Diffraction in Microwave Interference (site shielding)

Propagation prediction must take account of:

• bulk refractivity of atmosphere

  • effective Earth radius

• diffraction over irregular terrain

  • method of Rec. P.526

Diffraction just one of several interference modes to be considered.

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• To acquire the correct geometry for the path, must take account of the bulk refractivity of the atmosphere, i.e. whether to consider it as exhibiting normal or super-refractive conditions. This will determine the effective Earth radius for the path and in turn the degree of blocking or clearance over obstacles.

• Apply the multiple obstacle method as given in Rec. P.526.

• Note that diffraction will not be the only potential interference mechanism.