HAMNET Report 14 January 2018

Tropical Cyclone Ava passed through Madagascar on Friday and Saturday of last week, hitting mostly the Eastern coast of the island with wind speeds of between 140-190 kph.

“The provisional report of cyclone Ava hitting Madagascar, (shows) 29 people were killed,” Melisa Venance, communications officer of the National Office of Risk and Disaster Management, said.

The administrative region of Haute Matsiatra, located 400 km  South of Antananarivo, said that among those killed were eight people from a family who had been at a funeral vigil on Sunday when their house was hit by a landslide.

“The bodies were searched for all night, and the corpses of eight people, including an 11-month-old baby, and the body of the deceased person were found under rubble on Monday morning,” the post said.

The National Office of Risk and Disaster Management had earlier on Monday put the dead at at least six, and that more than 13,000 people were displaced by the cyclone, while more than 16,000 pupils had classes suspended until Thursday, due to flooding and risk of landslides.

Meanwhile, as AVA has drifted away in a South-Easterly direction, Tropical Cyclone SIX-18, has formed East of Madagascar, and is not threatening the island country yet. It may in fact drift South and miss Madagascar completely. Maximum windspeeds are estimated at 176kph.

Tom Morgan, ZS1AFS/G0CAJ, reports in Southgate Amateur Radio News that many rare DX operations are by hams who are working in that ‘needed’ location – and giving contacts is secondary to the reason the operator is in that far-flung spot. So, operation is limited.

It is very rare that an operator has to go QRT because he or she is in a life-threatening situation. One in which fuel and food are in short supply, happened recently on Marion Island.

With fuel restricted to essential purposes, ham operation ceased in November. There is doubt whether ZS8Z will be on the air again before the South African ship arrives in April 2018 for the changeover.

Fortunately, an Indian relief ship was found that was able to take supplies and is in passage with food and fuel. The fuel is for the one remaining operational generator – two are in need of maintenance and repair.

At the American Astronomy Society’s meetings this week, the intriguing matter of Fast Radio Bursts was discussed. Fast Radio Bursts, or FRBs, are brief, bright flashes of radio energy from extragalactic sources. They are hard to study because they’re so short and they don’t repeat, except for one. The Repeater, as it’s known, offers a window into the nature of these objects because it repeats, allowing for multiple and higher-precision measurements of this source. It has, for example, allowed astronomers to pin down its location to a dwarf galaxy over 3 billion light-years away. It’s also sitting conveniently close to a source of persistent radio emission.

Based on the duration of the bursts, some of which are only about 30 microseconds, the source itself must be small — only about 10 kilometres across, which is conveniently the size of a neutron star (which was already the likeliest candidate). It was learned that the polarization of the signal is extremely “twisted,” which may hold clues about its environment, which must have strong magnetic fields responsible for twisting it in the first place. The persistent radio source near the burster is also a likely clue. Currently, the best theories state that this Repeater is likely a neutron star bursting from either the region very near its galaxy’s supermassive black hole, or from within its own extremely bright, young nebula. These ideas still remain theories, but within the next few years, we may finally begin getting some answers as more FRB’s are recorded and more is learned about their origins and environments. In response to a question, it was noted that FRB121102 is the only repeating burst, and that it perhaps doesn’t represent the rest of the class of FRBs. It’s still hard to tell, and only more data and more discoveries will hold the answers.

Fortunately, astronomers estimate that about 10,000 of these go off every day, resulting in one about every 10 seconds. As radio telescopes become better able to catch these events, those answers may be just on the horizon.

Perhaps it’s someone out there trying to teach us superfast morse code! Thank you to the AAS for these notes.

The HAMNET Duty Logistics Manager has been busy round and about Table Mountain this week. From Monday morning until Saturday evening, eight rescues were logged, and needed some help from HAMNET. Of course, SANParks rangers, Mountain Club of SA rescuers and the Off-Road Rescue Club were also involved, so it was always a combined effort. Thank you to all who volunteer.

As of the beginning of this week, the Cape dams stood at 29.7% full. A small amount of rain fell last Sunday the 7th, perhaps 5mm in the suburbs, not enough to do anything for the dams. The community in Cape Town is pre-occupied with one mission – to acquire a rainwater tank to catch every last drop of rain or dew that might fall. In that there’s not much rain about, it is going to take a long time to fill all these tanks! Professional water-tank suppliers are having a very good season, and the rest of us are rigging up all sorts of Heath-Robinson devices to get the water from the gutters into the tanks. It’s all quite fun, actually! We have all developed a very healthy respect for that stream of water coming out of our taps, and are catching every wasted drop possible.

And, from your writer’s point of view, a new medical condition has sprung up in Cape Town. It has been termed “bucket-carrier’s elbow”, like tennis elbow, and just as painful, but  can be acquired without ever having played tennis! I wonder whether I should write it up in a medical journal somewhere!

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