On which frequencies to use various modulation methods is specified in the Radio Amateur Band Plan published by the RSGB, and for 2m and 70cm digital mode is as follows :

2 Metres

• 144.6125 CALLING CHANNEL
• Then use the analogue channels except 145.500 (S20) and 145.550 (S22) as these are only for FM analogue calling and AM usage respectively.

70 cm

• DH1 438.5875
• DH2 438.6000
• DH3 438.6125 CALLING CHANNEL
• DH4 438.6250
• DH5 438.6375
• DH6 438.6500
• DH7 438.6625
• DH8 438.6750

Now with Digital there are a few more parameters you need to programme in for simplex digital working in addition to the frequency.

For the UK:

• Talk Group (TG) 9
• Slot 1
• Colour Code 1

A bit like CTCSS, if the radio you want to talk to does not have the identical set-up, you will not communicate. The parameters don’t have to be as above but they must be the same in each radio.

If you do not have a digital receiver you can still tune into the above frequencies and the DMR modulation will sound like really fast Morse.

Next: Digital Repeaters