HAMNET Report 19th November 2023

BBC.com reported on Friday that Zimbabwe has declared a state of emergency in the capital Harare over a cholera outbreak. The outbreak has so far killed dozens of people with more than 7,000 suspected cases.

The city authorities say the outbreak, spreading throughout the city, has invoked memories of a deadly outbreak in 2008, in which thousands died. “We have declared a state of emergency because of cholera,” local media quoted Mayor Ian Makone as saying.

The authorities are now asking for help to contain the spread and provide safe water, saying the aid being received is inadequate. Health authorities have been struggling to contain the high number of admissions following the outbreak, according to the International Federation of the Red Cross (IFRC).

It cites a lack of health workers to manage the cases, as well as lack of supplies to stop the transmission. Zimbabwe has been battling the deadly cholera outbreak in recent months amid a lack of access to clean water.

The epicentre of the latest outbreak is Harare’s high-density suburb of Kuwadzana, which accounts for nearly half the reported cases, according to the authorities. On Tuesday, the ministry of health announced that the country had recorded 7,398 suspected cases, 50 confirmed deaths, and 109 people in hospital.

It came as the health minister visited the epicentre, announcing measures to deal with the outbreak – including the removal of street food vendors, and trucking of safe water.

The IFRC says the disease is quickly spreading, affecting multiple geographical areas in 45 out of 62 districts and in all 10 provinces of the country. It says the outbreak can be expected to cross the border.

I do not have to remind you that we share a border with Zimbabwe.

Here’s a clever concept. Hackster.io reports in its news department that Researchers at the Centre Tecnològic de Telecomunicacions de Catalunya (CTTC), the University of Luxembourg, and the Universitat Oberta de Catalunya (UOC) have taken CubeSat technology and blended it with 3D printing to design a nanosatellite which can be held aloft by balloon to deliver broadband connectivity to disaster-hit regions in as little as 90 minutes.

“Our project provides a solution that means that a communications network to provide help in emergency situations can be established quickly,” says Carlos Monzo Sánchez, a professor at the Universitat Oberta de Catalunya. “It uses equipment that offers a communications service quickly, when it would not otherwise be possible. It is especially designed for emergency services, so that they can work in a safer and more coordinated way in complex situations.”

The core of the concept is the CubeSat standard for nanosatellites, low-cost- highly-miniaturized satellites which have been used extensively for experimentation in space. In the team’s approach, though, it doesn’t have quite so far to go: the CubeSats, built on a 3D printer in as little as 90 minutes, are lofted above the disaster zone on a balloon, communicating with the ground over a LoRa low-power long-range radio.

“Our solution enables communication over long distances, as well as providing a scalable system for a large number of users that is reusable anywhere and at any time,” claims Raúl Parada, a researcher at the CTTC and first author of the paper. “We chose [a] CubeSat as for communications in difficult environments due to its speed of deployment and functioning. It operates independently of current communication systems, which may be damaged during a disaster, and enables long-range communication.”

The team’s prototypes are based on the Semtech SX1278 LoRa transceiver, which can be connected to an antenna as simple as a length of metal ruler. The 1U CubeSat in which the transceiver is installed was 3D printed and fitted with a sensor package including a Bosch Sensortec BME280 environmental sensor, a TDK InvenSense MPU-9250 inertial measurement unit (IMU), a Hanwei MQ-135 air quality sensor, and a Roithner LaserTechnik GUVA-S12SD ultraviolet light sensor, all linked to an Arduino Nano microcontroller — with a GPS receiver added at a later date to make it easier to recover downed satellites.

“Our solution is designed to provide a rapid service in complex scenarios, and as such we have prioritized its ease of deployment over its use as a telecommunications solution in normal situations, where other infrastructures would be more suitable,” Monzo concludes. “The next step is to work on the services that could be included in this type of infrastructure, minimizing deployment times and ensuring it can be used in a wide range of situations.”

The team’s work has been published in the journal Aerospace under open-access terms.

Now Hackaday’s Dan Maloney reports on a Ham who used a can of “ham” to make a pretty effective 70cm “cantenna”. If you’d have asked us for odds on whether you could successfully turn a canned ham into an amateur radio antenna, we’d have declined the offer. Now, having seen [Ben Eadie (VE6SFX)]’s “hamtenna” project, we’d look at just about any “Will it antenna?” project with a lot less scepticism than before.

To be painfully and somewhat unnecessarily clear about [Ben]’s antenna, the meat-like product itself is not included in the build, although he did use it as sustenance. Rather, it was the emptied and cleaned metal can that was the chief component of the build, along with a few 3D printed standoffs and the usual feedline and connectors. This is a slot antenna; a design [Ben] recently experimented with by applying copper foil tape to his car’s sunroof. This time around, the slot was formed by separating the top and bottom of the can using the standoffs and electrically connecting them with a strip of copper tape.

Connected to a stub of coax and a BNC connector, a quick scan with a NanoVNA showed a fantastic 1.26:1 SWR in the centre of the 70-cm ham band, and a nearly flat response all the way across the band. Results may vary depending on the size of canned ham you sacrifice for this project; [Ben]’s can measured just about 35 cm around, a happy half-wavelength coincidence. And it actually worked in field tests — he was able to hit a local repeater and got good signal reports. All that and a ham sandwich? Not too shabby.

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