DMR

OK, great. So what exactly is DMR?

DMR stands for Digital Mobile Radio.  DMR is an open standard created to make an inexpensive digital radio system that was simple to operate and which would allow different radio manufacturers to develop interoperable radios. While some radio manufacturers have proprietary digital modes that only work within their own brand (D-Star, Fusion, C4FM) any brand of DMR radio is capable of communicating with a different brand of DMR radio. DMR users are able to communicate with other DMR users worldwide.

Understanding DMR requires learning a few new terms.

DMR ID:

To use a DMR radio, you will need to get DMR ID which is a unique identification number assigned to you and your call sign.  Your DMR ID identifies you as a unique user on DMR radio networks and repeater systems.

Time Slots:

DMR systems divide a frequency into two Time Slots creating two logical channels.  Each time slot can carry a different conversation at the same time.  These are referred to as Timeslot 1 and Timeslot 2.    

Color Codes:

DMR uses a component called Color Codes.  Color Codes are very similar to the CTCSS or PL tones used on analog repeaters.  You will need to get the appropriate Color Codes from the club or repeater owner running a DMR system to access the repeater.  Without the correct Color Code, you will not be able to access the repeater.

Talkgroups:

Talkgroups are a way of organizing radio traffic on the DMR network.  As an example, unique talk groups can be created for countries, states, regions, or cities.  Talkgroups have been created for interests such as technology and off-roading. 

Codeplug:

A code plug is a software file that tells your radio what to do and how to operate.  Creating a custom code plug for your radio is a learning experience coming from a world of analog radio.  Enlisting the help of an experienced DMR user may be a big help.  

Cross Roads Ham Radio Club DMR Repeater Parameters

The CRHRC network has three DMR Repeaters.  They are:

• • WJ1D –   Wharton, TX –  441.750 (+) Color Code 12 (Member Owned)
  • W5PAS – Pasadena, TX – 442.275 (+) Color Code 3   (CRHRC)
  • W5LCR – Edna, TX –        444.050 (+) Color Code 7   (CRHRC)

All DMR repeaters are configured identically with the following TALK GROUPS (TG):

• • TG 11 – Time Slot 2 (Linked to AllStar 28528 – CRHRC Linked Repeater System)
    15 Minute PTT (must PTT to activate this Talk Group)
    
    
  • TG 33 – Time Slot 2 (Linked to CRHRC YSF Reflector 6246)
    15 Minute PTT (must PTT to activate this Talk Group
    
    
  • TG 50 – Time Slot 2 (DMR Talk Group) – Full Time
    
    
  • TG 3148 – Time Slot 1 (Texas Lone Star Talk Group) – Full Time

• PTT means when you transmit to the repeater from that specific Talk Group, the Talk Group is dynamically enabled through the repeater. After a given time of no activity (15 minutes), the Talk Group is disconnected.

Additional DMR Resources

• DMRTexas.net – Great resource for Texas DMR repeaters and general DMR information.
• RadioID.net – Get your DMR ID here.