The Development and Application of Marine Radio Direction Finding Equipment by the United States Coast Guard

The various problems dealt with in the evolution, development, and practical application of radio direction finding equipment by the United States Coast Guard are discussed. The equipment in use at the present time is described. Difficulties encountered with marine equipment due to the electrophysical properties of vessels are explained. The methods employed in overcoming these difficulties are described. Some notes on deviation are presented along with curves and photographs showing the results obtained on various types of vessels. Deviation as a function of frequency is discussed in brief. The material presented is based on data obtained from more than one hundred direction finder installations on vessels of various types and sizes ranging from 75-foot motor boats to cutters of 3000 tons displacement. A brief description of aircraft equipment and an account of the results obtained therewith is included. The object of this paper is to present a résumé of the results obtained with modern equipment under the actual conditions encountered in service use, accompanied by such notes and comments by the author as are deemed of interest to those concerned with the development, improvement, and application of marine and aircraft radio direction finders. The fundamental principles underlying the art of direction finding by means of radio are not recounted as it is realized the reader has available numerous current publications on the subject. This paper is published by permission of the Commandant, United States Coast Guard.