An outdoor antenna metrology facility for candidate Square Kilometre Array antennas

The Square Kilometre Array (SKA) will be the largest radio telescope ever built operating at multiple frequency bands. The lowest band, SKA-low, covers 70-450 MHz and consists of sparse aperture arrays. The International Centre for Radio Astronomy Research (ICRAR) is investigating conical spirals as one candidate antenna for SKA-low. These large (~1 m) low frequency antennas are characterized using a quick and efficient procedure called the `car-park´ pattern measurement method. To verify the viability of the method, the characteristics of scaled conical spiral antenna prototypes, measured in both the car-park and an anechoic chamber, are compared in this paper. Initial indications confirm the reliability of the car-park measurement method and, by extrapolation, its suitability measuring full-sized antennas.