Measures for control of EMI and RFI at the Murchison Radioastronomy Observatory, Australia

The development and operation of a radioastronomy observatory site requires the evaluation and control of interference, both electromagnetic interference (EMI) from electrical equipment and radiofrequency interference (RFI) from radiocommunication transmitters. Interference may arise from activities external to the telescope site, such as transport, industry, or agricultural settlements, and also from sources on the site due to the operation of the observatory itself. This paper reports on measures being taken in Australia to protect the Murchison Radio-astronomy Observatory, where a significant component of the Square Kilometre Array will be sited and which already hosts two precursor telescopes. Public standards for interference levels from radiocommunication systems have been developed, based on internationally approved ITU-R standards. Local requirements for EMI from equipment on the site have also been established. The infrastructure for the site has been specially designed to eliminate RFI and to reduce EMI to acceptable levels. Potential interference from industry is managed by CSIRO as the MRO Entity, by the ACMA and by WA State Government measures.