PMR446

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

PMR446 (Private Mobile Radio, 446 MHz) is a licence exempt service in the UHF radio frequency band and is available for business and personal use in most countries throughout the European Union.[1]

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.

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.

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 PMR446 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 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.[10] 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.


Analog (NFM) and digital TDMA (DMR)
Channel Frequency Bandwidth Comments
1 446.00625 MHz 12.5 kHz FM => Emergency channel with subtone 67 Hz => 1/12[citation needed]
2 446.01875 MHz 12.5 kHz
3 446.03125 MHz 12.5 kHz
4 446.04375 MHz 12.5 kHz FM => Drone pilots intercom channel with subtone 107.2 Hz => 4/14[citation needed]
5 446.05625 MHz 12.5 kHz FM => Scouts channel with subtone 79.7 Hz => 5/5[citation needed]

DMR => Scouts => CC1 TG907 TS1[citation needed]

6 446.06875 MHz 12.5 kHz
7 446.08125 MHz 12.5 kHz FM => Mountain channel with subtone 85.4 Hz => 7/7[citation needed]

(Spain, France)[citation needed]

8 446.09375 MHz 12.5 kHz

FM => Calling channel with subtone 88.5Hz => 8/8[citation needed]

FM => Emergency Com with subtone 114.8 Hz => 8/16[citation needed]

(UK, France, Germany, Italy)[citation needed]

9 446.10625 MHz 12.5 kHz DMR => Calling channel (CC1, TG99, TS1*)[citation needed]

DMR => Emergency Com (CC1, TG9112, TS1*)[citation needed]

* for DCDM radios

(All Europe)

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

Note that channel usage given under comments is not officially mandated.

Digital FDMA[edit]

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.[11] Before January 2018, only the upper 16 channels were allowed for digital FDMA operation.

Digital FDMA (dPMR)
Channel Frequency Bandwidth Comments
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 Calling channel (CC1, TG99)

Emergency Com (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

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.CS1 maint: BOT: original-url status unknown (link)
  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]