Wideband propagation measurements of the VHF-mobile radio channel in different areas of Austria

A good knowledge of the mobile radio channel is the key for an optimized digital communication system. Especially in mountainous areas the channel is very critical, because the topography of the different mountains and valleys leads to scenarios with a lot of multipath propagation. A wideband channel sounder, developed in our laboratory, uses a chirp impulse compression technique based on a surface acoustic wave (SAW) filter, synchronized by a Global Position System (GPS) time reference. Using these highly stable references the compressed chirp can be demodulated coherently and the time-variant channel impulse response, which gives a very compact description of the radio channel, can be calculated from the measured data. Results of measurements of the propagation characteristics in the VHF frequency range (30-88 MHz) are reported. The radio channel of three different regions (flat terrain, hilly terrain, mountainous area) is compared and suitable parameters for their characterization are presented.