加拿大線
Mid-Canada Line Site 070 Kempis was a part of the Mid-Canada Line air defence network. During the late 1950s, the Mid-Canada Line (MCL) was developed as a secondary line of detection in case enemy aircraft penetrated the Distant Early Warning Line. This consisted of approximately 90 unmanned sites and eight Sector Control Stations located along the 55th parallel. Each site sent out a radio beam to its neighbouring site. If an aircraft interrupted the beam, an intruder alarm would sound.