The Motorola Radius M100 radio that was built to last!

The Motorola Radius M100 is a classic two-way mobile radio introduced in the late 1980s. It earned a reputation for being rugged and "built to last" due to its heavy-duty die-cast aluminum chassis, high-grade commercial internal components, and compliance-level structural toughness designed to withstand harsh industrial and vehicular environments.

Design and Durability

• Tough Chassis: Built with a thick metal frame that dissipates heat effectively and protects internal logic and RF boards from physical shock and vibration.
• Industrial Use: Widely deployed in commercial fleets, public safety back channels, and construction sites where equipment faced constant movement and dust.
• Simple Controls: Offered a straightforward, no-nonsense interface (often 2 channels) that reduced mechanical failure points on the faceplate. 

Technical Legacy and Limitations

• Power Output: Typically pushed an honest 25 to 40 watts of RF power, depending on the specific VHF/UHF split.
• Programming Hurdles: These vintage units rely on legacy DOS-based Radio Service Software (RSS) and a dedicated Radio Interface Box (RIB), making modern programming a notable challenge for hobbyists. 

I have a Motorola Radius M100 VHF radio connected to the ZS1I AllStar HUB Node in Mossel Bay since 2016.  This radio is now running full output power for 10 years as a linked radio to the HUB and is connected to world wide Echolink, AllStar and DMR networks seven days a week.  This radio is being used for what it was never intended for.  It was designed as a mobile radio and not as a full time simplex or repeater radio.

I am flabbergasted that this radio is still working the way it did 10 years ago without skipping a beat taking into account the heavy duty cycle it goes through, sometimes transmitting for 1 hour or longer.  We need to take into account that this radio was introduced in the late 80's  and is a real brick of a radio.  Another important factor apart from being rugged and built to last is curtailing the heat created by the pre-driver, driver and final transistors.  Heat can be the enemy of many radios.  Incorrect heat distribution and high temperature can cause radios to fail.  In this case I chose to install an outboard computer fan (80mm x 80mm) to the heatsink of this radio.  I also installed a homebrew fan controller which was described in my article available HERE.

The fan does not run all the time but comes on when the radio is in TX Mode for longer that 30 seconds depending on the temperature in the shack an whether it is winter or summer. 

I constantly monitor the radios's output power as well as SWR with an inline SWR and Power Meter combination.   So far I have not detected any indication of lower output power or higher SWR than first measured when I installed the antenna.  Apart from making a COS modification to the radio nothing else was modified or fixed.  

The Motorola Radius M100 is an ultra-reliable, vintage analog mobile transceiver built like a tank.  It is widely praised by retro radio fans and amateur operators as a classic "no-nonsense" workhorse.  Housed in a heavy-duty metal chassis, the M100 takes physical abuse, high vehicle vibrations, and extreme field environments far better than modern lightweight plastic radios. Features exceptionally crisp, clear analog receive and transmit audio that easily cuts through noise Delivers a solid 25 watts of power (depending on the specific VHF/UHF band split), making it great for base stations or mobile setups. Most base M100 models support very few channels/modes (often just 2 channels) unless upgraded with specific logic boards.

Obsolete Programming - Requires an archaic DOS-based computer environment, a Radio Interface Box (RIB), and specific Radio Service Software (RSS like RADMBL) to change frequencies. 

Final Verdict: If you find a working unit cheap, the Motorola Radius M100 is a fun piece of radio history and a bulletproof analog link radio to have in your shack.    Let's see if this radio will last another 10 years from today forward.

Thank you Motorola for making such quality radios!! 

Images:  (Click on image for larger view.)

 

My current thoughts on the Meshtastic and Meshcore "hype" and why I prefer AREDN!

