Looks to not be operating 24/7.
. JORN was designed and acquired for the defence of Australia. In the context of the defence of Australia and peacetime military operations, JORN is not resourced or tasked to conduct surveillance operations 24-hours-a-day 7-days-a-week. To this end, JORN’s peacetime use is focused on searching for those objects that the system has been designed to detect, thus ensuring efficient peacetime use of JORN’s fiscal and staff resources
From
https://www.airforce.gov.au/docs/JORN_FAQS.pdf