Properties of Tropospheric Scattered Fields

Tropospheric scatter tests were performed in the Southern California region in conjunction with extensive meteorological measurements. The turbulent spectra were found to be, in the region of interest, proportional to k
^-5/3
. In general, the scattered signals were found to agree with the turbulent single scattering model predicted by such a dielectric spectrum. Horizontal beamswinging experiments gave a dependence on the scattering angle of θ
^-14/3
. A stronger θ dependence was observed for vertical beamswinging and is explained by a height dependence of the turbulent fluctuation spectra rather than anisotropy. This explanation is further supported by agreement with Booker and deBettencourt aperture-to-medium coupling loss. A λ
^-1/3
wavelength dependence was observed under standard atmospheric conditions. In the presence of weak turbulent layers a λ
^0.9
dependence in the lower frequency region was observed and is explained in terms of a frequency dependent layer reflection phenomena. The spectra of the envelope of the scattered signal are also given. They are generally Gaussian in shape with the width dependent upon the range, frequency and scattering angle. Other details of their fine structure are also discussed.