Laboratory Victory.

    Like the atomic bomb, the story of American and British radar is the story of victory in a laboratory race against the enemy.  Both Germany and Japan used it, but they never caught up with the Allies.  As one Army spokesman put it:
     "In the technical field, where so much of this war has been fought, the failure of the Nazis and the Japs to keep pace with Allied radar has been probably the major single reason for defeat."
     In peacetime, radar is expected to make air and sea navigation foolproof, regardless of night or weather.  Its immediate use in land transport is less sure.  In its present form, it is not very useful on automobiles or locomotives. 
     A joint scientific board of the Army, Navy and the Office of Scientific Research and Development said its greatest benefit will be its effect upon the electronics industry.
     "Radar has made the electronics industry one of America’s major ones, now comparable in size to the prewar automobile industry," the board said.  "This new industry, can be expected to find innumerable applications in a wide variety of fields."

     Television Around Corner. 

     "If television is still around the corner after the war, economic factors, not technical ones, will have kept it here.  Communications, especially radio, will have a tremendous flowering.
     "Altogether, it is fair to say that radar, as radar, will have a mild immediate beneficial effect on all our lives.  But the impact on electronics generally of techniques developed during the war because of radar will have profound and far-reaching effects on the shape of our daily life."
     Radar’s name is coined from the words which tell its function - radio detection and ranging.  Here is a typical picture of how it works in naval warfare:
     An enemy fleet approaches, radar detects its size and direction.

     How It Works.

     Here, in principle, is the way radar works:
     Unlike other communications, the transmitter and receiver are at the same place.  The transmitter sends out intense bursts of energy called pulses.  They may be only one millionth of a second in duration.  During the interval between pulses, the receiver is receiving "echoes" which a pulse produces when it contacts a nearby object.  Echoes from the nearest objects form soon after the pulse is sent.  Those farther away give later returns.  The interval between the transmissions of the pulse and the reception of its echo measures the distance of the object - ship, plane, mountain or building.
     Direction of the target is determined by a rotating antenna which sends out pulses in a narrow beam, like a searchlight.  When the antenna is pointed toward the target, a "pip," or direction indicator, is flashed back.  The strongest pip is returned when the antenna is beamed directly at the target.  The bearing of the antenna then is used to point a gun, to set the course if a bomber, to direct a fighter plane, or for innumerable other uses.

     IFF Tells Foes.

     The reflected radio pulses are recorded on a "scope," a cathode ray screen similar to that used in television.   One of the most ingenious of the scopes is the PPI - "plan position indicator."  The antenna rotates in a full circle.  A luminous line moves around the scope, like the hand of a clock.  It leaves a map-like reproduction of the surrounding area.
     Another device is IFF - "identification of friend or foe."  It sends out a signal which brings an automatic coded response, identifying friendly craft.  Still another set automatically