Image: DMR Repeater, Southern Cape (Click on image for larger view.)
Great news!! The first and currently the only DMR Repeater in the Southern Cape Area of South Africa is now on the air. I hear you ask but what is all the fuzz about. This is no big deal! Well everybody is entitled to his own opinion in this regard. For radio amateurs living in the Southern Cape it means that they have several more options to communicate with other radio amateurs locally and world wide. Furthermore the addition of this DMR Repeater increase the size of the ZS Link Network even further. Be as it may the Southern Cape now have a DMR Repeater on the air!
Tell me more about a DMR Repeater.
From the on-set let me make it clear - DMR is far from being complicated to setup and operate. You will find an abundance of information on the Internet that will assist you in setting up / programming your radio etc. And please give DMR a try without lending out your ears to those who do not like digital radio.
A
DMR (Digital Mobile Radio) repeater is a specialized two-way radio system used in amateur radio to extend communication range by receiving a digital signal and re-transmitting it at higher power, often from an elevated location. Unlike traditional analog repeaters, DMR repeaters use digital technology based on the ETSI DMR standard, which allows for clearer audio, enhanced data features, and highly efficient use of radio spectrum.Key Technical Concepts
DMR
repeaters differ from analog systems due to several "digital magic"
features that allow multiple conversations to share the same frequency:
- Time Slots (TS): DMR uses TDMA (Time Division Multiple Access) to divide a single 12.5 kHz channel into two alternating time slots. This effectively allows two simultaneous, independent conversations on the same frequency without interference.
- Color Codes (CC): Functioning like digital CTCSS/PL tones, color codes (range 1–15) act as a "gatekeeper". Your radio must be programmed with the correct color code to access and trigger the repeater.
- Talkgroups (TG): These are virtual "channels" or rooms within the digital network. They allow users to join specific groups (e.g., local, regional, or worldwide). Most repeaters assign certain talkgroups to specific time slots to keep traffic organized.
- Network Linking: Many DMR repeaters are connected to the internet through global networks like BrandMeister or DMR-MARC. This allows a ham with a simple handheld radio to talk to other operators across the globe via their local repeater.
Equipment and Setup
Using a DMR repeater requires more advanced configuration than analog FM:
- DMR Radio: You must use a radio specifically designed for DMR (e.g., Anytone, TYT, Radioddity). Most of these also support standard analog FM.
- DMR ID: To transmit on most networks, you must register your callsign at RadioID.net to receive a unique digital identification number.
- Codeplugs: Programming a DMR radio involves creating a "codeplug"—a file containing frequencies, color codes, time slots, and talkgroup lists for the repeaters you wish to use.
Benefits Over Analog
- Spectrum Efficiency: Doubles the capacity of a single licensed channel.
- Superior Audio: Digital processing filters out static and background noise, maintaining clear audio right up to the edge of the coverage range.
- Battery Life: Because the radio transmits in short bursts (sharing time slots), handheld batteries typically last longer than in continuous analog mode.
- Advanced Features: Supports text messaging, GPS location sharing, and private calling.
Are you looking for the DRM Repeater Information to setup your DMR radio / station?
Key Technical Parameters & Setup
- DMR ID: A unique identification number assigned to your call-sign, necessary for network access.
- Color Code (CC): Similar to PL tones in analog, ranging from 0–15.
- Time Slots (TS): DMR divides a 12.5 kHz channel into two distinct slots (TS1 and TS2), allowing two separate conversations on one frequency pair.
- Talkgroups (TG): Used to direct traffic to specific groups of users.
- Code Plug: Programming software is required to configure these settings into your DMR radio.
ZS1I DMR Repeater Information:
Mode: DMR
Mode: DMR
Band: 70cm
TX Frequency: 438.262500 Mhz
RX Frequency: 430.662500 Mhz
Radio Mode: Duplex
Talk Group (TG): 65522
Colour Code: 1 or 2
Time Slot: 1
Band Width: 12.5 khz
TX Time Out Time: 3 Minutes
TX Power: 10 Watt
TX Frequency: 438.262500 Mhz
RX Frequency: 430.662500 Mhz
Radio Mode: Duplex
Talk Group (TG): 65522
Colour Code: 1 or 2
Time Slot: 1
Band Width: 12.5 khz
TX Time Out Time: 3 Minutes
TX Power: 10 Watt
Site: ZS1I Station Shack, Heiderand, Mossel Bay
License: ZS1I Amateur Radio License
Note: This repeater is not located on a remote site which requires a separate license. The repeater will only be available daily from 05h00 SAST to 21h00 SAST. This allows the owner to monitor and control the repeater while it is on the air. This repeater is linked to the ZS Link Network (Analog Repeaters / Simplex Link Radio / Echolink / SVXLink / AllStar / South Cape Reflector) via the ZS1I DMR Bridge.
Requests and Reminder:
IMPORTANT: PLEASE leave a "6 second delay" between replying to a station to allow ALL the systems to reset and connect.
Please note this is a global network and you will be transmitting on RF all over the world.
It is extremely important that you spend time ensuring your audio levels are correct before connecting and using the DMR Bridge, DMR Repeater and the ZS Link Network.
Correct operating procedure is a distinct characteristic of Amateur Radio. It’s important that you convey to the public, and to new radio amateurs, the image that Amateur Radio Operators are courteous, patient, and really know what they’re doing. A friendly style is great, but we also need to operate professionally. You never know who may be listening.
Do not cause intentional interference, to links, repeater, hubs, nodes or conversations on the network. Intentional interference is not only heard locally but World Wide. Just remember that intentional interference can today easily be traced to your call sign as all connecting RF and Digital stations leave an identifiable script in a log file.
Finally:
Re-structuring and expansion of the ZS Link Network is an ongoing process and the network is getting bigger and bigger with the time. Do not panic we will not leave our local radio amateurs in the cold. I recently overheard a conversation were a radio amateur indicated that the ZS Link Network is not for local use but caters more for world wide activity. This is far from the truth. If you not certain how the ZS Link Network functions you will find more info on the ZS Link Network Blog Pages.
IMPORTANT: PLEASE leave a "6 second delay" between replying to a station to allow ALL the systems to reset and connect.
Please note this is a global network and you will be transmitting on RF all over the world.
It is extremely important that you spend time ensuring your audio levels are correct before connecting and using the DMR Bridge, DMR Repeater and the ZS Link Network.
Correct operating procedure is a distinct characteristic of Amateur Radio. It’s important that you convey to the public, and to new radio amateurs, the image that Amateur Radio Operators are courteous, patient, and really know what they’re doing. A friendly style is great, but we also need to operate professionally. You never know who may be listening.
Do not cause intentional interference, to links, repeater, hubs, nodes or conversations on the network. Intentional interference is not only heard locally but World Wide. Just remember that intentional interference can today easily be traced to your call sign as all connecting RF and Digital stations leave an identifiable script in a log file.
Finally:
Re-structuring and expansion of the ZS Link Network is an ongoing process and the network is getting bigger and bigger with the time. Do not panic we will not leave our local radio amateurs in the cold. I recently overheard a conversation were a radio amateur indicated that the ZS Link Network is not for local use but caters more for world wide activity. This is far from the truth. If you not certain how the ZS Link Network functions you will find more info on the ZS Link Network Blog Pages.
Feedback regarding the DMR Repeater and ZS Link Network can be forwarded by clicking HERE.
Images: Click on images for larger view.
