I have located a 1934 authority from the Privy Council to purchase 25 No. 1.B. sets (for vehicles) from the UK for use by the Canadian Corps of Signals.
Full text:
http://www.rcsigs.ca/index.php/Privy_Council_1934/2004
This might not have been the only acquisition but it does indicate that Canada had these relatively early in their life.
Photos of Canadian Vehicles outfitted with WS No. 1 can be found here:
http://www.rcsigs.ca/index.php/Wireless_Set_No._1
Joe