Venezuela is in the spotlight this weekend, after two massive 7.2 and 7.5 magnitude earthquakes struck within a minute of each other on the night of Wednesday, at midnight our time. The epicenters were about 13km below ground, in the province of Yaracuy, and exposed at least 790000 people to severe shaking. As of the next morning, casualty numbers were not reported as high but that number has changed as the days go by.

On Friday night, CNN was reporting at least 920 fatalities, and over 3000 injured souls. Many thousands are still missing. Rescuers were racing to reach survivors beneath the rubble before the so-called “golden” window of time closes. Thousands are displaced and homeless in Caracas, La Guaira and surrounding areas. Residents are calling for civilian volunteers to help clear debris, saying that the emergency response is insufficient. The building damage and destruction is apparently massive.

Many countries have reacted via diplomatic channels, and rescue teams from surrounding countries are pouring in to aid in the search for survivors.

Carlos CO2JC, IARU Region 2 Emergency Comms Coordinator issued a message on Thursday, saying he had been in communication with Domingo L. Hernández Lima, YV5IZE, director of the Venezuelan Radio Club’s National Emergency Network, and learned that a large part of the capital was without electricity, and communication systems were operating on battery power. They were already activating their emergency shortwave (HF) frequency and also using digital frequencies and communication modes.

For this reason, Carlos requested that all amateur radio colleagues in the Americas and the rest of the world protect the following frequency used by Venezuelan amateur radio operators, namely:

40 m: 7135 kHz  Lower Side Band.

At the same time, the emergency communications coordinators of amateur radio operators from Colombia, Cuba, Guatemala, Honduras, Nicaragua, El Salvador, and other countries in the region, as well as members of the Board of Directors of the International Amateur Radio Union Region 2 (IARU R2), remain on standby to provide any assistance that may be needed.

The above message was conveyed to Region 1 of the IARU by Greg Mossop G0DUB, even as he convened the emcomm workshop at Friedrichshafen, where the second biggest Hamvention in the world is taking place this weekend.

All radio operators are strongly advised to avoid this frequency until the emergency is over. There are local VHF frequencies being safeguarded as well, but they won’t be trampled on or heard by South Africans.

Philippines has also experienced a magnitude 6.5 earthquake, this one on Friday the 26^th at 13h34 our time, and at the very bottom of the province of Central Mindanao, and at a depth of 42km. About 36000 people experienced severe shaking, and news of any casualties is awaited.

As I’m sure all radio amateurs are aware, this weekend is seeing the American Field Day exercise taking place. Since 20h00 hours our time last night (Saturday) thousands of hams in the Americas have gone off line and off grid to use their radios, mobile power sources and temporary antennas out in the countryside, to test their ability to make contact with, and transmit information between, similar setups in other parts of the country, and even of the world, if propagation conditions permit. Local weather and solar weather either contributes to, or spoils, the fun, until 23h00 our time tonight (Sunday). Amateurs will use the 160, 80, 40, 20, 15, 10 and 6 metre bands, as well as VHF bands above 6 metres, and see what they can achieve.

The American press has been full of advisory reports from every county in every state, telling us who is doing what and where, and the next few weeks will see countless “post mortems”, as people report on what did or didn’t happen, and why. In the middle of the Northern Hemisphere’s summer, this event is hugely looked forward to, and much will be written before the excitement dies down. I’ll try to put together some sort of short report after it’s all over.

Local news in the Western Cape is that one of our local repeaters started behaving peculiarly a few days after our most recent storm, at the beginning of June. This repeater is sited on the top of Sir Lowry’s Pass, on the N2 out of the Peninsula, direction George. Users noted they could access it with high power and at close range, but not with average or low power or at a distance. It was speculated that water had got into the coax, and reduced the efficiency of the antenna system.

The actual cause was far worse. Someone was able to get up to the site (there are many, many radio repeaters on the site), and sent down a picture of the mast torn out of its concrete base, snapped in  half about halfway up, and lying on the ground, as a result of the wind experienced during that storm! Luckily the coaxial cable between VHF repeater and antenna had survived, and the repeater was trying its best to operate in a horizontal orientation on the ground, instead of a vertical one, and usually about 10-15 metres off the ground.

Repairs were very hastily made to get our antenna on a short 6 metre galvanised pole and bracketed to the repeater building at the site, and it is responding more normally again today (Saturday). Our grateful thanks are due to the members of the repeater working group team, who did a hurried MacGyver on the thing. This repeater forms an important link in the chain from Cape Town central all the way to George.

It is interesting to note that such towers on high sites are getting loaded more and more these days with microwave dishes, used for internet, or commercial or industrial links, and in fairness, the resistance to the wind created by all the dishes, which didn’t used to be there, probably makes the tower construction inadequate. I wonder how one calculates the effect of the dishes added to the wind resistance of the tower and radio dipoles. Should there not be a limit to the number of microwave dishes permitted on such a structure, or perhaps a revision of the minimum structural strength of these towers to cope with the wind load buffeting the dishes? Definitely food for thought! I hope they put up a stronger structure when this one is repaired.

This is Dave Reece, ZS1DFR, grateful that my miserable little 9 metre mast system is down at about 30 metres above sea level, and not on the top of a mountain, and reporting for HAMNET in South Africa.

May I start by wishing all the fathers out there a happy Father’s Day? I hope you enjoy this day, and realize how lucky you are to have children who appreciate you, as much as you love them. And if you still have fathers, tell them how special they are to you.

In a report from westerncape.gov.za, premier Alan Winde and members of his Cabinet have provided an update on the Western Cape Government’s ongoing response to the severe weather disasters that have affected the province and the assessment of the damage.

Premier Winde has welcomed the progress made so far, while emphasising that significant recovery and reconstruction work still lies ahead.

“In an extreme weather event like this, our immediate reactions are always about saving lives. We have now turned our attention to the recovery efforts. Since the devastating storms struck our province, all spheres of government, municipalities, emergency services, and our partners have worked tirelessly to restore access to affected communities and critical infrastructure. Through these coordinated interventions, about 70% of the roads that were closed have since been reopened in some form, restoring vital connectivity for residents, businesses and emergency services,” said the Premier.

While emergency access has largely been restored, extensive damage to road infrastructure remains a major challenge.

Western Cape Minister of Infrastructure, Tertuis Simmers, said, “Many roads, bridges and related structures have sustained significant damage and will require major repairs or, in some cases, complete reconstruction. These are complex projects that require detailed assessments, engineering investigations and design work before construction can commence.”

To support longer-term recovery efforts, the Western Cape Government has identified 19 emergency provincial road repair projects at critical locations across the province. Contractors have already been mobilised, and work has commenced on a number of these priority projects.

Premier Winde noted that recovery work will be prioritised and implemented in a phased manner, subject to the availability of funding. The cost of the damage caused by the storms currently stands at over R9 billion.

“We are focused on restoring infrastructure as quickly and safely as possible, but the scale of the damage means that recovery will take time. Our approach is to prioritise the most critical routes and infrastructure while ensuring that all work is properly planned and executed to build greater resilience against future disasters,” continued the Premier.

