CONTENTS

 

RECOMMENDATION  ITU-R  P.618-9     2
Propagation data and prediction methods required for the design of Earth-space telecommunication systems     2
Scope     2
Annex 1     3
 1     Introduction  3
 2     Propagation loss  5
        2.1     Attenuation due to atmospheric gases  6
        2.2     Attenuation by precipitation and clouds  6
                  2.2.1     Prediction of attenuation statistics for an average year 6
                  2.2.2     Seasonal variations � worst month  9
                  2.2.3     Variability in space and time of statistics  9
                  2.2.4     Site diversity  9
                  2.2.5     Characteristics of precipitation events  12
        2.3     Clear-air effects  13
                  2.3.1     Decrease in antenna gain due to wave-front incoherence  13
                  2.3.2     Beam spreading loss  13
        2.4     Scintillation and multipath fading  14
                  2.4.1     Calculation of monthly and long-term statistics of amplitude scintillations at elevation angles greater than 4�     14
                  2.4.2     Calculation of the deep fading part of the scintillation/multipath fading distribution of elevation angles less than 5�     16
                  2.4.3     Calculation of the shallow fading part of the scintillation/multipath fading distribution at elevation angles less than 5�     18
        2.5     Estimation of total attenuation due to multiple sources of simultaneously occurring atmospheric attenuation     19
        2.6     Attenuation by sand and dust storms  20
 3     Noise temperature  20
 4     Cross-polarization effects  21
        4.1     Calculation of long-term statistics of hydrometeor-induced cross-polarization  21
        4.2     Joint statistics of XPD and attenuation  22
        4.3     Long-term frequency and polarization scaling of statistics of hydrometeor-induced cross‑polarization     22
        4.4     Data relevant to cross-polarization cancellation  23
 5     Propagation delays  23
 6     Bandwidth limitations  23
 7     Angle of arrival 23
 8     Calculation of long-term statistics for non-GSO paths  24