Report ITU-R P.2345-3 (06/2025) - Propagation model for IF77
Foreword
Policy on Intellectual Property Right (IPR)
Scope
TABLE OF CONTENTS
1 Introduction
2 Method description
     2.1 Transmission loss
     2.2 Power available
     2.3 Power density
     2.4 Desired-to-undesired signal ratio
3 Horizon geometry
     3.1 Effective earth radius
4 High antenna height
     4.1 Smooth earth horizons
     4.2 Facility radio horizon
     4.3 Higher antenna (aircraft or satellite) horizon
5 Diffraction region
     5.1 Rounded earth diffraction
     5.2 Knife-edge diffraction
     5.3 Diffraction attenuation
6 Line-of-sight region
     6.1 Two-ray path length geometry
     6.2 Effective reflection coefficient
          6.2.1 Divergence and ray length factors
          6.2.2 Surface roughness factors
          6.2.3 Antenna pattern gain factors
          6.2.4 Plane earth reflection coefficients
     6.3 Line-of-sight transition distance, d0
     6.4 Line-of-sight attenuation, ALoS
7 Scattering region
8 Terrain attenuation
9 Free space loss
10 Atmospheric absorption
     10.1 Surface absorption rates
          10.1.1 Determining ray length
          10.1.2 Line-of-sight paths (d ≤ dML)
          10.1.3 Single horizon paths (dML ≤ d ≤ dL1 + dLo1)
          10.1.4 Two horizon paths
11 Variability
     11.1 Variability due to long-term fading
          11.1.1 Time blocks
          11.1.2 Climates
     11.2 Variation due to multipath
          11.2.1 Surface reflection multipath
          11.2.2 Tropospheric multipath
          11.2.3 Variation due to multipath
     11.3 Rain attenuation
     11.4 Variation due to scintillation
     11.5 Mixing distributions
Attachment 1
1 Ray tracing
2 Counterpoise or ground plane
     2.1 Effective reflection coefficient
     2.2 Counterpoise factors
3 Cumulative distribution
Attachment 2  Abbreviations, acronyms and symbols
Attachment 3  Data sets from Figs 13 and 16
Bibliography