A successful hybrid radio pilot project between Altron Nexus and Telviva in the areas surrounding the Square Kilometre Array (SKA) will see the service now being offered more broadly to residents, businesses and public sector organisations across the Karoo, enabling them to seamlessly communicate with the outside world. In order to overcome restrictions related to the SKA, this project allows people to use their radio devices to make and receive regular phone calls.
The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope. It is not a single structure, but consists of many telescopes – or an array – spread over a large location and the first phase is being constructed in the Northern Cape of South Africa as well as in Australia.
A unique challenge in the Karoo
Because it is a radio telescope, rather than an optical one, it is susceptible to interference from other radio and electrical signals; to guard against this, the government declared the area around the SKA as a protected area as per the Astronomy Geographic Advantage Act. The restrictions are at the highest closest to the SKA core – so that their work is not compromised – and then decrease as you move outward. An impact in the region is that mobile operators have to reduce signal strength in areas surrounding the SKA, leading to poor network connectivity in some towns and in rural areas.
In order to ensure that local communities – or the scientists and other employees working at the SKA – are not cut off from the outside world, a two-way radio communication network that is also capable of connecting to the public switched telephone network (PSTN) had to be developed as an alternative.
This radio communications network is supported by four radio high sites placed in four towns surrounding the SKA area; this infrastructure is connected to an Altron Nexus main switching office, which in turn has a breakout to the Telviva platform that then provides the PSTN capability that connects these communities to the rest of the world. Transmitting at below 200 Mhz, these radio devices are designed to replace regular cell phones, while not interfering with the telescope’s sensitive instruments.
Keeping communities connected
The year-long pilot saw the introduction of 500 radio handsets within the community, each with a unique 087 number and capable of working as two-way radios as well as making calls to and receiving calls from fixed-line and mobile phone numbers, which is something that is not possible through traditional communications methods.
Those who got radio handsets include SKA personnel, municipalities, law enforcement and disaster management authorities, emergency services and farming communities. The flexibility offered means that these users can use the same device to make and receive regular calls while also using the radio functionality for traditional uses such as farm management, emergency broadcasts and more.
Users can make calls directly rather than having to phone an operator number, while businesses with multiple devices on the radio network can now have a centralised number that can be called. When a user makes a call, however, that particular radio channel remains engaged and cannot be used by someone else at the same time – they are put into a queue.
To get by this there are a few different channels that can be selected, but that is also restricted in order to not interfere with the operations of the SKA. Despite the limitations, the pilot has made a huge difference in an area that only had some cell phone network coverage in the towns and none between and being able to communicate with the outside world – and be easily contacted – has put communities at ease.
Beyond just connecting more residents in the Karoo (or any rural area in South Africa), the flexibility of both two-way radio communication and public telephony means that this solution can be used by fishing vessels out at sea, the tracking industry, security companies or even in the oil and gas sector, which only allow two-way radios that have been built for dangerous environments. This is an exciting technology that has applications across multiple industries – and we are only at the start.
*Image sourced from the SKA Observatory.
