Virginia Tech electrical engineering professor Greg Earle, W4GDE, is heading up a National Science Foundation (NSF)-funded solar eclipse experiment dubbed CEDAR — Coupling, Energetics, and Dynamics of Atmospheric Regions. The experiment proposes to study the effects on the ionosphere of the August 21 total eclipse of the sun, using a combination of GPS receivers, the university’s SuperDARN (Super Dual Auroral Radar Network) radar system, HF Amateur Radio, and plasma modeling. Several graduate students and researchers, as well as the Virginia Tech Amateur Radio Association (K4KDJ) and the Amateur Radio community at large have been recruited to help.

“We want to understand how the ionosphere is affected by blockage of sunlight over a relatively short interval (~2 hours), understand how man-made systems are affected by the changes in the ionosphere, and use the data to improve our numerical models,” Earle told ARRL, noting that the “plan has morphed a bit” since the initial proposal of  more than a year ago. Virginia Tech students Magdalina Moses, KM4EGE, and Xiaoyu “Harry” Han, KM4ICI, along with Tech electrical engineering professor Bob McGwier, N4HY, are among those pitching in.

Earle and his team are will use the data they collect to characterize ionospheric plasma density variations caused by the eclipse, measure HF scintillation — rapid fluctuation of signal phase and/or amplitude — during the eclipse, study the motions of plasma irregularities produced in both the E and F layers, and use numerical models to test cause-and-effect scenarios to compare with empirical data.

“The proposed study will utilize diagnostic capabilities that have never before been used to study a mid-latitude eclipse,” the CEDAR abstract explains. “Through this work we will answer several fundamental questions that remain unresolved, despite previous eclipse studies, and we will engage a huge cohort of non-scientists in gathering data that will constrain our models and enrich our understanding of ionospheric behavior.”

That “huge cohort” includes participants in the Solar Eclipse QSO Party (SEQP), sponsored by ARRL and HamSCI. “During this event, radio operators will actively communicate throughout the eclipse interval over paths that transect the eclipsed region of the ionosphere,” the CEDAR proposal outlines. “These data will include information on the signal strength and maximum usable frequency in various HF bands, which are directly related to the density and altitude of the ionosphere.” The experiment will also draw on data generated by WSPR Net and the Reverse Beacon Network (RBN). “Thus, we expect this proposed effort to have wide-ranging impact on the Amateur Radio community, and exceptionally broad involvement of non-scientists ingathering the data required.”

The Solar Eclipse QSO Party on August 21 runs from 1400 until 2200 UTC. Stations will exchange a signal report and six-character grid locator on 160 through 6 meters (excepting 60, 30, 17, and 12 meters). Participants may work the same station again after 10 minutes have passed. Preferred modes are CW, RTTY, and PSK31, because automated receiving networks will record the contacts, but phone and digital contacts are okay too.

Virginia Tech teams at the start, middle, and end of the eclipse footprint in the US also will measure the phenomenon’s effect on low-frequency radar waves. The scientists will measure how long the waves take to go up and down off of the ionosphere and compare it to normal conditions.

Understanding the data and comparing it to models can help scientists better analyze the effects of space weather events on Earth, Earle said.