The Premier also highlighted ongoing efforts to restore electricity supply. In daily briefings with Eskom Western Cape management, the Premier and members of the provincial Cabinet have been informed that 97% of residents who were left without electricity due to the adverse weather have now been reconnected, with restoration operations being intensified across affected regions.

The Western Cape Government has further supported response and recovery operations through the provision of plant and equipment to assist with access restoration and infrastructure repair efforts.

Provincial Minister of Local Government, Environmental Affairs and Development Planning, Anton Bredell, said, “We cannot ignore the impact of climate change in our province. To recover properly from and avoid disasters in the future, a business-as-usual approach’ will not work and indeed is likely to erode our development progress. Together we need to find adaptive strategies that minimise risks and enhance benefits to people and the economy.”

Premier Winde concluded, “We remain committed to working closely with municipalities, Eskom, national government and all stakeholders to ensure that affected communities receive the support they need. While considerable progress has been made, we recognise that many residents continue to face hardship, and we will continue driving recovery efforts with urgency.”

Thanks to westerncape.gov.za for the report.

Lexology.com reports that High-Altitude Pseudo-Satellites (HAPS) are emerging as a promising technology positioned between conventional aircraft and orbiting satellites. Operating in the stratosphere at altitudes of 20 to 50 kilometres, HAPS are typically unmanned aircraft or airships designed to remain airborne for extended periods while delivering communications, surveillance, environmental monitoring, and data services. As demand grows for persistent connectivity and lower-cost aerial infrastructure, HAPS technology is attracting increasing attention from governments, aerospace companies, and telecommunications providers.

Unlike satellites orbiting the Earth, HAPS remain within the atmosphere and maintain relatively fixed positions over a target area. Most concepts rely on lightweight structures powered by solar energy, supported by high-efficiency batteries or fuel cells to sustain night-time operation. The appeal of HAPS lies in their ability to combine some of the coverage advantages of satellites with the flexibility and accessibility of aircraft. A single platform can potentially provide broadband connectivity, remote sensing, disaster response support, or border surveillance across large geographical regions.

Advances in materials science, solar panel efficiency, battery storage, and autonomous flight systems have significantly improved the feasibility of long-duration stratospheric flight Several aerospace and telecommunications companies have conducted successful test flights demonstrating impressive endurance, including a recent 12-day, 6,400-mile stratospheric flight from New Mexico to waters off Brazil. Modern HAPS designs increasingly focus on ultra-light composite airframes, intelligent energy management systems, and autonomous navigation capabilities capable of handling challenging stratospheric conditions.

The growth of 5G and future 6G communications networks has also accelerated interest in HAPS as a complementary infrastructure layer. In remote or underserved regions where terrestrial towers are impractical, HAPS may offer a faster and less expensive alternative to laying extensive ground infrastructure. Governments are likewise exploring military and civil applications, particularly for intelligence gathering, maritime monitoring, wildfire detection, and emergency communications during natural disasters.

HAPS technology is steadily moving from experimental demonstration toward commercial and governmental deployment. Continued improvements in battery density, autonomous systems, and lightweight materials are likely to enhance endurance and operational efficiency.

Rather than replacing satellites or terrestrial networks, HAPS are more likely to serve as part of a hybrid communications and monitoring ecosystem. Their unique position in the aerospace landscape allows them to fill capability gaps where conventional solutions are either too expensive, inflexible, or technically unsuitable.

As the sector matures, companies developing HAPS technologies may increasingly focus on protecting innovations relating to energy systems, autonomous control, communications architecture, and platform design. Patent protection for such innovations is therefore expected to become an increasingly important aspect of competition within this rapidly evolving field.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.

GDACS reported on Friday a GREEN notification for Tropical Cyclone JANGMI, active in the North West Pacific, with maximum wind speeds of up to 150km/h, threatening up to 8 million people in Japan with wind speeds of at least 120km/h. It is not over the land yet, but is expected to track parallel to Japan’s South Island at its most damaging stage.

Techxplore.com says that a popular sodium-ion battery designed by the company HINA and used in cars and large-scale energy storage systems in China matches performance parameters and production quality of Tesla’s lithium-ion batteries, according to new research published in Cell Reports Physical Science.

Once the Hina battery is tweaked to charge more effectively at low temperatures and function better at high energy densities, it could provide a cost-effective alternative for future electric vehicle batteries that depend on sodium—an abundant and easily sourced material—instead of lithium.

“The combination of good uniformity, high power capability, and strong low-temperature performance makes these cells attractive for stationary storage, grid services, and shorter-range or commercial vehicles where potential lower cost and resource availability matter more than maximum driving range,” says Moritz Schütte, a battery researcher at RWTH Aachen University in Germany.

To assess how Hina batteries compare to more advanced Tesla batteries, Schütte’s team used a non-destructive technique called impedance spectroscopy to measure the uniformity of 120 sodium-ion battery cells.

Next, to map out the power and energy performances of individual cells under real-life conditions, the team tested the batteries at varying currents and at temperatures from −20 °C to +45 °C. They also used X-rays to see the battery’s internal structure, then opened up the cells to measure their electrode dimensions, compositions, and microstructures.

They found that the battery uses a tab-less double-aluminum current collector design that reduces resistance and ensures a uniform temperature distribution—and also mirrors the current design of Tesla batteries.

“We were positively surprised by how uniform the cells are,” says Schütte.

However, the sodium-ion battery has some limitations when it comes to energy density and charging at low temperatures. “The high-power performance was better than one might expect from an early commercial sodium-ion product,” says Schütte.

“However, for applications that require frequent charging at low ambient temperatures, appropriate thermal management or operating strategies will be important because low-temperature charging remains a clear weakness.”

Since sodium is much more abundant and widely available than lithium, using it for batteries could cut raw material costs for manufacturers and reduce long-term supply chain risks. Sodium-ion batteries also perform well under load at low temperatures, making them an appealing option for both stationary power storage and mobile applications in cold climates.

Thank you to techxplore.com for these notes.

Here’s something that I know has been keeping you folk awake at night for decades. How pigeons fly hundreds of kilometers and still find their way home has long fascinated people. Now, researchers say a surprising answer may be hidden, not in the brain or eyes of birds, but in the liver.

A study published in Science suggests that special cells in the liver of pigeons can sense Earth’s magnetic field, giving the birds an internal compass.

The special cells, known as “macrophages“, are immune cells that break down old red blood cells. As part of this process, they accumulate iron, giving them quantum properties that may allow them to respond to magnetic fields. Without these cells intact, pigeons could not navigate home, the study shows.

“What looks like a ‘gut feeling’ in bird navigation may actually have a physical basis,” adds Prof. Martin Wikelski, Director at the Max Planck Institute of Animal Behavior and a co-senior author of the study.

For decades, scientists have known that migratory birds and homing pigeons rely in part on Earth’s magnetic field to navigate. But exactly how they detect it remains one of biology’s unsolved mysteries.

Competing theories have suggested that birds might “see” magnetic fields through light-sensitive molecules in the eye, or detect them using tiny magnetic particles in the beak. None has come up with convincing experimental support. The new study proposes a different mechanism for magnetic sensing, supported by a combination of lab tests and behavioral experiments.

