285P RADAR OFFICE
285P Office. Starboard bulkhead.
285 transmitter; supply board for outfit DPA (50 volt, 50 cycle, 3 phase); At very rightmost, a valve heating box for CV-13.
RCN Photo HS 1749-71
Type 285 was a secondary-battery gunnery radar, first built in
1940 and then fitted in 1941. It employed two types of aerials; one
with 6 Yagi's and the other with 5 Yagi's. In the six Yagi version,
three aerials were used to transmit and three to receive. This
arrangement produced a narrower 18 by 43 degree beam. Bearing
accuracy was 3 to 4 degrees typical, with an accuracy of 100 yards
on the 15,000 yard scale. This 25 kilowatt set was keyed by 1.7
microsecond pulses and operated at a 50 cm wavelength. At maximum
range, it could detect a cruiser at 7 nm. On HAIDA, the 285 set was
fitted-on-build (1943).
285P Office. Starboard bulkhead.
Power board for outfit DPA; valve heating box. (Can anyone confirm that this was a pre-heater for mercury vapour rectifiers?)
After bulkhead. Power supply board and motor starter for outfit DUA (180 volt, 500 cycle).
RCN Photo HS 1749-72
285P Office. After bulkhead.
285 receiver.