| Abstract: | The data in the CCIR data banks were employed for a statistical study of the relative performance of several rain attenuation prediction procedures in temperate and tropical regions. The results show that the models worked well, in general, when used for prediction at latitudes more than 30° from the equator, but, in the equatorial region, significant prediction errors were observed for all the models. Three sources of error were discovered. The most important is the use of too few rain climate zones to span the wide range of rain conditions present in the equatorial region. The second is an inadequate procedure for taking the naturally occurring vertical variations of specific attenuation into account. Finally, for the CCIR attenuation prediction model, the use of a universal shape for the cumulative distribution of path attenuation must be called into question. |