To identify where magnetic cells are found in pigeons, the researchers used techniques known as “vibrating sample magnetometry” and “magnetic cell separation” to screen organs thought to be involved in magnetic sensing, including the eyes, beak, and brain. They also examined the liver and spleen.

“We had some clues that the liver and spleen have magnetic properties, because they break down red blood cells and so store much iron in the body,” says first author Dr. Clivia Lisowski, from the University of Bonn and the University Hospital Bonn, who led the immunological work.

The results supported that idea. Of all the tissues examined, the liver showed the highest concentration of iron.

“Iron is crystallized in oxide nanoparticles, making the cells superparamagnetic and reactive to magnetic fields. We found by far the strongest magnetic response in liver tissue,” adds Prof. Ulf Wiedwald, from the University of Duisburg-Essen.

Further analysis identified macrophages in the liver as the cells responsible. To test if liver macrophages played a role in navigation, the ornithological team conducted experiments on pigeons that were trained to return from distances over twenty kilometers back to their aviary at the MPI-AB in Konstanz, Germany.

After the macrophages were removed, pigeons lost their sense of direction on overcast days when the sun was obscured. When the sun was visible, however, the pigeons successfully navigated home, likely using solar cues. Together, these results illustrate the mechanism behind how birds use magnetic sensing, in addition to the sun’s orientation, for navigation.

With evidence that these cells influence navigation, the researchers then looked for how signals from the liver might be relayed. Electron microscopy showed that the iron-rich macrophages sit close to nerve fibers, suggesting a pathway for magnetic information to reach the brain.

Lisowski says, “These findings provide the first concrete evidence of how Earth’s magnetic field can be perceived within the body and passed on to the brain to guide movement.”

Thanks to Phys.org for this interesting study.

I don’t know about you fellows, but I’m wondering who will be the first radio amateur to bounce signals off homing pigeons livers as they fly home during a race, thereby demonstrating the first evidence of “pigeon-scatter”, after “meteor-scatter” and “aeroplane-scatter!

This is Dave Reece ZS1DFR, wondering if I can propagate a better signal, by bouncing it off all the scrap metal in my garden shed, and reporting for HAMNET in South Africa.

The Amateur Radio Emergency Service (ARES) newsletter of 20^th May reports that more than 100 Southern California hams mobilized to support public safety and medical functions during an Earthquake Full Scale Exercise (FSE) and Medical Response and Surge Exercise (MRSE) on 15^th April, in San Diego County, California, the fifth-most populated county in the United States.

Hams deployed to over 40 locations to provide communications support to hospitals, law enforcement, military bases, city and county emergency operations centres (EOCs), tribal communities, and evacuation shelters for the magnitude 6.9 earthquake exercise scenario. Damage was simulated along the busy north-south Interstate 5 corridor, in downtown San Diego, and in northern Mexico, knocking out key bridges, other infrastructure, and the San Diego International Airport. The exercise was planned by the California and San Diego County Offices of Emergency Services (OES).

Amateur radio organizations participating included the San Diego Amateur Radio Emergency Service (ARES), San Diego Sheriff’s Office Auxiliary Communications Service (ACS), American Red Cross Disaster Support Team (DST), and Community Emergency Response Team (CERT) groups such as the Poway Auxiliary Communication Team (PACT).

Radio amateurs were stretched thin to cover 40 locations, from hospital trauma centers in beach cities along the populated coast to rural mountain towns in the backcountry. With simultaneous activation of several amateur radio organizations, hams with membership in more than one group had to decide which organization to support, resulting in less-than-full staffing at some locations. Consequently, hams had to step up to fill roles that were vacant due to these challenges.

In the same newsletter, I read that an ARRL Mississippi Section ARES Simulated Emergency Test (SET), code-named “Operation Undead,” took place on Saturday, March 14, running for twelve hours from 7:00 AM to 7:00 PM. The scenario was a severe disruption of commercial communications infrastructure coupled with a localized biological threat—a novel pathogen outbreak mimicking an “undead” scenario requiring specialized public health coordination for quarantine and resource allocation.

The primary mission for Mississippi ARES was to coordinate amateur radio operators supporting overflow and emergency communications for public safety, public service, and state and local government entities, focusing specifically on the public health sector. ARES members were instructed to deploy from home stations, mobile units, and portable setups, often strategically positioned at emergency operations centers (EOCs) and public health agency locations.

The purpose of the drill was to evaluate emergency preparedness strengths and weaknesses, and demonstrate ARES capabilities to served agencies and the public. After-action summaries will show operational insights and provide guidance for future preparation efforts. All participants have been requested to submit online reports post-event, including Emergency Coordinator and Net Manager reports, as well as narrative After-Action Reports (AARs). Additionally, preparations for the 2026 SET included Mikah Crochet, K5WZL, EC for Pearl River County, coordinating with Mississippi State Guard communications assets, confirming their active participation and necessitating further meetings to ensure coordination and interoperability.

Thanks to the ARES newsletter for both these reports.

At the Cape Town Amateur Radio Centre monthly meeting yesterday afternoon, and on behalf of the President of the SARL, awards were handed out as announced at the AGM on 2^nd May. The four recipients of the HAMNET Shield for their services to HAMNET communications in the Western Cape (Danie, ZS1OSS, Shawn ZS1LED, Ian ZS1BR and Michael ZS1MJT) were gratefully thanked for their services to HAMNET in the Peninsula. Christo ZS1CBY, David ZS1GA and Neil ZR1ABO had previously received Jack Twine awards at the AGM, for their services to HAMNET in the Winelands area, with particular reference to the establishment of a linked system of Raspberry PI APRS digipeaters, which have increased the range of visible moving vehicles and beacons to as far as Touws River on the N1. With one more digipeater still to be installed at Langeberg, the system should cover the far side of the Hottentots Holland Mountains from Worcester down to Swellendam and along the N2. These digipeaters are linked to the Peninsula APRS system over the mountains by a very high digipeater running on solar power only on the very top of du Toit’s Kloof, which was installed by helicopter before Pierre ZS1HF’s key went silent. This ZS0DZ digipeater is currently working flawlessly and I hope I haven’t cast a spell on it by saying so!

Hamvention has come and gone. Of course, the American Press is full of aspects of the exhibits, the forums, and the markets. We, unluckily, won’t get much exposure to the forums, which are usually the most valuable part of the convention. And, as far as I can see, the new products by the big manufacturers are few and far between. It looks to me like a new repeater from YAESU, a new tunable vertical telescopic HF antenna from ELECRAFT, a new antenna tuner from ICOM, and an update to the dualband FM and D-star radio also by ICOM. It may take a while for these items to appear on the market, so don’t hold your breath

Belganewsagency.eu says that The European Space Agency (ESA) is set to launch the SMILE mission on Tuesday the 26th, in collaboration with China, to study the Sun’s influence on Earth. Belgium is making a significant contribution to the mission, the Belgian Science Policy Office (Belspo) announced.

