DX news September 2023

 

The Arecibo Telescope was a 305 m (1,000 ft) spherical reflector radio telescope built into a natural sinkhole at the Arecibo Observatory located near Arecibo, Puerto Rico.

 

Nearly three years after the rapid unplanned disassembly of the Arecibo radio telescope, we finally have a culprit in the collapse: bad sockets.

 

In case you somehow missed it, back in 2020 we started getting ominous reports that the cables supporting the 900-ton instrument platform above the 300-meter primary reflector of what was at the time the world’s largest radio telescope were slowly coming undone. From the first sign of problems in August, when the first broken cable smashed a hole in the reflector, to the failure of a second cable in November, it surely seemed like Arecibo’s days were numbered, and that it would fall victim to all the other bad luck we seemed to be rapidly accruing in that fateful year. The inevitable finally happened on December 1, when over-stressed cables on support tower four finally gave way, sending the platform on a graceful swing into the side of the natural depression that cradled the reflector, damaging the telescope beyond all hope of repair.

 

The long run-up to the telescope’s final act had a silver lining in that it provided engineers and scientists with a chance to carefully observe the failure in real-time. So there was no real mystery as to what happened, at least from a big-picture perspective. But one always wants to know the fine-scale details of such failures, a task which fell to forensic investigation firm Thornton Tomasetti. They enlisted the help of the Columbia University Strength of Materials lab, which sent pieces of the failed cable to the Oak Ridge National Laboratory’s High Flux Isotope reactor for neutron imaging, which is like an X-ray study but uses streams of neutrons that interact with the material’s nuclei rather than their electrons.

 

The full report reveals five proximate causes for the collapse, chief of which is “The manual and inconsistent splay of the wires during cable socketing,” which we take to mean that the individual strands of the cables were not spread out correctly before the molten zinc “spelter socket” was molded around them. The resulting shear stress caused the zinc to slowly flow around the cable strands, letting them slip out of the surrounding steel socket and — well, you can watch the rest below for yourself.

 

As is usually the case with such failures, there are multiple causes, all of which are covered in the 300+ page report. But being able to pin the bulk of the failure on a single, easily understood — and easily addressed — defect is comforting, in a way. It’s cold comfort to astronomers and Arecibo staff, perhaps, but at least it’s a lesson that might prevent future failures of cable-supported structures.

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TRIO OF HAMS JOIN TEAM ON ISS

 

A launchpad in Florida has sent three more ham radio operators into space.

 

Three amateur radio operators were among the four-member crew aboard the spacecraft Endurance as it lifted off on the 26th of August from Florida's Kennedy Space Center. The launch of the Crew-7 mission launch was provided by SpaceX for NASA.

 

US astronaut Jasmin Moghbeli, KI5WSL, is the commander of the mission and the pilot is Andreas Enevold Mogensen, KG5GCZ, an ESA astronaut from Denmark. One of the two mission specialists is Satoshi Furukawa, KE5DAW, of the Japan Aerospace Exploration Agency. Satoshi trained as a doctor in Japan, where he practiced as an anesthetist and surgeon. The trio is joined by another mission specialist, cosmonaut Konstantin Sergeyevich Borisov of Roscosmos.

 

This is the eighth commercial crew program launch for NASA and SpaceX. The crew is expected to be on board the International Space Station for about 190 days.

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UK RADIO FANS LAUNCH PETITION TO SAVE BBC's LONGWAVE SERVICE

 

Radio fans in the UK are raising their voices - and a petition - to convince the BBC to keep a longstanding favorite radio service. We hear about their efforts from Jeremy Boot G4NJH.

 

A petition drive has been launched to press the BBC to reverse its plans to take its longwave service on 198 kHz off the air by 31st March 2024. The BBC made the announcement in May 2022 that it was closing its longwave transmitter, describing it as a dying technology.

 

According to the petitioners on the Change.org website, the single longwave transmitter at Droitwich is efficient, covering most of the UK and northern Europe. It is viewed as one of the more historic features of the BBC, and its planned shutdown would come a mere six months before it marked its 90 years on the air. The Change.org petitioners called it

"a historic radio lifeline." [endquote]

 

BBC Radio 4 has already begun a public information campaign to convince listeners to make the change from longwave to the broadcaster's other platforms. Those platforms are expected to carry many of the programmes now on Radio 4 Longwave, including Test Match Special, Yesterday in Parliament, Shipping Forecast and the Daily Church Service. The BBC has been following listeners' trend toward favouring digital radio and has acknowledged on its website that a wide range of alternative listening services have become available.

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WORLD OF DX

 

In the World of DX, be listening for Greg, N9GB, operating holiday style as 8P9GB from Barbados, IOTA number NA-021) from the 8th to the 15th of September. He will be on 60-10 metres and possibly 6 metres. During the local afternoon hours he will be on SSB; in the evenings he will operate on CW. See QRZ.com for QSL details.

 

Listen for Harald, DF2WO, operating as D44TWO from Sao Tiago, (IOTA number AF-005), Cape Verde from the 2nd to the 17th of September. He will be using CW, SSB and FT8 on the HF bands and 6 metres. He will also operate via the QO-100 satellite. See QRZ.com for QSL details.

 

The special callsign VI7ALARA is active on the HF bands until the 8th of November, commemorating the Australian Ladies Amateur Radio Association's meeting to be held in Hobart, Tasmania. The callsign is being operated by a number of YLs in Tasmania and throughout Australia. See QRZ.com for more details.

 

9Q, DEMOCRATIC REPUBLIC OF THE CONGO Vlad, OK2WX is active as 9Q2WX until September 9. Operation on HF using CW, SSB and digi. QSL via IZ8CCW. 

 

E5, NORTH COOK E51D is on air from N. Cook Islands, Penhryn Atoll, grid BI11 until September 10. Operation from 160 to 10 meter and 6m using CW, SSB and FT8 (F/H). Like on previous RIB activations, there are a number of local and remote operators. Local operators are HA7RY, KN4EEI, HA5YG and AA7JV. 

 

T32, EAST KIRIBATI Ken, KH6QJ will once again be operating as T32AZ from Crystal Lodge between September 1 and October 17. Operation on 80, 40, 20, 15 and 10 meter using CW and SSB. 

 

V4, ST KITTS Once again, John V47JA is operating until September 12. Operation from 160 to 6 meter using SSB. QSL via W5JON direct or LoTW. 

 

V5, NAMIBIA Dieter, DL5GAN is active as V5/call from multiple locations until September 7. QRV with QRP power from 40 to 10 meter using CW, SSB and FT8. QSL via homecalls. 

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Wishing You Good DX ! 73 de ZS6ZA