HAMNET Report 29th October 2023

The tropical cyclone belt is currently peppered with cyclones. Tropical Cyclone HAMOON is threatening 4.6 million people in Bangladesh, India and Myanmar, LOLA has already attacked the island of Vanuata, and the Solomon Islands, with 70000 people in danger, and NORMA has damaged the west coast of Mexico, affecting about 400000 people.

On Tuesday of this week, a new one arose in the Eastern Pacific, again threatening more than a million people on the west coast of Mexico with over 200km/h winds, and called OTIS.

The IARU Region 2 issued a statement on Wednesday, saying that, in the early hours of Wednesday, October 25, some states of Mexico with Pacific coasts received the impact of intense Hurricane Otis.

OTIS made landfall over the area of the coastal city of Acapulco, central Guerrero State, southern Mexico on 25 October around 6.25 UTC, with maximum sustained winds of 270 km/h as a Category 5 Hurricane, the strongest ever measured there.

By Thursday, 27 fatalities in Acapulco had been reported. Parks, buildings and streets were damaged, roofs ripped off homes and hotels, and all communications were interrupted, as were electricity supplies. OTIS wrecked the airport’s control tower, preventing all air traffic from arriving or leaving.

Due to the severe impact of the storm, communications in the area collapsed completely, posing challenges to government, emergency and first responder agencies working to assess the extent of damage and impact on residents of the area. Initial reports from the Mexico Defence Ministry indicate both ground and air travel is unavailable.

For the work carried out there by the emergency networks of the Mexican Federation of Radio Experimenters and the Association of Radio Amateurs of the Mexican Republic, they are requesting the protection of the following frequencies:

80m band: 3690 kHz
40m band: 7060 kHz and 7095 kHz.                                                                              
20m band: 14 120kHz

They would appreciate the protection of those frequencies to facilitate emergency communications for Mexican colleagues.

The communique was signed by Carlos CO2JC, IARU Region 2 emcomm coordinator.

The ARRL’s hurricane watch net was also activated at the National Hurricane Centre WX4NHC, on Wednesday, monitoring the frequencies of 14.325MHz and 7.268MHz, Winlink reports, and using the VoIP hurricane net.

Phys.org tells us this week that some 30 years ago, a young engineer named Christopher Walker was home in the evening making chocolate pudding when he got what turned out to be a very serendipitous call from his mother.

Taking the call, he shut off the stove and stretched plastic wrap over the pot to keep the pudding fresh. By the time he returned, the cooling air in the pot had drawn the wrap into a concave shape, and in that warped plastic, he saw something—the magnified reflection of an overhead lightbulb—that gave him an idea that could revolutionize space-based sensing and communications.

That idea became the Large Balloon Reflector (LBR), an inflatable device that creates wide collection apertures that weigh a fraction of today’s deployable antennas. Now, with the assistance of NASA’s Innovative Advanced Concepts (NIAC) program, funded by the agency’s Space Technology Mission Directorate, which supports visionary innovations from diverse sources, Walker’s decades-old vision is coming to fruition.

The concept turns part of the inside surface of an inflated sphere into a parabolic antenna. A section comprising about a third of the balloon’s interior surface is aluminized, giving it reflective properties.

With NIAC funding, and a grant from the U.S. Naval Research Laboratory, Walker was able to develop and demonstrate technologies for a 10 metre LBR that was carried to the stratosphere by a giant balloon. For comparison, the aperture of NASA’s massive James Webb Space Telescope is only 6.5 metres in diameter.

“There was no place other than NIAC within NASA to get this off the ground,” says Walker, now an astronomy and optical engineering professor at the University of Arizona in Tucson. “At first, I was afraid to share the idea with colleagues because it sounded so crazy. You need a program within NASA that will actually look at the radical ideas, and NIAC is it.”

Parabolic dish antennas use their concave shape to capture and concentrate electromagnetic radiation. The larger the antenna’s diameter, or aperture, the more effective it is for capturing light or radio waves and transmitting radio signals over great distances.

In astronomy, there is a tremendous advantage to placing telescopes above the Earth’s atmosphere, because it tends to distort or degrade signals coming from space. The challenge is that traditional large reflector antennas are heavy, unwieldy, and difficult to stow, leading to launch constraints and risky in-space deployment schemes.

