THE SIGNAL CORPS DEVELOPMENT of U.S. ARMY RADAR EQUIPMENT PART 1 Early Research and Development - 1918 - 1937 by H. M. DAVIS, 1st Lt., Signal Corps March 1943 CONFIDENTIAL DECLASSIFIED DOD DIR5200.9 1972 Control Approval Symbol SPSEO-100 Project "A-1"

NOTICE: This document contains information affecting the  national defense of the United states within the meaning of the  Espionage Act, 50 17. S. C. , 31 and 32. as amended.  The transmission or the revelation of its contents in any manner to an unauthorized person is prohibited by law. Copy No. 27of35copies made xiv plus 69pages and  31 illustrations Historical Section Field office Special Activities Branch Office Service Division Office of the Chief Signal officer Army Service Forces

       The following military characteristics were set up by the Chief of Coast Artillery in 18th Ind. dated 1 February 1936, file 413.684/AF and forwarded with approval by The Adjutant General to the Chief Signal Officer 29 February 1936.

1. Military purposes.
 

a. Detect the presence in a water area of marine surface craft of types that may be employed in operations by an enemy; the apparatus to be actuated by the heat radiation from some part of the craft.

b. Register, or indicate, in proper units of measure the current position of the located craft with respect to the detector or some other designated reference point; this indication of data to be continuous so that the vessel while in motion may be followed by a searchlight or observing instrument laid on such data.

2. Essential qualities of the device.
 

 a. Under all atmospheric conditions the accuracy of the indicated data must be such as to permit of laying the search-light or observing instrument in direction with a maximum deviation of 1 degree from the actual position of the craft.

b. It must begin to furnish data of the above specified accuracy immediately after the device begins to operate.

c. Under average atmospheric conditions it must function during daylight or darkness at ranges up to the limit of the horizon.

d. Under conditions of rain, mist, smoke, or fog, it must function at ranges up to 15,000 yards, so that a target may be located and reasonably accurate fire may be delivered on it.

e. The design of the apparatus and the material employed must be such as to permit of operation by the average skilled enlisted personnel.

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f. The material employed must be of such nature as to withstand the conditions of climate and service, including shock from gun fire, which ordinarily obtain in localities where the apparatus would be employed.

g. The bulk and weight of the apparatus must be such as to permit of its ready installation in detached positions along the shore line without forming a conspicuous target.

h. The requirements of agencies, such as electric current, to operate the apparatus must be such as to permit of its installation and use in the normal harbor defense command without the addition of complicated equipment or construction.