Variable-elevation beam-aerial systems for 1¿ metres

A method is described of producing a radio beam which is very narrow in the vertical plane, but has broad horizontal coverage, and the elevation of which can be varied rapidly. Two practical installations built in 1941 are described and explained. The first produces a 3-deg beam and measures elevation to an accuracy of about ± 0.3° over the range 1¿ to 15°. The second produces a 1¿ deg-beam and measures from ¿ to 15°, with a maximum error of 0.15°. The wavelength used is 1¿ m and the systems described are of the ¿commonaerial¿ type, the same aerial being used for transmission and reception of radar reflections from aircraft. The beam position is entirely calculable and the apparatus requires no calibration.