The LBR design solves both problems. Made of a thin film structure, it inflates like a beachball, providing a [lightweight] stable parabolic-dish shape without the need for bulky and complex deployable hardware, and can fold into a tiny volume.

It might be difficult to believe this all started because a young engineer’s idea of dinner one evening was what most would consider dessert. Then again, one could say the proof was in the pudding.

Meanwhile the International Space Station will be transmitting SSTV images before and after this weekend, to test some replacement hardware astronauts install on Monday and Tuesday.

Since Friday, postcards from the Service module have been transmitted, but there will be a hiatus on Monday and Tuesday to do the work. More images will be transmitted from 12 midday our time on Tuesday, until 8pm on Wednesday night, once the installation is complete, and to test the system.

The downlink frequency is 145.800 MHz, and the format will be the typical PD120 type. You should be able to receive the pictures on a handheld radio with a quarter wave whip, using normal 25KHz spaced FM. Amateurs in South Africa have been sharing their downloaded images on the HamSats whatsapp group this weekend.

This is Dave Reece, ZS1DFR, hoping you enjoyed the rugby final, no matter the outcome, and reporting for HAMNET in South Africa.

HAMNET Report 15th October 2023

Well, Tropical Cyclone KOINU still isn’t off the map. In spite of the original forecast that it would affect the Chinese coastline only, KOINU has dumped large amounts of rain over Taiwan, Northern Philippines, and Southern Japan. As of Wednesday, 3.7 million people were still in its path.

And a new one has developed off the Pacific coast of Mexico, travelling towards Mexico, called LIDIA, with maximum forecast wind speeds of 167km/h, and threatening 842 thousand people in its path. When it crossed the Mexican coast on Wednesday however, travelling north-east, wind speeds of 204km/h were measured.

Brian Jacobs, ZS6YZ, Deputy National Director of HAMNET, has reminded me of the Great ShakeOut, which is the world’s largest earthquake drill. It is held annually on the third Thursday of October, and millions of people participate all over the world. In 2022 over 45.6 million people registered their participation. The goal of the ShakeOut is to teach people how to protect themselves during an earthquake.

Great ShakeOut Earthquake Drills across the U.S. are coordinated by the Southern California Earthquake Center in partnership with ECA, CUSEC, state and national emergency management partners, with support from FEMA, NEHRP, NSF, and USGS.

The ShakeOut drill is simple. At the designated time (or whenever works for you or your organization), participants practice self-protective actions such as “Drop, Cover, and Hold On” or “Lock, Cover, and Hold On” if they use a wheelchair. You may want to register your group for the Great ShakeOut. Registrants will receive a certificate of participation from the ShakeOut organization.

The US Geological Survey (USGS) and Winlink are collaborating to provide “Did you feel it?” (DYFI) earthquake intensity reports via Winlink. SHARES and Amateur Radio Operators are therefore invited to send an EXERCISE Winlink “Did you feel it?” (DYFI) message to the USGS during Shakeout! In real events Winlink DYFI ground truths contribute to USGS earthquake intensity assessments and event response products, like PAGER. The PAGER system provides fatality and economic loss impact estimates following significant earthquakes worldwide and is used by governments, agencies, NGOs, private companies and citizens.

The third Thursday of October is this coming 19th, so please consider practising the sending of a notification, even if only in practice, to your local radio agency using Winlink if you can, announcing whether you imagine you “felt it”!

 Consider conducting local radio nets or functional radio exercises to test your group’s preparedness.

The ShakeOut is also an opportunity to learn more about earthquake preparedness. Participants can learn about the different types of earthquakes, how to create an earthquake safety plan, and how to make their homes and businesses more earthquake-resistant.

The Great ShakeOut is a great way to get ready for an earthquake. Many preparedness lessons from the Great ShakeOut also apply to floods, fires, landslides and other disasters. It is also a chance to connect with your community and learn how to help others in the event of an earthquake or other disaster.

Thanks, Brian, for the reminder.

This weekend has seen an annular solar eclipse, visible in large parts of North and South America. In that the distance from the moon to the earth varies, it sometimes happens that the moon is not “big” enough to block out the sun completely, and so a ring eclipse happens, also known as an annular eclipse.

Writing in sciencefriday.com, Emma Lee Gommetz notes that, while people across the eclipsed countries donned eclipse glasses and turned their gaze skyward for Saturday’s eclipse, amateur radio operators would have been heading to their transmitters. 

