Trainees in the "Wireless Air Gunner" (WAG) stream spent 24 weeks at a Wireless Schoo learning the theory and application of wireless communications. This included signalling with lights and flags as well as radio. Their "WAG" training was completed with four weeks at a Bombing & Gunnery School.
RCAF.info - RCAF Station Guelph ON - 4 WS
Guelph Historical Society
YouTube - Valour Canada Aerodrome of Democracy