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
DMR-ZA is the digital mobile radio amateur network in South Africa, built to link local repeaters and hotspots via the internet. It relies on Talk Group (TG) 655 for general South African traffic, acting as a virtual meeting place for radio amateurs across the country.
Key Network Details
- 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.
To participate in the net or use the network, you need a licensed amateur radio ID and an internet-linked DMR hotspot or local repeater.
- 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_Bridge
combined with Analog_Bridge
allow 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.
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!!
