Koeberg Simulated Emergency Exercise 22nd September 2022

In line with regulatory compliance for the management of a nuclear power station, regular safety exercises are held which involve a broad range of different agencies, which come together to practice their response coordination activities for dealing with any emergency which may threaten the safety of citizens living in the vicinity.

This exercise was led and coordinated by the City of Cape Town Disaster Risk Management Centre in Goodwood. Designated representatives from a broad range of agencies were assembled at Goodwood DRM to experience the full progression of the exercise from the first initial contacts, through the escalation levels, coordination, and the stand down and debriefing. Not only were there representatives participating from various provincial and city departments responsible for health and safety, water and sanitation, traffic services, environmental affairs and tourism, education, emergency medical services, recreation & parks, fire & rescue, agriculture, corporate media, human settlements, but also agencies such as HAMNET, Robben Island Museum, the SPCA, SABC media, SA National Defence Force, SA Police Service, Golden Arrow Bus Services, MyCiti busses, and a Koeberg technical advisor. As the Strategic Room was fully occupied, an upstairs auditorium was utilised for the monitoring by agencies such as the National Nuclear Regulator and others who could listen in to all the communications and watch the proceedings on projection screens which mirrored the video wall in the Strategic Room.

On Thursday 22 September 2022 the exercise was triggered in the early morning with an Unusual Event being declared by Koeberg to the City of Cape Town Disaster Risk Management Centre, for a simulated problem involving their pressurised water systems. This level is also triggered by anything unusual, such as a veld fire in their vicinity, jellyfish blocking a water cooling intake, etc. The Koeberg Station would normally try to deal with this alert level resolution on-site themselves. Every written and verbal communication was preceded with the words “THIS IS AN EXERCISE” to prevent any misinformation being broadcast outside of the exercise.

Bulk SMS messages were received by all participants to inform them of the situation. Normally, if this type of situation had developed at Koeberg, it would have escalated over a period of 2 or 3 days, but for the purposes of the exercise the time scale was compressed, so a while later Koeberg simulated some containment issues based on the loss of Fission product barriers, and they declared an Alert event level which was sent out to us by SMS necessitating the onsite assembly of the role-players at the Strategic and Tactical Rooms.

From this point our various teams reported our arrivals, and updates were sent through, using formatted message sheets. HAMNET, according to its plan, dispatched two members with one being present for the Strategic Room, and the other ready to man the radio room if required. HAMNET also sent a message to state it had additional members on standby if required for deployment to areas that had lost communications.

The exercise escalated through the Site Emergency severity level to one of General Emergency where members of the public and schools were to be evacuated within a certain radius downwind of the Koeberg station with the assistance of two bus services. At this stage roadblocks and holding points were in place, a Mass Care Centre had been established upwind of the station, frisking for radioactivity and decontamination were being performed, dosimeters were issued, and Potassium Iodide tablets were being issued or administered where needed.

At midday, after the simulated emergency had been contained, we all received the stand down SMS, and a lengthy debriefing period started. Every agency gave their feedback and a critique of their own performance, including many suggestions for future improvements. There was unanimous agreement by all the agencies, as well as observers, that the exercise had been a great success.

The purpose of the exercise was not just to perform all the procedural steps as per the planning, but more importantly to see how all the different agencies cooperated together as a team, and also to forge relationships with those who we will be working together with in future, if any real disaster requires it. And to this end the exercise was also a great success.

HAMNET was not required to deploy into the field as part of this exercise, but the role we were prepared for, was to bridge any communication gaps that might have arisen resulting from flat batteries and a blackout situation for the cell-phone towers or the TETRA radio network. As recently as two months ago, HAMNET WC had done a hands-on demonstration to the City and Provincial Disaster Managements, showing that we could establish radio communications across the Western Cape Province in the absence of any telephones or Internet connectivity. This is also the reason the City of Cape Town DRMC had funded and set aside a dedicated radio communications room for HAMNET to manage on their behalf.

HAMNET Western Cape was represented by Danie van der Merwe ZS1OSS and Dave Reece ZS1DFR.

Included is a picture of our dedicated radio room at Goodwood Disaster Risk Management Centre, which has facilities for all the usual amateur bands, crossband relays and all the usual digital modes, as well as monitoring of Aircraft and Marine traffic. We are linked to the internet, and run Echolink relays from here.


The station was established by Alister van Tonder ex ZS1OK, now ZS2OK, and is currently managed by Danie van der Merwe ZS1OSS. Its call sign is ZS1DCC.

