ID numbers used for DMR and other amateur radio digital networks are a finite resource.
Due to the growing popularity of these modes, along with some users requiring multiple IDs,
certain regions are expected to face ID shortages in the near future.
Beginning July 1, 2026, RadioID.net will implement an annual verification process. On the
anniversary of each account's creation, RadioID.net will send an email to the account holder
requesting confirmation that the assigned ID(s) are still needed and that the account
information remains accurate and up to date.
If no confirmation is received, the associated ID(s) will be temporarily deactivated. If
RadioID.net is unable to obtain a response after a reasonable period, the ID(s) will be
removed from the database and made available for reassignment. This process is intended to
preserve the long-term availability of ID numbers and maintain an accurate database for the
amateur radio community.
Year 1: If unable to contact you, we mark your account as unvalidated, IDs still work.
Year 2: If still unable, we mark your account/IDs as Deleted, IDs no longer work.
Year 3: If still unable to contact you for validation, Accounts and IDs are deleted.
** We are also using LastHeard data to help trim this list down.
1. Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST
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) 1. Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST 4. 145.550 Mhz Analogue Simplex RF Link Mossel Bay area.
5. DroidStar / VoxDMR Applications for DMR TG655
6. ASL3 to Mumble Bridge PC (Mumble Client) as well as Mobile Phone (Plumble Client)
7. BrandMeister - Hoseline Application (PC or Mobile Phone - Receive only.)
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. 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.
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!!
2. Earthquake - On 10 August 2026, at 07:34 a.m. local time, a magnitude 7.4 (Mw) earthquake struck western Colombia.
The death toll continued to rise past 200 in western Colombia after a 7.4 magnitude earthquake shook towns and cities on Monday the 10th of August, causing nearly 2,000 buildings to collapse and injuring nearly 3,000. It was the strongest earthquake to strike Colombia in 100 years and came only weeks after two earthquakes shattered Venezuela.
Members of the [Liga Colombiana de Radioaficionados -- LCRA] have deployed alongside the Colombian Red Cross to provide communications support in the wake of the Earthquake Disaster.
In Colombia, the [LCRA] uses the International Amateur Radio Union Region 2 (IARU R2) frequencies for emergency communications, as follows:
3. Ethics and Operating Procedures for the Radio Amateur, Fourth Edition
We are pleased to offer the fourth edition of the Ethics and Operating Procedures for the Radio Amateur (EOP). This edition incorporates the latest developments and best practices in the field of amateur radio. We believe these updates are essential to upholding the high standards of amateur radio and ensuring our community remains at the forefront of technological innovation and ethical operating practices.
IARU Region 1 President's Statement:
IT IS WITH GREAT PRIDE and a strong sense of responsibility that we present this new edition of the Ethics and Operating Procedures for the Radio Amateur – the first edition of our second century. For one hundred years, the IARU has supported the spirit of amateur radio: international friendship, technical progress, and service to the public. Today, more than ever, the way we behave on the air shows the values at the heart of our world-wide community.
This new edition is based on the well-respected work created more than fifteen years ago by two experienced radio amateurs. However, it is more than just a revision. It has been fully rewritten, clearer, more useful, and closer to the realities of amateur radio today. It is for everyone: experienced operators and newcomers alike. It gives us a shared basis for communication that is respectful, helpful, and enjoyable. In a time of fast technical change and global challenges, high standards are important. They help us protect our access to the spectrum and keep a positive image of amateur radio around the world.
Amateur radio is one of the few hobbies that crosses borders, languages, and cultures. This is a privilege, and it brings a duty to act with respect, patience, and courtesy. Our Code of Conduct reminds us that every contact is not only a technical exchange. It is also a reflection of who we are and what we share. This unity did not happen by chance. During a century that saw wars, political conflict, and division, the I A RU has survived because it has kept world politics off the air. Many times, there were reasons – sometimes strong – to bring the conflicts of the moment into our work together. Each time, we chose not to. I believe this is one of the main reasons we have lasted one hundred years.
I encourage every radio amateur to read these pages, to share them, and to follow them. Let us set a good example, not only for other operators today, but for the radio amateurs of the future.
We have just completed one hundred remarkable years. Here is to the next century of respectful and responsible communication!
Sylvain Azarian F4GKR President of the International Amateur Radio Union Region 1
Please feel free to download any version and to give a copy to your friends, newcomers and old-timers alike. Don’t forget, this is NOT a document for newcomers only, and this is not a document for DXers only. It is a document as well for old-timers and DXpeditioners.
