Some techniques for the elimination of corona discharge noise in aircraft antennas

Theories of noise generation and coupling are applied to the problem of devising techniques for the elimination of precipitation static interference in aircraft. The logical consequences of the theory are employed in devising several versions of a decoupled discharger capable of providing precipitation static noise reduction of 60 db. Optimum discharger locations are determined and successful flight tests of the dischargers are described. Various proposed discharger designs are considered in light of the coupling theory, and their performance when tested in the laboratory is discussed. Several antenna designs capable of providing precipitation static reduction on vehicles which do not permit discharger installation are proposed and tested in the laboratory. Electronic techniques for reducing precipitation static interference by operating on the signal at the receiver are considered. Although many of the proposed precipitation-static-elimination techniques are not entirely satisfactory, the decoupled dischargers and decoupled antennas work well enough that precipitation static need not pose a problem under normal flight conditions.