Metox radar warning equipment comes from occupied France

Germany turned to a capable electrical-engineering company in occupied Paris to create equipment that could detect British radar emissions. The resulting Metox receiver was adopted by both German and Italian forces, giving ships a warning when hostile radar was operating. It worked, but proved difficult to maintain and sometimes unreliable in service. The cause remains uncertain: technical complexity may have produced the faults, or employees under occupation may have designed weaknesses into the equipment.