Low Altitude Propagation Effects — A Validation Study of the Advanced Propagation Model (APM) for Mobile Radio Applications

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.