Eclipses have a documented effect on a layer of free-floating ions around the Earth, called the ionosphere. During the day, the sun’s ultraviolet rays and X-rays knock electrons off of their positive counterparts, separating the atmosphere into layers of charged particles. At night, the particles find their way back to one another and neutralize. When the ionosphere has a high density of electrons as a result of sunlight, radio signals (especially those at lower frequencies than those your typical radio station uses) can bounce off it and travel a great distance. But during an eclipse, darkness is focused onto specific places on Earth—neutralizing just a section of the atmosphere for a period of time. This means that eclipses, like weather and solar flares, can affect how radio works. But just how they affect it is unclear.

“We understand, on average, what the atmosphere is supposed to look like day compared to night, or June compared to January,” says Dr. Nathaniel Frissell, WA2NAF, a QSO party host and assistant professor at the University of Scranton. “But a lot of the small scale features, or the short time duration features, we just don’t have a good handle on,” he says. That’s where ham radio comes in.

During QSO parties, radio operators communicate with as many other stations as possible to see who can establish the highest number of connections, called “spots,” within a given time period. Thousands of radio connections can occur all over the country in one day. This high volume, and the fact that ham radio operators use a variety of frequencies, helps researchers pinpoint the locations where an eclipse is affecting radio contact. 

During the 2017 total eclipse, ham radio data showed that spots at a certain frequency (14 megahertz) started dropping out right as the path of totality passed over their midpoints. That data came from a NASA-funded QSO party that Frissell organized, and research based on the event showed that radio connections changed as a result of the eclipse.

Understanding how changes in the ionosphere impact different radio frequencies could help radio users better perform essential communications at distances across the world. “Ham radio operators, emergency responders…ships at sea, aircraft that are going over polar regions, they’re going to have radios that are equipped with these lower frequencies,” Frissell says. 

The fact that the eclipse was not visible from South Africa did not detract from the value of data collected by ZS stations, because our contacts with other stations in other countries could have failed to refract from the ionosphere at a point where the sky was dark. So any or all data is valuable to such research.

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

HAMNET Report 8th October 2023

By last Monday, GDACS was posting a red level warning for Tropical Cyclone KOINU, directed towards the Chinese mainland, and placing 10 million people in the path of winds of at least 120km/h. Travelling in a north-westerly direction, the cyclone had a chance of crossing the southern-most tip of Taiwan, before hitting the Chinese coast, east of Hong Kong, on about Saturday the 7th.

Very heavy rainfall was forecast over the whole island of Taiwan between 4th and 8th October, as well as over northern Luzon and Batanes islands in the Philippines.

Fortunately, by Wednesday, the alert level had been downgraded to an orange warning, and the number of people threatened by dangerous winds halved.

Nevertheless, heavy rain was forecast to start falling over south-eastern China from yesterday (Saturday).

And Tropical Storm PHILIPPE has been drifting slowly towards the Lesser Antilles Islands, and was due to pass east of Bermuda early yesterday morning, with sustained winds of about 110km/h. Heavy rainfall was predicted for the entire group of islands in its path.

On Tuesday the 3rd, a series of four strong earthquakes struck north-western Nepal, the strongest being of magnitude 6.2. Several milder aftershocks followed. About 400 houses were damaged or destroyed, and the quakes are thought to be partly the cause of damage to a hydroelectric plant’s dam in the north-eastern Sikkim state of India. Heavy rain and flash floods in the catchment area of that dam occurred at the same time as the earthquake over the border. News of casualties is slow to reach the provincial capital in Nepal, due to the remote location of the earthquakes.

And, while I am writing this news has come in of 4 earthquakes in Afghanistan of magnitude 6 or greater, and two 6.7 earthquakes in Papua New Guinea on Saturday morning. The earth under our feet is restless.

The Federal Emergency Management Agency (FEMA), in coordination with the Federal Communications Commission (FCC), conducted a nationwide test of the Emergency Alert System (EAS) and Wireless Emergency Alerts (WEA) on 4th October.

The national test was to consist of two portions, testing WEA and EAS capabilities. Both tests were scheduled to begin at approximately 2:20 p.m. ET on Wednesday.

The WEA portion of the test was to be directed to consumer cell phones. This was the third nationwide test, but the second test to all WEA-compatible cellular devices. The test message was displayed in either English or in Spanish, depending on the language settings of the wireless handset.

