Michael, ZS1MJT, Regional Director for HAMNET Western Cape, reports that HAMNET Western Cape was requested to assist with communications on and around Table Mountain on 19 September 2026, by the Cape Province Mountain Club and the Kirstenbosch Rotary Group.

The aim of the event was to introduce scholars to hiking and the outdoors. HAMNET’s task was to provide radio communications from various control points back to a Joint Operations Centre (JOC).

While marshals could communicate with each other over specific, short-range areas, their communications were geographically limited by line-of-sight. This was where HAMNET was able to fill the gaps and provide communications between the various control points and the JOC.

HAMNET members and other marshals met at 05h00 on Saturday morning at the JOC, near the Kloofnek parking area. The HAMNET trailer was set up and, once parked and levelled, we were ready to operate.

A briefing was held to ensure that everyone understood what was expected of them. From 07h00, everyone deployed to their respective positions. Once all stations were in position, contact was established with the JOC and we waited for the participants to start and eventually arrive at our various positions.

The route started at the Kloofnek parking area, heading up Kloof Corner and then along the contour path on the Cape Town side of Table Mountain.

At the Platteklip intersection, the participants ascended Platteklip Gorge and proceeded to the dams on the back of the mountain. They then continued to the Cape Province Mountain Club hut, where they were provided with drinks and food before heading towards and down Kasteelpoort.

At the Pipe Track on the Camps Bay side, they proceeded back towards Kloofnek and the finish.

The scholars were in good spirits and showed a high level of enthusiasm, except during the couple of uphill sections! Temperatures on top of the mountain were around 22.5°C, with a very gentle breeze, making it ideal weather for outdoor activities.

A fun day was had by all, and HAMNET would like to thank the organisers for involving us. We also extend our congratulations to all the participants for completing the challenge.

Thank you also to all the marshals, officials, medical staff and Volunteer Wildfire Services for their contribution towards making this a successful day.

Finally, I would like to thank the HAMNET crew for giving up their time and sharing their expertise. They were Andre ZS1ATX, Torsten ZS1ABT, Ian ZS1BR, Andrew ZS1BAT, Shawn ZS1LED, Rassie ZS1YT and of course Michael ZS1MJT.

Thank you for the report, Michael.

In the ARRL newsletter of 24^th September, it is noted that it’s been a half century since single sideband (SSB) supplanted amplitude modulation (AM) as the most popular voice mode on HF, due largely to its spectrum efficiency, occupying roughly half the bandwidth of an AM signal. Now, there’s a new digital voice mode from FreeDV called Radio Autoencoder, or RADE, that occupies half the bandwidth of an SSB signal and reportedly provides more natural-sounding speech.

According to Amateur Radio Digital Communications (ARDC), which funded research that advanced RADE’s development, “FreeDV RADE combines machine learning with classical digital signal processing (DSP) and can operate at signal-to-noise ratios (SNRs) as low as -2 dB. Its design also addresses spectrum use, speech quality, and power efficiency, all important considerations for voice communications over HF.”

Most significantly, ARDC reports that manufacturers are beginning to integrate the mode directly into their radios, starting with a module that can be downloaded and installed on certain FlexRadio models. Users of other transceivers may run the mode through computers connected to their radios. More details are available from FreeDV and on the ARDC website.

Thanks to the ARRL for these paragraphs.

Phys.org is reporting this week on research done to plan the layout of the antennas to be used at the SKA-Low radio-telescope in Australia.

Gaby Clark reports that the telescope being built in Western Australia will operate across a wide frequency range, from 50 to 350 MHz, and will be the most sensitive telescope of its kind ever built. The completed instrument will link 512 stations spread across an area roughly 75 km wide. All the station’s antennas work together like a single large dish, so their arrangement directly shapes what the telescope can detect.

An earlier prototype station, AAVS2, arranged its antennas in a scattered, pseudo-random pattern to avoid unwanted signal artifacts. But antennas placed too close together can interfere with one another, a problem known as mutual coupling. This interference grows stronger below about 150 MHz, squarely within SKA-Low’s operating range.