Report prepared by Danie ZS1OSS

HAMNET Report 25th September 2022

Tropical Cyclone Fiona, which entered the Caribbean this week, and has exerted its might on the Dominican Republic, Puerto Rico, the Turks and Caicos Islands, and then Bermuda, has turned out to be far more fierce than originally anticipated. Wind speeds of up to 220 km/h have been experienced, and by Wednesday, it had strengthened to a category 3 hurricane, with about 2 million people in the path of winds of at least 120km/h. Very heavy rainfall, and storm surges were being experienced. Over 2000 people were still in evacuation centres.

In Puerto Rico, 8 people died, and 1300 were sheltered, while there were 2 deaths in Dominican Republic, 13760 displacements and over 1000 in shelters. Guadalupe experienced widespread damage to infrastructure.

In extracts from the ARRL Letter of Thursday, we hear that the National Hurricane Centre (NHC), the Hurricane Watch Net (HWN), the Voice over Internet Protocol (VoIP) Hurricane Net, and the Salvation Army Team Emergency Radio Network (SATERN) all have been engaged in tracking Hurricane Fiona.

Amateur radio operators have been reporting weather conditions since Monday, September 19, 2022, and have received positive feedback on their assistance. The VoIP Hurricane Net was active for 14 continuous hours on Sunday, September 18, for Hurricane Fiona, as it pummelled the southern and southwestern portions of Puerto Rico with catastrophic rainfall and flooding with hurricane-force conditions.

In the ARRL Puerto Rico Section, Public Information Coordinator (PIC) Angel L. Santana-Diaz, WP3GW, who lives in Trujillo Alto, reported a widespread blackout as the hurricane made landfall on the island. Still, he explained, there were ham radio repeaters that remained on the air with amateurs sharing reports of damage, including downed trees and power poles, and roofs ripped from homes.

In advance of the hurricane, the Radio Society of Bermuda activated their Emergency Measures Organization (EMO) on Wednesday, September 21, at 1:43 PM ET and plans to have 14 active amateurs monitoring the hurricane network. Plans are to use local repeaters, unless there’s a power loss, then they’ll switch to simplex. They’re currently monitoring 14.283 MHz and will continue to monitor that frequency.

Thanks to the ARRL for those notes.

After Bermuda, the hurricane was forecast to head north off the coast of the U.S., and strike Nova Scotia yesterday afternoon. I can’t remember having heard of a Caribbean hurricane making it to Canada before.

There is also an early alert for Tropical Cyclone NORU, travelling due west in the China Sea, and threatening, in order, Philippines, China, Vietnam, Laos and Thailand, with winds of 120km/h or higher threatening a population of at least two and a quarter million.

The KwaZulu-Natal Department of Cooperative Governance and Traditional Affairs has said that disaster management teams remained on high alert following a warning of disruptive snow in the province this past week.

MEC Sihle Zikalala said disaster management teams continued to monitor the inclement weather conditions affecting large parts of KZN. He said that on Tuesday morning, the South African Weather Service issued a weather warning for disruptive snow in areas under the Harry Gwala and uThukela districts.

The snow was expected to lead to icy roads which could lead to traffic disruptions and closure of local routes.

“Residents in the affected areas are urged to continue to monitor the weather conditions and not embark on any unnecessary trips as they risk entrapment should conditions deteriorate,” Zikalala said.

He said that disaster management teams would continue to monitor routes with plans in place to mobilise equipment to clear roads that were blocked by the snow, should the need arise. High ground in the Eastern Cape, Lesotho and the Drakensberg were decked with a blanket of white.

A couple of times each year, the City of Cape Town Disaster Risk Management agency runs a Koeberg Nuclear Accident Exercise, and this week on Thursday, such an event took place.

Any and every agency you can think of, which might become responsible to all living things in the Western Cape, if Koeberg were to threaten to melt down, was involved. A huge team of these people gathered at Goodwood Disaster Risk Management Centre, and a scenario of leakage of steam and loss of steam pressure in the three phases of energy capture from nuclear fission to turbine power generation was played out. The action was concertinaed into a morning, although such an accident would probably have taken two or three days to develop, and all the agencies were given a chance to apply their prepared relevant strategies.

Danie ZS1OSS and I attended as HAMNET volunteers, and Danie has written a very elegant report of the workings of the exercise. It is quite long, but too good to hack to pieces for this report, so I will post it separately in its entirety to the usual HAMNET internet sites for you to read.

