DMR - Digital Mobile Radio
DMR (Digital Mobile Radio) is a digital radio standard used in amateur radio for efficient and high-quality communication. It was developed by the European Telecommunications Standards Institute (ETSI) and is widely adopted due to its ability to support multiple conversations on the same frequency using Time-Division Multiple Access (TDMA) technology.
How DMR Works in Amateur Radio:
Two Time Slots: DMR uses two time slots on a single frequency, allowing two separate conversations to occur simultaneously.
Talkgroups: Users communicate through talkgroups, which function like virtual channels, enabling organized discussions.
DMR ID: Each operator is assigned a unique DMR ID, which helps identify users across the network.
Repeaters & Hotspots: DMR signals can be transmitted via repeaters for extended range or hotspots for personal use.
Internet Linking: Many DMR networks connect repeaters via the internet, allowing global communication.
DMR provides clear audio, efficient bandwidth usage, and worldwide connectivity. If you're interested in getting started, you'll need a DMR-compatible radio and a valid amateur radio license. You can explore more details on DMR For Dummies or SaveNetRadio.
Radio ID
What Is a DMR Radio ID?
A Radio ID is a unique number assigned to by the RadioID.net Team. Like a telephone number or IP address, your Radio ID identifies you as a unique radio user on the various DMR networks and repeaters around the world. Every time you PTT your DMR radio, your Radio ID gets transmitted to the DMR network and everyone can see who you are.
How Do I Get a Radio ID?
You have to register with RadioID.net to get your Radio ID. Follow the instructions on the RadioID website to complete the registration process. In order to complete the account registration and get an ID you must get the official FCC document to upload to their site. This is the only way to verify you are the License Holder. A ‘Screen shot’ of a webpage, or the ‘Reference Doc’ can be taken by anyone and are NOT acceptable.
To obtain a valid official copy of your FCC license do the following:
Log into FCC system at https://wireless2.fcc.gov/UlsEntry/licManager/login.jsp. The FRN and password are the same you use when you registered with the FCC the first time or when applying for Vanity callsigns and address changes. If you don’t know your FRN number, go to FCC ULS License Search and search for your callsign. Your FRN will be listed in the column FRN.
On the left side menu, click on ‘Download Electronic Authorizations’.
On the new page, select the callsign you want to print the license for and click on the button ‘ADD >’.
Now, on the bottom right of the page, click on the button ‘Download >’. Make sure your pop-up blocker is disable, otherwise you won’t be able to download the PDF for your license.
You will be asked to save a PDF file. Save it and submit it to RadioID.
You will receive an email, usually within 24 hours, with your unique Radio ID, which you can promptly program into your radio(s). You do not need a Radio ID for every radio you own. The Radio ID is linked to your license. If you operate multiple hotspots or direct to internet connected devices at the same time, it is recommended to append a 2-digit sub-ID to the radio ID for every device. This will provide the network to source where a connection comes from.
TalkgroupS
A Talkgroup is a method of organizing radio traffic specific to the DMR users that all want to hear the same thing and not be bothered by other radio traffic on a DMR network that they are not interested in hearing.
Talkgroups can exist for many purposes. You can have talkgroups for countries, states, counties, regions, cities, special interest groups etc. Just about any group of DMR users could have a talkgroup assigned to them if they wished to organize traffic that they can all monitor and take part in, without having to talk to each other one by one.
Talkgroups are also specific to individual DMR networks, BUT they all generally follow the same numbering scheme. So you need to make sure that you know what the various Talkgroups are for each of the DMR networks that you may use.
For example, Talkgroup 3129 on the MARC network might not be the same as Talkgroup 3129 on the Brandmeister network.
If you own your own hotspot, you are unrestricted which Talkgroup to use. But if you use a repeater to access the network you will be restricted to the Talkgroups the repeater owner has defined. It is a good practice to check out the repeater’s or operating clubs’ website to find out about the rules and restrictions before using it.
Talkgroups can be assign as static (permanent) or dynamic (temporary). Most repeaters have some static talkgroups permanently linked. Dynamic linked talkgroups are established when the radio first keys up with that talkgroup as destination. They time out after 15 minutes.
Color code
Another DMR parameter which is new for none DMR people, is the color code. However, it is equivalent to a CTCSS or PL tome on an analog repeater. It just is a filter. If you have your own hotspot, you just have to make sure that your radio is set to the same color code as the hotspot (usually 1). If you use a repeater you have to find out the correct color code to program into your radio. It is the same as you need the right PL tone to access an analog repeater.
