Frequency scaling of slant‐path attenuation in tropical regions

Measured slant‐path attenuation data currently available do not cover every eventuality, thus requiring the use of scaling algorithms to produce estimates of the transmission parameters at a particular site. Several multiple frequency propagation experiments have been conducted over the same path, and the resultant data have been used to derive frequency‐scaling models of path attenuation. Most of these experiments have been conducted in temperate latitudes, and there is some doubt that the scaling models will fit other latitudes, particularly those subject to severe rain climates. James Cook University of North Queensland, Australia has been operating a number of radiometers as part of an experiment conducted for INTELSAT. The radiometers used in this experiment operate at 7·5, 11·6, 19·5 and 28·5 GHz with a common azimuth and an elevation angle of 63°. This paper compares the results at the various frequencies with an existing frequency‐scaling model and comments on the comparison.