Height Gain, Location Gain, and Correlation in Irregular Terrain at 20, 50, and 100 Mhz

摘要

Results on height gain, location gain, and correlation are presented which are based on data obtained from a comprehensive measurement program in irregular terrain at frequencies of 20, 50, and 100 MHz. Specifically, it was found that height gain, but not location gain, is independent of path distance for transmission paths up to 80 km long. Location gain is defined as the reduction in transmission loss obtainable by a search within a 100-m radius of a nominal receiving point. The measurement program permitted simulation of the interaction between net and relay type communication links by simultaneous recordings of signals received from a test station with low transmitting antenna height, and a commercial frequency modulation broadcast station (not co-located) with a high transmitting antenna. It was found that the correlation coefficient between transmission loss values from the two sources is close to unity when the transmission paths have a small angular separation, but decreases with increasing angle between transmission paths. (Author)