Precipitation-Static Interference on Aircraft and at Ground Stations

The effect of precipitation static on aircraft reception is described and a history of previous work on the subject given. The results of an expedition assembled by the United Air Lines for a study of the subject are described under a series of chapter headings. The meteorological conditions producing the static areas were explored by flights through them and the theory of their formation is discussed. Flight tests of all known types of antistatic antennas were made in bad-weather areas and their effectiveness compared. A theory that the interference results from corona produced on the plane structure was developed and tested by mounting the plane on insulators and charging it to 100,000 volts with all radio equipment and personnel on board. A method for reducing the corona was developed as a result and proved by flight tests. A study of the electromagnetic radiation from corona discharges was made with a synthetic static generator and the operation of the metallically shielded antistatic loop antennas explained and its limitations established. A commercial form of plane discharge system was developed and its advantages and limitations are described. The application of the aircraft results to ground radio reception is discussed.