What’s with a GPS that suddenly stops working, radio communications that cut out, or blocked electricity grids? The potential source of disruption in all these scenarios is the phenomenon of the solar wind. The Sun emits charged particles that can collide with the Earth’s magnetic field, thereby disrupting technology on Earth and in space. This can, for example, put astronauts in serious danger.

The SMILE mission aims precisely to map this phenomenon better. “Thanks to the new data collected by the satellite, scientists will be able to analyze when and why so-called space weather causes problems,” stated Belspo in a press release. In this way, scientists will in the future be able to predict where disruptions will occur.

Belgium plays a role in both the satellite’s instruments and the research. The Liège Space Centre, for example, contributed to the development of SMILE’s ultraviolet instrument. The University of Liège will help examine the data from that instrument. The Royal Belgian Institute for Space Aeronomy is also a co-investigator, but specifically focusing on the properties of the solar wind.

The SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) will launch on Tuesday from French Guiana, heading for an orbit around the Earth for at least three years.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.

I wasn’t joking when I mentioned the possibility of storms hitting the Western Cape in last Sunday’s report. I’m sure by now you are all aware of the National State of Disaster announced by the Government as a result of storms and flooding in six provinces. The Western Cape was one of them.

Large swathes of the Winelands, the Swartland, and the Peninsula itself were flooded with rainfall in the hundreds of millimetres. Almost a week later, farms, small towns, roads, bridges, pleasure resorts and all low-lying living areas are still under water, impassable, or washed away.

Towns like Worcester, Ceres, and Robertson were isolated. A problem at Ceres raised concern, when Emergency Medical Services were unable to provide their ambulance services, or make contact with any of their outlying clinics, because all cell-phone and landline communications were cut off.

HAMNET Western Cape was approached for help in Ceres, to provide comms back to Provincial Emergency Medical Services at Tygerberg, in case of serious illness or accident amongst inhabitants, as well as with dispatch and control of their ambulances. Michael ZS1MJT, our Regional HAMNET Director, undertook to drive to Ceres in his camper van, suitably equipped with communications and antennas, and drove a very circuitous route of 310km, via Wellington and Gouda, then almost to Touws River on the N1, to be able to turn North, and then head towards the Tankwa Karoo, before doubling back to use the only open route into Ceres, on Wednesday. (Interestingly, the Western Cape’s APRS digipeaters tracked him for the entire distance.)

The Disaster Risk Manager in Ceres made good use of his capabilities and he was able to assist with radio comms amongst official vehicles and ambulances there. Getting back to the Peninsula via HF radio was a bigger problem however, but luckily, he had just finished building our first QO-100 satellite dish and radio the weekend before, and used it to good effect, to transmit to a geostationary satellite 36000 km above the equator over DRC, and back to similarly equipped stations in Cape Town, to be able to convey messages to Provincial EMS. The satellite communication was rock steady, and unaffected by the glancing blow to the earth of a coronal mass ejection off the sun, after an M class 5.7 Solar Flare, which raised the noise floor on HF to almost unusable levels via ordinary HF propagation.

Michael was able, at night, to use 80m HF using an end-fed long wire, and made contact with several HAMNET members in Cape Town, who in turn contacted EMS at Tygerberg. Thank you to all those who managed to keep skeds with Michael and relay news.

By Friday, communications between ambulances and their base in Ceres were returning to normal, and Michael arrived back on Friday evening, having driven about 700 km, to reach a town just 135km away, if the usual roads had been passable!

Meanwhile, most of the Winelands towns have been heavily flooded, and are still without fresh water supplies, because pumping stations are themselves underwater and out of action. And in the greater flood area, 10 deaths were reported, and over 83000 people living in 21500 dwellings were affected or displaced by the floods.

The silver lining to the grey cloud that was the storm, was the rain in the catchment areas of the Western Cape dams, whose levels have already risen in a week by about 20% as I write this, with more water in the rivers still to reach the dams. If this is the way our winter rainfall season starts, all our dams should be at 100% by the end of it.

Brian, ZS6YZ, our HAMNET National Director has sent me a very long and comprehensive write-up from the ITU about what happens when digital systems fail. I have tried to reduce the executive summary for you a bit. It says:

“What if, tomorrow, mobile phones and the internet stopped working, payments failed, hospitals lost patient data, and emergency alerts never arrived? What may sound like science fiction could become reality. A large-scale, escalating failure of critical digital systems, a ‘digital pandemic’, is a plausible scenario that current management frameworks are not yet designed to address.

“A solar storm of the magnitude that narrowly missed Earth in 2012 could have knocked out power grids and communications across entire continents. Growing space debris already threatens to push low-Earth orbit toward failure, jeopardizing satellite navigation, financial networks, and weather forecasting all at once. Extreme weather, which is growing more violent with climate change, has already shown its capacity to sever digital infrastructure entirely, turning disasters into humanitarian crises.

“This report shows that digital disruptions rarely remain isolated events. They cascade. What begins with a local failure can rapidly spread across sectors and borders. In fact, up to 89% of digital disruptions from natural hazards are caused by secondary spillover effects rather than from the initial damage. The number of people ultimately affected can be up to ten times higher than those initially exposed to the initial event. Digital risks often remain invisible until they reach a critical threshold. Systems simply stop working while our physical world is seemingly unaltered. This may delay crisis response when action matters the most.

“Meanwhile, our ability to cope without digital systems has eroded. Across sectors, analogue skills and fallback options have disappeared or are no longer tested. When systems fail at scale, manual alternatives often cannot replace them. However, the severity of this challenge varies significantly across contexts: countries with more limited infrastructure redundancy, including small island developing states and least developed countries, face distinct and in some cases more acute vulnerabilities.

“Finally, a critical gap persists in how risks are understood. Cyber threats attract significant attention, but non-intentional disruptions of material infrastructure follow different dynamics. The knowledge exists, but we are not paying sufficient attention. And even when we do, we lack the necessary frameworks, standards, and coordination capacities needed to turn that knowledge into preparedness.

“Addressing these risks requires action across six priorities, identified through a co-creation process with senior expert practitioners spanning international organizations, national authorities, academic institutions, and the private sector:

1. Building the knowledge base to identify critical risks, model chain reactions, and map cross-sector dependencies;

2. Updating risk management frameworks to recognize non-intentional digital disruptions as a core risk;

3. Strengthening international standards for resilience, encouraging cooperation for analogue fallback capacity, and joint scenario planning;

4. Ramping up proactive coordination on the most acute risk vectors; enhancing societal capacity to absorb and recover from digital disruptions;

5. Building the trust, and shared situational awareness; and

6. Global collaboration needed to translate early warnings into collective action.

The entire document is available on the ITU website and is named “s-rep-wtisd-2026-pdf-e.pdf”

This weekend sees the Dayton Hamvention taking place in Xenia, Ohio, with about 35000 visitors and exhibitors expected to attend. All the major manufacturers will have stalls there, as well as the ARRL and the RSGB societies. There will have been many seminars held over the three days, and manufacturers are expected to showcase their new devices for amateurs to drool over. I hope to bring you news of new developments in the next week or so.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.

