Royal Australian Air Force 211 Radar Station
- Radar/signal station
Charlie’s Hill Road, Charlie’s Hill, Home Hill 4871
RAAF 211 Radar Station at Charlie’s Hill became operational in late 1943, and was one of five British-designed Advanced Chain Overseas (ACO) radar stations constructed in Queensland during World War II: four being completed (Benowa, Toorbul, Bones Knob and Charlie’s Hill) with a fifth not completed (Paluma). The site is located in a reserve about 1.5 km along Charlie’s Hill Road, east of the Bruce Highway, about 5km south of Home Hill.
Two reinforced concrete semi-circular igloos, both about 10m long by 6m wide, are located over 50m apart at the summit of Charlies' Hill. Each has a small concrete tower at the north end.
The eastern (receiving) igloo has a square steel box on top of its tower. Four concrete footings (approximately 1.5m by 1.5m each) for a timber tower are located approximately 10m northeast of the igloo. Northeast of the footings is a chest height, concrete lined hole, reputedly a Voluntary Air Observers’ Corps (VAOC) spotters post.
The western (transmitting) igloo has exit holes for the aerial cables in the concrete floor. To the southwest of the igloo are four concrete footings for a timber tower. Located in the middle of the tower foundations is another concrete lined hole.
Radar stations were established along the north Queensland coast during WWII to give the earliest possible warning of approaching enemy aircraft. The RAAF installed 211 Radar Station on Charlie’s Hill in late 1943.
The delays that Australia experienced in acquiring British radar equipment spurred an innovative period of radar development by Australian scientists from late 1941. By the time the British Advanced Chain Overseas (ACO) radar system was installed at Charlie’s Hill, features of its design, especially its two conspicuous tall timber towers, had already been superseded by the Australian designed Light Weight Air Warning (LW/AW) radar.
One tower in ACO stations was for transmitting and the other was for receiving radar signals. The towers were spaced about 100 metres apart to ensure that radio pulses were received as echoes and not confused with transmissions. The towers did not rotate like those commonly used in other radar models. The ACO radar installation consisted of 14 switches on the receiver tower and more on the transmitter. These had to be constantly relayed from on to off, lower to higher, and between different directions. At Charlie’s Hill the two timber towers, which were assembled in kit form, were over 40m high.
The igloos were built to house the radar electronics and two tonne consoles for the transmitter and receiver. At Charlie’s Hill the eastern igloo housed the receiving equipment whilst the western igloo housed the transmitting equipment. The reinforced concrete igloos could be covered with earth, and were designed with a small tower at one end which was equipped with a ladder and served as a ventilator and escape passage. However, the ACO igloos used in Australia were not buried. Entrance doorways at the other end were large enough to accommodate the radar consoles.
The ACO electronics were the second generation of the British CH (Chain Home) type of radar, a 'floodlit' system operating on the VHF band. The transmitter was a British MB3 model which put out 250 kW of power at 42.5 MHz. The transmitter aerial system was in two parts set at different heights to enable height finding using the floodlit system. Each part had four elements to cover four sectors of 120 degrees.
The receiver was a British RF7 (receiver fixed location) built in four vertical racks held in a frame of 2 x 2 x 0.6 metres. The receiver detected radio echoes from all directions simultaneously, and compared the strength of an echo from within a radius to identify the direction from which the signal was originating. The receiver had two parts on the tower plus crossed dipoles used for the height finding of an aircraft by comparing the echoes from the higher and lower sections on the tower.
Nine British ACO radar stations were completed in Australia by the end of 1943 (while others were built but were never made operational). Four were completed in Queensland. As well as RAAF 211 at Charlie’s Hill, there was RAAF 209 at Benowa (since demolished); RAAF 210 at Toorbul; and RAAF 220 at Bones Knob, Tolga. An ACO station was started at Paluma, and concrete igloos were built that still exist on Lennox Crescent, but the towers were never built as the ACO program was cancelled in late 1943.
RAAF 211 was formed at Mascot in New South Wales on 12 June 1943, and moved to Home Hill in September 1943. The radar equipment was operational soon after Christmas 1943 and was maintained and operated by a radar unit made up of members of the RAAF and (from early 1944) Women’s Auxiliary Australian Air Force (WAAAF). The radar units were usually small, numbering around 35 personnel. The station was operated for 24-hours a day. Each shift comprised three-four people - one operator calling out the bearing and distance of the aircraft, one recording the plots, one working on the plotting table, and a fourth person to communicate by telephone to a Fighter Sector HQ. The RAAF staff, who lived on site, maintained and operated the station. The WAAAF staff, who worked as operators, plotters, and recorders, were on site during daylight hours only, and were accommodated in the hotel at Home Hill.
The camp site for RAAF 211 was west of the hill, on what is now farmland. Electricity appears to have been generated in two smaller concrete igloos northwest of the hill, but these no longer exist.
Following the surrender of Japan in August 1945 military installations in north Queensland were disbanded. The Charlie’s Hill Radar Station ceased operating on 1 October 1945. The equipment was dismantled and removed. Before leaving the area, the officers and operators of the unit, in return for the hospitality of the Home Hill residents, hosted a tennis afternoon, dinner and dance in the town.
Radar Station, Charlie’s Hill. Queensland Heritage Register 601716
WWII RAAF 220 Radar Station. Queensland Heritage Register 602741
Pearce, Howard. January 2009. WWII-NQ: A cultural heritage overview of
significant places in the defence of north Queensland during World War II. EPA, Brisbane.
Smith, N and Simmonds, E, (eds), 2007. Radar Yarns. Radar Returns, Hampton, Victoria.
Simmonds, E. (ed), 2007. More Radar Yarns. Radar Returns, Hampton, Victoria.
National Archives of Australia, ST156. RAAF radio location 1943
"No 202 Radar Station, Victor Harbour", Twentieth Century Heritage Survey, Stage Two (1928–1945)
WWII RAAF Radar Station 208 (former), NSW Heritage Register