Lets build a Compact Low Power Automated WSPR Monitoring Station (Part 1)

Image:  Current ZS1I test setup (Click on image for larger view.) 

As mentioned before I am busy gearing up for the next 6 Meter DX Season soon to open in South Africa. There is little to no activity in the Mossel Bay,  Southern Cape area where I live.  So why not create activity?  I decided to embark on "The ZS1I - 6 Meter Magic Band Project in the Southern Cape Area of South Africa".  I am currently getting my equipment ready for this venture.  

Now one need a few handy "tools" to assist you in "playing" on the 50 Mhz band.  In future articles I will explain what I am using and how I set it all up.  Apart from a radio, computer, firmware, antennas etc.  I was looking for an easy and relative cheep way to spot openings on the 6 Meter band and also to monitor WSPR signals.  The setup must be fully automated and be able to send spots to WSPRNET.  Another must have was the function to use a Telegram phone alert bot that pushes an instant notification to my smartphone the exact millisecond the monitor intercepts an opening on 6 Meters.

Now what is a Compact Low Power Automated WSPR Monitoring Station?

An automated WSPR Monitoring Station is a compact, low-power radio receiver setup. It listens for specific Weak Signal Propagation Reporter (WSPR) radio signals transmitted by amateur radio operators globally.

Image:  Raspberry Pi Zero 2 W  (Click on image for larger view.)

Here is a breakdown of what it is and what it is used for:

What It Is

• The Brain: A Raspberry Pi Zero 2 W microcomputer running automated listening software like rtlsdr-wspr or WSJT-X.
• The Operation: It runs 24/7, automatically tuning to specific radio frequencies, decoding digital WSPR signals, and uploading the data to the internet via Wi-Fi.

What It Is Used For

• Atmospheric Testing: It measures how well radio waves travel through Earth's ionosphere at any given moment.
• Antenna Benchmarking: It helps operators see how well their antennas perform by checking if their signals can reach your station.
• Space Weather Tracking: It monitors how solar flares, sunspots, and day/night cycles affect global radio communications.
• Data Crowdsourcing: It automatically uploads reports to WSPRnet, contributing to a live, global map of radio propagation.
• Catching Band Openings: It acts as an early warning system, instantly detecting when changing atmospheric conditions suddenly allow signals to travel thousands of kilometers on a previously "dead" frequency. 

Here is how the system works from the antenna to your phone.

Image:  RTL SDR Receiver V4  (Click on image for larger view.) 

1. Recording the Spots

• The Radio: Your SDR dongle constantly listens to a set radio frequency (like 14.0956 MHz for the 20-meter band).
• The Software: Digital software on the Pi cuts the audio into strict two-minute windows.
• The Decode: The software processes the audio to extract the caller's call sign, grid square, and signal strength.The Local Log: Every successfully decoded message is instantly written to a local text file called ALL_WSPR.TXT.

2. Sending Spots to WSPRnet

• The Upload: Right after writing to the local log, the software uses your Wi-Fi to bundle the data.
• The Network: It sends an automated internet request to the central WSPRnet database.
• The Map: Your station’s data joins thousands of others to update global propagation maps in real time.

Image:  Telegram Bot  (Click on image for larger view.)

3. Connecting Smartphone Push Alerts (Telegram)

To get instant alerts when a specific distance or rare call sign is logged, you connect a custom script to your log file:

• Create the Bot: You message @BotFather on Telegram to create a free bot and get an API Token.
• Get Your ID: You message @userinfobot to find your personal Telegram Chat ID.
• Monitor the Log: You run a lightweight Python or Bash script on the Pi that actively watches (tails) the ALL_WSPR.TXT file for new entries.
• Trigger the Alert: The script checks each new line. If it meets your criteria (e.g., a signal from > 5,000 km away), it sends a web request to Telegram, and your phone buzzes instantly. 

Beneath is a few decodes on 40 meters run with the current test setup: 

 

Images:  Decodes  (Click on image for large view.

I have ordered a few "goodies" that will be used to complete the project.  In Part 2 we will be looking at the setup and use of the WSPR Monitoring Station.  I will also look at setting up an automated band monitor for FT8. Very similar to the WSPR Monitoring Station except that we need much more processing power and a wider bandwidth.  More on this in a future posting.

Update: The ZS1I - 6 Meter Magic Band Project in the Southern Cape Area of South Africa. (Part 2)

Image:  AI  (Click on image for larger view.)

