Radar: Oahu’s cutting-edge technology
In theory the island’s protection should have been rounded off by its radar, but America’s expertise with radar was minimal in 1941. There were, according to an official army history, six mobile radar stations on the islands. But, says the same historian ‘[they] had not yet been integrated into a functioning aircraft warning service’. This is a polite way of saying that the army in general and Short in particular neither welcomed the installations nor understood their value. As it was operated, the radar was useless against a surprise attack since it was only manned for four hours each day and some of the units had no means of direct communication with the command centre. There was not even a telephone at all the units. But it was arithmetic that revealed the fatal flaw in Short’s thinking. The radar could detect planes up to about 150 miles away. This gave about a one hour warning of approaching planes. Such planes needed to be intercepted well before they reached Oahu. In other words, Short had about 30 minutes from a radar sighting to getting his planes into the air if he was to have any hope of forestalling an attack. But nowhere on Oahu was there any command centre capable of taking and implementing such a decision in such a time frame.