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Radio Quietness For Largest Radio Telescope

LS telcom carries out DTT and GSM coverage simulations and airborne antenna radiation measurements

The Square Kilometre Array, SKA, is an international effort to build the world’s largest radio telescope, with eventually over a square kilometre (one million square metres) of collecting area.
To host the telescope, South Africa’s semi-desert Karoo region was chosen together with Western Australia’s Murchison Shire, for its radio quietness, amongst other scientific and economic reasons. The Karoo regions of South Africa provide the perfect radio quiet backdrop for the high and medium frequency arrays that will form a critical part of the SKA’s ground-breaking telescope spanning continents.
Although South Africa’s Karoo region was chosen for its radio quietness, SKA still has to ensure that DTT and GSM transmission sites, situated closest to the SKA surroundings, will meet the defined interference levels of their radio telescope.

SKA commissioned LS telcom to determine the radiation levels of such DTT and GSM antenna sites. Previously, LS telcom performed coverage simulations and signal strength predictions of existing facilities in the direction of the core area of the radio telescope using the software SPECTRAemc. The results were communicated to SKA and consequently the DTT and GSM site operators which, in a spirit of excellent industry cooperation, reviewed their antenna designs and commenced with the implementation of changes as required.
On SKA’s commission LS telcom then undertook antenna pattern measurements via remotely piloted aircraft (RPA). The remotely piloted aircraft (RPA) carries measurement and high-resolution position and orientation sensors, an autopilot, a high-powered processor and storage unit and a telemetry system. The measurement and navigational data is stored on board and also streamed to the ground control station in real time. The technology determines the horizontal and vertical antenna radiation pattern as well as radiated power. Airborne antenna measurements were done at SKA nominated installations where the performance of the transmission systems was quantified to allow SKA to determine compliancy with their stated radio quiet requirements.
SKA chose LS telcom for their extensive experience in radio frequency studies and measurements.
The final compliancy assessment of these installations will be done by SKA.

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