I came across a short piece about radar during World War II by Jevon MacDonald at the Fast Forward blog, when I was tidying up my talk on the same subject for the SLS conference this week.
"Radar was cheap, fast, and you could mash it in to existing process and workflow. Everything seemed rosy.
Those who worked on Radar each day, like Private Eliot at Pearl Harbor, came to trust their radar completely. They saw each and every aircraft coming and going within their range and often coordinated large influxes of aircraft. The problem, however, was that nobody else got to seem much of Radar in action. It was a few miles from Pearl Harbor itself and communicated by radio.
People couldn’t understand it, and they couldn’t trust it much either.
The 7th of December 1941, the Pearl Harbor Radar operator saw something new on his screen. It was filling up with dots. Little dots blinking on the radar screen.
This was the moment of crisis. 1 hour before the attacks would begin. Certainly enough time to move some ships and prepare some sort of defense.
When word came through that something was coming, nobody got very excited, until finally someone remembered that a group was flying from the mainland that day. The command was sent back that it was just friendly planes and not to worry, “you probably have your bearings off” or something like that.
Sure enough, Radar was right. It was a massive group of Japanese fighters coming to launch a full scale attack."