The title of this article sounds like click-bait but really I believe there is no "amateur radio" reason why operators cannot tune into the weekly DMR-ZA Net on TalkGroup 655 on a Tuesday evening at 19h30 SAST. Let me explain!
First some background information about the DMR Net
- Primary Talk Groups: Talk Group 655 is the open national calling channel. Regional channels (such as province-specific groups) and local repeater talk groups manage localized traffic.
- Network Infrastructure: The South African portion of the radio network largely relies on the BrandMeister Wiki server, specifically
brandmeister.net.za. - Weekly Net: The official DMR-ZA Net takes place on Tuesday evenings at 19h30, hosted on Talk Group 655. All stations are welcome to check in.
- Get an ID: You must register your callsign to receive a specific ID via RadioID.net
- Network Configuration: If you are setting up your own MMDVM hotspot, the server and network settings are available on the South Africa - BrandMeister Wiki page.
The above is one way to get connected but I have a few other ways to tune-in / connect to the DMR-ZA net on a Tuesday evening. I am talking about cross-linking and using equipment that you already have available in the Shack.
Cross-linking digital radio modes (like DMR, D-STAR, or C4FM) to an analogue radio means translating these proprietary digital voice streams into standard analogue FM so both legacy users and digital operators can talk to each other.
Mixed-mode operation: This function allows a digital repeater to transmit a digital signal to modern digital radios while simultaneously rebroadcasting the audio in standard analogue FM to users who have not yet upgraded
AllStarLink or Echolink VoIP Gateways: To connect a local analogue radio to distant digital radio networks (such as DMR or D-STAR talkgroups), operators use VoIP systems like AllStarLink.
By connecting a simple analogue transceiver (like a Baofeng) to a PC running AllStarLink software, you create a gateway node.
The digital network converts the data into internet packets, which are subsequently sent to the analogue node where they are broadcast over the air.
Cross-linking digital radio modes (like DMR, D-STAR, or C4FM) to an analog radio requires external hardware or bridging software because analog FM radios cannot directly encode or decode digital transmissions. To achieve two-way communication, the digital signal must be decoded into audio and re-transmitted in analog, or routed through an internet-linked VoIP gateway.
The most effective ways to cross-link between digital and analog radios include:
1. VoIP Gateways (Echolink or AllStarLink)
You can bridge analog radios to digital talk groups by connecting an analog "link radio" to a computer or Raspberry Pi running bridging software.
How it works: Software like AllStarLink or Echolink creates a node that connects your local analog transmission to a digital network (via IP).
Hardware Needed: A USB soundcard interface (such as a SignalLink or a homebrew sound card fob connected to your radio's data or mic port.
2. Cross-Mode Hotspots (MMDVM)
If you operate an MMDVM (Multi-Mode Digital Voice Modem) hotspot, you can cross-convert digital modes on the fly.
How it works: While most MMDVM units link digital to digital (e.g., DMR to D-STAR), advanced bridging configurations like
MMDVM_Bridgecombined withAnalog_Bridgeallow digital networks to talk to analog VoIP nodes.Transcoding: The system transcodes digital voice packets into analog audio that standard FM radios can receive.
3. Analog-to-Digital Repeaters (Mixed Mode)
Certain local amateur or commercial repeaters are hardware-equipped for cross-mode operation.
How it works: Systems like Yaesu System Fusion often feature Automatic Mode Select (AMS), which automatically detects an incoming analog FM signal and converts it into a C4FM digital transmission (and vice-versa).
Now that we know a little bit more about cross-linking / cross-mode operation let's look at how I am doing it here in Mossel Bay. I will explain how I do it but there are always other ways to do it to achieve the same result in the end.
Let's have a look at the flow-chart below in order to give you an overview of all the systems I am running, but also the networks that connects to the ZS1I Hub in Mossel Bay.
Image: Flowchart (Click on images for larger view.)
Herewith a list of different equipment / apps and images that cross transmit / receive the DMR-ZA Net on a Tuesday evening. (Click on images for larger view.)
1. ZS1I 49355 AllStar Hub Network which incorporates Echolink. (ZS1I-R)
2. DMR / DVSwitch /AllStar Bridge (TG 65522)
3. ZS1I MMDVM Digital Repeater (TG 65522)
4. 145.550 Mhz Analogue Simplex RF Link
5. DroidStar / VoxDMR Applications for DMR
6. ASL3 to Mumble Bridge PC (Mumble Client) as well as Mobile Phone (Plumble Client)
7. BrandMeister - Hoseline Application (PC or Mobile Phone)
8. DVSwitch Mobile Application (PC or Mobile Phone)
9. Many Analog-Repeaters and Links are connected to the ZS1I Hub Network on a daily basis. (See column on the right hand side of the flow chart above.)
Some of these analogue repeaters will be connected to the ZS1I Hub Network on a Tuesday evening and they might also be linked to other repeaters country- and world wide. So why not link up with your local analogue repeater. You might just be able to connect to the DMR-ZA Net on a Tuesday evening at 19h30 SAST.
Optional Cross-Linking to be added:
1. SVXLink Reflector / Node
2. AREDN Mesh Network Node
3. ZS1I MMDVM Hotspot
Finally: There are an abundance of means illustrated above to connect to the DMR-ZA Net on a Tuesday evening at 19h30 SAST. The DMR-ZA Net is an open net and all radio amateurs are welcome to join / connect to the net. Brian ZS5BR is the net controller and I would like to thank him for professionally conducting the net each Tuesday evening. Highly appreciated!!