To address this, researchers at the observatory proposed a new arrangement inspired by the spiral pattern seen in sunflower heads, known as the Vogel layout. Spacing the antennas this way reduces interference between neighbors while preserving the station’s collecting power. The SKA Observatory built a new prototype station, AAVS3, using this layout to test it under real-sky conditions.

Simulations run while AAVS3 was being built predicted a loss of sensitivity directly overhead at around 125 MHz. The team traced this to repeated antenna spacings, about 2.4 meters apart, throughout the sunflower pattern. Those spacings create interference patterns that reduce sensitivity. The older prototype, AAVS2, showed no such problem with its scattered layout.

Observations confirmed the prediction. When the galactic plane passed directly overhead, images clearly showed the same dip in sensitivity at 125 MHz. This confirmed that the problem was a built-in consequence of the antenna geometry, not a flaw in the equipment or method.

Because of the sensitivity loss at 125 MHz, engineers ruled out the original sunflower layout for the finished telescope. Further simulations led them to a modified version, called “Perturbed Vogel,” which keeps antennas spaced to avoid interference while removing the repeating pattern that caused the problem.

The AAVS3 results give SKA-Low’s teams practical guidance for building and calibrating the stations during construction. Combined with lessons from AAVS2, this work has directly shaped the observatory’s testing process and supported a key construction milestone, known as AA0.5, marking the first stations to come online.

South Africa’s SKA antenna system will apparently not have this problem, because we will rely on incoming focused beams striking dishes, being undisturbed by neighbouring dishes and of course operating in much higher frequency ranges, where mutual coupling will not occur.

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

Greg Mossop, G0DUB reports that a message sent by the Organization for Amateur Radio in Indonesia (ORARI) on Friday announces that, in response to the activation of the ANAK KRAKATAU volcano in the Sunda Strait between Java and Sumatra, The frequencies of 7100 and 7110 kHz LSB will be used for emergency voice comms and JS8Call data comms respectively.

Operators are encouraged to maintain a listening watch where possible and to follow any further operational announcements issued by ORARI.

The cooperation and support by radio amateurs during this emergency communication operation are greatly appreciated.

The message is signed by YB1BTM, Ageng Aditya, Disaster Communication Committee Chair in IARU Region 3,

ANAK KRAKATAU is the name given to the resurgence of the volcano that was KRAKATAU, a mountain which literally blew up and disappeared in the largest volcanic eruption in recorded history in 1883. ANAK means “child of” in local dialect, and refers to the remnant of the original volcano which has slowly been brewing, spitting out lava, and rebuilding a volcanic mound again.

Its last severe eruption was in 2018, when the south west portion of the volcanic mound slid into the ocean triggering a tsunami resulting in 437 deaths and 31900 injuries, when the waves struck coastal regions of western Java and southern Sumatra.

It would appear that the spirit of KRAKATAU is still alive and smouldering in central Indonesia.

In its letter for 10^th September, the ARRL honours James Clerk Maxwell, regarded as the “grandfather” of radio, for his theory of electromagnetic radiation, which laid the foundation for all modern electronic communication techniques, in spite of the fact that the average person knows little or nothing about him. The community where he is buried hopes to change that, as does the James Clerk Maxwell Radio Society, MMØPMS.

James Clerk Maxwell died in 1879 and is buried at the church in Parton, Scotland. The Church of Scotland has put the Parton Kirk, or Church, up for sale. The local community has been given the first option to purchase the building and is attempting to raise the funds to do so. According to Richard Hopkins MM1BHO, co-founder of the James Clerk Maxwell Radio Society, the town of Parton is keen to preserve the Church and develop a Science and Community Centre named after him, to celebrate his scientific contribution and life, and at the same time provide a legacy facility for the community. More information is available on the MM0PMS page on QRZ.com.

Amateur radio emergency communications does not usually require messages to be sent more than 14000km, but a story from the Falkands war 44 years ago bears repeating.

Bob McLeod was a radio ham on Falklands and was the first to break the news to the world that the Falklands had been invaded. However, he drew attention to his own presence by his signals, and his equipment was quickly confiscated by the enemy.

