Measurement and modelling of amplitude and phase scintillations in an Earth¿space path

This paper gives a complete summary of the theory and experimental results obtained by Portsmouth Polytechnic on the subject of amplitude and phase scintillations on a down-link path through the atmosphere during the Orbital Test Satellite campaign of research at 11.786 GHz and special and emphasis is given to engineering applications. The paper introduces first a brief summary of relevant theoretical studies, inclusive of antenna aperture smoothing, which facilitates the understanding of the scintillation process and the use of the experimental results in system design and planning. The results include chart recording observations, spectra of the scintillations and correlation with meteorological conditions together with results of cumulative distributions of scintillation fade, fade rate and intensity. The subject of propagation-induced phase noise is also dealt with and includes the theoretical estimates of the phase noise due to turbulence and precipitation as well as an outline of the experimental techniques used to measure the f.m. noise of the beacons.