The Army Air Forces in World War II, Vol. 1 (archived PDF)

T H E A R M Y A I R F O R C E S I N W O R L D W A R I 1
borne interception equipment before the end of 1940 and was given
prototypes of the British VHF radio set early in 1941.Similarly, the
IFF device developed in England was copied by the Signal Corps and
was adopted in August 1941as standard American equipment.'l'
Equally important were the ideas the British supplied on the proper
organization of an air defense net. The assignment of full responsibil-
ity for air defense to the Air Corps in the spring of 1941was prompted
in no small part by the demonstrated advantage in Britain's well-
integrated system.' l7 Under the newly established defense commands,
four regional interceptor commands, as components of the four conti-
nental air forces, were charged in their several areas with control for
purposes of air defense of air warning equipment, fighter planes, anti-
aircraft artillery, and barrage balloons." These so-called active agents
of defense were to be supplemented by such passive measures as pro-
vision for civilian air raid warning and blackouts, which were made
the responsibility of organizations working under the supervision of
the Office of Civilian Defense.lls
The warning network planned in the spring of 1941for the United
States represented a compromise with the ideal. A perfect arrangement
would have depended primarily upon a series of radar stations suffi-
cient in number to assure mechanical detection of any hostile force.
But there were not enough radar sets or technicians qualified to man
them for coverage of the entire area of the country; and radar had
not reached a stage of development which permitted it to operate over
land with the same effectiveness it showed over the ocean. No radar
equipment in existence in 1941 outside the laboratories could locate
low-flying airplanes without detecting as "permanent echoes" the
images of prominent landmarks.11QAccordingly, the War Department
planned to recruit civilians to serve as ground observers for report on
the identity and movements of aircraft over land and to use radar to
provide a seaward extension of the warning network.lZ0
In the six months which immediately preceded Pearl Harbor, the
four interceptor commands worked feverishly to create a coastal radar
net and a supporting ground observer corps as components of the Air-
craft Warning Service. When war came, sites had been picked for
thirteen radar stations along the East Coast, and eight of the stations
were approaching completion.'21 On the West Coast, there were ten
radars to guard the 1,200 miles from Seattle to San Diego.'" This
* See above, pp. 153-54.
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