Polarization Phenomena of Low-Frequency Waves

In this paper, the writer outlines the experiments of determining the state of polarization of a downcoming wave by using a cathode-ray oscillograph of Braun-tube type. Observations have been made at the Hiraiso Radio Laboratory near Tokyo for the transmissions of JAA and JND, both of which are the high power low-frequency transmitting stations located at a short distance (about 150 and 360 km respectively) away from the laboratory. The writer summarizes from the results of a series of observations that a downcoming wave is usually in a state of linear polarization during the daytime, and a sudden change occurs at sunset, the wave being changed into an elliptically polarized state, and that the wave transmitted from the station JAA located north of the laboratory is almost always in the state of left-handed polarization at night, while that transmitted from the station JND located west is nearly in the state of linear polarization during both day and night.