A cut-off low pressure cell has been hovering over the south-eastern Cape for about a week now, and the extreme rain conditions, to which the Eastern Cape is not used, struck in midweek. You have probably all noted the heavy rainfall round about Knysna and inland of it, since midweek.

48-hour rainfall figures up to 8am Thursday morning revealed 300 mm in Joubertina, 280 mm near Knysna, 216 in George, 110 in Uitenhage and 106 in Port Elizabeth. And there has been more, and there will continue to be more in to the middle of this week.

The Kouga, Groendal, Loerie, Impofu and Churchill dams all rose from an average for all 5 dams of 36.3% full before the rains, to 117% full by Friday the 8^th. The Kromme river became a raging torrent and people along the banks were encouraged and then ordered to evacuate to high ground to prevent disaster.

two men spent a very cold 2 days in an abandoned shed above the river when Meiringspoort’s N12 mountain pass was washed away. They were eventually rescued by helicopter.

Mayor Hattingh Bornman, of the Kouga Local Municipality has posted many reports on FaceBook of areas being flooded or washed away, low-lying communities being saturated as rivers overflowed their banks, and continuing icy rain.

The NSRI was activated in Oyster Bay to rescue multiple people and animals trapped at Kingsway Resort on the Gamtoos river. NSRI in Gqeberha, Jefferys Bay, St Francis Bay and Oyster Bay were all activated,, together with SAPS and other rescue organisations. Rescue swimmers, CROCS (small floating canoes) police divers. EMS rescue squads and lots of Good Samaritans were all roped in.

In the end 49 people were rescued aged from 5 to 80 years old, and an undetermined number of animals as well

Andrew Gray ZS2G, of HAMNET Eastern Cape reports that 2000 flood affected victims in Nelson Mandela Bay area were moved to shelters, and will need donations of food and blankets to keep them going.

And the Western Cape is threatened with heavy and disruptive rainfall starting this morning early, affecting the Winelands and the Overberg regions as well, and resulting in about 140mm of rain being predicted by Tuesday. This is very good news for our dams which have been showing signs of impending emptiness over the hot summer, provided of course that some of the rain falls in their catchment areas.

Low temperatures are also expected in Gauteng, following the typical winter pattern characterized by icy mornings, mild afternoons and cooler evenings.

In another of his very nice reports after a motor rally in the Western Cape, Ian Bradley ZS1BR has noted that amateur radio operators once again played a vital supporting role at the 2026 Swartland National Rally, held on 24 and 25 April in the Swartland region of the Western Cape. As one of the key rounds in the South African National Rally Championship calendar, the event brought together rally crews, officials, support teams and volunteers from around the country.

Operations were conducted on 145.650 MHz via the Hawequa Repeater, which provided dependable wide-area coverage for the duration of the event.

Day 1 began at De Werf Padstal, where the radio team met to fit mobile radios and mag-mount antennas into the Clerk of the Course (CoC) vehicle, the Zero Cars and the commentator’s vehicle. The commentator’s vehicle was fitted with a radio but intentionally not equipped with a microphone, as no dedicated radio operator was assigned to that vehicle. This allowed the commentator to monitor the control net and maintain situational awareness without risk of transmitting.

Once the mobile installations were complete, the control station was established at Hermitake Restaurant, just outside the town of Hermon, which served as the primary Rally HQ for Day 1 operations.

Due to delays accumulated throughout the day, Stage 6 was ultimately scrubbed, and Stage 5 was run as the designated night stage, concluding at 20:30.

While there were no major incidents requiring the medical team to be dispatched there were plenty of retirements due to mechanical failure throughout the day. Of the 33 starters, only 19 teams completed all 5 stages.

Less than 12 hours later Day 2 operations began with control being established at Hoërskool Swartland at 08:00. Who said being a radio amateur was easy?

With the previous day’s challenges resolved and lessons from Day 1 already applied, the second day started far more smoothly.

The first two stages ran on time and were incident free. However, an accident in the third stage brought the rally to a halt. The CoC was quickly informed as soon as Control received the message so that the stage could be stopped and the medics sent in. It was soon determined that a spectator had been hit by a rock, kicked up by one of the passing cars, which broke his leg. While all safety measures were in place, rallying is still a dangerous sport, and unfortunate accidents do happen from time to time. We wish him all the best with his recovery.

No further incidents were reported for the day; however, the delays in Stage 3 did push the end time for the rally back by about 50 minutes.

ZS1BR comments that, In a motorsport environment where timing, safety and rapid coordination are critical, dependable communications remain essential—and amateur radio continues to prove its value in exactly this role. The 2026 Swartland National Rally once again highlighted one of amateur radio’s enduring strengths: the ability to provide reliable, infrastructure-independent communications in support of safety, coordination and event operations under real-world field conditions.

A sincere thank you goes to ZS1MJT, ZS1ATX, ZS1ES, ZR1JL, ZS1LAM, ZS1WV and ZS1YT who gave their time, equipment and expertise in support of the event, as well as to ZR1FR and ZS1JM for working their magic behind the scenes.

As a point of interest, 827 times were passed on top of all the other transmissions over the two days!

And thanks of course to Ian, who conveniently leaves himself out when he thanks the crew, for your efforts Ian at control, and for the report.

I’m sure you’ll all join me in celebrating the hundredth birthday of Sir David Attenborough this week, whose videos of nature all around the globe, have increased our knowledge of the world we live in. I see the plastic block company that is Lego has changed its meme on its boxes of kits that say for people from 2 to 99, to now say 2-100+, so that Sir David isn’t excluded from enjoying playing with the stuff! Happy Birthday, Sir David.

This is Dave Reece ZS1DFR, remembering with pain the occasions when he has trodden on a Lego block unseen on the carpet, and reporting for HAMNET in South Africa.

Wednesday the 29^th April saw the first commemoration of the International Day in Memory of the Victims of Earthquakes, as the United Nations called on governments, cities, schools and workplaces to take part in the global campaign “Drop. Cover. Hold On.”

Led by the United Nations Office for Disaster Risk Reduction (UNDRR), the campaign promotes simple, life-saving actions to take during an earthquake and encourages the conduct of earthquake drills at least twice a year, including the 29^th April, to help make safe behaviour an automatic reflex when the ground begins to shake.

The International Day, designated by the United Nations General Assembly last year and observed annually on 29^th April, honours the victims of earthquakes while renewing global commitment to preventing future tragedies through stronger disaster resilience.

In a message marking the first observance, United Nations Secretary-General, António Guterres, highlighted the devastating impact of earthquakes:

“Earthquakes are one of nature’s deadliest hazards. In seconds, they can turn homes into ruins, undo decades of progress and claim thousands of lives,” he said, adding that while “earthquakes are inevitable, the devastation they cause does not have to be.”

Earthquakes are among the deadliest natural hazards. In the first two decades of this century, earthquakes — and resulting tsunamis — were responsible for nearly 60 per cent of all disaster-related deaths. Yet it is not the shaking of the ground that causes most fatalities, but the collapse of homes, buildings and infrastructure that are not built to withstand seismic risk. This makes resilience building through better planning, enforcement of building codes, and stronger risk awareness essential in reducing earthquake deaths and economic losses.

