UHF forest propagation measurements

The authors describe an experimental program addressing wideband UHF radiowave propagation through forests. The principal objective of the measurements was to determine the dependence of the transmission loss and delay spread upon such radio path parameters as path length, antenna height, and polarization and upon such forest parameters as tree type, trunk number density, trunk diameter probability density, and forest height. Radio measurements were obtained using the US Army´s Wideband Propagation Measurement System (WPMS), designed for measuring ground-to-ground communication channel characteristics in the 200-2000 MHz band. A preliminary overview of the measured data reveals not only the expected increase of transmission loss with distance, but the unexpected greater transmission loss with horizontal polarization than with vertical at the higher frequencies.<>