Included will be a picture of HAMNET’s radio room at Goodwood Disaster Risk Management Centre, sponsored by the city of Cape Town, and with call sign ZS1DCC. (We have a smaller and less well-equipped radio room at the Provincial Emergency Management Centre at Tygerberg Hospital, with call sign ZS1DZ.)

Thanks very much for the report, Danie.

Tomorrow (Monday) night, an hour or so after midnight will see NASA’s special suicide spacecraft DART crash into the little moon called Dimorphos, of a binary asteroid, called Didymos.

NASA’s Double Asteroid Redirection Test (DART), the world’s first mission to test technology for defending Earth against potential asteroid or comet hazards, will impact its target asteroid—which poses no threat to Earth—at 1:14 a.m. CAT on Tuesday, Sept. 27.

DART’s target is the binary near-Earth asteroid Didymos and its moonlet, Dimorphos. Launched in November 2021, the mission will see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future. This test will also show that a spacecraft can autonomously navigate to a target asteroid and intentionally collide with it in a way that can be measured using telescopes on Earth.

The plan is to watch the little moon critically with several telescopes worldwide, with a view to deriving its orbit, to see if the impact made any difference. It will be amazing if it does, won’t it?!

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

HAMNET Report 18th September 2022


This last week has seen a flurry of cyclones appearing in the equatorial Pacific and Atlantic Oceans. Tropical Cyclone MUIFA was expected to make landfall over the Chinese coast near Shanghai on 14th September, with wind speeds of about 140 km/h. By then over 1.3 million people would have been preventively relocated to safer areas.

By last Wednesday, Tropical Cyclone NANMADOL was threatening millions of people in Japan, and, by Thursday, its alert level had been raised to RED, as its expected wind speeds were raised to a possible 220 km/h. After approaching the Chinese coastline in a north-westerly direction, it is forecast to change direction to north-east today, and travel directly up the length of the main Japanese Island, making landfall over Japan this afternoon.

Meanwhile, Tropical Cyclone FIONA has arisen in the Atlantic, and preliminary forecasts predict it will threaten every country in the Caribbean with winds of greater than 120 km/h.

Jagersfontein and nearby Charlesville in the Free State experienced their mini-Laingsburg Flood last Sunday when the slimes dam wall associated with a nearby open-pit mine collapsed, and dumped a huge amount of slimy mud on the area. Initially three people were said to have died, and more than 500 animals were rescued, some having to be euthanized.

The Daily Maverick reports that the area of Charlesville was hardest hit. Houses, personal belongings and animals were washed away, cell phone towers damaged and roads affected.  Power and clean water supplies were cut off. Houses that remained were left embedded in mud, up to windowsill level, and the area has taken on a uniform grey appearance.

Unsurprisingly, The Gift of the Givers organisation has quickly rallied to help those left destitute, and the greatest concern is to supply clean drinking water to the marooned residents. Restoring power and cell phone communications will come next as dwellers are assisted with temporary accommodation.

HAMNET Western Cape has been asked to join the City of Cape Town’s Disaster Risk Management exercise taking place this coming Thursday at the Goodwood Centre. These are recurrent Koeberg Nuclear Power Plant Disaster exercises, held theoretically, and involving all the main agencies in the Peninsula which might be involved in dealing with an imaginary nuclear accident, evacuation plans, road routes, and planning for available food and safe drinking water, as inhabitants in the area are moved away, in theory..

No radio comms or actual vehicles will drive, but all the agencies will direct their “operators” virtually from the Disaster Risk Management Centre. I may have more news of this event next week..

The ARRL Letter of this Thursday tells us that a North Carolina ham Oscar Norris, will celebrate his 105th birthday next Sunday, and has been a member of his amateur radio club since 1979. Oscar lost his sight at age 24 in 1942, and this indirectly led to his amateur radio licence in 1949. He is currently most active on DMR using a handheld radio, and his club will be operating a special event call N1O from the 20th September to the 1st of October.

Hamnet salutes a grand gentleman on this even grander achievement! After all, he was almost ten when Queen Elizabeth was born!

In a follow up report by Southgate Amateur Radio News, we read that radio amateurs in Ukraine appear to be diligently maintaining radio silence as the state of emergency declared there just prior to the Russian military invasion remains in effect.