My mind has been filled with many projects that I would like to construct in the next few years.  Only time will tell if this will be possible as many unforeseen things can happen that prevent me from completing projects.  Now one of the projects that I work on from time to time is the 6 Meter Magic Band Project in the Southern Cape Area of South Africa.  Read more HERE about this project.

I have been reading every single day to gain as much knowledge and information as possible on the various projects that I am busy constructing or putting together.  What a great privilege to still have good health and eye sight  that makes reading and learning possible.

Awhile ago I completed the 6 Meter CW Beacon but it is still not on the air.  One reason for this is I will have to relinquish other RF radio systems to ensure that I have optimal "conditions" in and around the shack for 6 Meter operations.   I also need to use current antenna poles to install 6 Meter antennas.  I need to remove the 2 Meter antenna pole to be used for 6 Meters. 

Be as it may my brain runs in "overdrive" when it comes to amateur radio ideas and projects.  I came up with the following question:

Which mode, CW or WSPR is better for a 6 meter magic band project? The ZS1I 6 meter magic band project for amateur radio involves building or using equipment (radios, antennas) to exploit the unique, unpredictable long-distance propagation (Sporadic-E, F2 skip, Aurora) on the 50-54 MHz frequency, offering both short-range VHF and surprise HF-like DX (long-distance) contacts, often using simple DIY antennas like halo loops or Moxons for great results and rewarding challenges. Projects focus on maximizing these propagation modes, especially during peak seasons like summer (Sporadic-E) and solar maximums (F2).

I was interesting to find out what mode will provide the "better"  outcome taking into account the local factors in the Southern Cape and the equipment I will be using to achieve ultimate success with the 6m project.

I decided to call on AI to answer my question: 

"The question of whether a WSPR (Weak Signal Propagation Reporter) beacon or a traditional CW (Morse Code) beacon is "better" for the 6-metre band (50 MHz) depends entirely on how you plan to monitor the band and what equipment you want to use.

---

Direct Comparison

Feature	WSPR Beacon	CW Beacon
Sensitivity	Superior (Decodes down to -28 to -31 dB SNR)	Inferior (Human ear cuts off around -10 to -15 dB)
Required Equipment	Radio + Computer/Interface or dedicated digital transmitter	Just a standard receiver (and your ears)
Reporting Network	Automated logging to WSPRnet	Dependent on the Reverse Beacon Network or manual logs
Bandwidth	Ultra-narrow (~6 Hz per signal)	Narrow (~100-200 Hz)
Time to Results	2-minute fixed transmission cycles	Instantaneous identification

---

Why WSPR is Better

• Extreme Weak-Signal Decoding: WSPR is specifically designed to dig deep below the static. It can decode signals as low as -31 dB SNR. This allows you to spot micro-openings or tropospheric ducting paths on 6 metres that a human ear scanning a CW frequency would completely miss.

• Set-and-Forget Automation: When you leave a WSPR beacon running, automated listening stations worldwide upload the data directly to WSPRnet. You can pull up a live map on your phone or PC to see exactly where your 6-metre signal is landing without relying on anyone manually copying your Morse code.

• Ultra-Low Power: Because of its heavy forward error correction (FEC), you can run a 6-metre WSPR beacon on just a few milliwatts to 1 Watt and still get spots thousands of miles away.

Why CW is Better

• Instant Band Awareness: 6 metres is known as the "Magic Band" because it can open to sporadic-E propagation instantly. WSPR takes exactly 2 minutes per transmission cycle to decode. If you are actively sitting at your desk waiting for a band opening to make contacts (like FT8 or SSB), listening to a cycling CW beacon provides immediate auditory confirmation the second the band pops open.

• No Computer Required: You don’t need an interface, software (like WSJT-X), or precise GPS time-syncing to use a CW beacon. You just spin the dial to the 50.000–50.100 MHz beacon sub-band and listen.

• Indicator of Communication Readiness: If you can hear a CW beacon with your ears, the band is open enough to support live, two-way human communications (SSB, CW, or FT8). WSPR signals can be decoded even when the path is too weak to support a normal conversation.

---

The Verdict

• Choose WSPR if your goal is long-term propagation research, antenna testing, or seeing if a path exists when the band appears "dead".

• Choose CW if you are an active operator waiting to jump on the radio the moment 6 metres opens up for live voice or Morse code contacts."

Many modern beacon builders actually combine the two by setting up a transmitter that alternates—sending a 2-minute WSPR cycle followed by a brief CW identification so that both digital systems and human ears can utilize the signal!