On 29^th May 1982, 2 PARA had fought a gruesome battle to take Goose Green, freeing more than 100 villagers who had been held captive in a hall by the Argentinians for almost seven weeks. Eighteen British soldiers died in that fight. Back at home, the families of 2 PARA had heard nothing since the soldiers had set sail and had no way of contacting them.

Alan Bullock was the Forward Observation Officer of D Company, 2 PARA and while walking through the main street of Goose Green, spotted an antenna on the house belonging to Bob. (The antenna had not been confiscated by the enemy.) So he knocked on the door of the house, and Bob answered, and admitted to being a radio amateur, but without equipment.

Bob’s wife suggested that Bob’s 50w amplifier could be used. This had been hidden away under the stairs. As a Forward Observation Officer, Alan had his state-of-the-art at the time, military clansman radio which, with power of only 20 watts for communicating over short distances, could be hooked up to the amplifier.

To get messages back to the UK, Bob made contact with John Wright, a radio amateur in Oxford who he had been chatting to over the airwaves for many years. Together, Bob and John devised a cryptic code for their conversation and each transmitted on a different frequency, in case anyone was listening.

John was sent a soldier’s phone number and a short message over the air to pass on to his family.

Word quickly got around the troops and soon it wasn’t just D Company’s families Bob and John were contacting. Before long, there was a queue outside Bob’s door, with each message always the same – ‘I am safe’. 

John said: “Normally, amateur radio enthusiasts talk about their radio equipment, or experiments they’re doing.

“In this case, the communication was to pass family (third party) traffic which, under normal circumstances, isn’t allowed, but I threw caution to the wind and did what I could as quickly and as clandestinely as possible.”

Successfully, this took a lot of worry off the shoulders of the soldiers whose families were contacted, and they agreed they were all very grateful for that.

Thanks to forcesnews.com for the gist of this story.

Such messages are being passed in Tibet after the glacier and landslide, in Indonesia after the volcanic eruption, and in many other emergency situations worldwide. The role of the amateur radio emergency operator will never fall away.

For most radio amateurs, whether they use Morse Code on a daily basis or not, the rhythm of Continuous Wave, as it is formally called, is recognizable and to an extent reassuring.

The seemingly trivial ability to hear a regular pulse in music is a remarkable—and perhaps distinctively human—feature of the brain. In a wide-ranging critical review, Gábor Háden of the HUN-REN Research Centre for Natural Sciences and Henkjan Honing of the University of Amsterdam evaluated more than two decades of research into how this capacity develops and has evolved. Their paper was published this week in the Annals of the New York Academy of Sciences.

Beat perception allows us to extract a regular pulse from a rhythm. It makes it possible to clap along, dance together and coordinate a musical ensemble. The review critically examines four often-made claims: 1) that beat processing is near-universal across human cultures, 2) that it develops spontaneously, 3) that it supports a distinctive form of predictive timing and 4) that it is rare across other species. The conclusion of the paper is deliberately nuanced: The foundations of beat perception appear to be present at birth and are refined by experience, movement and culture, but the available evidence does not justify every stronger claim made in the field.

However, you are fully justified in playing CW conversations to your infant children. They will resonate with their innate rhythms just as well as lullabies.

This is Dave Reece ZS1DFR, preparing for the flack, and reporting for HAMNET in South Africa.

Huge rescue efforts are still underway in Nepal, in the wake of the collapsed glacier and resulting landslide that has killed more than 1000 people. It appears that there are still about 1000 people trapped in hydropower station tunnels.

Rescue Specialist Arnold Dix is coordinating remote assistance to locate survivors in those underground facilities, with teams drilling from above, hoping to be in the right locations to get into the tunnels, whilst facing extreme challenges including boulders up to 10 metres in size, hardened mud and floodwaters that are estimated to have travelled at nearly 200km/h down the valley.

Masses of tourists from around the world were visiting the area for religious festivals, and many countries are searching for 40 to 50 of their citizens still unaccounted for. They may perhaps never be found, buried in tonnes of mud.

The disaster has destroyed 14 or 15 hydropower stations in the valley, and any rescue work is hampered by difficult terrain requiring all rescue equipment to be brought in by helicopters, whose maximum weight carrying limit is 3 tonnes.