A February 24 decree from President Volodymyr Zelensky included a ban on the operation of amateur radio transmitters for personal and collective use. The Ukraine Amateur Radio League reported this past week that it has received many messages of encouragement from the worldwide amateur radio community.

The LRU informed international amateur radio organizations about Russia’s military invasion of Ukraine, said the message from UARL Vice President Anatoly Kirilenko, UT3UY. To date, there have been many reports from radio amateurs around the world in support of Ukraine.

The IARU has adopted a neutral stance. IARU is an apolitical organization focused on promoting and defending amateur radio and the amateur radio services, the IARU said. The amateur radio service is about self-instruction in communications and friendship between people. IARU Region 1 has said it continues to monitor the development and expects all radio amateurs to follow their national laws and regulations.

IARU Region 1 also re-posted part of an advisory from the Deutscher Amateur Radio Club (DARC) HF Committee on February 27. Any radio amateur currently transmitting from Ukraine is risking his or her life. If you hear a Ukrainian station, do not broadcast its call sign, location, or frequency, whether on the band, in a cluster, or on social media. You may be putting lives at risk. The DARCs overarching advice: In the current situation is that the best we can do is “listen”.

Sound advice indeed!

Your writer has watched, on and off, and with amazement, the incredibly long queues of supporters of the British Monarchy waiting their turn this week, to file silently past the lead-lined coffin containing the mortal remains of Queen Elizabeth as she lies in state.

On Friday, it was reported that the queue had been stopped when it was 4.9km long, and further loyal subjects had been grouped together in a holding area beyond the end of that queue. Based on the speed at which the queue, divided into two streams when inside the building where she lies, moved, it was estimated that it would take those at the back of the queue 14 hours to get to walk slowly past her coffin, stop, turn towards her, silently bow, salute or curtsy, mentally greet her, and then turn, and walk stiffly out into fresh air. This process has apparently been going on 24 hours a day since she was brought to London from Scotland, and will continue until Monday morning, before her state funeral takes place.

And people are not perturbed by the thought of standing in a queue for 14 hours! I have been mesmerized by the collective amount of grief, sad thoughts, loyal devotion, and resigned acceptance that must be experienced by these thousands of mourners, not to mention of course the collective amount of vitriol gathered in the knitted brows of non-royalists who have done their best to be as far away from the location as possible.

Unquestionably, the British have developed the art of standing in a queue to perfection, and we will remember them all tomorrow as they formally say goodbye to undoubtedly one of the most influential women of the 20th century.

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

HAMNET Report 11th September 2022

In a summary of the major disasters befalling the world this week, the Pakistani flooding situation has raised the death toll to at least 1314, of which 458 were children. A freshwater lake was breached last Sunday before it could burst its banks naturally, preventing a further flood, but displacing 100000 people from their homes.

A magnitude 6.6 earthquake struck China’s Sichuan province on Monday the 5th, killing at least 74 people. 35 others are still missing, and 270 have been injured. At least 20000 have been evacuated to shelters. Videos and security camera pictures abound on the internet showing the destruction.

And Tropical Cyclone HINNAMNOR-22 has spent this week travelling down the north-west coast of Japan in the general direction of North and South Korea, with maximum wind speeds of 160 km/h, 10 deaths, 2 still missing, and about 5000 people displaced.

I found an article in the website “Briefly” which sums up the major natural disasters we have experienced in this country in the last 100 years. There were more than I had realized.

The worst include (in date sequence):

The Limpopo hailstorm of 1936, which killed hundreds of cattle, and at least 10 people immediately. Another 9 died of the flooding that followed the storm. Hailstones the size of fully grown coconuts were measured.

The Tulbagh earthquake of September 1969, which measured 6.3 on the Richter scale, and which resulted in extensive infrastructural damage and numerous deaths in the surrounding area, including children.

The Laingsburg Flood, in January 1981, during which 104 people died, when almost the entire town was washed away after heavy rainfall caused the Buffels River to deliver a massive wall of water to the town. Only 32 bodies were ever recovered. The late Ozzie Carstens ZS1DZ used Amateur Radio to provide the only means of communication with the town for about 3 weeks.

The Sobantu floods of September 1987, which delivered 1000 mm of rain in five days to parts of KZN, resulting in flash floods, landslides and the washing away of an entire island in the Umgeni River. More than 500 people lost their lives in this one.

The Eastern Cape Tornado of January 1998 (or was it 1999?), of strength F4, which tore through the areas around Tabankulu and Mount Ayliff, leaving 95% of local residents homeless, extensive property damage, and more than 20 deaths.

