 Early British wartime radar technology evolved rapidly and the ACO system was already outdated when introduced in Australia in 1943.ACO radar stations were built to the design of the Directorate of Works for the British Air Ministry and were very conspicuous through their two high timber towers and two reinforced concrete radar transmitting and receiving shelters.RAAF 220 Radar Station, located at Bones Knob near Tolga on the Atherton Tableland, became operational in September 1943.