4. Vyf nĂ¡ byna drie dae uit sneeubedekte Drakensberg gered
Vyf mense is vroeg Donderdag uit die noordelike Drakensberg gered nadat swaar sneeu, stormsterk wind en ysige toestande hulle dae lank in uiters moeilike omstandighede gestrand gelaat het.
Some 60 years ago Ham Radio had young people joining the hobby. Now the median age is greater 65. At that same time, it was a technical hobby. Now its dumbed down to contests and operating.
QST and the Handbook are nothing compared to what they used to be.
ED. Pete N6QW is well known for his participation in the "Soldersmoke Podcast". Personally I think he has made some very valid comments which some like and others do not like. Be as it may there is some real food for thought in this video!!
6. Ham Radio's Worst Invention - The SWR Meter.
Mark the Ham Florida Man explores common misconceptions regarding SWR meters and standing wave ratio in ham radio setups. This demonstration explains how these devices measure directional traveling wave power at specific points in a transmission system and clarifies how impedance mismatches affect meter readings throughout an antenna installation.
7. Introduction to DMR: The Four Wheels on the Car
DMR asks new users to understand codeplugs, timeslots, talkgroups, and networks before they’ve even keyed the mic — and most guides bury that in jargon before you get near your first contact. This piece cuts through it with one idea: DMR is like a car, and those four concepts are its four wheels. Get all four turning and you’re on the air; skip one, and you’re not going anywhere. Part 1 of Tommy’s Guide to DMR builds that mental model — no gear list yet, no codeplug, just the four ideas you need before any of the rest makes sense.
8. Winlink Tells You What Happened. APRS Tells You What’s Happening.
Two Tools, Two Jobs, and Why Most EmComm Plans Only Cover One
Winlink is the digital mode of record for emergency communications, and it has earned that standing: its forms library is why served agencies can file, route, and audit what we hand them. But forms are retrospective by design. They tell you what happened, in a shape somebody can defend later. They cannot tell you what is happening while you can still do something about it, and most EmComm plans carry no second tool that does. This is a long look at APRS as the missing half of that capability: what it does beyond dots on a map, why it keeps working when the internet doesn’t, where its bridge to Winlink quietly breaks, what the research says about why ICS was never built to produce situational awareness in the first place, and why the ARRL’s own ARES Plan names situational awareness in its mission statement without naming a single tool that provides it. It’s long. The short version is that reporting and awareness are two faces of one coin, and most plans are carrying only one of them.
1. Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST
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) 1. Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST 4. 145.550 Mhz Analogue Simplex RF Link Mossel Bay area.
5. DroidStar / VoxDMR Applications for DMR TG655
6. ASL3 to Mumble Bridge PC (Mumble Client) as well as Mobile Phone (Plumble Client)
7. BrandMeister - Hoseline Application (PC or Mobile Phone - Receive only.)
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. 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.
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!!
2. Would WSPR work on DMR?
No, WSPR (Weak Signal Propagation Reporter) will not work over a DMR (Digital Mobile Radio) voice/data channel. They use completely incompatible modulation schemes, bandwidths, and timing structures.
Why WSPR and DMR are Incompatible
Modulation Type: WSPR uses continuous phase 4-tone Frequency Shift Keying (FSK) at an ultra-slow 1.46 baud, designed for analog SSB audio passbands. DMR uses 4-level and 2-slot TDMA Time-Division Multiple Access with 4FSK phase modulation at 9600 baud, processed by proprietary voice codecs.
Bandwidth: A WSPR signal occupies a tiny 6 Hz slice of spectrum (inside a ~200 Hz to 2.5 kHz audio window). A DMR channel requires a strict 12.5 kHz channel spacing.
Transmission Length: WSPR transmissions are precisely timed and take nearly two full minutes (110.6 seconds) of uninterrupted carrier shifting per burst. DMR cuts transmissions into rigid 30-millisecond frames and timeslot bursts.
Decoding: Standard WSPR decoders (like WSJT-X) look for specific FSK tone sequences and timing relative to UTC seconds. Passing a WSPR audio tone through a DMR digital voice codec will completely distort and destroy the weak signals, turning them into noise or data errors.
3. Ham Radio Etiquette: Do's And Don'ts On Digital Modes [2026]
Amateur radio, minding the gap refers to the crucial practice of leaving a short, deliberate pause (typically 3 to 4 seconds) between transmissions (Overs). This is essential for digital voice and data networks to properly reset, synchronize, and pass traffic without causing system-wide dropouts.