The international day in memory of the victims of earthquakes provides an annual opportunity for remembrance and renewed commitment to protecting lives and livelihoods from earthquake disasters. It also reinforces the priorities of the Sendai Framework for Disaster Risk Reduction 2015-2030, which calls for understanding disaster risk, risk-informed planning, investing in resilience and enhancing preparedness to “build back better” after disasters.

Thanks to the UN Office for Disaster Risk Reduction for this report.

iol.co.za is reporting that Gift of the Givers activated its disaster response teams to provide aid on Thursday and Friday in the Northern Cape after severe hailstorms and flooding left communities vulnerable and homes damaged.

The humanitarian organisation confirmed it received requests for assistance from the Northern Cape Provincial Department of Cooperative Governance and Traditional Affairs (COGTA), the ZF Mgcawu District Municipality Disaster Management teams, and the Dawid Kruiper Municipality.

The hailstorms left a trail of destruction in the areas of Karos, Leerkrantz, and Lambrechtsdrift, causing property damage and heightening the vulnerability of residents already facing difficult conditions.

In a separate incident, the Kuruman Disaster Management Centre also requested aid after flooding damaged several homes in the Joe Morolong informal settlement, which falls under the John Taolo Gaetsewe District Municipality.

Gift of the Givers said: “Humanitarian aid distribution to affected families in both districts will commence tomorrow.

“Gift of the Givers has responded to multiple disasters in these regions over the past few years and maintains a strong working relationship with the Northern Cape Government and local disaster management centres.”

The ARRL is reporting that amateur radio operators will participate in the Department of Defence’s Armed Forces Day (AFD) Crossband Test on May 9, 2026. The annual event will not impact any public or private communications.

For more than 50 years, military and amateur stations have participated in this interoperability exercise between the amateur and government radio services. The AFD Crossband Test provides a unique opportunity to conduct two-way communication between military communicators and stations in the Amateur Radio Service (ARS). These tests present both opportunities and challenges for radio operators to demonstrate individual technical skills in a tightly controlled exercise scenario.

The National Association for Amateur Radio hails the Armed Forces Day Crossband Test as an example of the core principles of the US Amateur Radio Service, with its volunteers contributing technical proficiency and readiness in support of public service and national needs.

Military stations will transmit on selected military frequencies and will announce the specific ARS frequencies they are monitoring.

Amateurs affiliated will then reply to the transmissions on the frequencies the military stations are listening to, thus confirming the crossband interoperability.

Thanks to the ARRL for those details.

A nice article this week by Chris Warren, who calls himself Off Grid Ham, discusses the advantages of Near Vertical Incidence Skywave (NVIS), in filling in the gap between local communications and DX.

He notes that you can use whatever HF radio you’ve already got. As for antennas, a simple wire antenna will do. There is no need for towers, beams, or specialty hardware.

NVIS is simply sending a signal deliberately intended not to “skip” great distances. To send an effective DX signal, one must transmit at a low wide angle to the ionosphere. In NVIS, the signal is sent at a very sharp, acute angle, almost ninety degrees upwards. That’s where the “near vertical” part comes from. This is how NVIS works. By “throwing” the signal at an acute angle, it by nature will not travel as far.

NVIS is perfect for filling the gap between local VHF/UHF and DX. For those concerned with survival/preparedness/emergency communications, you probably will not have a need to run DX. But regional comms in the 500-800 km range would be practical and useful.

Since NVIS intentionally discourages DX transmissions, it also by default discourages DX reception. This translates into less noise and interference. It’s like having a built-in filter on your receiver. And antennas need only be simple long wires or dipoles mounted 0.1 to 0.25 wavelengths above ground to ensure an almost vertical radiation pattern and the short range comms.

Visit www.offgridham.com/2026/04/nvis-is-an-overlooked-jewel for the complete article.

I’d like to greet the SARL on the day after the Annual General Meeting and the Awards Banquet, and thank the outgoing Council for a year of hard work keeping us steered in the right direction. Then I’d also like to congratulate the new Council on their election, and welcome the new office bearers to their posts.

Finally I’d like to congratulate all the awards recipients who were recognized, particularly the HAMNET members, nominated for their service to amateur radio and to the community, and for their willingness to help where needed. These are the radio amateurs who possess true ham spirit.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.

Within a span of seven hours on Friday morning early, the Sun unleashed two powerful X-class solar flares, disrupting high-frequency radio communications across parts of the Pacific, Australia, and East Asia. The bursts, rated X2.4 and X2.5, coming from Active Region 4419 on the sun, are the strongest in over two months and signal heightened solar activity as the current cycle nears its peak

This rapid succession, just seven hours apart, is unusual and points to a highly unstable magnetic configuration. Such events occur when complex sunspot magnetic fields suddenly release stored energy, sending intense radiation across the solar system within minutes of eruption.

NOAA and space weather agencies are tracking the magnetically unstable region responsible for the flares. Clusters of strong flares often precede larger solar events, and if future eruptions are accompanied by coronal mass ejections aimed at Earth, they could trigger geomagnetic storms. Such storms have the potential to disrupt satellites, GPS, and power grids, prompting heightened preparedness among infrastructure operators.

Thanks to MSN.com for this summary.

Brian ZS6YZ, our National HAMNET Director tells me that he and Willem ZS6WIM attended a National Disaster Management Strategic Indaba at Emperors Palace, in Gauteng on Tuesday 14^th April 2026.. The Indaba covered an update on the Review of the Disaster Management System and planned interventions to get Disaster Management back on track.

Here in South Africa our weather patterns are becoming more severe and with devastating impact on communities. Disaster management needs to step up their efforts to reduce the impact on the communities by helping them to be better prepared. One of the ways is to provide early warning of approaching severe weather.

At the meeting, one of our colleagues from the Gauteng Provincial Disaster Management Centre presented an update on the Early Warning System that is being planned, noting that there would be a meeting soon, to continue the quest to find a solution.

An early warning system work in two ways:

Firstly, the weather services needs to know that is happening on the ground. The weather forecasters have access to weather radar systems that can provide them with an understanding of where a storm is and how severe it may be. They also have knowledge from previous storms of what to expect. However, they do not know what is happening on the ground in real time. In other countries such as the US, there is a Skywarn System where radio amateurs are trained to be storm spotters and provide real time information from the ground on the effects of the storm that is being seen on the weather radar.

Secondly, there needs to be a way for the communities who may be severely affected to be warned so that they can take the necessary precautions prior to the storm approaching them.

There are various ways that this can be done, including using the cellular broadcast facilities that are built into the GSM systems to disseminate information. The Weather Services also have Impact Based Warnings WhatsApp groups where forecasters and Disaster practitioners can exchange information. But, what happens if the cellular systems are down? What will plan B or C be?  Are there other technologies that can be deployed to assist with early warning systems? 

The other challenge is that the Government has lost a tremendous amount of knowledge, expertise and skills over the years, and they now look to volunteer organisations to assist them in filling the gaps.

