A comparison between predicted and measured propagation loss in the VHF/UHF range in rugged terrain

Data from field measurements were compared with predictions based on the Longley-Rice model applied to individual path profiles. The field experiments were designed to reflect the communications deployment situation experienced by group forces. It is indicated that the value of accurate transmission loss calculations is doubtful, particularly in rugged terrain. Strong local variations introduce significant spread in the observed field strength at a given location. The median prediction error was 13 dB at 390 MHz and 20 dB at 34.5 MHz in a moderately rugged area. It is believed that reflections from objects in the horizontal plane are an important contributing factor in reducing prediction reliability at VHF and UHF. The possibility of modelling such phenomena is discussed in a context of tactical applications.