Nomograms for the Statistical Summation of Noise in Multihop Communications Systems

Several authors have shown methods for calculating the long-term fluctuation of noise power of multihop systems in which the propagation loss has a log-normal distribution such as in troposcatter FM. However, these methods involve exponentials, the computations are necessarily laborious and time-consuming, and the formulas do not readily reveal the effects of changing parameters. These shortcomings are remedied by two pairs of homographs which eliminate the laborious exponential computations and permit the noise performance calculation to be made within seconds. The nomograms display the effects of varying parameters and clarify the understanding of noise addition. Supplemental data is given reviewing the basis for the calculation, and also in order to enable the reader to extend the nomograms to any other range.