Field Strength Prediction in Irregular Terrain – the PTP Model

This report describes a prediction technique for the calculation of the field strength of radio waves over irregular terrain paths. The concept of an "equivalent rounded obstacle" is used to account for radio propagation losses over various possible irregular terrain shapes, including shapes which cannot easily be described geometrically. The technique replaces an arbitrary terrain profile with an equivalent rounded obstacle for which a value of path loss can be calculated using appropriate formulas.