Engines of Our Ingenuity

No. 42:
RADAR

by John H.Lienhard

Click here for audio of Episode 42.

Today, we suffer a devastating loss by failing to trust a new technology. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

I'd like to begin by telling you just a little about radar. Radar is a concept that's almost as old as radio itself. The radio pioneers Marconi and Tesla both pointed out that we could locate metal objects by bouncing radio signals off them; and as early as 1904 a German engineer named Hulsmeyer patented a radio echo device for locating ships at sea.

During the 1930s, all the major powers were trying to develop workable airplane and ship spotting systems that used radio waves. By the way, the acronym radar, which stands for RAdio Detection And Ranging, wasn't coined until 1942, when the U.S. Navy started using it.

American Army and Navy engineers discovered in 1936 that they could detect aircraft at distances of more than a hundred miles when they used long enough wavelengths. They had mobile detection units in production by 1940. The first of these units were field-tested in Panama; and late in 1941 five of them were being field-tested in Hawaii.

One of the Hawaiian units was stationed on the northern tip of Oahu on the night of December 6th, 1941. Private Joseph Lockard was training Private George Elliot, and they were to go off duty at 7:00 in the morning, when a truck was to pick them up for breakfast. The truck was a little late, and Lockard was trying to give Elliot some extra time on the unit. At 7:02, Elliot saw a very large reflection, 136 miles due north of them.

They tracked the signal for 18 minutes; then Lockard called the Information Center where the Lieutenant on duty dismissed it as -- in his words -- "nothing unusual." They went on tracking the signal until 7:39, when the 183 Japanese dive-bombers and fighters that were creating it were only 20 miles away. Then the truck arrived to take them to breakfast, so they folded up their equipment and left. 16 minutes later, the planes hit Pearl Harbor. By ignoring the signal, we lost 3000 men, dozens of large ships, and 80 percent of the airplanes on Oahu.

Still, it's too easy to criticize shortsightedness. Radar was a new invention. And an invention is alien, or it wouldn't be an invention. We have to be introduced to it -- gradually brought to understand what it can do. Unless it appears just when we're ready for it, it must be championed. The great inventions that've revolutionized the world were usually unrecognized in their first incarnations. The light bulb, the steamboat, and the telegraph had all been invented long before Edison, Fulton, and Morse came on the scene to show us their full potential.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Wohlstetter, R., Pearl Harbor: Warning and Decision. Stanford, CA: Stanford University Press, 1962.

Worth, R. H., Jr., Pearl Harbor. Jefferson, NC: McFarland & Company, Inc., Pubs., 1943, Section Three, "Radar: The Great Missed Opportunity."

This episode has been considerably revised as Episode 1364


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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