Why all the hype about Meshtastic and Meshcore nowadays in Amateur Radio?  Is there really a hype in this regard?   To answer the hype question I must honestly answer yes, if you look around you will literally find hundreds of videos and articles in this regard. I have been watching and reading quite a bit regarding these two entirely different open-source software projects since Meshtastic started a few years ago and Meshcore joined in later.  A few local radio amateurs in the George area setup a few nodes and some information were exchanged amongst radio amateurs in the area.  I looked into the feasibility of setting up such a mesh network at the time but came to the conclusion that it will be of no benefit to me or the general public as I was already running a AREDN ( Amateur Radio Emergency Data Network) Network on 2.4 Ghz and 5.8 Ghz in the Mossel Bay area.  The benefits of an AREDN Mesh Network clearly over shadowed Meshtastic and Meshcore.   But you are talking a lot of rubbish now!  What about emergency communications?  Surely Meshtastic and Meshcore can be used during a disaster to assist in emergency communications?

Let me explain a few reasons why I decided not to go the Meshtastic or Meshcore route and let me make it very clear that I an not against any of these open source projects.  I might in future consider to join both these open source projects depending on further development of the software, hardware and a substantial price drop etc.

Here is a few reasons why I rather use AREDN: (I will only provide a cryptic explanation.)

• An AREDN (Amateur Radio Emergency Data Network) system is a high-speed, self-discovering wireless mesh network built specifically by and for amateur radio operators using commercial off-the-shelf radio hardware. It is fully open source.  Its source code, custom Linux-based firmware, and build tools are publicly available on GitHub under the GPL-3.0 license. This allows amateur radio operators to inspect, modify, and contribute to the network's software development.
• I already have all the equipment setup for the AREDN Mesh Network including a fully functional web-site and server. It can connect to the ZS1I AllStar Hub Network and DMR Repeater and Bridge Network even when the Internet goes down.  I can connect  AREDN to any repeater, radio link, digital radio link etc for emergency communication use.
• The AREDN Mesh Network has already been successfully used during the Knysna Fire Storm in 2017 and proved that it is up to the task of providing voice, video, image, text, email and data communications. (forwarding and storage)
• The AREDN Mesh Network can be split into several mesh networks.  For example the 2.4 Ghz network can be opened for public use and a person only needs his cellphone (without a cellular network connection) to communicate to the AREDN 2.4 Ghz Network or a node in his/her vicinity.  This will allow the public important direct access communications during a disaster.  Same as Meshtastic and Meshcore but with more power and directional gain antennas for AREDN.
• Video / Images / Email and Data Communications are vital during a disaster.  AREDN can provide these with ease having great bandwidth etc. One can even "tap" into existing CCTV Cameras that might be offline or install portable cameras on tripods if there is a need for it.
• Now let's look at the cost.  For what I am getting from a Meshtastic or Meshcore node / repeater I might just as well use commercial off-the-shelf radio hardware for AREDN which is found in abundance secondhand or sometimes as give-a ways.   On several occasions I received freebee's which I used as AREDN Mesh Nodes.  Older and redundant antennas for 2.4 Ghz and 5.8 Ghz can be obtained free from many Internet Service Providers and the general public.  All the antennas I currently use was free of charge. 
• I hear you say but the Meshtastic and Meshcore nodes are small and compact and can be used with solar battery power.  Yes the form factor is small and compact but have a look at the AREDN web-site to see how small and compact some of the AREDN nodes are and they can also use solar battery power.
• RF Power Output -  As radio amateurs we are permitted to use higher power than any of the Meshtastic or Meshcore nodes can provide.  Higher power is not always the answer but it is available if needed.  Always just use enough power that is needed to make a reliable connection / contact.  I am not a QRO operator by any means but it is good to know that one can use higher power if needed.
• Interconnection of AREDN to other amateur radio equipment and networks.  This is were AREDN is shining and I have touched on this earlier.  Bridging / interconnection / linking call it what you want has become very important in this day and age.  On many occasions in the past I have talked about the  disparity in radio communications among emergency responders—often called a lack of interoperability—occurs due to incompatible hardware frequencies, differing agency protocols, and decentralized funding. Police, fire, and medical teams often use completely separate networks that cannot talk to each other directly during a crisis.  
• In my opinion AREDN is a far better and trustworthy mesh network system.  Agree there are also some areas that need to be upgraded but the AREDN Team is working tirelessly to release software and hardware updates to keep AREDN in the loop and relevant today.

