Estimation of the Single Obstacle Attenuation in MF Band from Field Data

Emerging digital technologies for MF and HF bands need revision of the propagation and prediction methods. In particular, MF digital radio services are affected by field strength attenuation due to terrain irregularities and specific features of urban areas. The aim of this study is to analyze the signal attenuation caused by terrain obstruction of path profiles. The terrain irregularities will be modelled as triangular wedge shaped obstacles. Two parameters are considered on this study: the distance between the obstacle and the receiver, and the height of the obstacle over the line of sight that links transmitter and receiver. The relation between these two parameters and the signal level attenuation behaviour has been modelled, and assessed by representative curves. Field data used in the analysis were collected from a digital MF band experimental transmission.