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Measurement of integrated sky noise is desirable in radio astronomy for flux density calibration and cosmological signal detection. The ultimate goal is to make such measurement while adding negligible system noise. This is the challenge of zero-spacing interferometry. We discuss the theory of an interferometer that consists of a vertical array whose outputs are correlated, weighted, and then summed to realize the zero-spacing response. We describe a design equation based on array synthesis and provide a simple example that covers the 50–250 MHz frequency band.

The Murchison Widefield Array (MWA) radio telescope is the precursor instrument to the future international SKA-Low radio telescope. The MWA is pursuing a number of ambitious key science programs, the most challenging of which is to make the first detection of the faint signal from the early universe. Fundamental to achieving the very high fidelity imaging required for MWA key science programs is an accurate and flexible model of the MWA's primary beam. This work will present an advanced, frequency dependent, fully general model of the MWA primary beam. The model has been implemented as a set of spherical harmonics such that the beam response can be predicted anywhere on the sky without the need for interpolation.

The Australian Radio Quiet Zone — Western Australia (ARQZWA) has been established to protect new generation radio astronomy instruments, including the Australian component of the Square Kilometre Array (SKA). Using characteristics of typical transmitters and applying propagation prediction methods, various zones were established with appropriate protection measures. Legislation and regulatory policy has been implemented at Commonwealth and State level to protect the site from terrestrial radio transmissions and incidental emissions. Radio frequency interference detected by telescopes on the site has originated from distant sources, typically via anomalous propagation. The quietness of the site is already demonstrated in new astronomical discoveries.