licensee who are not family members are not covered by the license. Non-family members must be licensed separately. GMRS radios are typically handheld portable d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Mobile Radio Service
The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-distance two-way communication and authorized under part 95 of 47 USC. It requires a license in the United States, but some GMRS compatible equipment can be used license-free in Canada. The US GMRS license is issued for a period of 10 years by the FCC. The United States permits use by adult individuals who possess a valid GMRS license, as well as their immediate family members.The FCC definition of “immediate family” includes the licensee’s spouse, children, stepchildren, parents, stepparents, siblings, grandparents, aunts, uncles, nephews, nieces, and in-laws. See . Immediate relatives of the GMRS system licensee are entitled to communicate among themselves for personal or business purposes, but employees of the licensee who are not family members are not covered by the license. Non-family members must be licensed separately. GMRS radios are typically handheld portable d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Spectrum
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. There is no known limit for long and short wavelengths. Extre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Propagation
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for amateur radio communications, international shortwave broadcasters, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems. Several different types of propagation are used in practical radio transmission systems. '' Line-of-sight propagation'' means radio waves which travel in a straight line from the transmitting antenna to the receiving antenna. Line of sight transmission is used for medium-distance radio transmission, such as cell phones, cordless phones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family Radio Service
The Family Radio Service (FRS) is an improved walkie-talkie radio system authorized in the United States since 1996. This personal radio service uses channelized frequencies around 462 and 467 MHz in the ultra high frequency (UHF) band. It does not suffer the interference effects found on citizens' band (CB) at 27 MHz, or the 49 MHz band also used by cordless telephones, toys, and baby monitors. FRS uses frequency modulation (FM) instead of amplitude modulation (AM). Since the UHF band has different radio propagation characteristics, short-range use of FRS may be more predictable than the more powerful license-free radios operating in the HF CB band. Initially proposed by RadioShack in 1994 for use by families, FRS has also seen significant adoption by business interests, as an unlicensed, low-cost alternative to the business band. New rules issued by the FCC in May 2017 clarify and simplify the overlap between FRS and General Mobile Radio Service (GMRS) radio serv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical cir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal 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 the radio regulation functions of the 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 of North America. The FCC is funded entirely by regulatory fees. It has an estimated fiscal-2022 budget of US $388 million. It has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-Use Radio Service
In the United States, the Multi-Use Radio Service (MURS) is a licensed by rule (i.e. under part 95, subpart J, of title 47, Code of Federal Regulations) two-way radio service similar to the Citizens band (CB). Established by the U.S. Federal Communications Commission in the fall of 2000, MURS created a radio service allowing for licensed by rule (Part 95) operation in a narrow selection of the VHF band, with a power limit of 2 watts. The FCC formally defines MURS as "a private, two-way, short-distance voice or data communications service for personal or business activities of the general public." MURS stations may not be connected to the public telephone network, may not be used for store and forward operations, and radio repeaters are not permitted. In 2009, Industry Canada (IC) established a five-year transition plan, which would have permitted the use of MURS in Canada starting June 2014. In August 2014 IC announced a deferral of MURS introduction, as "the Department does no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-way Radio
A two-way radio is a radio that can both transmit and receive radio waves (a transceiver), unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and receiver in one unit, used for bidirectional person-to-person voice communication with other users with similar radios. Two-way radios are available in stationary (base station), mobile (installed in vehicles), and hand-held portable models. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds. Two-way radios are used by groups of geographically separated people who need to keep in continuous voice communication, such as aircraft pilots and air traffic controllers, ship captains and harbormasters, emergency services personnel like firefighters, police officers, and ambulance paramedics, taxi and delivery services, soldiers and military units, fast food and warehouse employees, and radio amateurs. Two-way radio systems may use a single radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
