PMR446 is typically used for small-site, same-building and line of sight outdoor activities. Equipment used ranges from consumer-grade to professional quality walkie-talkies (similar to those used for FRS/GMRS in the United States and Canada). Depending on surrounding terrain range can vary from a few hundred metres (in a city) to a few kilometres (flat countryside) to many kilometres from high ground.
Historically, analogue FM is used but a digital voice mode has been available in radios conforming to digital private mobile radio (dPMR446) and digital mobile radio (DMR Tier 1) standards designed by ETSI.
Originally 8 channels were available in analogue mode but this has now been increased to 16 channels.
The first steps towards creating licence-free short range radio communications were taken in April 1997 when the European Radio Communications Committee decided on a 446 MHz frequency band to be used for the new radios. In November 1998, ERC Decision (98)25 allocated frequency band 446.0-446.1 MHz for analogue PMR446; another two decisions established licence exemption for PMR446 equipment and free circulation of the PMR446 equipment. The first country which introduced these frequencies for licence-free use was Ireland on 1 April 1998. The United Kingdom introduced PMR446 service in April 1999; since 2003, it has replaced the former short-range business radio (SRBR) service.
In October 2005, ECC Decision (05)02 added unlicenced band 446.1-446.2 MHz for use by digital DMR/dPMR equipment.
In July 2015, ECC Decision (15)05 doubled the number of analog channels to 16 by extending analog operation onto the 446.1-446.2 MHz band previously used by digital DMR/dPMR equipment, effective January 2016; from January 2018, the number of digital channels will also be doubled by extending onto the 446.0-446.1 MHz band used by analog FM.
Until recently, PMR446 radios were handheld transceivers with fixed antennas (see Technical information). In November 2015, Midland Radio announced the release of the GB1 mobile PMR446 radio for vehicular use.
The range of PMR446, just like any VHF or UHF radio, is dependent on many factors like environment (in-city range is far less than in an open field), height above surrounding obstructions, and, to a lesser extent, weather conditions. The antenna type and location, transmit power and receive sensitivity also affect range. However, with PMR446 most of these variables are fixed at manufacturing to comply with the PMR446 specifications. Most of the time the maximum range that a user in a city can expect is a few hundred metres or less.
Range may be many kilometres, for example between hilltops, or only a few hundred metres, if for example a hill or large metal object is in the transmission path between radios. The best known long distance record is 333 mi (535.8 km) from Blyth in the United Kingdom to Almere, Netherlands. This was the result of enhanced propagation conditions, not a line-of-sight signal.
Instead, the U.S. and Canada uses the FRS system, which provides a similar service on different frequencies, around 462 and 467 MHz. These frequencies are allocated to the emergency services in Europe, notably the fire brigade in the UK, police in Russia and commercial users in Australia. Interference with licenced radio services may result in prosecution.
PMR446-compliant equipment may be used anywhere throughout Europe.
Type approved PMR446 radios with power up to 500mW can be used without any licence in India. The devices may not be base stations or repeaters, and must use integrated antennas only.
PMR446 covers band 446.0-446.2 MHz. Radios may now have removable antennas in some countries as long as the ERP does not exceed 500 mW, for example in the UK. The general ECC decision however still requires integral antennas and the actual implementation varies between different countries.
Analogue PMR446 uses 16 FM channels separated by 12.5 kHz from each other. Maximum power is 500 mW ERP and equipment must be used on a mobile basis. CTCSS is usually used, with more upmarket models also featuring DCS and/or fixed-carrier voice inversion. Before January 2016, only the lower 8 channels were allowed for analog FM operation.
Digital PMR446 DMR Tier I (TDMA) uses 16 digital voice channels separated by 12.5 kHz from each other with 4-level FSK modulation at 3.6 kbit/s. Before January 2018, only the higher 8 channels were allowed for digital TDMA operation.
Some models (Hytera BD305LF, Retevis RT40, ...) have DCDM function (Dual Capacity Direct Mode); DCDM function enhanced the frequency utility ratio, It's a feature which allows two slots operation on simplex => 16 channels x 2 slots = 32 ways, equivalent of the 32 FDMA channels.
