DMR or C4FM Simplex Frequencies.

Posted by Fred C. (W6BSD) on May 18 2019

To work simplex with your DMR or C4FM radio please do not use the FM analog national call frequencies 2m (146.520 MHz) or 70cm (446.000 MHz). Do not use these frequencies for any digital work. Below are the recommended simplex frequencies to be used with DMR in the United States and Canada.

In addition to this information, please note the following radio configuration items. By convention simplex calls on DMR are made on the talk group TG-99, time slot TS-1, color code CC-1.

There is not talk group or time slot to program for C4FM. Just enter one of these frequency on your VFO and you are good to go.

ChannelFrequencyAdmit Criteria
1 (VHF) 145.790 MHz Free or Always
2 (VHF) 145.510 MHz Free or Always
1 (UHF) 441.000 MHz Free or Always
2 (UHF) 446.500 MHz Free or Always
3 (UHF) 446.075 MHz Free or Always
4 (UHF) 433.450 MHz Free or Always

Note: By convention the 2 meters D-Star simplex frequency for the US is 145.670.

You can select any admit criteria of your liking. By setting the admission criteria to always, you can talk at any time, even if someone else is using the frequency/time slot. By setting it this way, you have no restriction, but you can experience “doubling” like you would in traditional analog FM.

Setting the admission criteria to Channel Free will prevent you from transmitting when the channel is busy. This setting prevents "doubling". The radio will play a tone, telling you that the channel/TG is not free.

Use the same frequencies for For C4FM. It is easier to work with C4FM than DMR. On C4FM, just punch the frequency in your VFO and start transmitting. The radio should take care of everything if you set it to AUTO. You can cycle through FM, "Digital Narrow" or "Voice Wide" by pressing the button AMS.

You can also refer to your country band plan. For the US it is available on the ARRL website.

Tags:  Digital Radio    DMR    C4FM

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