Phase Interference Phenomena in Low-Frequency Radio Transmission

The importance of phase interference phenomena in low-frequency radio transmission (as well as in the high-frequency regions) is emphasized. In the case considered (i.e., reception of WCI near Boston, Massachusetts) these phenomena are shown to exhibit periodicities coincident with cosmical phenomena, i.e., the solar and lunar periods and their harmonics. Strong evidence for the existence of these periods in long-distance low-frequency transmission data and in field intensity data for transmission in the broadcast band is also demonstrated. An automatic field intensity recorder constructed particularly for use in extending the low-frequency observations in progress at Tufts College (and made possible by grants from the National Research Council) is also described, and field intensity records obtained by its use are shown. These records also exhibit phenomena which are probably due at least in part to phase interferences. The effects of magnetic storm phenomena are also displayed.