In this paper, some existing radio wave propagation loss models for the forested environments are briefly reviewed. As
a continuation of the research progress on radio propagation characteristics through forested channels, the experimental measurements carried out on the radio wave propagation loss at VHF (92.1MHz as a case study) through long (~64km) forested communication channels are reported. The experimental measurement results obtained are compared with some existing propagation loss models: Free Space Attenuation (FSA), Ground Reflection (GR) and Canopy Ground Reflection (CGR) models, and integration of foliage-induced effect and reflection effect models: CGR plus ITU-R or SUM(CGR, ITU-R) and CGR plus Weissberger or SUM(CGR, Weissberger). Using the method of least square fit to the experimental measured data,
CGR model gives the best fit for the radio wave propagation loss at VHF (92.1MHz) through long tropical forested channel.
This paper is organized as follows: Section I gives the introduction of the behaviour of the propagation of radio wave through forest channels. Section II briefly review some related work on the