A Scanner is a radio receiver generally capable of picking up AM and FM (and sometimes SSB) radio signals anywhere from 100kHz to 2.4GHz. Popular amongst hobbyists, reporters, bounty hunters, prying neighbors, corporate spies, criminals and lawyers alike, scanners allow chosen frequencies to be stored in memory banks to allow them to be monitored later and will only stop 'scanning' when there is a signal strong enough to break the radio's squelch setting. Radios that do not have the ability to scan through frequencies are just referred to as receivers. The word receiver has a number of different meanings: In communications and information processing, a receiver is the recipient (observer) of a message (information), which is sent from a source (object). ... Amplitude modulation (AM) is a form of modulation in which the amplitude of a carrier wave is varied in direct proportion to that of a modulating signal. ... The abbreviations FM, Fm, and fm may refer to: Electrical engineering Frequency modulation (FM) and its most common applications: FM radio, used primarily to broadcast music and speech at VHF frequencies FM synthesis, a sound-generation technique popularized by early digital synthesizers Science Femtometre (fm), an SI measure of length... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ... A signal may refer to: an abstract element of information, or, more exactly, usually a flow of information (in either one or several dimensions). ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... This article is about pastimes. ... A reporter is a type of journalist who researches and presents information in certain types of mass media. ... A bounty hunter is an individual who seeks out escaped fugitives in return for a monetary award. ... Neighbourhood is also a term in topology. ... A corporation (usually known in the United Kingdom and Ireland as a company) is a legal entity (distinct from a natural person) that often has similar rights in law to those of a Civil law systems may refer to corporations as moral persons; they may also go by the name... Spy and secret agent redirect here; for alternate use, see Spy (disambiguation) and Secret agent (disambiguation). ... for other uses please see Crime (disambiguation) A crime is an act that violates a political or moral law. ... A lawyer or attorney at law is a person licensed by the state to advise clients in legal matters and represent them in courts of law (and in other forms of dispute resolution). ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... The terms storage (U.K. and U.S.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ... The word monitor, depending on context, may have one of the following meanings: A computer display A speaker used on stage or in a studio to enable musicians to hear what is being recorded or broadcasted An operating system mechanism that synchronizes operations on shared data by multiple processes A... A signal may refer to: an abstract element of information, or, more exactly, usually a flow of information (in either one or several dimensions). ... In telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver. ...

Radio scanners first became popular and widely available during CB Radio's heyday in the 1970s. The first scanners used crystals and had only a few programmable channels. Modern scanners allow thousands of frequencies to be stored in various 'memory banks' and can scan at a very fast rate due to modern micro-processors, they even allow scanning of the specific DCS or CTCSS code used on a specific frequency should it have multiple users. One memory bank can be assigned to overseas broadcasters, another can be for local marine communications and yet an other for local police frequencies that can be switched depending on the user's preference. Many modern amateur radio (tranceive-capable) hand-helds (H/T's) are being designed with advanced wide-band scanning features for little more money than their receive-only cousins and are usually more ruggedly built. Lists of local frequencies are often available through the internet or local amateur radio clubs. A telescoping (extendable) antenna is a good idea for optimum performance if you are monitoring a wide variety of bands (longer for lower frequencies). Radio scanners have historically been frowned upon by law enforcement agencies and the amateur radio community and championed by those supporting civil liberties. However, scanners are becomming obsolete in some communities as many local police, cellular providers, public service (and even amateur radio) agencies switch to trunked, digital, and encrypted radio systems. Although trunked and digital scanners have been developed, decryption capable scanners most likely would be outside the budget of the average consumer. Additionally, decryption of encrypted communications is a violation of U.S. law. See also: popularity. ... Citizens band radio (CB) is, in the United States, a system of short distance radio communication between individuals on a selection of 40 channels within the single 27 MHz (11 meter) band. ... The crystal radio receiver (also known as a crystal set) was first built circa 1900 by Greenleaf Whittier Pickard, who used crystalline minerals to detect radio signals. ... For the geographical meanings of this word, see channel (geography). ... DCS can mean: a distributed control system an illness related to pressure changes: decompression sickness a digital coded squelch in arms trade it means direct commercial sales in model railroading, the Digital Command System by MTH Electric Trains a Document Control System This is a disambiguation page — a navigational aid... In telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver. ... France Marines is the name of a commune in the département of Val dOise, France. ... Preference (or taste) is a concept, used in the social sciences, particularly economics. ... Amateur radio, commonly called ham radio, is a hobby enjoyed by many people throughout the world (as of 2004 about 3 million worldwide, 60,000 in UK, 70,000 in Germany, 5,000 in Norway, 57,000 in Canada, and 700,000 in the USA). ... Money is a marketable good or token that acts as a store of value, a medium of exchange and a unit of account. ... A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... For the band, see The Police. ... A digital system is one that uses discrete values rather than a continuous spectrum of values: compare analog. ... This article is about algorithms for encryption and decryption. ... A digital system is one that uses discrete values rather than a continuous spectrum of values: compare analog. ... This article is about algorithms for encryption and decryption. ... In mathematics, there are numerous methods for calculating the average or central tendency of a list of n numbers. ... In economics, consumers are individuals or households that consume goods and services generated within the economy. ... This article is about algorithms for encryption and decryption. ...

Under a law passed by Congress under the pressure of cellular telephone interests, a law enforced by the FCC, modern American scanners block the 800 MHz cellular band even though few cellular subscribers still use analog technology. Typically, there are Canadian and European unblocked versions available; these are illegal to import into the United States. The cordless phone bands at 46.000 - 49.000 MHz and 902.000 - 906.000 MHz can still be picked up by many scanners though. The proliferation of scanners led to cordless phone manufacturers going to a much more secure 2.4 GHz system using spread-spectrum technology. In the U.K. it is illegal to listen to almost anything outside amateur radio and mid-wave AM/FM stations in the broadcast band. Canada allows anything to be monitored but you may not disclose details of a conversation not broadcast to the general public. In the some parts of the U.S. there are extra penalties for the possesion of a scanner during a crime. Other countries consider the mere possesion of a scanner an offense. Manufacturers include: AOR, Yaesu, Alinco, Radio Shack, Icom, Uniden, etc. The Federal Communications Commission (FCC) is an independent United States government agency, created, directed, and empowered by Congressional statute. ... An analog or analogue signal is any continuously variable signal. ... This article is about the continent. ... This article is about law in society. ... A portable phone or cordless phone is a wireless telephone which is associated with a fixed telephone landline (POTS) and can only be operated close to (typically less than 100 metres of) its base station, such as in and around the house. ... This article is about law in society. ... Broadcast could refer to: Broadcast, an electronica musical group broadcasting, the distribution of audio and video signals Broadcast address, an IP address allowing information to be sent to all machines on a given subnet. ... A penalty is a punishment: a legal sentence, e. ... AOR can refer to any of the following: AOR is an abbreviation of Album Oriented Rock. ... Yaesu is an international manufacturer of ham radio equipment. ... RadioShack Corporation (formerly Radio Shack) (NYSE: RSH) runs a chain of electronics retail stores in the United States, as well as parts of Europe. ... Amateur radio, commonly called ham radio, is a hobby enjoyed by many people throughout the world (as of 2004 about 3 million worldwide, 70,000 in Germany, 5,000 in Norway, 57,000 in Canada, and 700,000 in the USA). ...