The EAS portion of the test was to be sent to radios and televisions. This will be the seventh nationwide EAS test.

FEMA and the FCC were coordinating with EAS participants, wireless providers, emergency managers and other stakeholders in preparation for this national test to minimize confusion and maximize the public safety value of the test.

The purpose of the test was to ensure that the systems continue to be an effective means of warning the public about emergencies, particularly those on the national level.

This is a very valuable ability on FEMA’s part, one which we should be investigating in this country.

Interestingengineering.com reported this week on an interesting, tiny satellite made by Estonian students which will soon be launched into space with a big mission: to test a novel technology that could help clean up the space junk orbiting our planet.

The satellite, called ESTCube-2, is the size of a shoebox and weighs only 4 kg. It was to hitch a ride on Europe’s Vega VV23 rocket, scheduled to lift off last week from Europe’s Spaceport in French Guiana.

The main goal of ESTCube-2 is to demonstrate the ‘plasma brake’ concept, a type of electric sail (E-sail) that uses a long, thin wire to interact with the charged particles in space.

The plasma brake was invented by Pekka Janhunen of the Finnish Meteorological Institute (FMI), who envisioned it as a way to explore the Solar System without fuel. By deploying a wire that is positively charged by a solar panel, a spacecraft could harness the force of the solar wind, a stream of protons and electrons that flows from the Sun.

However, near Earth, where the planet’s magnetic field blocks the solar wind, the plasma brake can do the opposite: it can slow down a satellite by repelling the plasma in the ionosphere, an electrically active layer of the atmosphere. This would cause the satellite to lose altitude and eventually burn in the atmosphere, avoiding becoming space debris.

As per the ESA’s press release, the plasma brake could offer a cheap and straightforward solution to deorbit satellites at the end of their lives, reducing the risk of space collisions and clutter. It could also remove existing debris by attaching it to them with a robotic arm or a harpoon.

ESTCube-2 will test this idea by deploying a 50-meter-long wire made of four aluminium strands, each as thin as a human hair. A 3-watt solar panel will charge the wire, creating a 100-volt potential difference with the surrounding plasma. The satellite will measure the force and the current generated by the wire and its effect on the orbit.

The wire is designed to be resilient against micrometeorites and other hazards that could snap it. It has a net-like structure with two parallel and two zigzagging wires that are bonded together.

Certainly, an idea that has been very well conceived. Let’s hope it works just as well.

Reuters.com reports that the flooding that killed thousands in Libya’s city of Derna last month damaged the ruins at the ancient Greek city of Cyrene in the mountains nearby, but it also revealed new archaeological remains there by washing away earth and stones.

The flooding caused mud and rubble to pile in Cyrene’s Greek-era baths that will require specialised clearing said local antiquities department official Adel Boufjra.

While causing great damage to the picturesque ruins at Cyrene, known locally as Shehat and a draw for travellers since the 18th century, the water has also washed clear a previously unknown Roman drainage system, Boufjra said.

“The flooding has revealed a new site – a water canal that I believe dates back to the Roman era. It is a distinctive discovery for the city,” he said.

Cyrene was a Greek colony and one of the principle cities of the ancient Hellenic world before becoming a major centre under the Romans until an earthquake destroyed it in the year 365.

One of Libya’s five UNESCO World Heritage sites, along with the extensive Roman ruins overlooking the Mediterranean at Sabratha and Leptis Magna, Cyrene’s stone pillared temples stand on a fertile hillside near rocky crags.

It is nice to know that, out of disaster, can sometimes come positive developments one might otherwise never have discovered.

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

HAMNET Report 1st October 2023

Oh gosh, here’s another Tropical cyclone, this one called KOINU, with maximum wind speeds currently measured at 205km/h active in the north-west Pacific, and threatening about 2 million people in coastal China. It was first announced yesterday and called JENNY by the Philippines, past which it hopefully will slide. It is also forecast to miss Okinawa, so China remains its main target.

It goes without saying that the Western Cape Local Government disaster management centre was activated after last Sunday and Monday’s cut-off low pressure cell produced a rain storm of huge proportions. All districts of the province were severely affected by the rain and stormy conditions, where upwards of 170mm of rain fell in 24 hours. Some 80 roads, passes and bridges were washed away, and, a week later, a large proportion of them haven’t been reopened yet.

