Digital Simplex Channels
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