The Cape storm of June 2017, which struck the Southern Coast of the Cape, with winds speeds as high as 120 km/h, waves as high as 12 meters, eight deaths, and extensive damage to at least 100 schools across the Western Cape.

The Knysna Wildfire of June 2017, fueled by the strong winds of that Cape Storm, which maintained speeds of 90 km/h, destroyed over 600 houses, and displaced more than 10000 people.

The Drought, which affected almost the entire country, starting in 2016, but reaching its peak in 2018, with soaring temperatures, crop failures, and deaths of hundreds of thousands of cattle and wildlife, and almost leading to Cape Town’s taps running dry as it approached what was termed Day Zero.

The Floods and Landslides of 2022, affecting the country’s south-east parts between April the 11th and 13th, and due to extremely heavy rainfall in most parts of the country. 448 people died, 40000 were displaced, and at least 12000 houses in the south eastern provinces were destroyed.

Gosh, when one looks at it like this, one realizes we are not as protected from natural calamities as one thinks!

This past week we noted the passing of Frank Drake, the first proponent of the search for extra-terrestrial intelligence, and the developer of the famous Drake Equation, which speculated on the possibility of life being present elsewhere in the galaxy and universe. When he first wrote up the equation, nothing was known of planets around distant stars, and so the equation minimized the possibility of habitable planets affecting the likelihood of life. Now that we feel that every star has planets orbiting it, and the vast majority of these stars will have planets in the so-called goldilocks zone, the equation tilts very heavily into the realm of likelihood of life all over the show. The problem is that those life forms may be so far away from us that we will never become aware of them.

However, if Professor Drake’s dream of meeting extra-terrestrial life ever befalls us, we ought to raise a statue to the man who had the vision to think of the possibility of that distant life, and also the passion to spend a good part of his life looking for it.

Then I would be remiss, were I not to note with sadness the passing this week of Queen Elizabeth ll at a grand age. Not all people are Royalists, and not all British citizens will be mourning her passing, but to all our Ham friends who are Royalists, please accept our collective sympathies at the loss of your Monarch, and the end of a very long era. If ever there was a funeral during which to maintain radio silence, this is it.

And this weekend marks the 21st anniversary of the loss of at least 3000 American citizens in the disaster that was 9/11. Amongst those citizens, and to be remembered by us with great respect, were the emergency rescue teams, like the firemen, who ran towards and into those building as they burned, and not away from them, as any normal person would have done. Those rescue teams were not normal, and they that lost their lives should be held in awe. So too, the radio engineers in the building at the time, managing the commercial radio and TV repeaters on the building, who lost their lives doing the things we amateurs love to do. May your signals always be 5 and 9.

Finally, a spot of technically interesting news: Voyager One, now scooting off into interstellar space, at a distance of 23.3 billion km, started speaking in tongues in May this year! The telemetry expected of it was all garbled and made no sense at all.

Nasa might have been forgiven for writing it off as long past its sell-by date, and not worthy of further interaction, but they didn’t. Working with communications lags of 22 hours in each direction, interrogating its functions and activities, they found a fault and hopefully a relatively simple fix.

The rest of the satellite’s behavior was nominal, so the fault appeared localized, and it turned out that the satellite had started sending its telemetry data via a computer that had stopped working years ago. This faulty computer corrupted all the detail and sent gobbledygook instead of clean data.

So all will be well that ends well, when they figure out how to disable the interfering and damaged computer, and return to normal data transfer once more. Which just goes to show you don’t write a youthful satellite of about 45 years old, off.

Don’t you just love it when a plan comes together?!

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

HAMNET Report 4th September 2022

Quietly, and without much reporting in the Western Hemisphere, Pakistan has been suffering the worst monsoon flooding in at least a decade.

CNN said last weekend that the country’s climate change minister reported that at least 33 million people have been affected by deadly flooding in Pakistan. This represents about 15% of the country’s entire population. At least 215000 people have been displaced by the rising water.

Since mid-June, over a thousand people have died from severe rain and flooding across the South Asian country, according to the country’s National Disaster Management Authority (NDMA).

Sherry Rehman, the minister for climate change, called the floods “unprecedented” and “the worst humanitarian disaster of this decade.”

“Pakistan is going through its eighth cycle of monsoon while normally the country has only three to four cycles of rain,” Rehman said. “The percentages of super flood torrents are shocking.”

She highlighted in particular the impact on the south of the country, adding that “maximum” relief efforts are underway.

