DMR Learning Series: Channels

If you’ve been following my series, you’ve now learned about Contacts, Talk Groups, and Receive Group Lists.  It’s now time to put that all together and set up a channel.

I recommend configuring one channel for every talk group on every repeater you plan to use.  This may sound like a lot of channels (and it is), but once you have your radio set up, it will be easy to navigate.

The screen shot below is from the TYT MD-380 software, but the concepts are the same regardless of which type of radio you are using.

 

The pertinent settings are as follows:

  • Channel Mode: Digital.
  • Bandwidth: 12.5KHz – all DMR repeaters use 12.5KHz bandwidth in digital mode.
  • Scan List: Assign a scan list if you have configured one.
  • TOT: Timeout timer.  I set the timeout timer on all of my radios to 60 seconds.  I recommend the same for everyone.
  • TX/RX Frequency: Same as analog, then input and output of the repeater.
  • Admit Criteria: For this, choose color code. This will ensure that you do not key up over someone talking on another talk group.
  • Contact Name: This is the name of the contact (in this case, talk group 3139) that will be the default when you key up on this channel.
    • Typical DMR radios allow you to manually select a different contact. Most people don’t use that functionality.
  • Group List: Controls which talk groups for which the radio will un-squelch.
    • Typically, you will want your receive group list to only contain one talk group – the same talk group on which you are transmitting.
    • Therefore, use the receive group list you configured that contains the same talk group as set above, in this case 3139.
    • You could use group lists with multiple talk groups, but this can be confusing and counter-intuitive – if you want to hear multiple talk groups, I recommend using scan lists.
    • Some radios do not require a group list to be specified and will automatically receive the talk group configured for transmit.
  • Color Code: Specific to the repeater.
    • Despite being called “color code,” it is a number.
    • You may think of it as being similar to a PL tone.
  • Time Slot: All DMR repeaters have two time slots, and specific talk groups are assigned to specific slots.
    • This means the repeater can handle two simultaneous conversations at one time, on different talk groups.
    • Be sure to configure the talk group for the correct time slot on the repeater or it will not work.

The other settings can be safely left at the default.

That should be it.  Once you have configured a channel, write the codeplug to your radio and try it out!  I recommend testing with a friend who already has a working radio.  Perhaps choose one of the TAC310-TAC319 talk groups to do your testing, make sure it is not in use first.  Create the channel with the talk group and try it out.

As always, if you have questions, concerns or comments, please leave them below.

 

DMR Learning Series: Channels
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