Early Fire-Control Radars for Naval Vessels.

New York, American Telephone and Telegraph Company, 1946. 8vo. In the original printed blue wrappers. In "The Bell System Technical Journal", Volume XXV, Number 1, January, 1946. Entire issue offered. Previous owner's name to front wrapper. A very fine fine and clean copy. Pp. 1-46. [Entire issue: 166 pp.]. First printing. The focusing ability of a lens or mirror type antenna is directly related to its width in wavelengths of the radar wave. The wider the antenna is in wavelengths, the smaller the angle of the beam that contains 50% of the radiated energy. The smaller the angle of the beam, the farther the radar can see the target and the more precisely the angle of the target can be known. Nike tracking radars had an effective antenna width of about 150 wavelengths. (The antennas were actually physically a little larger, but there are edge effects which decrease the focusing effect of the edge areas.).