Finally:  I am not against Meshtastic or Meshcore.  Each one has it's own rightful, place and uses and I think that it is wonderful technology that needs to be developed even further.  So before I jump on the "hype wagon" several changes and new features need to be released to make it an attractive option for me to use as an emergency communications tool. By all means feel free to follow the Meshtastic, Meshcore or AREDN "route".  Let's see what the future will bring in this regard.

ZS1I Mossel Bay DMR Repeater Coverage - Radio Mobile Maps

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:

===================================================================

RADIO HORIZON CALCULATION

===================================================================

Formula:

d = √(17 × h)

Where:

d = Distance to the radio horizon (in kilometres)

h = Antenna height above the ground/sea level (in metres)

-------------------------------------------------------------------

Your Setup Calculation (12-Metre Antenna Height):

d = √(17 × 12)

d = √(204)

d ≈ 14.28 km

Result:

The theoretical radio horizon for your repeater antenna is 14.28 kilometres.

===================================================================

• 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!!

UV-5R Baofeng 25th Anniversary Edition released in early 2026 to celebrate 25 years of the brand.

The Baofeng UV-5R 25th Anniversary Edition is a limited-run commemorative version of the iconic dual-band radio, released in early 2026 to celebrate 25 years of the brand. This special edition, limited to just 5,000 units, retains the core technical DNA of the original UV-5R but introduces several modern hardware and aesthetic upgrades.

Key Features & Enhancements

Transparent Design: The most striking feature is its "Glacier Ice" (transparent white) or "Solar Flare" (transparent orange) shell that reveals the internal circuitry.

USB-C Charging: Unlike the standard model that requires a desk cradle, this edition includes an 1800mAh battery with a built-in USB-C port for charging via power banks or car chargers.

Commemorative Details: Features a unique 25th-anniversary metal badge, a custom startup screen, and specialized "VFO/MR" keycaps.

Upgraded Antenna: Includes a longer, transparent high-gain antenna that shows the internal coil and capacitor.

Premium Packaging: Comes in a custom hard-shell carrying case.

Marking 25 years of the BAOFENG, this special edition brings a classic back with a refreshed design and modern upgrades. It keeps the trusted performance of the original, enhanced with commemorative accessories that add real value.

The transparent housing reveals the internal circuitry for a distinctive technical look, complemented by a custom “BAOFENG 25TH” startup screen, a dedicated “20th” keycap, a Metal Badge, and a thank you card for a subtle sense of exclusivity.

With built-in USB-C charging, you can power it up anywhere—at home, in your car, or in the field. The included hard-shell case keeps your gear protected and ready to go.

Whether you're just getting started or need a reliable backup, this all-in-one kit is designed for outdoor use, emergency prep, and staying connected when it matters.

Functions:
1. Frequency Range: 136-174MHz (Rx/Tx); UHF: 400-520MHz (Rx/Tx)
2. Dual-Band Display, Dual Freq. Display, Dual-Standby
3. Output Power: 5 /1Watts
4. 128 Channels 50 CTCSS and 104 DCS
5. Built-in VOX Function
6. 1750Hz Brust Tone
7. FM Radio (65.0MHz-108.0MHz)
8. LED Flashlight
9. Large LCD Display
10. High/Low RF Power Switchable
11. 25KHz/12.5KHz Switchable
12. Emergency Alert
13. Low Battery Alert
14. Battery Saver
15. Time-out Timer
16. Keypad Lock
17. Monitor Channel
18. Channel Step: 2.5/5/6.25/10/12.5/25KHz
19. Roger

Specifications：
Model: BAOFENG UV-5R 25th Anniversary Edition
Color: Glacier Ice/Solar Flare
Output: 5W/1W
Channel: 128
Frequency Stability: ± 2.5ppm
Antenna: Dual-Band High-Gain Antenna
Antenna Impedance: 50Ω
Operating Voltage: DC 7.4V
Wide/Narrow Band(25kHz/12.5kHz)
Dimensions: 2.1" x 1.2" x 3.7"/ 54 x 30 x 94mm(without antenna)
Weight: 7.1oz / 200g (including battery, antenna)

Images:  (Click on images for larger view.)