A Summary and Interpretation of Ultra-High-Frequency Wave-Propagation Data Collected by the Late Ross A. Hull

Until his death in 1938, Ross A. Hull, late editor of QST, the official publication of the American Radio Relay League, had been studying the propagation of 60-megacycle waves between Blue Hill, near Boston, Massachusetts, and his home on Seldon Hill, near Hartford, Connecticut. He was aided in obtaining facilities for this work by the Blue Hill Observatory of Harvard University. An analysis of portions of the data recorded by Hull indicates that, with certain extensions and minor variations, his theories were leading toward the now apparently correct solution of the ultra-high-frequency propagation problems. It was indicated that propagation far beyond the horizon was produced by refraction or reflection in the tropospheric strata. Calculations of radius of ray curvature have been made from data provided by the United States Weather Bureau, from stations near the propagation terminals points. It is indicated that radii of curvature less than the radius of the earth are coincident with conditions favorable to the propagation of strong signals over this path extending far beyond the horizon. A simple equation is given for calculating the radius of ray curvature. It is concluded that more accurate meteorological data with finer structure characteristics should make possible more precise calculation of propagation conditions. It also appears that certain meteorological conditions may be assumed when various propagation conditions are encountered.