A scanner is a radio receiver that can automatically tune, or scan, two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing scanning when that frequency goes silent. Generally, scanners cover the non-broadcast radio bands between 30 and 951 MHz FM, although there are models that cover more of the radio spectrum and use other modulation types. Early scanners were slow, bulky, and expensive.
Today, modern microprocessors have enabled scanners to store thousands of channels and monitor literally hundreds of channels per second. The newest and most expensive models can decode complex radio systems such as trunked and APCO-P25 digital transmissions. In addition, they are quite small and often in the form of a handheld, about the size of a large mobile phone. The traditional use of scanners is to monitor police, fire, Emergency Medical Services, and similar radio systems that use a number of frequencies but with only sporadic use of each.
History and use
Scanners developed from earlier tunable and fixed-frequency radios that received one frequency at a time. Non-broadcast radio systems, such as those used by public safety agencies, do not transmit continuously. With a radio fixed on a single frequency, many minutes could pass between signals, while other frequencies used in the area might be active. The scanning function allows the radio to progress through a routine of pre-programmed channels, or between two limits which define a band of frequencies. It will dwell on an active frequency and will usually resume scanning its defined routine until activity is again found.
Popular amongst hobbyists, railfans, off duty emergency services personnel, reporters and of course, regular people like you. 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.
Scanners first became popular and widely available during CB Radio's heyday in the 1970s. The first scanners often had between four and ten channels and required a separate crystal for each frequency received. Modern programmable scanners allow hundreds or thousands of frequencies to be entered via a keypad and stored in various 'memory banks' and can scan at a rapid rate due to modern microprocessors.
Many recent models will 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 air traffic control, another can be for local marine communications, and yet another for local police frequencies. These can be switched on and off depending on the user's preference. Most scanners have a weather radio band, allowing the listener to tune into weather radio broadcasts from a NOAA transmitter and receive weather warnings using the SAME protocol.
Some scanners are equipped with Fire-Tone out. Fire tone out decodes Quik call II tones and acts as a pager when the correct sequence of tones is detected.
Active frequencies can be found by searching the internet and frequency reference books or can be discovered through a radio's search function. An external antenna for a desktop scanner or an extendable antenna for a hand held unit is a good idea for optimum performance.
Amateur Radio
Amateur Radio, in Canada, is as old as the history of radio itself. Not long after Marconi transmitted the Morse code letter "S" from Poldhu, Wales, to St. John's, Newfoundland in 1901, amateur experimenters throughout the world were trying out the capabilities of the first "spark gap" transmitters.
For more information, please click to the Amateur Radio section.
Legal issues
The legality of radio scanners varies considerably from place to place. Surprising to some, the United States and Canada have very lenient scanner laws. However, there are sometimes very strict regulations on how a scanner radio is to be used. For example, it is a federal crime to monitor cellular phone calls in the US. Some states have regulations and/or permits that must be met to have a scanner in an automobile. It is sometimes illegal to monitor military activity. In some communities, law enforcement has chosen to encrypt their communications. Without a permit (e.g. private investigators[citation needed]), listening to most encrypted signal is almost always illegal. Although scanners capable of following trunked radio systems and demodulating some digital radio systems such as APCO Project 25 are available, decryption-capable scanners would be a violation of United States law and possibly laws of other countries.
Below, in the section, is part of the Canadian Radio Communications Act, that specifies sections that relate to the scanner.
Radio Communications Act (Canada)
The Radio Communications Act states:
4. (1) No person shall, except under and in accordance with radio a radio authorization, install, operate or possess radio apparatus, other than:
(b) radio apparatus that is capable only of the reception of broadcasting and that is not a broadcasting receiving undertaking.
9. (1)(b) without lawful excuse, interfere with or obstruct any radio Communication.
(c) decode an encrypted subscription programming signal or encrypted network feed otherwise than under and in accordance with an authorization from the lawful distributor of the signal or feed;
(d) operate a radio apparatus so as to receive an encrypted subscription programming signal or encrypted network feed that has been decoded in contravention of paragraph (c); or
(e) retransmit to the public an encrypted subscription programming signal or encrypted network feed that has been decoded in contravention of paragraph (c).
(1.1) Except as prescribed, no person shall make use of or divulge a radio-based telephone communication
(a) if the originator of the communication or the person intended by the originator of the communication to receive it was in Canada when the communication was made; and
(b) unless the originator, or the person intended by the originator to receive the communication consents to the use or divulgence.
(2) Except as prescribed, no person shall intercept and make use of, or intercept and divulge, any radiocommunication, except as permitted by the originator of the communication or the person intended by the originator of the communication to receive it.
(3) Subsection (2) does not apply in respect of radiocommunication that consists of broadcasting, a subscription programming signal or a network feed.
[1989, c. 17, s. 6; 1991, c. 11, s. 83; 1993, c. 40, s. 24.]
While in some areas there are local laws that prohibit the use of scanners in vehicles while on the local roadways, in Canada it is safe to have and listen to clear communications. But since most scanner manufacturers produce theirs scanners for the North American market, we are forced to buy scanners that have the Cell channels blocked out.
NOTE:
I have included sub-chapters c and e of Section 9 sub-section 1, as there has been some talk that Police Forces via the Association of Police Chief's, may start looking at using this part of the Act to shut down those that are re-broadcasting digital signals over the internet. There also has been talk that they have been looking at getting the Government to re-word or add to include Public Safety digital/encrypted signals.
If you plan on creating an internet audio stream, please consider not to re-broadcast the OPP or any other digitalized/encrypted signal as it may push the Police Chief's to move faster.
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