Here is exactly why we mind the gap:
Network Synchronization: For digital voice modes like DMR and C4FM/Wires-X, data travels via servers, nodes, and internet gateways. The gap gives the network’s VoIP protocol time to release the digital stream, clear buffers, and allow other stations to key up.
Preventing "Clipping": If you press your Push-to-Talk (PTT) button and immediately start speaking, the first syllable or two of your transmission is often swallowed by the digital handshaking process. Waiting a second prevents your voice from being clipped.
Allowing Break-Ins: Leaving a pause between your overs gives other operators a chance to break in. This is especially vital in emergencies when another user needs to pass priority traffic.
Avoiding "Time-Out" Timers: Many digital repeaters and network nodes have strict time-out timers (e.g., 3 minutes). Taking a breather resets these timers, preventing the repeater from dropping your transmission mid-sentence.
Thanks to Chris M9UCW For The Thumbnail Image.
Thumbnail Image For Illustration Purposes Only
73 de Mark 2E1CEQ Ham Radio Gadgets YouTube Channel Please Like And Subscribe
4. The Internet Re-Invented - - - - Internet Killer?
In this video, I build a Reticulum RNode and prove that completely different radios — LoRa and Wi-Fi — can communicate through a hardware-agnostic networking stack. Reticulum routes traffic above the radio layer, automatically bridging dissimilar frequencies, interfaces, and modulation types. I then run it over Wi-Fi HaLow Haven nodes to create a long-range, encrypted IP mesh with no traditional infrastructure. Finally, I push it further by running ATAK across the network, demonstrating a fully open-source, decentralized communication stack in action.
"Ham" started as an insult — and the frequencies amateurs were handed were dismissed as useless. So how did they end up crossing oceans, building their own satellite, and talking to astronauts?
This is the strange — and completely true — history of ham (amateur) radio, told as one story: from an invisible prediction on paper to a hobbyist satellite in orbit.
You'll meet James Clerk Maxwell and Heinrich Hertz (who thought his own discovery was useless), follow Marconi's first signal across the Atlantic, and finally find out where the nickname "ham" really comes from — and why the famous "three friends" story is a myth. You'll see how the "useless" short waves turned out to bend around the world off the ionosphere, how amateurs made the first two-way transatlantic contact in 1923, built OSCAR 1 — the world's first non-governmental satellite — and went on to talk with astronauts in space. Plus India's own proud amateur-radio story: Gooptu, Bose, the Amateur Radio Society of India, and a Prime Minister with the callsign VU2RG
00:00 Ham was an insult? 00:35 The invisible waves (Maxwell & Hertz) 01:22 Marconi crosses the Atlantic 01:47 The first home radio builders 02:30 Radio's first traffic jam 02:50 Why they're called "hams" 03:30 The band the experts called useless 03:53 The ionosphere changes everything 04:15 Relay: the birth of the ARRL 04:36 First two-way Atlantic contact (1923) 05:23 Hobbyists build a satellite (OSCAR 1) 05:48 Ham radio reaches space 06:16 India's amateur radio story 07:06 The real pattern of the story
1. Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST
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 Mossel Bay area.
5. DroidStar / VoxDMR Applications for DMR TG655
6. ASL3 to Mumble Bridge PC (Mumble Client) as well as Mobile Phone (Plumble Client)
7. BrandMeister - Hoseline Application (PC or Mobile Phone - Receive only.)
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. 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.
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!!
2. Linux Mint isn't the best Windows replacement anymore
And the replacement is ........ ?
ZorinOS is more modern and polished, making it easier for Windows/macOS users to switch.
Built-in Windows app support
installs .exe/.msi with a click; Mint requires manual WINE setup.
Ships Wayland by default:
crisper text, smooth animations, better scaling, NVIDIA and phone
integration.
ZorinOS has been getting a lot of hype ever since Microsoft dropped support for Windows 10. Turns out the hype is justified. Linux Mint has been my go-to recommendation.
3. 16-Year-Old ARRL Member Wins 2026 Student Coding Competition
ARRL The National Association for Amateur Radio® is pleased to announce that member Ben Leovy, KC3ZPQ, of Ellicott City, Maryland, has been named the winner of the 2026 ARRL Student Coding Competition. Leovy, 16, recently completed his sophomore year at Howard High School. He designed a mobile application to help users prepare for their amateur radio license examinations.
