On the question of the magnitude of the lunar variation in radio field strength

Eight years of continuous recordings of the field strength of station WIW, and nine years of recordings of station W8XAL, both located near Cincinnati, Ohio, were examined for a lunar variation. The recordings were made at Washington, D.C. approximately 600 km away. The transmitted frequencies were 700 and 6,080 kc, respectively. In the case of WIW, nighttime values of hourly median field strength were used. In the case of W8XAL, midday values were. used. In neither case was the amplitude of the lunar semi-diurnal harmonic obtained by the analysis significantly greater than the probable error. The probable error in each case was approximately 0.3 db.