Calculation of Ground-Wave Field Strength over a Composite Land and Sea Path

A brief discussion of the problem is given, together with a description of the three proposed methods of solution. The results of a practical experiment are shown, and curves calculated by the three methods are compared with the observed results. It is shown that the BBC method gives field strengths much nearer to the observed values than the P. P. Eckersley method, and that the method proposed by Millington, while somewhat more laborious to use, also gives results which agree well with observed values. The difference between the three methods is small at low frequencies and when the effect of the discontinuity is not large.