Leovy will receive a $5,000 prize awarded by ARRL. His project was selected by a panel of judges based on usability, clarity, stability, and code quality. The judges also recognized his enthusiasm for software development and creativity by awarding him a new MacBook Neo to encourage his continued exploration of programming and technology.
“The ARRL Student Coding Competition was created to encourage young radio amateurs to apply their skills to a real-world opportunity that will benefit the amateur radio community and future entrants,” said ARRL Senior Director of Marketing and Innovation Bob Inderbitzen, NQ1R. “Ben’s project demonstrated the kind of problem-solving skills and creativity that will help shape the future of amateur radio.”
The judges were also impressed with the strength of Leovy’s technical approach and the potential value of continuing its development. ARRL has offered him a consulting project this summer, to further refine and improve the application in collaboration with ARRL employees – an opportunity to gain professional experience. Upon successful completion of the project, Leovy will earn an additional $5,000. He will also be eligible for a $5,000 ARRL scholarship when he enrolls in college after high school.
“I’m excited about the opportunity to continue improving the application and working with ARRL,” said Leovy. “I hope it helps more people, particularly students my age, to get involved in amateur radio and to join ARRL.”
Leovy became interested in amateur radio through his grandfather and through friends involved with the scouts who shared an interest in the hobby. In addition to amateur radio and programming, Leovy participates in his school’s robotics club and enjoys exploring technology through hands-on projects.
The ARRL Student Coding Competition was launched in January 2026 as part of ARRL’s ongoing commitment to developing the next generation of radio amateurs. The competition encouraged ARRL Student members ages 21 and younger, who already have ham radio licenses, to combine their interests in amateur radio and software development.
“Programs like this help young people discover that amateur radio is more than a hobby — it is a pathway that inspires hands-on, practical, and technical experiences,” said ARRL CEO David Minster, NA2AA. “By investing in students and their ideas, ARRL is investing in the future of amateur radio.”
The competition is another ARRL program intended to develop student interest in future education and careers in STEM/STEAM fields. Other ongoing initiatives include the ARRL Teachers Institute on Wireless Technology, the ARRL Collegiate Amateur Radio Program, and the ARRL Foundation Scholarship Program.
The competition judges were ARRL First Vice President Kristen McIntyre, K6WX; Hudson Division Director Ed Wilson, N2XDD; previous Director of Education and Learning Steve Goodgame, K5ATA; ARRL VEC Manager Maria Somma, AB1FM; and Education & Learning Support Specialist Max Freedman, N4ML. Additional support was provided by past Pacific Division Director Anthony Marcin, W7XM.
Since 2024, ARRL Student Membership has been free for full-time students ages 21 and younger. This no-cost membership opportunity makes it easier for students to become involved in amateur radio and access ARRL resources while they explore radio, technology, and STEM-related learning opportunities.
For more information about ARRL Student Membership, visit www.arrl.org/student.
- ARRL
4. Paper Logging
As an amateur radio operator, logging and QSLing are topics that keep me busy all the time. While I recently stopped confirming my radio contacts (QSLing), it’s still very important to me to log my QSOs. I’ve tried many different options for this and most recently used Wavelog, with which I was generally satisfied. However, I’m currently trying (not just in amateur radio) to simplify things and return to the original ways. That’s why I’ve decided to switch to paper logging, even though the drawbacks are obvious: no automatic generation of statistics, no search options, and no quick way to tell if I’ve had a QSO with a station before. However, I like having the maximum freedom to enter whatever I want into the logbook, however I want. It also feels somehow more personal to log the QSOs by hand.
After testing this out for a while with an existing paper logbook, it turned out that while I like this approach, existing logbooks don’t suit my needs. I make contacts both on shortwave and via satellites. For the latter, I need fields such as the locator or the name of the satellite. That’s why I first designed my own logbook template in OpenOffice Calc, exported it as a PDF, and then had it bound into a ring binder by a professional printing service.
The following image shows the finished logbook with 100 pages, a transparent plastic cover page, and a black plastic page as the last page for less than 10 Euro:
Now all that's left is to see how long paper logging will keep me happy...
- DK1MI
5. The Technology We Killed in the 1960s Is Now Worth $3.3 Billion
In 1904, a British engineer built the first vacuum tube in a London laboratory. Within decades, it became the foundation of modern electronics. Radio, television, military radar, and the first computers all ran on vacuum tubes. Then in 1947, Bell Labs demonstrated the transistor, and by the 1960s the entire industry had moved on. Factories closed permanently, and the vacuum tube was declared dead.
