HAMNET Report 3rd March 2024

HAMNET Western Cape participated in the blackout exercise arranged by the Western Province Disaster Management agency, on this past Friday morning. The scenario was to be a progressive failure of all electrical power to the province’s communications systems with its outlying areas, at the same time tasking departments with keeping contact with their peripheral offices using less and less resources.

So the first stage involved keeping contact with regional agencies in Beaufort West, George, and the Overberg, using only cell-phone systems. The second allowed contact only by landline telephone, as electricity failed, and the third by radio only, as internet, landline and cell towers progressively failed.

For this third stage HAMNET was their only means of communication. We had previously tested the bands (last Sunday morning in fact), and found 40 metres to be the most reliable between about 9 and 10am, provided the sun played along of course and didn’t kill HF communications. Some 14 stations from around the province had called in last Sunday during our tests and proved to have good signals on 40 metres between each other. Although many stations had good signals on 60 metres as well, we at the JOC at Tygerberg Hospital running ZS1DZ found our antenna not to resonate well on 60, and received and gave low RS signal reports on 60.

Happily, on Friday morning the K index was dropping at the time of the exercise, and was 2 at the time of our tests, so all went well. At about 09h45, all systems failed, in the scheme of the exercise, and ZS1DZ was faced with several anxious departments wanting messages to be conveyed to their outlying agencies. All messages were successfully sent, though those to George needed to be relayed via ZS1L’s home station in Gordon’s Bay, and the organizers of the exercise were impressed at how quickly and effectively HAMNET functioned.

ZS1DCC, the equivalent Ops station of the City of Cape Town was also activated, though not needed to distribute messages, and we had a chance to try out our 5GHz microwave digital link between the two stations, sending keyboard to keyboard messages, pictures, and a unilateral video and audio stream from DCC to DZ, which was very clear. The distance between the two stations, as the crow flies is about 5km, and our microwave link is private and free of QRM.

All in all it was a successful exercise, and Michael ZS1MJT thanks all operators from around the province, who called in, and then acknowledged the messages sent to them, from the organizers of the event.

In a good news story from New Zealand, Amateur Radio Emergency Communications assisted in the search for a 72 year old man, who had gone hiking this last Monday in the Taruarua Ranges. Last seen at 4pm local time on Monday the 26th, he was found alive just before 7pm Wednesday evening by family who were helping the search in the Ohau Gorge. He was airlifted to Palmerston North Hospital.

Inspector Ashley Gurney said: “We are so pleased to be able to share this news.

“Obviously he has been through quite an ordeal after spending close to three days in the Ranges, but the community rallied together determined for him to return home, and he will.”

Police, land search and rescue, search dogs and a team from Amateur Radio Emergency Communications had assisted with the full-time search. Private helicopters, as well as a Royal New Zealand Airforce chopper, supported the operation from the air.

Police have thanked everyone who gave their time and expertise to the rescue mission. The man is receiving medical care and is being supported by his family.

Thanks to newshub.co.nz for that report.

My favourite volcano, named Popacatepetl, located in the States of Puebla, Morelos, and Mexico, central Mexico erupted on 27th February and the ash plume reached up to 2,000 m above the crater. 

According to Mexico’s National Centre for Prevention of Disasters (CENAPRED), a tiny ash fall was reported across several Municipalities in the States of Morelos, Tlaxcala, Mexico City, and Mexico. In addition, media report the cancellation of more than 20 domestic and international flights.

The authorities raised the alert level to 2, and recommended inhabitants to respect the exclusion radius of 12 km around the crater, because it is unsafe to be within this area.

Popacapetl last erupted in December 2018, so has been relatively dormant.

For my last story I was going to tell you of evidence found of phonon chirality from impurity scattering in the antiferromagnetic insulator strontium iridium oxide, but thought that would probably be too low-brow for you all.

Instead I will tell you that Phys.org says that a team of chemists and engineers affiliated with several institutions has found an electrolyte solution that can be used to reduce the recharging time of lithium-ion batteries while allowing battery capacity to remain comparatively high even at low temperatures.

In their paper published in the journal Nature, the group describes the new electrolyte and how well it worked during testing. Chong Yan and Jia-Qi Huang with the Beijing Institute of Technology have published a News and Views piece in the same journal issue, outlining the work done by the team on this new effort.

As Yan and Huang note, lithium-ion batteries have proven their usefulness in a wide variety of applications, but that does not mean there is no room for improvement. One improvement that users of battery-powered devices would like to see is faster recharging. They would also like to see improvements in battery capacity as temperatures drop during the winter months. In this new study, the research team found an electrolyte solution that they claim reduces charging time while also preventing loss of capacity when exposed to cold temperatures.

In their work, the team working in China found that the use of organic solvents could greatly improve the mobility of ions in a battery electrolyte, allowing for faster charging. They noted that such solvents could also be used to prevent loss of capacity in temperatures as low as -80°C.

In their work, the team used a solvent called fluoroacetonitrile, which has molecules that are much smaller than those typically used to make the electrolyte. The molecules of the solvent tend to surround the lithium ions, forming a shell. As the shells touch, they form a sort of tunnel, allowing the ions to move more quickly through the electrolyte.

Testing showed ionic conductivity approximately four times that of standard batteries. They also found that putting their test batteries in a freezer did not reduce their capacity.

This is actually very good news, because it will improve the efficiency of lithium ion batteries hugely.

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