INFLUENCE OF PROPAGATION CURVES ON THE COVERAGE FACTOR.

Variations of the coverage factor c with four types of propagation characteristics, i. e. , C. C. I. R. REP 264-2, C. C. I. R. REP. 400-1: Type 3, USSR (C. C. I. R. Doc. 10/82 (1970-1973), and CAIRO (N/S) (I. R. C. /CAIRO), have been examined. It was found that, under certain conditions, the shape of the curve of c for the type of CAIRO (N/S) is different from that for the type of REP. 264-2. This result has been explained by theoretical analysis. When the CAIRO (N/S) or the USSR curve is used as a sky-wave propagation characteristic, the coverage factor for the sky-wave service under nighttime conditions is considerably less than that for the ground-wave service under daytime conditions even by high power transmitters. Since the coverage factor c, which represents the percentage of area coverage with single frequency, can give only a partial view of the broadcasting coverage, the authors have tentatively proposed extending the definition of the coverage factor to include the effect of distribution of population and the reception quality.