But it never actually disappeared. It survived in places most people would never think to look, and in 2022 a geopolitical crisis exposed just how dependent the modern world still is on a technology it supposedly abandoned sixty years ago.
This is the full story of the vacuum tube, from the invention that started it all to the billion-dollar market nobody sees.
6. Listen to FreeSTAR SystemX Live No App Required [2026]
Stream the conversation. Anywhere. Anytime.
FreeSTAR SystemX Live Activity Feature Directly From Your Browser, No App is Required
Listen To Any FreeSTAR SystemX Talk Group Or Set Up A TG To Listen Once It becomes Active.
Z3DMR is a free, mobile push-to-talk application designed for licensed amateur radio operators to communicate over Digital Mobile Radio (DMR) networks directly from their smartphones.
Developed by the Radioamateur Club Z37CPR, it eliminates the need for physical DMR hardware, a hotspot, or an HT (handheld transceiver) to access digital ham radio networks
Key Features:
Network Support: Connects directly to major DMR networks, including BrandMeister and Homebrew
Talkgroup Management: Features network-specific talkgroup lists, alongside manual configuration options for master servers, contacts, and custom talkgroups.
Call Types: Supports both group calls and private calls.
Advanced Automation: Automatically activates Auto-Static talkgroups and allows multiple user profiles with Extended Service Set Identifier (ESSID) support.
Built-in APRS: Includes integrated Automatic Packet Reporting System (APRS) functionality for location data transmission
Accessibility: Available in 24 languages with a modern, clean, user-friendly interface.
Platform Availability:
Android: The app is fully released and can be downloaded from the Google Play Store.
iOS: An Apple iOS version is actively under development
Official Resources:
For the latest updates, configuration guides, and community support, you can visit the Official Z3DMR Website or join their support community via the Z3DMR Telegram Group.
Some time ago I "complained" in general about the operating procedures of some of our fellow radio amateurs in South Africa. Articles HERE, HERE and HERE.I indicated that ET cannot phone home from certain Nets in South Africa where bad operating practices exist. This of cause all tongue in the cheek but these blatant transgressions and bad incidents is of great concern, not only to me but many others as well. However one Net and that is the DMR-ZA Net is showing how it should be done.
Last night I listened to the Net and to Brian ZS5BR, the Net Controller. I would like to complement all those who participated in the Net and in particular Brian ZS5BR who "controlled" the Net. This is how a net should function and on the forefront was the excellent operating procedures of everybody involved in the Net. I listen to a few nets and also participate in some nets in South Africa but the DMR-ZA Net's outstanding procedures make it a real pleasure to listen and participate in. Great practice by all those involved.
No I am not going to go into detail but join this Net on a Tuesday evenings at 19h30 SAST and experience the net for yourself. The DMR-ZA Net has set the standard of how it should be done. It took me back to the olden day's where it was of the utmost importance and pride to run a net professionally and using good operating procedures and practices.
A big thank you to all involved in the DMR-ZA Net - "ET was able to phone home last night thanks to the DMR-ZA Net!!
Reminder: Do tune into the DMR-ZA Net this evening at 19h30 SAST
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 Mossel Bay area.
5. DroidStar / VoxDMR Applications for DMR TG655
6. ASL3 to Mumble Bridge PC (Mumble Client) as well as Mobile Phone (Plumble Client)
7. BrandMeister - Hoseline Application (PC or Mobile Phone - Receive only.)
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. 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.
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!!
I
wrote several articles in the past where I refer to innovation in
Amateur Radio. This morning a thought came to mind on why is
there currently not a satellite with a DMR Transponder (repeater) up
in space? I was trying to think "out of the box" and
look at ways and means to turn my thoughts into reality, if there is
such a possibility.
Thinking
"out of the box" is absolutely a great way to approach
innovation in amateur radio. Amateur Radio has a rich history
of development driven entirely by amateurs experimenting with limited
resources and unique constraints.
However,
true innovation in this hobby relies on a balance between
unconventional thinking and foundational science.
Why
Out-of-the-Box Thinking Works
Resourcefulness:
Limited power regulations and frequency bands force you to find
clever ways to maximize efficiency.
Historical
Precedent: Amateurs invented weak-signal digital modes (like
FT8) and bounce signals off the moon (EME) because someone asked
"what if?"
Cross-Pollination:
Bringing concepts from computing, machine learning, or material
science into radio often yields breakthrough results.
