Radar System Engineering

14 INTRODUCTION [SEC.1.6
England, France, and Germany, about ten years after the original work
of Breit and Tuve.
The research agencies of the American Army and Navy have a long and
complicated history of early experiment, total failure, and qualified success
in the field of radio detection. The interested reader will find this
dealt with at length in Dr. Guerlac’s history. 1 Here it will be sufficient
to report the earliest full successes. In early 1939, a radar set designed
and built at the Naval Research Laboratory was given exhaustive
tests at sea during battle maneuvers, installed on the U.S.S. New York.
The first contract- for the commercial manufacture of radar equipment
was let as a result of these tests, for the construction of six sets, designated
as CXAM (Sec. 6.9), duplicating that used in the trials. In November
1938, a radar position-finding equipment intended for the control of
antiaircraft guns and searchlights, designed and built by the Signal Corps
Laboratories of the Army, was given extensive tests by the Coast Artillery
Board, representing the using arm. This set also went into quantity
manufacture, as the SC R-268 (Sec. 6.14). An Army long-range aircraftdetection
set whose development had been requested earlier by the Air
Corps was demonstrated to the Secretary of Jt’ar by the Signal Corps
Laboratories in November 1939. A contract for the production of thk
equipment, the SCR-270 (and SCR-271; see Sec. 6.9) was let in August
1940.
British radar was developed at about the same time but its application
proceeded at a somewhat faster pace under the immediate threat to
England and with considerably greater realism during the early years of
the war. During the winter of 1934-1935, the Air Ministry setup a Committee
for the Scientific Survey of Air Defense. Among the suggestions
it received was a carefully worked out plan for the detection of aircraft
by a pulse method, submitted by a Scottish physicist, now Sir Robert
Watson-Watt, then at the head of the Radio Department of the National
Physical Laboratory.
The first experimental radar system of the type suggested by Watson-
Watt was set up in the late spring of 1935 on a small island off the east
coast of England. Development work during the summer led to the
blocking-out of the main features of the British Home Chain of earlywarning
stations (Sec. 6“9) by fall. Work began in 1936 toward setting
up five stations, about 25 miles apart, to protect the Thames estuary.
By March 1938, all these stations—the nucleus of the final Chain-were
complete and in operation under the charge of RAF personnel.
British radar development effort was then brought to bear on airborne
radar equipment. Two types were envisaged: a set for the detection of
surface vessels by patrol aircraft (called ASV, for air to surface vessel),
1op. ant.