Propagation Characteristics of VHF over a Distance of 125km

The statistical study of the field intensity of VHF wave over a distance of 125km was done by using mainly the observed data of 150Mc wave and partly those of 65Mc wave. For this purpose, the weather maps, the aerological data obtained at Tateno Aerological Observatory and the meteorological elements observed at Kokubunji and Hiraiso were fully investigated. The field intensity and the range of its diurnal variation are large in summer and spring, and small in winter and on the day of precipitation. The abnormally high field intensity which appears frequently and its severe variation are considered to be reduced to the complicated distributions of the meteoroloical elements in the lower atmosphere. The effect of front is recongnized and it seems to be more remarkable in the night than in daytime.