Color Code (0 to 16) is the equivalent of CTCSS for digital. It's used to isolate a population of users (a company, an association, a family,...).
By convention CC1 is used for public contact.
TalkGroups are used to separate groups of users (ex: TG1 for direction and TG2 for room service in a hotel using channel 12 CC7).
By contacting a specific TG, each user subscribing to this TG will hear you (Group Call).
A user can subscribe to many TGs (RX Group List).
It is also possible to contact all users in your color code (All Call).
Radio ID One for each user, to be contacted directly (Private Call).
|1||446.00625 MHz||12.5 kHz||CTCSS 67Hz - Emergency communication|
|2||446.01875 MHz||12.5 kHz|
|3||446.03125 MHz||12.5 kHz|
|4||446.04375 MHz||12.5 kHz|
|5||446.05625 MHz||12.5 kHz|
|6||446.06875 MHz||12.5 kHz|
|7||446.08125 MHz||12.5 kHz|
|8||446.09375 MHz||12.5 kHz||FM => DX & Calling Channel (8/8)
FM => Mutual assistance (8/16)
|9||446.10625 MHz||12.5 kHz||DMR => Digital Calling Channel (CC1 TG99)
DMR => Mutual asistance (CC1 TG9112)
|10||446.11875 MHz||12.5 kHz|
|11||446.13125 MHz||12.5 kHz|
|12||446.14375 MHz||12.5 kHz|
|13||446.15625 MHz||12.5 kHz|
|14||446.16875 MHz||12.5 kHz|
|15||446.18125 MHz||12.5 kHz|
|16||446.19375 MHz||12.5 kHz|
Digital PMR446 dPMR (FDMA) uses 32 digital voice channels separated by 6.25 kHz from each other with 4-level FSK modulation at 3.6 kbit/s. Before January 2018, only the upper 16 channels were allowed for digital FDMA operation.
|1||446.003125 MHz||6.25 kHz|
|2||446.009375 MHz||6.25 kHz|
|3||446.015625 MHz||6.25 kHz|
|4||446.021875 MHz||6.25 kHz|
|5||446.028125 MHz||6.25 kHz|
|6||446.034375 MHz||6.25 kHz|
|7||446.040625 MHz||6.25 kHz|
|8||446.046875 MHz||6.25 kHz|
|9||446.053125 MHz||6.25 kHz|
|10||446.059375 MHz||6.25 kHz|
|11||446.065625 MHz||6.25 kHz|
|12||446.071875 MHz||6.25 kHz|
|13||446.078125 MHz||6.25 kHz|
|14||446.084375 MHz||6.25 kHz|
|15||446.090625 MHz||6.25 kHz|
|16||446.096875 MHz||6.25 kHz|
|17||446.103125 MHz||6.25 kHz|
|18||446.109375 MHz||6.25 kHz|
|19||446.115625 MHz||6.25 kHz||dPMR => Calling Channel (CC1 TG99)
dPMR => Mutual assistance (CC1 TG9112)
|20||446.121875 MHz||6.25 kHz|
|21||446.128125 MHz||6.25 kHz|
|22||446.134375 MHz||6.25 kHz|
|23||446.140625 MHz||6.25 kHz|
|24||446.146875 MHz||6.25 kHz|
|25||446.153125 MHz||6.25 kHz|
|26||446.159375 MHz||6.25 kHz|
|27||446.165625 MHz||6.25 kHz|
|28||446.171875 MHz||6.25 kHz|
|29||446.178125 MHz||6.25 kHz|
|30||446.184375 MHz||6.25 kHz|
|31||446.190625 MHz||6.25 kHz|
|32||446.196875 MHz||6.25 kHz|
Recently some users have implemented the simplex repeater system, a cheap and easy way to extend the radio range by using extra radios connected to a small repeater controller. This is also known as "Parrot", "ATX-2000" or just "Echo Repeater" after how it sounds repeating every transmission it receives.
The band 420-450 MHz is used extensively by the military agencies for land-based, shipborne, and airborne radar systems to perform important national security functions.