A new MF and HF ground-wave model for urban areas

Abstract

Following discussions (Luo Lichun 1997) on the propagation and regularities of HF ground waves in urban areas in China, and processing the HF experimental data obtained from 1993 through 1997 and MF data obtained in 1995 and 1997 in Beijing, a new model for MF and HF ground-wave propagation in urban areas is proposed in this paper. The key novelty in the proposed model is the inclusion of three building-complex parameters, r/sub b/, r/sub s/ and r/sub e/, and a new height-gain factor, G/sub h/. A qualitative derivation of these is offered. The method of selecting these building parameters is discussed. Some HF and MF ground-wave propagation losses, which occur under different conditions of the operating frequencies, heights, and locations of the transmitting antennas, are calculated by means of the new model and, for contrast, by means of some earlier models. The new model can be used to calculate either the coarse prediction of ground-wave loss, or to calculate fine predictions, even for a point site. The accuracy of the calculation using the new model is superior to that of the earlier models.