There you have it.  I will have to make a decision as to whether I will be going the WSPR or CW "route".   The decision is quite simple.  

AI makes it easy: 

"Operating from KF15BT (located in the beautiful but radio-isolated Southern Cape region of South Africa, near Mossel Bay/George), you are uniquely positioned for long-distance DXing via interesting propagation modes, but you face the classic "lonely ham" problem. Because there is little to no local 50 Mhz activity to keep the band warm, you must rely entirely on automated "triggers" to tell you when a long-distance opening is happening. 

Given your excellent gear (6 Meter Yaesu Radio, Moxon, Delta Loop) and your homebrew Arduino/ESP32 hardware, digital modes (specifically FT8 for contacts and WSPR for monitoring) are absolutely the way forward. 

Here is the exact strategic blueprint for conquering the "Magic Band" completely solo from your grid square.

The Strategy: Digital over CW

    • The FT8 Reality: 95% of global 6m DX hunting is concentrated on 50.313 MHz (FT8). If the band opens from South Africa to Europe, South America, or up into Africa, those stations will be parked on FT8 waiting for signals. 

    • The Problem with CW: If you sit and text CQ on CW, no one will hear you unless their beam is pointed directly at KF15. Most European or DX stations leave their rigs automated on FT8 overnight or during the day to catch rare openings. "

For raw technical performance and automated global tracking, WSPR is vastly superior. However, for real-time human monitoring and instant "radio-in-hand" notification of sporadic-E band openings, CW beacons remain highly essential."

These last three lines is the crux of my question and answer. I will be using WSPR which is vastly superior and will hopefully provide the best outcome for the project. Along the way I will however also make use of CW. Time to get to work!

Is this possibly the end of the road for the ZS1I AllStar RF Link on 145.550 Mhz in Mossel Bay?

Image: AI (Click on the image for larger view.)

Is this possibly the end of the road for the ZS1I AllStar RF Link on 145.550 Mhz?  For the time being the ZS1I AllStar RF Link on 145.550 Mhz in Mossel Bay has been switched off and will not be available until further notice.

The following reasons are being presented as to why this decision has been taken:

1.  The 145.550 Mhz RF Link is solely being used by yours truly in and around the household.  Running at 25 watts output power this is a waste of RF energy and unnecessary stress on equipment.  To those that do not talk but listen (gooi varkoor) unfortunately you will have to find another source to listen.

2.  I have the following radio equipment running every day in the shack.

• DMR Repeater
• WSPR Beacon
• 2m RF Simplex Link
• 6 cm CW Beacon
• 70 cm RF Simplex Link (at times when necessary)
• 2 x WiFi Routers
• 5.8 Ghz AREDN Node 

I am getting ready for the 6 Meter "Magic Band" Season that will soon commence.  I want to keep RF levels in and around the shack as low as possible.  This will entail switching of other RF radio equipment that does not get used regularly.  

3.  I have indicated before that I want to concentrate more on DMR and 6 Meter Operation. Well the time has arrived for just doing that.  Unfortunately I will have to relinquish other systems to ensure that I have optimal "conditions" in and around the shack for DMR and 6 Meter operations.

4.  I also need to use current antenna poles to install 6 Meter and 70 cm antennas.  I will therefor remove the 2 Meter antenna pole to be used for 6 Meters.

5.  The current EMI / Ground Level Noise is running quite high in the shack due to various outside factors.  I need to lower this noise factor and need to eliminate the source of this noise if possible.  I will use the process of elimination to hopefully solve the high noise level. 

6.  I intend using separate TX and RX equipment for 6 Meters.  Power output will also differ depending on the mode of communication.  I do not want to run any equipment that is not being utilized regularly.  I will run all equipment from solar power, hopefully noise free!

There you have it.   Will the ZS1I AllStar Hub in Mossel Bay still be available and operational for use by radio amateur?  YES, it will work as before, just without the 2m RF Link on 145.550 Mhz.  I will monitor the running systems and might utilize the 145.550 Mhz RF Link again in future when the need arise.

#8 - Amateur Radio News and Announcements (18 August 2026)

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:

80 m: 3985 kHz
40 m: 7060, 7240, and 7275 kHz
20 m: 14300 kHz
17 m: 18160 kHz
15 m: 21360 kHz
2 m: 146.520 MHz (simplex)

PLEASE steer clear of these frequencies.
 

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.

Download file HERE (PDF)

4.  Vyf ná 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.

Lees meer HIER 

5.  Ham Radio is in the Toilet - Pete N6QW 

 

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.

