Pre-Radar Listener for Enemies
Have you ever pondered how militaries were able to prepare for battle before radar was created? Troops needed to innovate methods to detect enemy aircraft approaching their way in the past.
People were asked to stand in these cumbersome and odd-looking machines, which used acoustic mirrors and other pre-radar technologies to detect the sounds of approaching opponents. They could hear and track the sounds of aircraft engines to warn the soldiers ahead of time.