The NDMA, Pakistani Army, and the Provincial Disaster Management Authority are working to assist those affected — but there is a “dire” need for shelter and relief due to the rising number of homeless and displaced families, she said.

The southern province of Sindh, which has been badly hit by the flooding, has asked for 1 million tents, while neighbouring Balochistan province — largely cut off from electricity, gas and the internet — has requested 100,000 tents, she added.

“Pakistan’s priority, at the moment, is this climate-induced humanitarian disaster of epic proportions,” Rehman said, urging the international community to provide aid given Pakistan’s “limited” resources.

Since mid-June, when the monsoon began, more than 3,000 kilometres of road, 130 bridges and 495,000 homes have been damaged, according to NDMA’s last situation report.

From the United Nations News, we learn that, from record-breaking heatwaves in British Columbia, to wildfires in the Mediterranean, floods in Nigeria, and droughts in Taiwan; the period between 2021 and 2022 saw record-breaking catastrophic disasters in all corners of the world.

Some 10,000 people lost their lives, and an estimated $280 billion was incurred in damages worldwide.

The latest Interconnected Disaster Risks report, from the UN University Institute for Environment and Human Security (UNU-EHS), finds that many of these disasters shared root causes. At the same time, the study’s authors found that the solutions to preventing or managing them are also closely linked.

“Disasters occurring in completely different parts of the world at first appear disconnected from each other. But when you start analysing them in more detail it quickly becomes clear that they are caused by the same things, for example greenhouse gas emissions or unsustainable consumption,” said Dr. Zita Sebesvari, lead author and deputy director of UNU-EHS.

To connect the dots, the research team of the Interconnected Disaster Risks report looked “below the surface” of each disaster and identified the drivers that allowed them to occur in the first place.

For instance, deforestation leads to soil erosion, which in turn makes land highly susceptible to hazards such as landslides, drought, and sandstorms.

An even deeper dive shows that the drivers of disasters are formed by shared root causes which are more systemic in nature, such as through economic and political systems.

Deforestation can be traced back to placing economic interests over those of the environment and to unsustainable consumption patterns.

Other common root causes found in the report include inequality of development and livelihood opportunities, human-induced greenhouse gas emissions, and legacies of colonialism. It is root causes like these that can be found in disasters around the globe.

The connections do not stop at root causes and drivers either, but also with who and what is at most risk. Vulnerable groups, in both human settlements and natural ecosystems, continue to be the hardest hit by disasters.

“If we don’t want the disasters which we are currently experiencing to become the new normal, we need to recognize that they are interconnected, as are their solutions,” says lead author Dr Jack O’Connor.

“We have the right kind of solutions better to prevent and manage hazards, but we need urgently to invest in scaling them up and developing a better understanding of how they can work in combination with each other.”

Now here’s some revolutionary technology for you. Newatlas.com reports that, when it comes to communicating with one another while underwater, scuba divers typically use either hand signals or writing boards, both of which have limitations. Soon, however, they could be utilizing an app on their existing smartphone.

One of the problems with hand signals and boards lies in the fact that they can’t always be clearly seen from a distance – or in murky water – plus the diver who is sending the initial message has to make sure that the recipient is already looking in his direction.

Unfortunately radio communications aren’t an option, as radio waves don’t travel well through the water. There are acoustic voice communications systems, but they require both divers to be using expensive transceivers.

Seeking a simpler and more affordable alternative, a team at the University of Washington developed an app that can be used on a smartphone in an underwater [waterproof] housing. Named AquaApp, it allows users to choose between 240 pre-programmed messages which correspond to hand signals used by divers.

In order to keep things simple, messages conveying the 20 most commonly used signals are prominently displayed for quick access. Additionally, the messages can be sorted into eight subject categories, such as those relating to environmental factors or equipment status.

Once a message has been selected, the phone’s speakers send it through the water as a series of acoustic pulses. These pulses are detected by the mic of the recipient’s phone, where the app converts them back into a visual on-screen message. The app also alerts the recipient to the fact that a message has been received.

And thanks to a special networking protocol, up to 60 divers can communicate with one another at once, at one location. Based on field tests conducted in a variety of outdoor settings, the app is claimed to work well up to a distance of 30 m, and can transmit or receive an SOS beacon from as far as 100 m.

There are still some wrinkles to be ironed out, but expect the app to become more widely known over the next couple of years. Thank you to Newatlas for this report.

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