PMR446: Difference between revisions
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==Technical information== |
==Technical information== |
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Analog PMR446 covers band 446.0 - 446.1 MHz and digital dPMR/DMR cover 446.1 - 446.2 MHz; CEPT envisions that the digital band may be extended onto analog band in the future. |
Analog PMR446 covers band 446.0 - 446.1 MHz and digital dPMR/DMR cover 446.1 - 446.2 MHz; CEPT envisions that the digital band may be extended onto analog band in the future. From 2012, all PMR446 radios should be limited to 180 seconds of maximum transmitting time. |
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Radios may now have removable antennae as long as the ERP does not exceed 500mW.<ref>{{cite web|url=http://stakeholders.ofcom.org.uk/binaries/spectrum/spectrum-policy-area/spectrum-management/licence-exempt-radio-use/licence-exempt-devices/Analogue_and_Digital_PMR4461.pdf |title=Analogue and Digital PMR446 Information Sheet |publisher=Ofcom |date= |accessdate=2013-01-05}}</ref> |
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=== Analogue FM=== |
=== Analogue FM=== |
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Revision as of 19:41, 30 December 2013
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. It has roughly the same use as FRS or 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. It is ideal for small-site, same-building and line of sight outdoor activities. PMR446 is used in both professional and consumer-grade walkie-talkies similar to those used for FRS/GMRS in the United States and Canada.
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.
History
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 another three decisions followed which designated the new frequency band for PMR446, established licence exemption for PMR446 equipment and established free circulation of the PMR446 equipment. The first country which introduced these frequencies for licence-free use was Ireland and it did so on 1 April 1998. The United Kingdom introduced PMR446 service in April 1999; since 2003 PMR446 has replaced the former Short-Range Business Radio (SRBR) service. For an updated list of current status in different European countries see the page of European Radiocommunications Office.
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 8 PMR446 channels over shorter distances (<1 km).
Range
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.[1] This was the result of enhanced propagation conditions, not a line-of-sight signal.
Usage worldwide
PMR446 radios use frequencies that in the U.S. and Canada are allocated to amateur radio operators. PMR446 radios can only be used in North America by licensed amateur radio operators. The conflicting allocations have been something of a nuisance to North American amateur operators due to use of the equipment by European tourists in the U.S. and Canada.[citation needed]
Instead, the U.S. and Canada uses the FRS system, which provides a similar service on slightly different frequencies. FRS frequencies are allocated to the emergency services in Europe, notably the fire brigade in the UK, police in Russia.[2] Interference with licenced radio services may result in prosecution.
PMR446 compliant equipment may be used anywhere throughout Europe and Scandinavia except in Montenegro.[citation needed]
Technical information
Analog PMR446 covers band 446.0 - 446.1 MHz and digital dPMR/DMR cover 446.1 - 446.2 MHz; CEPT envisions that the digital band may be extended onto analog band in the future. From 2012, all PMR446 radios should be limited to 180 seconds of maximum transmitting time. Radios may now have removable antennae as long as the ERP does not exceed 500mW.[3]
Analogue FM
Analogue PMR uses eight 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.
| PMR 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 |
Digital FDMA
Digital dPMR446 uses sixteen digital voice channels separated by 6.25 kHz from each other with 4-Level FSK modulation at 3.6 kbit/s.[4]
| dPMR446 Channel | Frequency (MHz) |
|---|---|
| 1 | 446.103125 |
| 2 | 446.109375 |
| 3 | 446.115625 |
| 4 | 446.121875 |
| 5 | 446.128125 |
| 6 | 446.134375 |
| 7 | 446.140625 |
| 8 | 446.146875 |
| 9 | 446.153125 |
| 10 | 446.159375 |
| 11 | 446.165625 |
| 12 | 446.171875 |
| 13 | 446.178125 |
| 14 | 446.184375 |
| 15 | 446.190625 |
| 16 | 446.196875 |
Digital TDMA
Digital DMR Tier I uses eight digital voice channels separated by 12.5 kHz from each other with 4-Level FSK modulation at 3.6 kbit/s.[5]
| DMR Tier I Channel | Frequency (MHz) |
|---|---|
| 1 | 446.10625 |
| 2 | 446.11875 |
| 3 | 446.13125 |
| 4 | 446.14375 |
| 5 | 446.15625 |
| 6 | 446.16875 |
| 7 | 446.18125 |
| 8 | 446.19375 |
PMR446 gateways
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" or "ATX-2000".[6]
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). Repeaters and gateways are prohibited in the UK.[citation needed]
Law
See also
References
- ^ "Delboy's DX Contact UK to Amsterdam". Delboy Enterprises. 5 August 2003. Archived from the original on 2008-02-09.
- ^ "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.
- ^ "Analogue and Digital PMR446 Information Sheet" (PDF). Ofcom. Retrieved 2013-01-05.
- ^ "dPMR: A low cost digital successor to PMR446 is on the Horizon". Cmlmicro.com. Retrieved 2010-11-18.
- ^ "PMR446 Frequencies - Analogue and Digital". Homepage.ntlworld.com. Retrieved 2010-11-18.
- ^ "Anfy preview". Atx2000.altervista.org. Retrieved 2010-11-18.
External links
