Intruder alarm system using radar surveillance - has HF cable incorporated in walls surrounding surveillance area

摘要

The intruder alarm system uses radar surveillance, via a HF cable running along the walls surrounding the surveillance area. The cable is not screened, so that an intruder causes a variation in the HF signal transmitted along the cable, which is detected to actuate an alarm. Pref. the cable is attached to the walls of a room so as to surround the doors and windows facilitating access to the room, with standing waves set up by reflection of the HF energy from the walls of the room.