What technology was ignored prior the to the attack on pearl harbor?

Answer 1

The most notorious technological aspect of Pearl Harbor was the American use of radar. Radar was brand new, still in its infancy. Several radar sets had been sent to Hawaii a few months earlier. These were mobile sets, mounted in the back of trucks, as no permanent station had yet been built. The radar sets were used only a few hours each day, and were considered still in a training mode. The US realized they would be most vulnerable to a surprise attack at dawn, as reconnaissance planes could not fly at night. This would allow the aircraft carriers of any potential enemy (and this could only be Japan - only Japan and the US had carriers in the Pacific) to make a high-speed, all night run to get within flying range of Hawaii and launch its aircraft with the rising sun for a surprise attack - just exactly what the Japanese did. So, the radar sets were operated from from 4 AM to 7 AM.

On the morning of the attack the two operators of one of the radar sets were on the north coast of Oahu, the island where Pearl Harbor is. The truck that was to pick them up and take them to breakfast was late. They were supposed to secure the set at 7 AM, but one of the operators was a conscientious guy, trying hard, and he kept it turned on. They actually picked up the first wave of the Japanese attack force while it was still miles from the island, over the ocean. The operators knew that a flight of American B-17 bombers was due in that morning from California - the Army had paid the Honolulu radio station to stay on the air all night broadcasting, to give these bombers a radio signal to home in on. But there were only 12 B-17s due in, and this looked, to the inexperienced but conscientious radar operator, like a much bigger group of planes. And they weren't coming in on exactly the heading where one would expect to see planes coming from California. The operators talked it over and the one who was trying hard decided not to listen to his partner telling him to forget it, don't worry, its the B-17s from the states. He picked up the telephone and called in his report to the army's communications center.

Now, nobody anywhere in the world was used to dealing with radar sightings. And the officer on duty in the communications center was a very young and new one, who got stuck with the duty on a Sunday early morning. But still, he dismissed the report out of hand, leaping to the conclusion that what the radar operator was reporting had to be the B-17s from the mainland. He told the radar operator not to worry about it, hung up, and did not pass the word to anybody else. So the US frittered away this last chance to get its troops and ships alerted and guns manned, and fighter planes in the air.

The only good part of the story is that the conscientious radar operator was promoted to be an officer himself.

Answer 2

They used Midget Submaries, Aircraft and Aircraft Carriers, Bombs and Torpedos.