FREQUENCY ASSIGNMENT STUDIES.

The purpose of this study is to improve electromagnetic compatibility in the field army through development of improved frequency-assignment practices. The general frequency-assignment problem is defined in terms of exclusions imposed by the physical nature of equipments and geographic locations. The problem is formalized through use of mathematical set theory, and solutions discussed. The basis for design of frequency groups which automatically satisfy the set theory expressions is established. Methods for replication of assignments and the combination of the replication scheme with the frequency-group method are covered. Optimization methods, and problems arising from intermodulation and adjacentchannel interference are considered. Generation of spurious signals by nonlinear devices is discussed. Realistic prediction formulas have been developed which reflect the order of nonlinearity generating the signal, and which place no limit on the number of impressed signals which may be considered. Rules are established for an assignment sequence capable of eliminating all odd-order interference generation at a radio-relay type site. An exhaustive survey of the current state of knowledge pertaining to calculation of propagation-path loss is presented. The frequency range from VLF through EHF is examined. Calculation methods and attainable accuracies are discussed. Author