At the beginning of this report, and it being Remembrance Sunday, I should pause to reflect on those special people, both Radio Amateurs and signalers all across the world, who have lost their lives in the course of their duties. I hope and trust that their endeavours were never in vain, and that they shall not be forgotten.
An earthquake that struck Nepal last weekend, with magnitude 6.4, affecting the Karnali Province in southern Nepal, has turned out to have resulted in 157 fatalities, of which 82 were children. Another 349 people were injured, and 10000 displaced. 17740 houses were destroyed, and another 17127 partly damaged.
The Nepal Humanitarian Country Team estimate that 1.3 million were exposed to the shaking, and that 250000 people are still in need of assistance. Will it come before the next humanitarian disaster strikes that part of the world, I wonder.
HAMNET Western Cape is busy renovating and repurposing a horsebox-like trailer, acquired from a source in Division Six, with a view to equipping it with the necessary power infrastructure, coaxial cables, working surfaces, radios, antennas, solar panels, computers and screens, to become a fully operational mobile Emergency Operations Centre, which can be moved to wherever it is needed.
It is tall enough to stand up in, and can host at least three operators comfortably in chairs at desks built in. Its side wall flaps up like an awning to provide shelter to anyone standing next to it during bad weather, but a door has been cut into that awning, so that it doesn’t always have to be flapped up if not needed. It has been repainted with very weatherproof paint in a white colour, and will have suitable logos and identification from above, so that it will stand out at an event, and for helicopters from above.
A work party was held yesterday, to lay out the wiring from battery, mains, solar and generator sources, as well as reconnecting the trailer’s backlights to the 7 pin socket on the towing vehicle. A small group of HAMNET members has formed the trailer working group, under the command of Sybrand Cillie, ZS1L, the Deputy Regional Director of HWC.
Here’s some interesting technology described by TechXplore.com. Most anyone who’s used noise-cancelling headphones knows that hearing the right noise at the right time can be vital. Someone might want to erase car horns when working indoors, but not when walking along busy streets. Yet people can’t choose what sounds their headphones cancel.
Now, a team led by researchers at the University of Washington has developed deep-learning algorithms that let users pick which sounds filter through their headphones in real time. The team is calling the system “semantic hearing.” Headphones stream captured audio to a connected smartphone, which cancels all environmental sounds.
Either through voice commands or a smartphone app, headphone wearers can select which sounds they want to include from 20 classes, such as sirens, baby cries, speech, vacuum cleaners and bird chirps. Only the selected sounds will be played through the headphones.
The team presented its findings on 1st November at UIST ’23 in San Francisco. In the future, the researchers plan to release a commercial version of the system.
“Understanding what a bird sounds like and extracting it from all other sounds in an environment requires real-time intelligence that today’s noise-cancelling headphones haven’t achieved,” said senior author Shyam Gollakota, a UW professor in the Paul G. Allen School of Computer Science & Engineering.
“The challenge is that the sounds headphone wearers hear need to sync with their visual senses. You can’t be hearing someone’s voice two seconds after they talk to you. This means the neural algorithms must process sounds in under a hundredth of a second.”
Because of this time crunch, the semantic hearing system must process sounds on a device such as a connected smartphone, instead of on more robust cloud servers. Additionally, because sounds from different directions arrive in people’s ears at different times, the system must preserve these delays and other spatial cues so people can still meaningfully perceive sounds in their environment.
Tested in environments such as offices, streets and parks, the system was able to extract sirens, bird chirps, alarms and other target sounds, while removing all other real-world noise. When 22 participants rated the system’s audio output for the target sound, they said that on average, the quality improved compared to the original recording.
In some cases, the system struggled to distinguish between sounds that share many properties, such as vocal music and human speech. The researchers note that training the models on more real-world data might improve these outcomes.
Thank you to Phys.org for bringing that post to our attention.
I was going to start the bulletin off by warning you of the rogue white dwarf star WD 0810-353 which is due to hit our solar system. This latest scare came about in 2022 when astronomers Vadim Bobylev and Anisa Bajkova analysed the data sent back by ESA’s Gaia space observatory, which was launched in 2023. By studying the shift in the spectrum of the white dwarf star WD 0810-353 in the constellation of Puppis 36 light-years away, they calculated that the star was on a collision course with our solar system.
Since the rogue star will only pass within 31,000 AU (4.6 trillion km) of the Sun, this doesn’t seem much to lose sleep over, but that distance means it will pass through the Oort cloud, which is home to icy objects only kept in position by the tenuous grip of the distant Sun. When something like a rogue star passes through it, it can dislodge these objects and send them into the inner solar system.
Long story short: it could cause a rain of comets and asteroids, like the one that may have killed off the dinosaurs.
Taking new spectra of the rogue star confirmed that the first calculations hadn’t taken into account the powerful magnetic field of the star. Such fields can distort a spectrogram, spreading out the spectral lines and shifting them into new wavelengths. In the case of WD 0810-353, it made it look as if it was coming our way. By correcting the spectrum using a polarizing filter, a more accurate calculation was possible, which showed that the first estimate was more than a little bit off.
“We found that the approach speed measured by the Gaia project is incorrect, and the close encounter predicted between WD 0810-353 and the Sun is actually not going to happen,” says Stefano Bagnulo, an astronomer at Armagh and co-author of the study.
So I moved this item to the bottom of the bulletin instead. Oh, and by the way, it was only due to affect our solar system in 29000 years, so there is still time to take in the washing and bath the baby.
This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.