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last updated 22 Oct 2009
Here are the frequencies of the 8 channels from 446-1 to 446-8. If you try to listen with a scanner or ham radio that doesn't support 6.25kHz tuning steps ( which is not allowed - so don't blame me! ) you may find that 5kHz steps will get as close as possible, with a maximum error of 1.25kHz. These frequencies are shown in brackets.

The frequency range is shared in the UK with on-site PMR Private Mobile Radio using conventional 12.5kHz spaced channels, but only in specific heavily populated areas such as large towns and cities, not in the countryside (where the military may be using them instead!). This shows how they are interleaved between those - each PMR446 channel is 6.25kHz from the PMR channels above and below it :


    Analogue

  --446.000----band edge
1 - 446.00625 (446.005)
    446.0125
2 - 446.01875 (446.020)
    446.025
3 - 446.03125 (446.030)
    446.0375
4 - 446.04375 (446.045)
    446.050
5 - 446.05625 (446.055)
    446.0625
6 - 446.06875 (446.070)
    446.075
7 - 446.08125 (446.080)
    446.0875
8 - 446.09375 (446.095)
  --446.100----band edge


446MHz has a wavelength of 67.2cm - a quarter wave (a fundamental unit used in antenna design, such as a simple vertical antenna or each side of a dipole) is 168mm or about 6 and 5/8 inches on a more human scale.

The 446.0 to 446.1 band allocated to PMR446 lies within the 400-470 MHz (70cm) part of the radio spectrum used for various comms services. There is an amateur band at 430-440, the national Dolphin digital network between 410 and 425, low power car keys etc at 418 and 433.7, various private channels, emergency services, outside broadcast use, the military etc. TV uses 470-850, and above that are cellphones (900MHz, 32cm), and all the microwaves above 1000 MHz.

Heading down the spectrum there is a military air-band at 225 to 400, Digital Audio Broadcasting at 217 to 230, more general comms from 137 to 217 including the 156 MHz marine VHF band and the 144-146 amateur 2 meter band. The main air-band covers 108 to 137 MHz, and below that there's FM Stereo broadcasting on the 3 meter wavelengths from 87.5 to 108 MHz. From 87.5 down to 30 MHz is used by the military and for private channels, with amateur bands at 6m (50-52) and 4m (70 to 70.5), and low power devices of various sorts. Under 30 MHz (over 10 meters) is the realm of shortwave receivers, CB, funny noises and morse code, long-range amateur bands, shipping, transatlantic aircraft, MW and LW broadcasting etc. Note that the wavelength (in meters) times the frequency (in MHz) equals 300 - due to there only being one speed of light / radio waves. The more waves pass you in one second (frequency) the smaller the distance between each wave (wavelength). But enough of that!
For a detailed look at the whole spectrum, see the spectrum page.


Here are the DMR frequencies (announced in 2005), not really of interest unless you're just curious or you enjoy listening to buzzing noises! There are 8 channels if using 12.5kHz spacing, or 16 channels with 6.25kHz spacing.


  Digital

--446.100-----band edge--
  446.103125  1 ( 6.25)
1 446.10625     (12.5 )
  446.109375  2
  446.115625  3
2 446.11875
  446.121875  4
  446.128125  5
3 446.13125
  446.134375  6
  446.140625  7
4 446.14375
  446.146875  8
  446.153125  9
5 446.15625
  446.159375  10
  446.165625  11
6 446.16875
  446.171875  12
  446.178125  13
7 446.18125
  446.184375  14
  446.190625  15
8 446.19375
  446.196875  16
--446.200-----band edge--