Performance of long range terrestrial wireless communication is critically affected by terrain variation. Of particular interest is the case of a transmitter (base station) placed above clutter, while the mobile receiver is immersed in clutter. Recently published analytical results provided compact asymptotic expressions for pathloss for clutter-covered parabolic terrain, both for valleys and ridges. In both cases, ray-optical term dominated for short ranges, while a single mode dominated at large ranges. Strong focusing was found to occur in valleys. In this work, analytical predictions are compared to measurements collected across a deep valley formed by the Columbia River in Oregon. In comparison to measured power across a valley, mean errors of less than 1 dB were found, a marked improvement over standard terrain-unaware models that produce a mean error of 30 dB.
VHF signal strength data from two NOAA weather radio transmitters, located in southern California and southwestern Arizona, were collected over a wide range of topography ranging from relatively flat to mountainous terrain. Signal strength data were collected using a mobile receiver traveling from 20 km to over 100 km, with the receiving antenna at a constant height of 2.2 meters above the ground. Meteorological information was obtained from local radiosonde measurement stations at Miramar (NKX) and Yuma Proving Ground (1Y7). This data is used as the basis for a validation study of the Advanced Propagation Model (APM) to determine its applicability for low altitude mobile radio communications applications over terrain
Distillation at an infinite reflux ratio in combination with an infinite number of trays has been investigated.