|Title||Ionospheric Disturbances at Dawn, Dusk, and During the 2017 Eclipse|
|Publication Type||Conference Paper|
|Year of Publication||2019|
|Conference Name||Hamvention HamSCI Forum|
|Publisher||Dayton Amateur Radio Association|
|Conference Location||Xenia, OH|
The author recently participated in the HamSCI propagation experiments during the August 2017 total solar eclipse and the ARRL November 2017 Frequency Measuring Test. This paper presents some interesting propagation phenomenon observed during both activities. For the eclipse experiment a well-defined propagation enhancement of both 60 kHz WWVB and 5 MHz WWV for a path between Ft. Collins, CO and San Antonio, TX was documented. Additionally, deep propagation nulls of WWVB over this path were observed to occur every morning and evening, suggesting predictable multipath interference between competing daytime and nighttime modes. During the Frequency Measuring Test, propagation-induced frequency variations of 5 MHz WWV were observed to occur at night and especially during dawn and dusk.