This is an old page saved for posterity. It is no longer updated.
PMR446 is a European licence-free radio service offering 8 channels in the 446Mhz band, PMR446 radios can be bought from as little as £30 a pair. All PMR446 sets must use an integrated antenna and the max ERP (Effective Radiated Power) is limited to 500mw (0.5W) which gives a realistic range of approximately 0.5 to 1 mile around town and up to 2 miles in open country. In line of sight conditions and at high altitude some people have managed a range of over a hundred miles.
eQSO Internet Gateway
I run the UK095-L eQSO Internet Gateway in Warrington, Cheshire, UK which you can find on Channel 4, CTCSS 19. The radio in use for the link is an Xtreme XT1000 which is mounted in the loft on the end of a 4.5′ long plank of wood so it is right up in the apex of the roof.
More information and coverage maps here.
eQSO is a “voice-over IP” system – that is, voice delivered using Internet Protocol. People all around the world are connecting their PMR446 sets (and UHF CB in Australia) up to their internet connected computers to form a network which allows people from all over the world to communicate via PMR446.
As an example of what this does, someone within range of my gateway link can talk through my link radio, over the internet, and out through another gateway in, say, Belgium or Australia. Someone within range of that second repeater gateway can then communicate back and thus establish a conversation.
Even if you don’t have a PMR set yet you can still participate in the network using your computer with a microphone and speakers.
Unoffical Conventions for PMR446
A few unofficial conventions are now becoming commonly used on PMR446:
Calling Channel: Channel 8, CTCSS 8
Data is confined to Channel 1
Activity/DX on 1st Sunday of each month
DX Weekend: Sat 2nd and Sun 3rd August 2003
External Antennas & other mods
Warning: Any modifications to a PMR446 set renders its type approval void making the set illegal. The biggest improvement to range on 446 is to be found by mounting the radio and thus antenna up as high as possible, whilst this might be fine for an eQSO link where the radio isn’t touched once set up it may not always be practical in other situations so quite a few people add an external antenna to their set, mounting the antenna high up and having the radio in a position where it can be operated.
70cm ham band antennas are ideal for PMR446 use although using one would entail fitting a BNC or similar socket to your radio. SWR is not really critical as PMR446 uses such low power a high SWR is highly unlikely to damage the radio, but of course a high SWR would affect the signal output so getting it as low as possible is still advantageous. One possible problem with adding an external antenna is impedance matching, a communications transceiver usually expects to output to a 50ohm load and so antenna designs are based on this assumption. However, there is no guarantee that this stands for any particular 446 radio so it is a bit of a ‘suck it and see’ situation.
- Spoddy’s 446 Page
- RF-Man’s Radio Site
- SIMPLEX, a Software Simplex Repeater
- EchoStation, another Software Simplex Repeater
- Oregon Scientific TP-326 Radio Mods
- Xtreme XT1000 Base Station Mods
- Telcom TE-150 Radio Mods
- UHF Tropospheric Ducting Forecast