The
Innovation Blueprint in Amateur Radio
To
make your creative ideas successful, pair your out-of-the-box
thinking with these structured approaches:
Master
the Fundamentals: You must understand Maxwell's equations, wave
propagation, and circuit design to break the rules effectively.
Identify
Real Constraints: True innovation solves a specific problem,
such as reducing noise, shrinking antenna size, or bridging
communication gaps during disasters.
Iterate
and Test: Build prototypes, collect data, and use antenna
analyzers or software simulation tools to prove your theories.
Share
with the Community: Amateur radio thrives on open-source
collaboration. Presenting your ideas on forums, Git repositories, or
at club meetings helps refine them.
Prominent
Areas Needing Innovation
If
you are looking for modern challenges to apply your creativity, focus
on these emerging sectors:
AI
and Machine Learning: Using neural networks for predictive
propagation filtering or automated signal decoding in dense noise.
Alternative
Materials: Experimenting with meta materials, fractal geometry,
or everyday conductive liquids for stealth antenna designs.
Digital
Signal Processing (DSP): Developing open-source algorithms to
extract ultra-weak signals from high-noise urban environments.
Green
Energy Integration: Creating ultra-efficient, off-grid solar or
kinetic power management systems for remote field operations.
Now
reading the above my thoughts ran away with me regarding a DMR
transponder (repeater / beacon / node / hotspot) payload on a South
African satellite. Can it be done and is it possible to
communicate using DMR via a satellite? Is there a
satellite specifically named "Oscar-DMR 1" in existence or
being built in South Africa's space programme or amateur radio
history. Currently this type of communications is not possible.
If
you are waiting for a homegrown South African satellite or an OSCAR
(Orbiting Satellite Carrying Amateur Radio) series spacecraft to
launch, here is the factual reality of what has actually happened and
what is currently in progress.
The
Real South African Satellites
South
Africa has already successfully launched multiple satellites. If you
are looking for local aerospace achievements "seeing the
daylight," they have already made it to space:
SUNSAT
(SO-35):
Launched in 1999, SUNSAT
was South Africa's very first satellite, built by Stellenbosch
University. Critically, it carried an amateur radio payload and was
officially designated as OSCAR
35 (SO-35)
by AMSAT. It saw plenty of daylight before its mission ended.
ZACUBE-1
& ZACUBE-2:
Developed by the Cape Peninsula University of Technology (CPUT).
ZACUBE-1 (TshepisoSAT) launched in 2013, and ZACUBE-2 launched in
2018.
MDASat-1
Constellation:
In January 2022, South Africa successfully launched a
three-nanosatellite constellation via a SpaceX Falcon 9 rocket.
These operational maritime domain awareness satellites track
shipping traffic off the South African coast.
ZS1I
created the fictional "DMR 1" Satellite Name
The
term DMR
stands for Digital
Mobile Radio,
which is a widely popular land-based digital protocol used by radio
enthusiasts and businesses across South Africa.
Terrestrial,
Not Space:
Amateur radio operators in SA heavily utilize the South
Africa DMR Repeater Network.
This network relies on ground-based repeater towers, not dedicated
South African "DMR satellites."
Conflation
with Commercial Satellites:
You may be thinking of commercial mobile satellite services or
push-to-talk satellite radios that interface with DMR-style dispatch
systems on the ground.
Future
South African Space Missions
If
you are wondering about the next major government-backed leap into
orbit, the Department of Science and Innovation has active plans:
National
Communication Satellite:
The government has been exploring multi-billion-rand plans to
acquire or launch a dedicated communications satellite to bridge the
digital divide and reduce reliance on international space entities.
However this look like a very "far in the future" project
with many logistical and financial issues to first solve.
Deep
Space Ground Tracking:
While not a satellite itself, South Africa broke ground on a
massive, state-of-the-art Deep-Space
Ground Station
in Matjiesfontein (Karoo), built in partnership with NASA to track
future lunar missions.
Sadly
you cannot work DMR (Digital Mobile Radio) directly through orbiting
amateur radio satellites. Hopefully by means of innovation in
technology my thought on building such is satellite is not far
fetched and will not forever just be a thought. In South Africa
building such a satellite will be problematic but that is a topic for
another time.
Let's
see why this can or cannot currently be implemented.
You
can absolutely build a physical DMR repeater and launch it into orbit
on a satellite. However, doing so introduces a severe physics
and timing challenge
that standard DMR protocols are not designed to handle.
