EYE ON THE SKY:  A boy enjoys a tour of the SKA site in the Northern Cape. About 131,500ha of land surrounding the telescope’s 176-dish core, which lies 80km from Carnarvon, needs to be free from radio frequency interference. Picture: SUNDAY TIMES
EYE ON THE SKY: A boy enjoys a tour of the SKA site in the Northern Cape. About 131,500ha of land surrounding the telescope’s 176-dish core, which lies 80km from Carnarvon, needs to be free from radio frequency interference. Picture: SUNDAY TIMES

A POSSIBLE ban of certain radio frequencies in the Karoo as a result of the Square Kilometre Array (SKA) project could see aircraft flying the Johannesburg-Cape Town route being redirected via Port Elizabeth, the Atlantic Ocean or over Upington.

The SKA, an international science project located in SA and Australia, will be the world’s most powerful radio telescope once completed. After completion of the design phase of the telescope last year, scientists mapped out the size and shape of the land required to protect the site from radio frequency interference.

About 131,500ha of land surrounding the telescope’s 176-dish core, which lies 80km from Carnarvon, needs to be free from radio frequency interference. As a result, radio frequencies in the spectrum 100MHz to 25.5Ghz could be banned from a large portion of the Karoo. The ban would also have a negative effect on mandatory search, rescue and alerting services in the area. SA’s aviation authorities are opposed to a possible ban on the frequencies.

The Civil Aviation Authority (CAA) said a ban on the frequencies would hamper two-way communication between pilots and the relevant air traffic control sector.

The frequency range encompasses various aviation band frequencies including those used for voice communication and signals broadcast by radio navigation aids, according to the CAA.

On-board aircraft communication systems and ground station transmissions will also be affected by a ban.

"Moreover, activities such as the search and rescue and alerting services, which are mandatory to (air traffic control) would be impacted negatively.

"All radio communication will have to be stopped over the central portion of SA, which is an untenable situation," said CAA spokesman Kabelo Ledwaba.

If a ban is imposed, aircraft flying from Joburg to Cape Town may have to be rerouted through Port Elizabeth, north of Upington or over the Atlantic Ocean.

Ledwaba said the matter had been raised by a number of role-players in the aviation industry.

He said the CAA was in discussions with the Department of Transport and the Department of Science and Technology regarding the matter.

"This development will affect frequencies in the Karoo area, and will, therefore, most certainly impose a number of abnormalities upon aviation operations."

Air Traffic Navigation Services (ATNS) said it is opposed the banning of aviation-related frequencies as a result of the SKA project.

"The banning of any aviation frequencies will severely impact the safety and efficiency of air traffic management in the area and especially air traffic on the busy route between Johannesburg and Cape Town," said ATNS spokesman Percy Morokane. He said ATNS was in talks with "the parties concerned" and waiting for results from objections raised.