By Nathaniel A. Frissell (W2NAF), Philip J. Erickson (W1PJE), Ethan S. Miller (K8GU), William Liles (NQ6Z), Kristina Collins (KD8OXT), David Kazdan (AD8Y), and Nathaniel Vishner (KB1QHX)
Photo by Laura Gooch (N8NFE)
The Ham Radio Science Citizen Investigation (HamSCI) is an international collective of professional researchers and amateur radio operators working together to simultaneously advance the fields of space science and amateur (ham) radio activities. The 2nd US HamSCI meeting was held March 22-23, 2019, organized by Nathaniel Frissell of the New Jersey Institute of Technology (NJIT) and hosted by the Case Amateur Radio Club (Case ARC) at Case Western Reserve University (CWRU) in Cleveland, OH. The theme of this year’s meeting was “Ionospheric Effects and Sensing,” which includes the use of amateur radio techniques for the characterization and observational study of ionospheric phenomena such as traveling ionospheric disturbances, sporadic E, response to solar flares, geomagnetic storms, and other space weather events.
This article starts with a brief description of historical observations that have been made concerning the effects of solar eclipses on the strengths of distant medium wave signals. It continues with a description of how medium-wave DXers used software defined radios (SDRs) for the first time during the solar eclipse of August 2017 to record the entire AM broadcast band (535-1705kHz) for later analysis. Although no plan had been made to create a formal experiment, it appears to be possible to use the data collected to analyze the effect of the eclipse on radio propagation. An example is presented, derived from recordings made at four different receiver locations in western North America, describing large variations in the signal strength from Salt Lake City's KSL-1160kHz during the course of the eclipse. The times that peak signal strengths occurred at the four locations are then compared relative to the times of eclipse totality along the signal paths.