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
