Variation of clutter height and its impact on path loss in the VHF/UHF band

A large scale multi-transmitter field strength measurement was conducted in the VHF and UHF bands to investigate the effect of clutter height variation on frequency dependent path loss models. The measured signal was profiled and compared with the prediction of widely used empirical path loss models over the terrain. The results show that all models' prediction errors follow the terrain elevation. The prediction errors were normalized to fit into the Gaussian normal distribution (GND). A close agreement between the measured and predicted distributions show that the GND is an excellent approximation for the prediction error for both UHF and VHF data with a slight deviation observed from the two curves due to terrain variation.