HAMNET Report 15th May 2022

Our National HAMNET Director, Grant ZS6GS has sent out a message he received from the IARU Region 1 inviting stations of Emergency Communications Groups in Region 1 to participate in a Simulated Emergency Test on Saturday 21st May, 2022 from 14.00 – 16.00 UTC

The operation will take place on and near the emergency Centre-of-Activity (CoA) frequencies on 40 and 17 metres (+/-QRM ).

This is a short notice event to test how well emergency communications groups can set up networks from home or temporary locations. Messages will be passed in both directions so please keep notes of who you can work as you may be asked to relay outgoing messages to their destination.

The objectives of the test are;

To increase the common interest in emergency communications, to test how usable the CoA frequencies are in IARU Region 1, to create practices for international emergency communication and to practice the relaying of messages using SSB and CW.

Each participating station will send messages to the Control station formatted using the IARU HF International Emergency Operating Procedure. Stations should relay messages received towards the Control station for that band or mode. To comply with licence regulations, all messages should be addressed to a licensed radio amateur taking part in the exercise.

Messages sent should be shorter than 25 words, and contain nothing which would be considered as a real emergency message by accidental listeners who don’t understand that this is an exercise. A weather report at the station location, the number of operators available and interesting facts about the station would all be acceptable messages.

There is no limit to the number of messages to be sent but each one must have a unique message number. To create a more realistic situation, operators are asked to limit their transmitting power during the exercise to 100 Watts. The organisers are especially interested in stations operating mobile/portable and/or on emergency power.

All HAMNET members will have seen this email, and will have the URL’s to download formatted message sheets, and to log contacts. These logs, but not the messages themselves, should be sent to Greg at g0dub@iaru-r1.org

Thanks to all who participate in the exercise.

Western Cape HAMNET members were invited to participate in an EMS emergency training session this week, when maritime and aeronautical agencies, together with the EMS services, dealt with a man-overboard in Table Bay in 12 degree water on Thursday morning, followed by an oil spill off Greenpoint washed by the prevailing current on to Milnerton beach, before drifting northwards and towards Robben Island, on Thursday afternoon and Friday.

A variety of rescue agencies dealt with the man over-board, who was rescued by helicopter, while oil-control agencies dealt with the spill, and environmental people managed the damage to the ocean and land environment from the oil.

Communications around the harbour and Table Bay were managed on an EMS radio channel, assisted by a temporary repeater installed for EMS by a HAMNET member on Signal Hill, and relays of messages from the waterfront to the training arena in Durbanville were attempted from the Disaster Management station ZS1DCC via the 145.700MHz repeater. Some voice messages were also monitored in Durbanville on a Zello relay from ZS1DCC, there being no line of sight reception of the EMS repeater channel there.

The two operators at ZS1DCC had air-band privileges, so kept a listening contact with the helicopter, and reconnaissance Cessna light aircraft, as well as using Marine channels 10 and 69 to keep an ear out for marine communications.

An X-50 antenna was installed on the roof of the conference centre in Durbanville, where the training for large numbers of personnel from each agency took place, based on the events as they unfolded. Three HAMNET members monitored the VHF messages intercepted at Durbanville.

Sybrand, ZS1SJ, our Deputy Regional Director, thanks the operators who assisted him, namely ZS1MTF, ZS1OSK, ZS1JFK, ZS1ABT and ZS1DFR.

Communications for future exercises and training procedures of this sort will function more effectively, if the training centre can be positioned to hear all radio traffic as the exercise plays itself out, and not have to rely on second hand news relayed by intervening stations, because it is topographically not exposed to the rescue scenario.

Reporting on Astronomy, Liz Kruezi and Emily Conover report that Astronomers announced on May the 12th that they have finally assembled an image of the supermassive black hole at the centre of our galaxy.

“This image shows a bright ring surrounding the darkness, the tell-tale sign of the shadow of the black hole,” astrophysicist Feryal Özel of the University of Arizona in Tucson said at a news conference announcing the result.

The black hole, known as Sagittarius A*, (Sgr A*), appears as a faint silhouette amidst the glowing material that surrounds it. The image reveals the turbulent, twisting region immediately surrounding the black hole in new detail. The findings were also published May 12 in 6 studies in the Astrophysical Journal Letters.

A planet-spanning network of radio telescopes, known as the Event Horizon Telescope, worked together to create this much-anticipated look at the Milky Way’s giant. Three years ago, the same team released the first-ever image of a supermassive black hole. That object sits at the centre of the galaxy M87, about 55 million light-years from Earth.

But Sagittarius A* is “humanity’s black hole,” says astrophysicist Sera Markoff of the University of Amsterdam, and a member of the EHT collaboration.

At 27,000 light-years away, the behemoth is the closest giant black hole to Earth. That proximity means that Sgr A* is the most-studied supermassive black hole in the universe. Yet Sgr A* and others like it remain some of the most mysterious objects ever found.

That’s because, like all black holes, Sgr A* is an object so dense that its gravitational pull won’t let light escape. Black holes are “natural keepers of their own secrets,” says physicist Lena Murchikova of the Institute for Advanced Study in Princeton, N.J., who is not part of the EHT team. Their gravity traps light that falls within a border called the event horizon. EHT’s images of Sgr A* and the M87 black hole skirt up to that inescapable edge.

Sgr A* feeds on hot material pushed off of massive stars at the galactic centre. That gas, drawn toward Sgr A* by its gravitational pull, flows into a surrounding disk of glowing material, called an accretion disk. That accretion disk is where the action is — as the gas moves within immensely strong magnetic fields — so astronomers want to know more about how the disk works.

And I want to know if that is where all my unmatched socks have gone to. They’re certainly nowhere here at home!

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