Western Australia, Rottnest Island, Signal Ridge / Wadjemup. Naval Signal Station.

September 1937 saw Rottnest Island declared a permanent station for Australian troops, with personnel from the Army, Navy, Airforce, and the Australian Women’s Army Service (AWAS) and Women’s Royal Australian Navy Service (WRANS). To perform their vital defence duties, a number of other buildings were constructed to support Bickley Battery and Oliver Hill Battery.
As well as construction of a barracks at Kingstown, in 1938 a four-storey Battery Observation Post was constructed at Signal Ridge, and another at Bickley Battery. The upper floor housed instruments to observe and direct gunfire from the Oliver Hill Battery. The floors below were used by Fire Command, or Fortress Command, as it was known, a station that coordinated gunfire of all the batteries in the Fremantle Fortress area. They shared the space with important roles such as the searchlight control engineer, a signal group, and other personnel.
Wadjemup / Signal Ridge, the highest point on the Island was chosen as the site of strategic signalling and military installations. A Signal Station was originally sited at Bathurst Point in 1904, but was subsequently dismantled and moved to this more practical location. A new signal station with modern communications, signal lamps and a signal flagstaff formed part of the defence upgrade in the late 1930s. The new site allowed the signallers to see ships approaching in any direction, allowing better communication with incoming ships, and ensuring faster response times should the guns be required. Staffed by WRANS personnel, the two-storey building afforded a full 360-degree view over the island. An accommodation building and other support structures formed part of this establishment.