Invisible Searchlight ?

Auckland Star, Volume LXXII, Issue 3, 4 January 1941, Page 1 (Supplement)

Invisible Searchlight ?

THE United States Army is 1 pushing experiments with a secret military weapon created by four scientists from Standford University near San Francisco, and it is stated that the new device may rival the United States Navy's bomb sight in importance. It is an ultra short wave radio generator called the klystron. If it fulfils the promise seen in its present stage of development it will furnish the army with an "invisible searchlight , ' that will find an enemy aeroplane in blackest night, through fog or cloud, and give the 'plane altitude exactly. The value of such a weapon in the European war, where the bombing of great cities is settling down to night raids, is obvious. The U.S. army is relying on the same company which developed its bomb sight —the Sperry Gyroscope Company —to develop the klystron. Three of the four Stanford University men who participated in its development will work at the Sperry firm at Long Island. They are William W. Hansen, professor of physics, credited with inventing the klystron's basic feature; Sigurd Varian, a former commercial airlines pilot, and his brother, Russell, a television engineer.

Details of the present stage of the klystron's development and the exact manner in which it will work are military secrets. It is known, however, that the principle is the same as the absolute altimeter developed two years ago. The absolute altimeter tells a pilot his height above the terrain by shooting a short wave radio beam downward. The beam bounces back to the plane. Gauging the time required for the beam to bounce back, the pilot can compute accurately his height above the terrain. The reverse of this —use of a radio beam from the ground to find something in the sky—previously was not possible. Incidentally, some of the principles contained in the klystron appear to be something similar to those comprising Britain's latest location finder of enemy planes, and known as the predictor. Officials at Stanford University told reporters that they could not discuss military aspects of the klystron. Several departments of the University, working under direction of Dr. David L. Webster, head of the physics department and one of the four developers of the klystron, are experimenting with the invention. Their work is directed toward such commercial application as use of the klystron in television and telephonic comnnmiratinn