 Further reading:  What Your FWD/REV SWR Power Meter Is Actually Showing

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.

Read more HERE 

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.

Read more HERE

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.)

 

ICASA investigates illegal radio transmissions in Germiston

Image:  AI

Investigation targets alleged illegal use of amateur radio frequencies in Germiston.

An investigation led by the Independent Communications Authority of South Africa (ICASA), is clamping down on businesses operating illegally on amateur radio frequencies.

Read more HERE 

Once again the Internet has failed in the Southern Cape Area of South Africa

Image:  AI 

This is not going to be a moaning or groaning topic however I must admit that the lack of Starlink Internet is definitely felt in this fifth world country we living in.  For the past three days I have experienced sporadic Internet outages for whatever reason, this does not matter. Matter of fact is there is currently no reliable Internet service from my providers and once again let me rather not mention them.  What really matter is that there is really no alternative except amateur radio when the Internet fails.  Lots of talk about an alternative for Starlink which they say is going to be a South African Satellite Service Provider.  I can just wonder what is going on behind the scenes and how this so called "brilliant" provider is going to provide and alternative to Starlink with old satellites.  I have my thoughts about this but I will keep it to myself. Time will tell what this third world service and outdated satellites will provide as opposition to Starlink.  I doubt it this fifth world country is able to compete with Starlink.  Enough!!

Let's see what the future holds but until then I presume we must be satisfied with a firth world Internet service in this country.

Finally:  I still say we as radio amateurs need to find alternatives for the Internet and don't tell me it is HF Radio or VHF/UHF Repeaters.  I am working on a few projects that if successful will be used as alternatives for the Internet.  What are you doing to find alternatives? 

 

Let's build a passive RF Field Strength Meter (Part 1)

This is very useful test instrument that every radio amateur should have in the shack and can be built for next to nothing.  Let's look at this very handy instrument and its uses.

A passive RF field strength meter is a simple, un-powered device used to detect and compare relative radio frequency signal levels. It uses an antenna to capture RF energy, germanium diodes to rectify the AC signal into DC, and a sensitive analog micro ammeter to display the relative output level without requiring a battery.

Core Components

• Antenna: A telescopic whip or tuned dipole to pick up local RF radiation. 
• Germanium Diodes: Low forward-voltage components (like 1N60 or OA47) used for RF rectification.
• Analog Meter Movement: A highly sensitive zero-center or standard 50µA / 100µA panel meter.
• Capacitor & Potentiometer: Optional bypass capacitors to filter RF and a variable resistor/potentiometer to attenuate strong signals.

Common Uses

• Checking transmitter output and relative power.
• Adjusting and comparing directional antenna radiation patterns.
• Testing the efficiency of baluns, tuners, and antenna setups. 

I decided to build two of these instruments.  In this issue we will be looking at the passive RF Field Strength Meter version.

Diagram

Bill of Materials

2 x Germanium Doides (IN34, OA70, OA90, IN60, BAT43 or 85)

1 x 470 pF (471) Cap

1 x 10 K Potentiometer

1 x 50 uA Meter

2 x DC Power Posts (Red + Black)

1 x Piece of Veroboard (PCB)

1 x 500 mm Stiff Copper Wire (Antenna) or old FM Radio Antenna

1 x Instrument Cabinet

1 x Potentiometer Knob 

 

Construction

 

I am not going to go into detail as the diagram provides more than enough information to construct  the meter successfully.

 

Images (Click on images for larger view.)

 

 

 

Video

 

 

#7 - Amateur Radio News and Announcements (4 August 2026)

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.

Build your own unstoppable network today. Full implementation guide: 👉 https://buildwithparallel.com/product.. 

 

 

5.  "HAM" Radio? The Strange True Story  

 "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 

END. 

#1 What's in the Box / Parcel?

This guy (ZS1I) is getting like the YouTube video posters with his "What's in the Box?"  I received several requests to please continue with the series "What's in the Box?"  From all accounts these postings were of great interest to some of the readers of the previous Blog.  I will oblige in this regard and will from time to time post images and information of what is in the boxes I receive.  I am also looking at providing a review of equipment, components, modules etc.  I have not yet decided in which format to publish these reviews.  It will either be done on this blog or via a YouTube channel.  Now I must say I do not regularly buy items via the Internet.  So do not expect many posts in this regard.  Some of the equipment in the boxes is not new so do not expect the latest amateur radio state of the art equipment to be unboxed.

Lets get cracking in unboxing this item:  (Click on images for larger view.)