This situation provides opportunities for communications specialists from HAMNET who have a varied knowledge base and who understand the inherent weaknesses of communications systems, to be able to partner with disaster practitioners to explore solutions that do not depend on commercial infrastructure.

On Saturday afternoon 18 April 2026, a small group of HAMNET Gauteng members met at the equipment container at the Brakpan airfield to discuss the use of technology in emergency communications. Brian delivered the presentation “Using Technology to provide effective HAMNET emergency communications” that was first presented at the 2026 National Technical Symposium. A discussion then took place on the importance of not only focussing on amateur radio digital modes, but on all technologies that could be used to pass information in the event of an emergency or disaster, be it wireless, microwave link, or even satellite services like Starlink. It is important that the best available technology be used, backed up by layers of alternate solutions that could be deployed should the primary solution fail or not be available.

Thank you for this summary of the communications associated with weather and the way forward, Brian.

wbng.com reports that a historic radio tower in Binghamton was used to connect with others around the world yesterday to commemorate the birthday of one of the inventors of radio.

Happening on Saturday, April 25, members of the Binghamton Amateur Radio Association (BARA) talked to amateur radio operators around the world using the historic Marconi Tower at 45 Lewis St.

The event commemorates the birth of Guglielmo Marconi, one of the inventors of radio, and is held annually on the Saturday closest to his actual birthday.

BARA operated using the tower from 9:30 a.m. to 4 p.m. local time, reaching out to stations worldwide that were operating at other historic sites related to Marconi’s life and career. This event has been happening in Broome County annually since 2017.

Binghamton’s Marconi Tower is the last of four towers, two built in Binghamton and two in Scranton, that were put up by Marconi in 1913 as part of a pioneering experiment that first demonstrated radio-communication with a fast-moving vehicle, specifically a train traveling between Scranton and Binghamton.

This is a final reminder now to you all to appoint a proxy for the Annual General Meeting taking place next week Saturday the 2^nd May. Please note that the SARL website will be offline on Wednesday the 29^th for scheduled maintenance, so, if you want to download that proxy form, do it today! Please send it back to the secretary by midnight on Wednesday. And note the SARL office will be closed all of the coming workdays this week, so you cannot direct enquiries to Admin before the AGM. Please be proactive.

This is Dave Reece ZS1DFR, wishing the attendees a useful AGM and a pleasant banquet next Saturday, and reporting for HAMNET in South Africa.

By 16 April at 03:00 UTC, Tropical Cyclone SINLAKU’s centre was located over the ocean approximately 144 km west of Alamagan Island, with maximum sustained winds of 185 km/h.

According to the Federal Emergency Management Agency (FEMA), a total of 1 080 people remain evacuated in 16 evacuation centres, 320 in the Northern Mariana Islands and 760 in Guam. Additionally, FEMA and media report power and water outages, particularly on Guam, Saipan, Rota and Tinian.

Over the next 48 hours, heavy to very heavy rainfall, strong winds and storm surges are forecast for most of the Northern Mariana Islands and Guam. A Typhoon Warning remains in effect for Rota, Tinian, Saipan, Alamagan, Pagan and Agrihan islands.

The US Coast Guard News advised mariners of outages in VHF radio communications coverage in the vicinity of Guam, Rota, Saipan and surrounding areas in the Commonwealth of the Northern Mariana Islands on Wednesday.

Mariners should anticipate reduced reception and transmission capabilities that may potentially impact distress and safety communications.

Remote fixed facility tower outages have impacted coverage around Guam, Rota, and Saipan, extending from coastal areas to 20 nautical miles offshore.

Joint Rescue Coordination Center Honolulu watch-standers issued a safety marine information broadcast and SafetyNET broadcast informing mariners of outages.

Meanwhile, Malaysia, Indonesia, Panama and Haiti are also all experiencing severe weather and flooding.

And you can take it from me that winter officially started on Friday the 17^th in the Western Cape. A powerful cold front arrived in the early morning, with lots of rain, with a large amount of cold Antarctic air behind it, resulting in snow being experienced in the Matroosberg mountains, and, according to snowreport.co.za, forecast for the peaks of Franschoek, Paarl, Worcester, De Doorns, Montagu, Ceres, Tulbagh, the Koue Bokkeveld and the Cedarberg, as well as the Swartberg mountains, for the weekend. Time for the thermal underwear indeed!

Meanwhile, the measles epidemic in children in Bangladesh is spreading, with 19161 cases hospitalized and 166 deaths reported. 22 million doses of vaccine are being distributed, and 943000 children under the age of 5 have been immunized so far. Vaccinate your children, people!

For those of you still suffering from the heat trapped inside your closed car parked somewhere, you’ll be excited to hear that a transparent radiative cooling film technology that dissipates heat directly to the outside without consuming electricity has been developed to reduce vehicle overheating during summer. The technology was validated through real-vehicle experiments conducted under diverse conditions—including different countries, seasons, and both parking and driving scenarios—and demonstrated the ability to lower cabin temperatures by up to 6.1°C and reduce cooling energy consumption by more than 20%.

The website phys.org says that Seoul National University College of Engineering announced that a research team has designed and fabricated a large-area Scalable Transparent Radiative Cooling (STRC) film applicable to vehicle windows. Through real-vehicle evaluations conducted under various climatic and driving conditions, the team demonstrated both energy-saving and carbon reduction effects.

This research was published online on February 4 in the journal Energy & Environmental Science.

Vehicles exposed to solar radiation in summer experience rapid increases in cabin temperature, resulting in substantial cooling energy consumption. Conventional automotive Low-E coatings and tinting films can partially block incoming solar radiation but fail to dissipate effectively heat already accumulated inside the vehicle, thereby limiting their cooling performance.

Radiative cooling technology, which has attracted attention as an alternative, simultaneously blocks incoming solar energy and emits internal heat to the outside, enabling passive cooling without electricity. However, most previously developed radiative cooling materials are opaque, making them unsuitable for application to vehicle windows, which are the primary entry points for heat.

To overcome this limitation, the research team developed a large-area transparent radiative cooling film with a multilayer structure that maintains over 70% visible light transmittance, reflects near-infrared solar radiation, and emits heat from the vehicle interior in the mid-infrared range. This film suppresses temperature rise inside the vehicle without consuming electrical energy and reduces the time required to reach thermal comfort, thereby minimizing energy consumption in electric vehicles.

Real-vehicle experiments conducted across different climatic regions—including Korea, the United States, and Pakistan—and under varying conditions such as summer and winter, as well as parking and driving scenarios, confirmed that vehicles equipped with the STRC film consistently maintained lower cabin temperatures under all conditions.

And in bad news for the vapers of the world, phys.org also reports that a study published in Analytical and Bioanalytical Chemistry by University of Technology Sydney (UTS) researchers showed that even short-term vaping at exposure levels below typical daily human use resulted in measurable accumulation of toxic metals in lung tissue—including lead, copper and nickel.

Lead researcher Dr. Dayanne Bordin, a lecturer in analytical chemistry, said the pre-clinical study provides the first evidence that e-cigarette aerosols include metal-containing (organometallic) species, including those associated with tin and mercury—forms that are often more bioavailable and biologically reactive than inorganic metals.

