last updated 29 Sept 2004PMR446 is a radio service introduced in 1999 that allows us to enjoy free Personal Mobile Radio communications in Europe, using relatively cheap and usefully small handheld sets. These PMR446 sets usually feature 8 radio frequency channels at 446MHz, with non-removable antennas delivering half a Watt of Effective Radiated Power. Tone Squelch (CTCSS, or digital squelch DCS) is allowed to allow monitoring a channel without hearing any interference (see lower). Ranges of a couple of miles can be achieved, or even further under line-of-sight conditions, although half a mile or less may be experienced with many obstructions such as in a very built-up area. PMR446 is the European version of the USA's slightly earlier (1996) Family Radio Service, with the same power output and fixed antenna restrictions, although they have more channels - 14, all different to PMR446.
A European standard - yes something good at last from
Europe - the 1998 CEPT/ERC decisions :
Some claim that 446 was only intended to be for business use, rather than for the general public - even with hindsight it seems incredible that they did not see how FRS was catching on in the USA and they didn't have the imagination to forsee how popular cheap unregulated radios could be! 446 is NOT the natural successor to SRBR, that title really goes to UK General. 446 is more like a version of handheld CB that actually works, albeit without the range of CB with external antennas - and with the distinction that CB has tended to be a general social affair whereas 446 is bought for closed groups. This is only a distinction by current general convention though, not a legal one. Only technical differences seperate 446 and CB in effect, so to my mind it IS fair to compare the two (this is often a bone of contention!). See the 'Alternatives' page for more on CB.
introduced the PMR 446 service
in April 1999, they have an
Here is a summary of European PMR446 status,
from the ERO RR working group,
(used to include proposals for packet, time division duplex).
A list of all approvals is here.
(UPDATE: the ERO website
is now too fancy for its own good, each URL is a bizarre long affair possibly generated on the
fly. If links here no longer work, 446 information is under 'ECC activities'..'RR Working Group'. 'Deliverables'..'decisions' is
where to find (98)25 etc.)
Popular - already in my area there is more activity on PMR446 than on all of the 50,70,144,430,1290 MHz amateur bands and legal CB together! Not difficult - CB here is disused (too much QRM), and even if you're lucky to have a good location and big beams there still isn't much to work on the ham bands. From a local high point I've heard every channel in use on PMR446, not CB style but rather closed groups. This could change.
These radios will be used by groups engaging in various activities, small businesses etc.
There is nothing in the regulations to prevent you listening to others using these radios.
This is the first time (discounting CB) that you are free to monitor radio
communications by such people. The scanner crowd have been monitoring various channels and
trying to work out who is who for years - and now PMR446 users can do the same, legally,
without having to conceal their radios in deep pockets etc :o)
People tend to buy PMR446, for specific reasons - probably in pairs at least. CB however, caught on because people bought into the craze with the aim of talking to strangers, installing a base station or mobile and finding plenty of other such stations within range. PMR446 will be used by groups of people who will be mostly unaware of other users or uninterested in making contact with them. I think there is scope for PMR446 to become a CB for the new millenium - all we need is ...
A general calling channel - this gives PMR446 a sociable aspect - channel 8 tone 88Hz - for a friendly system that CB could have been. Or even amateur style use, for UHF DX exploits, there are Distance records up for grabs! For more information, please read the Calling page, and the DX & Records page.
BUT - you are not allowed to listen on a scanner, however absurd that may seem. The UK's radio regulatory body the Radiocommunications Agency (part of the Dept of Trade and Industry) doesn't permit listening with scanners. For more details, technical information, and how some people modify their radios for extra range, please visit the Technical and Naughty pages.
Other uses? The voice operated (Vox) facility makes these devices quite useful for other applications. A makeshift baby alarm, perhaps? A "bug" of sorts, if strategically placed? You might need to build an microphone pre-amp with compressor to wire into the mic socket for better results though. Anyone care to contribute example circuits?
A door entry phone of sorts? A visitor speakes into a secured handy at the doorway, and several floors up you can talk back so long as they're not talking at that moment - the vox needs to be set so that only close-up speech triggers transmit. Could get embarrasing if the kids accross the street use the same channel/tone combination!
How about remote monitoring of your base station? This could be VERY useful if your main scanner/ham/CB base station is in a den, shack or bedroom, you could effectively monitor what's happening while spending time with the family in the lounge! You could even answer calls remotely too, hehe.
Paintballing comms repeater? An FM transmitter covering the area, relaying PMR446 comms. Players would listen to their walkman tuner with earbuds, and have the volume down on their PMR446s. You'd only need to get the handy out of your pocket to send messages.
Tamper alarm. Place a PMR446 in your car overnight and hear if anyone breaks a window. Or if you want the play the local vigilante part if the local public conveniences are frequently being vandalised... it might be better to devise a circuit that only activates when the characteristic sound of smashing toilets occurs!
Got a scanner with no CTCSS or DCS decode? Feed the unfiltered discriminator output (as used for data) to a cheap non-CTCSS FRS/PMR446 (one which doesn't filter the bass from speech) via a wired connection (may require level dropping with a resistive divider). Any CTCSS/DCS tones/codes used on a channel received by the scanner will be relayed on your UHF channel. Then you can use a second, decent FRS/PMR446 (with CTCSS/DCS decode) to determine the tone/code. Use vox, perhaps, to save on power! A low power setting on the sending unit will help, to reduce overload to the scanner and to reduce interference/interception to/from others.
446 radios in the air? In gliders, balloons, hangliders, paragliders etc., this is currently a bit of a grey area. "The current Air Navigation Order, Article 15 para 5 states that radio equipment carried for use in a UK registered aircraft must be of a type approved by the CAA (PMR446 is not - but neither is it a fixed installation). The CAA also produced Aeronautical Information Circular 109/2000, which defines a Foot Launched Powered Flying Machine (FLPM) which covers paramotors. This document exempts FLPMs from most of the Air Navigation Order including Article 15. If I have interpreted this correctly, it means that PMR446 radios are perfectly legal to use from a paramotor in fight." I believe the RA once said 446 is not to be used while airborne, but there is currently no mention of this on their website. This may allow fun experiments with kites and model aircraft.
446 radios while driving? Using a mobile phone while driving would get you into trouble, but two-way radios are exempt. You could try printing out Statutory Instrument 2003 No. 2695 (http://www.legislation.hmso.gov.uk/si/si2003/20032695.htm) to show to any over-eager enforcement officer.
" 110. - (1) No person shall drive a motor vehicle on a road if he is using -
Models available : To see the current range of PMR446 radios you can buy, select Radios List in the menu frame.
CTCSS? DCS? Sub-channels? For more information about Continuous Tone Coded Squelch System and Digital Coded Squelch please see the CTCSS tones page.
Choosing the best batteries for the job can seem daunting, with all the different choices available. I personally recommend NiMH rechargables, with a slow 15 hour charger. Check out the batteries page for more information.