HAMNET Report 17th October 2021

As Hurricane season continues in the lower latitudes, we have two tropical cyclones to mention this week.

One is Tropical Cyclone KOMPASU, which headed across the South China sea, brushed the top of the Philippines, and went westwards directly into the coast of Vietnam this week. Forecasts predicted it would cross the coast of Vietnam on Thursday the 14th at 06h00 local time.

The other is Tropical Cyclone PAMELA, which was travelling innocuously up the West coast of Mexico, until Tuesday this week, when it turned north-eastwards, and crossed the Mexican coastline on Wednesday at roughly midday, with wind speeds of the order of 120 km/h. It is threatening the safety of about 130 000 people in its path.

The Global Disaster Alert and Coordination System has been reporting regularly on both these storms, but has not made mention of casualty numbers or structural damage, so hopefully they will soon pass into history.

Sotirios Vanikiotis SV1HER, the National Emergency Communications Coordinator for IARU Region One in Greece, reported this week, that another large 6.4 magnitude earthquake hit the Greek island of Crete on Tuesday the 12th, and a tsunami warning had been issued.

The quake struck the east coast of the island at a depth of 10km under the village of Palekastro, according to the US Geological Survey. The village is 84km from Agios Nikolaos, which is a popular destination.

It comes three weeks after an earlier tremor killed a man on the island and damaged hundreds of buildings.

The quake struck the east coast of the island at a depth of 10km. Crete’s deputy regional governor, Yiannis Leondarakis, said the quake was felt ‘all over the island’

There were no immediate reports of serious damage or injury after Tuesday’s earthquake, which, according to the Geodynamic Institute in Athens, was followed by aftershocks measuring 4.1 and 4.6 in magnitude. Authorities said police and fire crews were checking buildings in eastern Crete for damage.

In the ARRL Newsletter of the 14th, there is a write-up after that successful ARISS contact by hearing impaired school children with the ISS. It states:

“Ten students at the Mary Hare School for deaf children in the UK took part in what appears to have been a world-first event for Amateur Radio on the International Space Station (ARISS). Facilitating the late-morning direct contact with astronaut Mark Vande Hei, KG5GNP, at NA1SS were ARISS-UK volunteers and members of the Newbury and District Amateur Radio Society (NADARS).

“The ground station used the call sign GB4MHN. ARISS-UK volunteers handled the technical aspects, while NADARS members provided students with the “amateur radio experience” through events and activities.

“Students asked their questions orally, and the astronaut’s replies — as well as questions and answers posed by the audience before the contact began — were displayed in closed caption format beneath a huge video screen.

“The Mary Hare School is an aural school for the deaf that teaches students to develop lip-reading skills and to make use of technology. Students range in age from 5 through 19 years old. An enthusiastic audience of some 250 individuals was in the auditorium, where the contact took place, while another 600 students at other locations in the school observed the contact via a web feed.

“Leading up to the contact, students at the school learned about radio- and space-related topics that touched on physics, chemistry, and biology. Student activities have included designing and flying model rockets, making astronomical observations, and observing authentic spacesuits.

“Students wanted to know if the astronauts used sign language in space in case something goes wrong, how the ISS would be evacuated in the event of a fire, and whether mobile devices such as cell phones work in space.”

Thanks to the ARRL for this report.

It is very gratifying to note that even those with hearing impairment can participate in a totally auditory experience, using modern technology to sidestep the inability to hear the spoken word. May this kind of technology only improve? I am on record as being certain that auditory impairment is a more difficult disability to overcome than the impairment associated with blindness.

Now TechXplore reported on Friday that, between September 1982 and December 2020, at least 51,512 people were rescued on land and at sea with help from a network of Earth-orbiting satellites able to detect and locate emergency distress beacons.

ESA’s OPS-SAT Space Lab recently demonstrated that by processing data from these beacons in space, instead of on Earth as currently happens, the whole process could be made more efficient, saving data and perhaps helping to save lives.

The international Cospas-Sarsat cooperative was established in 1979 and remains a fundamental, life-saving system. Using a network of instruments on board more than 50 satellites, it detects emergency beacons from aircraft, ships and people anywhere on Earth, passing the coded information to ground stations to be processed and then forwarded to local Rescue Coordination Centres for a response.

Distress beacons are fundamentally radio transmitters that can be activated in emergencies, either manually by pressing a button or automatically upon detection of certain triggers—a physical shock, contact with water, a sudden drop in altitude etc.

The Cospas-Sarsat system detects radio transmissions in the protected 406-MHz frequency band, gathering information on the type of vessel in distress and relaying its signals to ground stations on Earth known as Local User Terminals (LUTs). While some beacons contain the location of the vessel in question, many don’t, and for these ground stations must perform a mathematical analysis to determine the location of the beacon.

Many satellites in low, medium and geo-stationary orbit carry ‘repeater instruments’ which shift the frequency of the 406 MHz beacon transmissions to a different frequency in order to avoid interference with the original transmissions. The so-called ‘up-converted’ signals are sent to User Terminals where they are processed and decoded.

Once verified, beacon information is forwarded to the nearest Rescue Coordination Centre.

In a recent “In Orbit Demonstration,” OPS-SAT Space Lab, an orbiting Cubesat, performed the first in-orbit decoding and processing of radio-signals from emergency beacons on Earth, using open-source software running on the satellite.

This reduced the amount of unnecessary data sent back to land stations, making for more efficient communications, and, more rapid response times

This is progress, clearly to be applauded.

Reporting for HAMNET in South Africa, I’m Dave Reece ZS1DFR.