The
core issue is the
speed of light and the Doppler effect.
The
Timing Problem (TDMA Breakdown)
DMR
relies on TDMA
(Time Division Multiple Access).
It divides a single frequency channel into two distinct time slots
(Slot 1 and Slot 2).
The
Rule:
Each radio must transmit in an incredibly precise window—exactly
30
milliseconds
long.
The
Margin:
The standard protocol only accounts for standard terrestrial
distances, leaving a guard timing buffer of about 1.25
milliseconds
to handle propagation delay.
When
a satellite is orbiting overhead (even a Low Earth Orbit, or LEO
satellite at ~500 km), the distance from the ground station to the
spacecraft changes continuously and rapidly. Because the radio waves
must travel hundreds of kilometers to space and back, the propagation
delay exceeds that 1.25 ms guard window.
Consequently,
your radio's packet arrives late, shifts out of its slot, and bleeds
into the adjacent time slot.
This completely breaks the synchronization, causing the repeater's
onboard computer to reject the handshake.
The
Frequency Problem (Doppler Shift)
DMR
uses 4FSK
digital modulation.
It relies on precisely mapping four distinct, narrow frequency shifts
to represent binary data.
Because
a LEO satellite travels at roughly 27,000 km/h, the frequency shifts
dramatically as it approaches and moves away from you. This Doppler
shift
warps the digital signal. While a human ear can decode an uncorrected
analog FM signal through a bit of static, a digital DMR modem will
see the warped 4FSK signal as corrupted gibberish and refuse to
decode it.
How
to Make a Space-DMR Repeater Work
If
an amateur radio group or space agency wanted to make a true DMR
satellite work, they would have to implement one of two workarounds:
Modify
the Radio Firmware (Software Solution)
The
ground station's DMR radio would need custom firmware capable of
predicting the satellite's exact orbit. The radio would then have to
continuously alter its timing (transmit early or late to hit the
slot perfectly) and automatically adjust its frequency to cancel out
the Doppler shift in real-time.
Put
the Spacecraft in a Geostationary Orbit (Hardware Solution)
If
you put the DMR repeater on a geostationary satellite (35,786 km
above Earth), the satellite remains stationary relative to the
ground. This eliminates the Doppler shift entirely. While the time
delay would be much larger, it would be constant,
allowing engineers to build custom terrestrial radios with a
massive, fixed timing buffer specifically for space.
Consolation Prize
There
is currently a "consolation prize" on how you can use your
DMR Radio to connect to satellites indirectly.
You
can use your DMR radio to connect to satellites indirectly by talking
through an MMDVM hotspot (or a local digital repeater) connected to
the internet. From there, your signal is routed to space through a
commercial geostationary satellite (such as QO-100) using an up/down
converter, a dish, and an SDR (Software Defined Radio).
Unlikely that a dedicated amateur satellite named "Oscar
- DMR 1" will be built in South Africa
It
is highly unlikely that a dedicated amateur satellite named "Oscar
- DMR 1" will be built specifically for standard DMR voice
communications in South Africa. While amateur radio organizations like AMSAT
constantly develop new spacecraft, standard commercial DMR protocol
is fundamentally incompatible with the physics of Low Earth Orbit
(LEO) satellites.
The Geostationary Exception, there is hope!!
The
only way a true DMR transponder could work in space is on a
Geostationary (GEO) satellite like QO-100. Because GEO satellites
remain completely stationary relative to the Earth's surface, there
is zero Doppler shift or changing propagation delay. While there is
no official "Oscar - DMR 1" payload planned, experimental
digital voice links are routinely tested via GEO transponders using
specialized ground stations. More on this in a future article
once I put on my "out of the box" and "innovation"
hat.
Was
this article a waste of time? NO definitely not. I now
have more questions than answers that I will be looking into.
ED. This article was compiled by ZS1I with the assistance of AI.
Image: Mossel Bay Area (Click on image for larger view.)
The ZS1I DMR Repeater in Heiderand, Mossel Bay has been running from time to time since June 2023. It is permanently on the air from the 1 May 2026 after several hardware and software modifications were done for optimum functioning. Several radio amateurs have provided reports and positive comments with regard to the repeater. It is quite strange that I never plotted the coverage area using Radio Mobile since June 2023. I have now plotted the expected coverage area of the repeater.
Before I publish the images it is important to first publish the repeater- , equipment- , feedline- and antenna information.