Time Slot
DMR supports two simultaneous time slots for two independent voice or data streams on the same channel. These are called time slot 1 and time slot 2. With TDMA (time division multiple access) system the participating radios are synchronized. A DMR radio transmits for 30 milliseconds and then receives for 30 milliseconds. It listens for a permission to transmit and then begins a call to all other talk group members who will also receive on that same time slot, e.g., Time Slot 1. Meanwhile, a different group of users on another talk group could be using Time Slot 2 simultaneously. If the radio can’t get the permission to talk it will stop transmitting for group calls. This switching between transmit and receive has to happen very fast. Therefore, devices not designed for it will not work for DMR, e.g., linear amplifiers.
Usually, with hotspots you use time slot 2 and leave the other time slot unused. For repeaters, you will have to check on their website which time slot to use for what purpose.
Users List
On DMR networks most the time only the Radio ID will be transmitted. Without any special provisions you only see that number and not callsign, name and QTH on your radio display. There are exceptions were a repeater, or a hotspot does a lookup and sends this information as “Talker Alias to your radio. However, this is not necessarily supported in all cases, and a better way is to load a user list into your radio to do the lookup. These lists are equivalent of a phone book with 10s of thousand entries for all Radio IDs in the world. Your radio might not have enough memory to support a full worldwide list. A work around is to delete the content in columns of lesser interest (e.g., last name) and skimming the user list file down.
these user lists are CSV files and can be downloaded from radioId.net. Because there are new radio ID’s added every day, it is necessary to download a new user list file frequently and update your radios “phone book”.
The dffferent systems
DMR Brandmeister
BrandMeister is a digital voice network designed for amateur radio operators using DMR (Digital Mobile Radio) technology. It operates as a worldwide infrastructure of master servers and peer repeaters, enabling seamless communication across different regions.
Some key features of BrandMeister include:
Flexible Routing: It allows dynamic call routing based on stored data and scripts.
Interconnectivity: Users can connect to other DMR networks like Motorola DMR-MARC and Hytera DMRplus.
Embedded Applications: Supports APRS (Automatic Packet Reporting System), SMS messaging, and remote-control functions.
Global Reach: With over 1300 repeaters and 3000 hotspots worldwide, it provides extensive coverage.
You can explore more details on the BrandMeister website.
DMR TGIF
TGIF is a Digital Mobile Radio (DMR) network designed for amateur radio operators. It provides an alternative to larger networks like BrandMeister, offering a more controlled and community-driven experience.
Some key aspects of TGIF include:
Custom Talkgroups: Users can create private or custom talkgroups tailored to their needs.
Hotspot-Focused: Unlike BrandMeister, TGIF primarily supports hotspots rather than repeaters.
Simplified Setup: The network is designed to be user-friendly, making it easier for newcomers to get started.
Stable Connectivity: Due to its smaller user base, TGIF experiences fewer congestion issues compared to larger networks.
TGIF was founded in 2018 and has grown to host hundreds of active talkgroups. You can explore more details on the TGIF Network website.
DMR+
DMR+ is a Digital Mobile Radio (DMR) network that provides amateur radio operators with a structured and flexible communication system. It has been widely used in Europe and is gaining popularity in North America.
Some key features of DMR+ include:
Talkgroups & Reflectors: Users can communicate via talkgroups or reflectors, which act as hubs connecting multiple users.
Interoperability: DMR+ integrates with other digital voice modes, allowing cross-network communication.
Stable Audio Quality: Many users report fewer dropouts and lower packet loss compared to other DMR networks.
Configurable Options: Users can set static talkgroups, reflectors, and timers for automatic relinking.
You can explore more details on the DMR+ website.
DMR-MARC
DMR-MARC (Motorola Amateur Radio Club) is one of the original Digital Mobile Radio (DMR) networks, providing a structured and reliable communication system for amateur radio operators. It is known for its extensive global reach and high-quality connectivity.
Some key features of DMR-MARC include:
Global Network: It connects repeaters in over 74 countries through more than 500 repeaters.
Static Talkgroups: Unlike some other DMR networks, all talkgroups assigned to a repeater timeslot are static, meaning users cannot dynamically link talkgroups.
Motorola Equipment: The network primarily uses Motorola repeater equipment, ensuring compatibility and reliability.
Roaming Capability: Motorola radios on the network can automatically select the strongest repeater in the area, improving communication quality.
You can explore more details on the DMR-MARC website.
How to guides
How to configure a Pi-Star based Hotspot. Read it here->
How to configure a RADTEL RT-4D for DMR (coming soon)
How to configure a AnyTone AT-D168UV for DMR (coming soon)
How to configure a AnyTone AT-D878 for DMR (coming soon)
If you like to see guides for any other radios, you can help if can borrow the radio for a few weeks. I can’t buy every radio there is. Please contact me at communications@ns9rc.org.
Repeaters in our area
There are currently no Brandmeister or TGIF repeaters in the Chicago area. If you know of one who is accessible and open, please send e-mail to: communications@ns9rc.org.
There is one DMR-MARC repeater in Schaumburg (K9MOT / N9KNS). For details go here ->