A study for optimizing the field strength prediction of the digital services for ground-wave propagation in the mw band

Résumé

Emerging digital radio systems developed for their use in the LW, MW and SW take advantage of the excellent propagation conditions at these frequencies. The numerous experimental networks to verify the operation of these systems, the increasing trading emissions and the requests promoted by the ITU for further exploration of the propagation below 30 MHz demonstrate the revitalization of these bands. These systems due to their digital nature require a very high degree of coverage and thus, a high accuracy in planning tools. To achieve the required accuracy it is necessary a deep analysis of the ground-wave propagation channel and the spatial variability of the signal under several reception conditions. This thesis provides a method for predicting field strength level for ground-wave propagation in the MW band for digital services planning. Firstly, this thesis makes contributions related to the influence of several factors in the field strength variability in the MW band. Then, a method for field strength prediction, which provides more accurate results than the existing methods for the analogue services, is proposed. The proposed method is composed of a point-to-point model and a point-to-area model.