CONTENTS

RECOMMENDATION  ITU-R  P.1812     2
A path-specific propagation prediction method for point-to-area terrestrial services in the VHF and UHF bands     2
Scope     3
Annex 1     4
1 Introduction  4
2 Model elements of the propagation prediction method  5
3 Input parameters  5
        3.1 Basic input data  5
        3.2 Terrain profile  6
        3.3     Radio-climatic zones  6
        3.4 Terminal distances from the coast 7
        3.5 Basic radio-meteorological parameters  7
        3.6 Incidence of ducting  7
        3.7 Effective Earth radius  8
        3.8 Parameters derived from the path profile analysis  8
 4     The prediction procedure  9
        4.1     General 9
        4.2 Line-of-sight propagation (including short-term effects) 9
        4.3 Propagation by diffraction  10
                  4.3.1 Median diffraction loss  10
Median diffraction loss for the principal edge     10
Median diffraction loss for transmitter-side secondary edge     11
Median diffraction loss for the receiver-side secondary edge     12
Combination of the edge losses for median Earth curvature     13
                  4.3.2 The diffraction loss not exceeded for β₀% of the time  13
Principal edge diffraction loss not exceeded for β₀% time     13
Transmitter-side secondary edge diffraction loss not exceeded for β₀% time     13
Receiver-side secondary edge diffraction loss not exceeded for β₀% time     14
Combination of the edge losses not exceeded for β₀% time     14
                  4.3.3 The diffraction loss not exceeded for p% of the time  14
        4.4 Propagation by tropospheric scatter 15
        4.5 Propagation by ducting/layer reflection  16
        4.6 Basic transmission loss not exceeded for p% time and 50% locations ignoring the effects of terminal clutter     17
        4.7 Terminal clutter losses  19
        4.8 Location variability of losses  20
        4.9 Building entry loss  22
       4.10 Basic transmission loss not exceeded for p% time and p_L% locations  23
       4.11 The field strength exceeded for p% time and p_L% locations  23
Appendix 1 to Annex 1  Radio-meteorological data required for the prediction procedure     24
Appendix 2 to Annex 1  Path profile analysis     25
1 Introduction  25
2 Construction of path profile  26
3 Path length  27
4 Path classification  27
5 Derivation of parameters from the path profile  28
        5.1 All paths  28
                  5.1.1 Transmitting antenna horizon elevation angle, θ_t 28
                  5.1.2 Transmitting antenna horizon distance, d_lt 28
                  5.1.3 Receiving antenna horizon elevation angle, θ_r 29
                  5.1.4 Receiving antenna horizon distance, d_lr 29
                  5.1.5 Angular distance θ (mrad) 29
                  5.1.6 “Smooth-Earth” model and effective antenna heights  29
Appendix 3 to Annex 1  An approximation to the inverse complementary cumulative  normal distribution function     32