“From a risk perspective, the findings reveal under-recognized hazards associated with vaping,” she said.

“Metal emissions and their biological effects are rarely incorporated into current safety assessments or public understanding. Unlike cigarettes, which are relatively consistent products, e-cigarettes and devices are often manufactured with poor quality control involving materials and components with unknown toxicological relevance.

“The metal profiles observed are consistent with emissions from heating coils and electrical components, identifying the device itself as a critical source of exposure and highlighting important gaps in how vaping risks are evaluated.”

Dr. Bordin explains this is important because many people believe vaping carries less risk than conventional cigarettes. This perceived reduction in harm, along with misleading marketing campaigns, has contributed to the rapid uptake of e-cigarettes globally, particularly among younger demographics. In Australia, for example, e-cigarette use among young adults increased from 5.3% in 2019 to over 21% in 2023, with a similar rise in adolescents.

“Our findings challenge the assumption that e-cigarettes are safer and show how critical it is to review current vaping regulations, which should be expanded to include device-derived emissions, not just the e-liquid composition,” she said.

“Vaping can deliver toxic metals directly into the lungs, even after short-term use. This information is important for anyone considering vaping, especially young people, because these metal exposures are largely invisible and rarely discussed.”

Thank you to phys.org for this alarming report.

I hope I don’t need to remind you that increased levels of heavy metals in the body and the brain are associated with an increased risk, at an earlier age, of dementia.

This is Dave Reece ZS1DFR, having given up smoking in 1972, and thankfully never having tried vaping ever, and reporting for HAMNET in South Africa.

On Friday the 10^th, the Global Disaster Awareness Coordination System (GDACS) announced a Red Alert for Tropical Cyclone SINLAKU, travelling from South-east to North-west, and threatening the islands of Guam and the North Mariana Islands. With maximum wind speeds of 194 km/h, and as a category 3 hurricane, it was threatening 180000 people in its path. The maximum effect is expected to be felt on Monday the 13^th and Tuesday the 14^th of April, as SINLAKU first makes landfall over Guam.

In last week’s bulletin, I promised to share the other half of the report on the SASOL Marathon of 28^th March, received from Riaan Greeff ZS4PR, Divisional Director for HAMNET in the Free State. He wrote further:

”HAMNET acquired “Single Frequency Repeater” (SFR) Digital Mobile Radio (DMR) technology in the form of 3 repeaters and 20 hand radios for the race.  The principle of SFR is to make use of the 6.25kHz channels with 2 alternating timeslots and transmit AND receive simultaneously on the two RF channels at either timeslot 1(TS1) or timeslot 2 (TS2). 

“DMR is a digital radio mode utilizing Time Division Multiple Access (TDMA) modulation.  This feature allows a repeater network to be deployed systematically into areas of need fast and effectively. Only one frequency is used, so no cavity filters are needed.  The hand/portable radios are set to follow TS1 and TS2 in the two channels and seamlessly switch between simplex and repeater mode as the signal’s strength indicator is evaluated in real time.

“The Technical team set up three repeaters in a triangle around the route. This worked well. However, when all 15 radio users were active it became troublesome to decode the DMR signals.  On investigation, it was found that the two 6,25kHz TS1 and TS2 signals were creating heterodyning for the receiving radios.  The better way to set up three or more SFR units would be to deploy the repeaters in a straight line and not in a triangle/circle/looping arrangement.

“Why is this important for HAMNET? The Barberton aeroplane accident in 2025 highlighted the need to set up repeaters quickly and easily at local high sites.  A SFR is extremely portable, and an ordinary ham can set it up in 10 minutes. The handheld radios are issued to specialists on the ground to do their work. HAMNET provides the infrastructure to deploy the hand held radio capabilities with the SFR repeaters. SFR allows effective radio signal selection management and relays signals autonomously. “

Google tells me that “a Single Frequency Repeater is a digital radio device that extends communication range using only one frequency, rather than the two required by traditional repeaters. It works by using Time Division Multiple Access (TDMA) to receive a signal on one time slot and simultaneously retransmit it on the other time slot within the same 12.5kHz channel, eliminating the need for a duplexer and allowing for cost-effective coverage extension.

“The repeater receives a snatch of data in time slot 1 and immediately forwards it in time slot 2 (that is: 60-90 milliseconds later), enabling direct mode operations to extend range without needing to change frequencies, as is used in analogue communications. The timing is so fast that the listener cannot discern the very short breaks in the received signal. Effectively, the repeater is alternating between receiving and transmitting the signal every 60-90 milliseconds but on the same frequency.”

Furthermore, if the received signal from the sending station is strong enough, as monitored in the Received Signal Strength Indicator algorithm of the repeater, it will not be repeated, but allowed to pass directly. So the transmission proceeds in the least complicated manner.

Thank you, Riaan, for telling us of your experiments with this technology.

If you have ever worried about the efficiency of your car’s brakes, spare a thought for the Orion capsule astronauts, as they came in to splashdown at about 2am our time on Saturday morning. While still approaching our atmosphere, they were travelling at 11km per second, about 40000km/hour, 40 times faster than a typical passenger jet.

After smashing through the Earth’s atmosphere, travelling at more than 30 times the speed of sound, the spacecraft had to slow to a safe speed for landing.

As it crashed into the top of the atmosphere, the craft created a shockwave that saw the surrounding air reach temperatures of 10,000C or more. To keep humans inside safe, Orion’s heat shield is made of Avcoat, a mixture of silica, epoxy and resins that NASA also used for the original Apollo missions to the Moon.

After the initial shockwave, the heat shield experienced temperatures of around 2,700C as the crew module plummeted through the atmosphere on re-entry. The coating of 200 Avcoat tiles is just a few inches thick and is designed to burn away, transferring heat away from the spacecraft.

The astronauts then fell 122000 metres through Earth’s atmosphere and were completely out of communication with mission control as superheated plasma around the capsule disrupted radio signals.

During this descent, the crew experienced 3.9G’s, or nearly four times normal gravity. This means their bodies felt four times heavier than normal. Astronauts had to train to withstand these high G-forces on re-entry. As Orion slowed it started to cool and radio communications resumed.

At around 11000 metres, around the cruising altitude of a passenger plane, Orion opened its first of two sets of parachutes designed to slow it for the final landing. The main chutes opened at around 1800 metres, and at 900 metres they fully opened for a gentle landing.

After splashdown, a system of five airbags on top of the capsule inflated, turning Orion right side up if the capsule landed upside down.

Thank you to mirror.co.uk for that summary of events.

Finally, a reminder to all HAMNET members who are unable to attend the SARL Annual General meeting from the 1^st to 3^rd of May, to give your Proxy to vote to a HAMNET member near you who is attending. Download the Proxy Form at https://forms.gle/GeWRwJnT1aSzyZPw9, fill it in, and return it as instructed on the form. Thank you.

This is Dave Reece ZS1DFR, wondering if I should install a deployable parachute on the back of my little car to guarantee my ability to stop, and reporting for HAMNET in South Africa.