Cbc.ca reports that Geoscientist Jakob Steiner says it looks like “someone took a knife,” cut a 1,300-metre-wide chunk from the lower part of a glacier on Nepal’s Himalayas and “dropped it off the mountain cliff.”

The researcher at the University of Graz in Austria says the “blast” of ice, rock and sediment that came crashing down 1.2 km, from a height of 5,000 metres above sea level, temporarily dammed the river below and created a lake.

Once that lake filled with the enormous amount of water released from the glacier, Steiner says the dam breached and unleashed the violent torrent that pummeled downstream villages on either side of the border and buried them in mud. 

This accounts for the secondary floods that affected towns and villages further downstream, as well as across the border in Tibet.

The Guardian says that over 4000 people were still unaccounted for, but that Nepal’s Chitwan district has become the site of mass burials for hundreds of unidentified victims whose bodies were swept away by the devastating flash floods. Authorities have dug ⁠hundreds of graves in the district’s Devghat forest, which is serving as a temporary burial ground for bodies too badly decomposed to be identified.

Morgues across Nepal are already overflowing. Authorities have been overwhelmed trying to identify the dead, with many bodies beyond recognition, turning up miles downstream.

Happily, 11800 people were rescued after the flood and the Nepalese army deployed 9200 personnel to assist with search and rescue activities.

On the Chinese/Tibetan side of the border, advanced technologies were mobilized to support rescue operations, including disaster-information datasets, aerial assets overcoming road and communication blockage, reconnaissance drones surveying the disaster area and searching for stranded people, and satellite remote sensing for disaster monitoring, according to media reports.

Meanwhile Tropical Cyclone SAUDEL, mentioned in last weekend’s bulletin seems to have stalled in the South China Sea, not reaching coastlines, and situated southwest of Japan, northeast of Philippines, and southeast of the coast of China. 13 million people remain threatened by winds of greater than 120km/h, and maximum wind speeds in the cyclone are being measured at 210km/h.

Dig.watch notes that, at the beginning of Deaf Awareness Month, South Africa’s Department of Women, Youth and Persons with Disabilities has called for South African Sign Language to be integrated into public services to improve access to information and government services for deaf and hard-of-hearing people.

Speaking at the launch of Deaf Awareness Month, the department’s Chief Director for Advocacy and Mainstreaming, Rights of Persons with Disabilities, Phuthi Mabelebele, said accessible communication should be incorporated into government planning, budgeting, procurement, monitoring, and accountability systems. She also called for public service information, including emergency and disaster communications, to be provided in accessible formats.

South African Sign Language was recognised as an official language following the signing of the South African Sign Language Bill into law in 2023. The department said improving accessibility in public services is necessary to enable deaf and hard-of-hearing people to access information and exercise their rights on an equal basis.

As more public information and services are delivered through digital and other communication channels, inaccessible formats can prevent people with disabilities from accessing essential information and services. Making accessibility part of government planning and procurement can help address these barriers before services are introduced.

For deaf and hard-of-hearing people, access to information in a recognised language is closely connected to participation in public life. Ensuring that communication systems and public services accommodate South African Sign Language can therefore support more equal access to government and civic services.

Ian Bradley, ZS1BR has sent me a short report of the Malmesbury motor rally, held yesterday the 5^th. He writes:

“Eight radio operators were asked to assist at the Malmesbury Rally this year, with responsibilities ranging from riding with the officials to manning the start and end of rally stages.

“Primary operations were carried out on the 145.650MHz repeater, but, to complicate the situation, the start of stage 1 could only be reached by the 145.625MHz Picketberg repeater.

“All stages ran on time with only three withdrawals due to mechanical failure and the event was wrapped up by 15:00.

“Thanks go to Johann ZS1JM, Jan ZS1LAM, Conradt ZS1ES, Andre ZS1ATX, Justin ZR1JJ, and extra special thanks to our two first timers Andrew ZS1BAT and Michail ZR1CS for volunteering their time and equipment to make it a safe and enjoyable day out!”

And thanks to you Ian, for your part in the comms plan, and for writing the report.

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