Multifrequency Observations of Extremely Low Frequency Electro-Magnetic Radiation

摘要

Multifrequency observations of naturally occurring EM Radiation at ELF were made at Sagamore Hill Radio Observatory, Hamilton, Mass. during the past three years. Some results of these measurements were compared with similar ones made at Kiruna, Sweden. From July 1963 to Aug. 1964 continuous recordings of 8 cps EM radiation were made at Sagamore Hill. A distinct diurnal variation of high nighttime to low daytime level was observed for this period. It is shown that the observed diurnal variation can be correlated with thunderstorm activity. Observations made during the eclipse of July 20, 1963 showed that a return to high nighttime level occurred during the eclipse. Measurements of EM radiation for frequency range 10 cps to 10 kc/s are compared for Sagamore Hill and Kiruna, which is located in the Auroral zone. Measurements of N-S and E-W components of 5 kc/s radiation for November, December, and January of 1963-1964 were also made at Sagamore Hill. From Jan. 1962 to March 1963 continuous recordings of 18 kc/s from a transmitter located at lat. 8 degrees 57 minutes N and long. 70 degrees 34 minutes W were made at Sagamore Hill. (Author)