Large areas are without water-supplies, ironically enough, after washaways destroyed water supply infrastructure, and electricity supplies were even more erratic than loadshedding already made them.  Masses of holidaying people, who had left the Peninsula to visit areas along the southern Cape Coast over the long weekend couldn’t get back for work or school on Tuesday, and national braai day didn’t happen at all in the Western Cape.

Sadly 15 deaths were reported, but many more rescues were effected, so the emergency organizations are to be congratulated on their excellence over the weekend. Luckily the cut-off low pressure cell was identified and the correct warnings and forecasts made. An estimate of the cost of restoration has, to my knowledge, not yet been made.

By Tuesday, the disaster response of the Western Cape Government to the recent severe weather had shifted from saving lives to recovery and humanitarian aid coordination. And by this weekend, Hermanus had decided to cancel its famous whale festival weekend, because large areas of the town are still without water or electricity!

HAMNET was not formally activated during the rain and flooding, though we have a seat at the disaster management centre during provincial activations.

Now, here’s a report back on last week’s successful arrival of material from the Asteroid BENNU. After travelling 3.86 billion km in a circuitous sort of way back from Bennu, the satellite OSIRIS-Rex dropped its heat-shielded capsule off on the desert floor in Utah, but three minutes ahead of time at 14h52 UTC last Sunday afternoon! After 3.86 billion km, I guess we can forgive OSIRIS-Rex for being a bit off schedule. The 250 grams or so of asteroid material will eventually get to the Johnson Space Centre, before being divvied up and sent to scientists around the world for study. This material is thought to be 4.5 billion years old.

Meanwhile, OSIRIS-Rex fired its rockets to avoid colliding with earth, has changed its name to OSIRIS-APEX, and is now on its way to an infamous asteroid called APOPHIS, which it will reach in 2029. In that year, APOPHIS will come within 31600km of earth, with no chance whatsoever of colliding with us, so please don’t have sleepless nights about it. The satellite will orbit and study APOPHIS for a year and a half.

What a remarkable feat of engineering and navigation!

Writing in TechXplore, Peter Wharton says that his researchers have designed a robot which can change form to tackle varying scenarios.

The team at the University of Bristol and based at the Bristol Robotics Laboratory have built a tetrahedron shaped robot with flexible piping known as Tetraflex that can move through small gaps or over challenging terrain. It can also encapsulate fragile objects (such as an egg) and transport them safely within its soft body.

The findings, (“Tetraflex: A Multigait Soft Robot for Object Transportation in Confined Environments,” published in IEEE Robotics and Automation Letters), show that the Tetraflex robot is capable of locomoting in multiple different ways. This makes the robot potentially useful for mobility in challenging or confined environments such as navigating rubble to reach survivors of an earthquake, performing oil rig inspections or even exploring other planets.

The object transport capability demonstrated also adds another dimension to potential applications. This could be used to pick up and transport payloads from otherwise inaccessible locations, helping with ecological surveying or in nuclear decommissioning.

Lead author Peter Wharton from Bristol’s School of Engineering, Mathematics and Technology explained, “The robot is composed of soft struts connected by rigid nodes. Each strut is formed of an airtight rubber bellow and the length of the strut can be controlled by varying the air pressure within the bellow.

“Higher pressures cause the bellow to extend, and lower pressures cause it to contract. By controlling the pressure in each bellow simultaneously we can control the robot’s shape and size change.

“After this, it was simply a matter of experimenting with different patterns of shape change that would generate useful motions such as rolling or crawling along a surface.”

Their design uses soft struts which can change length freely and independently. By changing the lengths of the struts by the right amount and in the right sequence, they can generate multiple different ways such as rolling or crawling, change the size of the robot, and even envelop and transport payloads.

Peter said, “I would say these capabilities are a natural consequence of working with such a versatile structure and we hope that other interesting capabilities can be developed in the future.

“The most exciting aspect of this study for me is the versatility of Tetraflex and how we might be able to use these robots to explore challenging terrain and achieve tasks in areas humans cannot access. The multiple gaits available to Tetraflex and object transport capability show this versatility well.”

After exploring some capabilities of Tetraflex in locomotion and object transport, the team now plan to apply machine learning algorithms which could allow them to explore movement patterns really thoroughly, as well as optimizing their current ones.

Peter added, “There could be some really creative and effective ways of moving around or interacting with the environment that we haven’t yet discovered.”

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