PMR446

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Motorola TA288 PMR446 licence-free radio
Motorola TLKR T40 radio tuned to PMR channel 1

PMR446 (personal mobile radio, 446 MHz) is a part of the UHF radio frequency range that is open without licensing for business and personal use in most countries of the European Union.[1]

PMR446 is ideal for small-site, same-building and line of sight outdoor activities. It is used in both professional and consumer-grade 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.

In addition to PMR446, some countries in the EU have begun to introduce LPD433 (low power device 433 MHz) licence-free short range transceiver radios as part of short range device regulations. These radios give an additional 69 channels (LPD433) which can be used with CTCSS or DCS to improve co-operation on shared channels. These extra channels have been introduced to reduce the burden on the 16 PMR446 channels over shorter distances (<1 km).

History[edit]

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 unlicensed 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.

Range[edit]

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.[2][3][4]

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.[5] This was the result of enhanced propagation conditions, not a line-of-sight signal.

Usage worldwide[edit]

PMR446 radios use frequencies that in Australia, the U.S., and Canada are allocated to amateur radio operators. PMR446 radios can only be used in those countries by licensed amateur radio operators. The conflicting allocations have been something of a nuisance to amateur operators due to use of the equipment by European tourists.[citation needed]

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.[6] Interference with licensed radio services may result in prosecution.

PMR446-compliant equipment may be used anywhere throughout Europe.[7]

Technical information[edit]

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.[8] The general ECC decision[9] however still requires integral antennas and the actual implementation varies between different countries.

Analogue FM and digital TDMA[edit]

Kenwood TK3301 and TK3501 PMR446 radios

Analogue PMR uses 16 FM channels separated by 12.5 kHz from each other. Per regulation, maximum power, like FRS, 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 DMR Tier I uses 16 digital voice channels separated by 12.5 kHz from each other with 4-level FSK modulation at 3.6 kbit/s.[10] Before January 2018, only the higher 8 channels were allowed for digital TDMA operation.

PMR/DMR Channel Frequency (MHz)
1 446.00625
2 446.01875
3 446.03125
4 446.04375
5 446.05625
6 446.06875
7 446.08125
8 446.09375
9 446.10625
10 446.11875
11 446.13125
12 446.14375
13 446.15625
14 446.16875
15 446.18125
16 446.19375

Digital FDMA[edit]

Digital dPMR446 uses 32 digital voice channels separated by 6.25 kHz from each other with 4-level FSK modulation at 3.6 kbit/s.[11] Before January 2018, only the upper 16 channels were allowed for digital FDMA operation.

dPMR446 Channel Frequency (MHz)
1 446.003125
2 446.009375
3 446.015625
4 446.021875
5 446.028125
6 446.034375
7 446.040625
8 446.046875
9 446.053125
10 446.059375
11 446.065625
12 446.071875
13 446.078125
14 446.084375
15 446.090625
16 446.096875
17 446.103125
18 446.109375
19 446.115625
20 446.121875
21 446.128125
22 446.134375
23 446.140625
24 446.146875
25 446.153125
26 446.159375
27 446.165625
28 446.171875
29 446.178125
30 446.184375
31 446.190625
32 446.196875

PMR446 gateways[edit]

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.[12]

PMR446 gateways extend the range of PMR446. These gateways are connected through internet using a client/server VoIP system such as eQSO or the Free Radio Network (FRN).

Law[edit]

See also[edit]

References[edit]

  1. ^ "Analogue and Digital PMR446 Information Sheet" (PDF). Ofcom. Retrieved 2013-01-05. 
  2. ^ World First Midland GB1 PMR 446 Mobile Attached Antenna
  3. ^ Midland GB1 First Look Midland GB1 Mobile PMR446 - Manual Download Includes Specs
  4. ^ Midland GB1 First Look *Updated With English Manual*
  5. ^ "Delboy's DX Contact UK to Amsterdam". Delboy Enterprises. 5 August 2003. Archived from the original on 2008-02-09. 
  6. ^ "Can I bring my FRS / GMRS Radio to Europe - Austria, Germany, Switzerland : British Expat Discussion Forum". Britishexpats.com. 2005-05-10. Retrieved 2010-11-18. 
  7. ^ dPMR446 - Welcome to the dPMR Association
  8. ^ "Analogue and Digital PMR446 Information Sheet" (PDF). Ofcom. Retrieved 2013-01-05. 
  9. ^ ECC Decision (15)05 (PDF) (Technical report). 3 July 2015. 
  10. ^ "PMR446 Frequencies - Analogue and Digital". Homepage.ntlworld.com. Archived from the original on 2008-05-28. Retrieved 2010-11-18. 
  11. ^ "dPMR: A low cost digital successor to PMR446 is on the Horizon". Cmlmicro.com. Retrieved 2010-11-18. 
  12. ^ "Anfy preview". Atx2000.altervista.org. Retrieved 2010-11-18. 

External links[edit]