Medium-wave propagation in built-up areas

An investigation has taken place into the problems of medium frequency (m.f.) ground-wave propagation in built-up areas. Measurements were made which showed that, in such conditions, the field-strength/distance relationship is often different from that expected on the basis of conventional theories. These conventional theories have been extended and applied to explain the results. A computer prediction method has been devised which uses an integral equation to allow calculations over an inhomogeneous earth, and incorporates a new concept in the value given to surface impedance. Close agreement is shown to exist between the new method and the measured results.