RESPONSE OF THE MOLONGLO OBSERVATORY SYNTHESIS TELESCOPE TO TERRESTRIAL INTERFERENCE

In conjunction with the Australian Government's Spectrum Management Ag ency, experimental tests have been carried out to determine the suscep tibility of the Molonglo Observatory Synthesis Telescope (MOST) to int erference from terrestrial transmitters. The motivation for the tests was to reconcile the conflicting requirements of the MOST, which is co mmitted to an extensive survey of the southern sky at 843 MHz, with th e commercial use of the 825-845 MHz band, which is being prepared for sale. The tests show that the far sidelobe gain of the MOST, relative to an isotropic antenna is generally less than 1, and that an appropri ate interference criterion would be that in-band interference irradian ce should not exceed -173 dBWm(-2). This value is similar to that cons idered by the International Telecommunications Union to be detrimental to radio astronomy continuum observations at nearby frequencies.