DMR+ with Pi-Star

Posted by Fred C. (W6BSD) on Mar 19 2020

When it comes to DMR, especially in North America, people think of BrandMeister. There is another network of interconnected repeaters and talk-groups called DMR+.

Pi-Star hotspot.

DMR+ was the first network that developed tools to interconnect ETSI Tier 2 DMR repeaters. It started in Europe and has grown in popularity in many countries. Thanks to the collaboration with DMR-MARC, it has finally arrived in North America and the South Pacific.

The DMR+ architecture is similar to D-Star or FCS for C4FM. The DMR+ network is more aligned with the experimentation and interoperability of technologies. Like BrandMeister, DMR+ uses talk-groups; they can also use reflectors1. Many talk-groups or reflectors bridge other networks such as AllStar, D-Star of C4FM.

DMR+ supports a configuration that features the traditional DMR-MARC talk-groups like North America, Europe, South Pacific, Worldwide, ... on TS1 and the DMR+ reflectors network on TS2.

Configuring your Pi-Star

We are not going through the entire configuration of the Pi-Star software, but we are going to focus on how to set up your hotspot for DMR+.

You already have your DMR ID configured on your hotspot, the frequency is set, and you can already make contacts through BrandMeister. If this assumption is not correct, you need to configure your hotspot and upload the right code plug onto your radio. Check out the Amateur Radio Notes for the complete documentation on how to configure your pi-star.

Connect to your hotspot with your favorite web-browser. Click on the configuration option on the menu at the top of the page. Scroll down and go to the DMR Configuration section.

First, you need to select DMRGateway in the field DMR Master:, and click on the button Apply Changes at the bottom of this section. The configuration page will reload, displaying a few more fields in the configuration section, as shown in the following screenshot.

The DMR Gateway allows connections for up to six different DMR networks. The networks can be an XLX reflector, DMR+, BrandMeister, TGIF, or local HBLink systems.

To continue to use BrandMeister as before, you need to verify that the fields for BrandMeister are still correctly configured.

Configuration example

Pi-Star DMR+ configuration.

DMR+ Fields

DMR+ Master:
Enter here the DMR Master server, also called IPSC2 server, of your
choice. You can use any IPSC2 server you like, but I recommend a
server that is close to where you are. Make sure the server you are
selecting runs a recent version of the software.
You can check the list of IPSC2 masters, find one close to you,
check its status, and the version it is running.
DMR+ Options:
This field tells the gateway where to connect when pi-start
starts. For more information on the options, you can check this
github document
  • StartRef=4541 Set the default reflector in TS2 to the QuadNet Array.
  • RelinkTime=60 (optional) Number of minutes of idle time before relinking to StartRef.
  • UserLink=1: This defines if users are allowed to link to another reflector. (1=yes, 0=no)
  • TS1_1=11: First of five talk-groups that is set static. (talk-group 11 in this example is for French)
  • TS1_2=310: Second of the five talk-groups that is set static. (talk-group 310 in this example is for North America TAC-310)
  • TS1_3 .. TS1_5: Third to the fifth not set in our case.

The fields TS1_1 to TS1_5 are optional.

DMR+ Network ESSID:
This field should be set automatically with the DMR ID you entered
in the general configuration section.
DMR+ Network Enable:
This field enables the use of DMR+. Make sure that the field is
checked.

Save your configuration by clicking on the Apply Changes button. Once the new configuration is applied, you should see your hotspot connected to the master server of your choice. In my case, my hotspot is connected to the New York server. I can see my call sign in the status section, as well as the number of the default reflector I set in the Options field.

TYT MD-380.

Radio Configuration.

All the talk-groups you have on your code-plug to work through BrandMeister should still work the same as before.

All the code-plugs to program DMR radios are different; this is why I will not give any specific information on how to program your particular brand of receiver. I will provide you with all the information you will need to understand how things work. It will help you modify your actual code-plug to use DMR+.

The DMRGateway channel used by Pi-Star for DMR+ traffic is on the talk-group 8. It means all the traffic concerning DMR+ between your radio and your hotspot will be on this talk-group.

Everything on the timeslot (TS1) is static and should work the same way they are working for BrandMeister. Program a radio channel with timeslot TS1 and the talk-group number.

MD-380 Screenshot.

What's on the timeslot TS2 is more exciting, and this is how I am using it. I have a channel programmed on my radio with just timeslot TS2 and the talk-group 8. This is all I need to connect to any dynamic talk-group.

On my MD-380, I have programmed the channel 12 with timeslot 2 talk-group 8, as shown on the screenshot on the right. Since, in our configuration, the hotspot is connected to the reflector 4541 by default, I can hear all the traffic coming from the QuadNet group.

MD-380 Screenshot.

To disconnect from a reflector, I can use the keypad on my radio to make a private call to the talk-group 84000. As we discuss before, Pi-Star uses the number 8 to tell the DMRGateway command is addressed to DMR+. The 4000 is a special talk-group that tells the DMRGateway service to disconnect.

After pressing on the PTT for a second or two, Pi-Star disconnects from the current talk-group.

MD-380 Screenshot.

I use the same method to connect to a reflector. For example, to connect to the reflector Canada English (4580), I use the keypad on my radio to make a private call to the talk-group 84580. Don't forget the number 8 before the reflector number to tell the DMRGateway service to connect to a DMR+ reflector.

A short press of one or two seconds to the PTT to send the command.

Then I can switch back to the channel programmed with the talk-group 8 and GroupCall to make my QSO.

The talk-group 5000 will give the connection status of your Pi-Star. I use my keypad to make a private call to the talk-group 85000.

After pressing the PTT for one or two seconds to send the command, the Pi-Star reply by voice with the reflector number where it is connected.

Radio programming recapitulation

  • All the static talk-groups you have set in the options field (TS1_1 to TS1_5) should be programmed in your radio like you would do it for BrandMiester.
  • To connect to a reflector, make a private call to the talk-group 8 followed by the reflector ID; e.g., 84580.
  • To disconnect from a reflector, make a private call to the talk-group 84000.
  • To talk to a reflector, make a group call to the talk-group 8.
  • To get the connection status make a private call to the talk-group 85000.

You can find the DMR+ reflector list on the Pi-Star website.

Conclusion

DMR+ is different from what you are used to on BrandMeister. DMR+ encourages experimentation and interoperability of technologies; this is why some of the reflectors are bridged with other modes such as D-Star, C4FM, P25, or even AllStar.

To most users, DMR+ appears to have better audio quality than BrandMeister, with fewer dropouts and lower packet loss. The audio quality largely depends if the reflector has a bridge in place to other modes.

I hope you decide to give DMR+ a try. If you have any questions, you can leave a comment at the bottom of this page. You can usually find me on the DMR talk-group #311433 or the C4FM Bayarea-YSF room.


  1. A reflector is a computer-based server that connects two or more "nodes." 

Tags:  DMR    Digital Radio    Pi-Star


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