ZS1I Digital Mobile Radio (DMR) Repeater
DMR Repeater Talkgroup 65522: This repeater is NOT located on a remote mountain site but is situated in the Shack of ZS1I in Heiderand, Mossel Bay. This allows ZS1I to monitor and control the repeater while it is on the air. Mossel Bay DMR Repeater Information:
Mode: DMR Band: 70cm TX Frequency: 438.262500 Mhz RX Frequency: 430.662500 Mhz Radio Mode: Duplex Talk Group (TG): 65522 Colour Code: 1 Time Slot: 1 or 2 RF Power Output: 15 Watt Logarithmic power level: 41.76 dBm Antenna EIRP: 46.96 dBm Antenna: Diamond X50 Antenna Gain: 7.2 dBi Antenna Height: 12 Meters Coax Cable: RG213 Mil-Spec (West Germany)
This repeater is linked to the ZS1I AllStar Hub Network (Node 49355) (Analog Repeaters / Simplex Link Radio / Echolink / SVXLink / AllStar / South Cape Reflector) via the ZS1I DMR Bridge and Repeater.
With
your system operating at 440
MHz (70cm UHF band)
with an EIRP of 46.96
dBm
from an antenna height of 12
metres at sea level in Mossel Bay,
your real-world coverage will be highly asymmetrical.
Because
UHF signals rely almost entirely on line-of-sight
propagation
and are easily blocked by solid earth, your coverage splits into two
completely different zones: vast open coverage over the ocean, and a
sharp cutoff to the north caused by the Outeniqua Mountains.
Here
is how your 46.96 dBm EIRP system will perform under these specific
local conditions:
Line-of-Sight
Horizon Limit
The
theoretical radio horizon for an antenna 12 metres above sea level is
calculated using the standard RF horizon formula:
To
a Handheld Radio (Ground Level):
If communicating with a person holding a radio at ground level
(approx. 1.5 metres high), their radio horizon is about 5 km. Adding
your horizons together means you will have clean, high-clarity
Line-of-Sight
coverage up to 19–20 km away
over the flat ocean surface or open coastal flats towards Hartenbos
and Klein Brak River.
2.
Terrain Obstacles: The Outeniqua Mountains
To
the north of Mossel Bay, the Outeniqua Mountains rise sharply to
heights between 800 and over 1,500 metres (such as the Robinson Pass
area).
The
Shadow Effect:
At 440 MHz, radio waves behave much like light beams. When your
signal hits the massive sandstone slopes of the Outeniquas, the
mountains will cast a massive "radio
shadow"
directly behind them.
The
Cutoff:
Your signal will cleanly illuminate the southern, seaward-facing
slopes of the mountains. However, coverage will completely drop off
on the northern side of the ridge. You will not be able to reach
deeper inland areas like the Little Karoo (Oudtshoorn region) unless
you bounce a signal off a mountain-top repeater.
3.
Signal Penetration in Town (Urban Factor)
Because
your antenna is mounted at 12 metres, it is likely sitting just above
or level with standard two-story residential rooftops in Mossel Bay.
Structural
Losses:
440 MHz UHF is excellent at bouncing between buildings and
penetrating walls.
Local
Range:
You can expect highly reliable, punchy coverage throughout the
immediate town, even over the hilly terrain of the Cape St. Blaize
peninsula. The 46.96 dBm (approx. 50 W) of effective directional
power is more than enough to overcome urban attenuation within a 10
to 15 km radius
through town structures.
✅
Summary
of Estimated Range
Over
Ocean / Flat Coastline:20–35
km
(Excellent clarity to marine traffic or coastal stations with
elevated antennas).
Urban
Mossel Bay:10–15
km
(Robust signal piercing through local neighborhood obstacles).
To
the North (Mountains):Up
to the ridge line
(Signal stops abruptly at the mountain peaks; no coverage in valleys
behind them).
Images: Courtesy Radio Mobile (Click on images for larger view.)
Above image: Mossel Bay wide coverage area
Above image: Mossel Bay close-up image 1
Above image: Mossel Bay close-up image 2
Above image: Repeater coverage Albertinia Town. Bad coverage!!
Above image: Repeater coverage George Area. Good coverage!!
Above image: Repeater coverage Mossel Bay and Hartenbos Areas. Good coverage!!
Above image: Repeater coverage West of Mossel Bay / Gouritz River Areas. Spotted coverage!!
Above image: Repeater Coverage - Still Bay, Heidelberg, Riversdale, Albertinia and Herbertsdale. Bad coverage!!
