@proceedings {858, title = {Analysis of the HamSCI Solar Eclipse High Frequency Time Difference of Arrival Experiment Observations Using Automated Techniques}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

The objective of our research is to analyze the effects of a solar eclipse on High Frequency (HF) radio by extracting the time difference of arrival (TDOA) due to multiple ionospheric paths of ~3 kHz bandwidth chirp signals sent and received with unmodified commercial off-the-shelf (COTS) single sideband (SSB) amateur radio transceivers. We use programming techniques learned in the Digital Signal Processing course at The University of Scranton in the Python language to automate this process. On the day of the 14 October 2023 eclipse in Texas, WA5FRF transmitted a series of chirps every 15 minutes to receiving stations N5DUP and AB5YO on 5.3 MHz and 7.2 MHz. Received signals were digitized, then squared and low-pass filtered to detect the waveform envelope. Correlation with a matched signal is then used to identify the start time of each chirp, after which a Fast Fourier Transform (FFT) is used to identify the beat-frequency (and TDOA value) generated by the multipath propagation. This TDOA value is then used to compute an ionospheric reflection height. On the WA5FRF-N5DUP path, this analysis shows that the F region reflection point raised from 262.5 km at 17:00 UTC to 300 km at eclipse maximum at 17:30 UTC and then returned to approximately 280 km at 18:00 UTC. This result is in good agreement with the hmF2 observations of the Austin ionosonde.

}, author = {Alexandros Papadopoulos and Gerrard Piccini and Thomas Pisano and Nicholas Guerra and Matthew Felicia and Evan Hromisin and Aidan Montare and Kristina Collins and Paul Bilberry and Samuel Blackshear and Steve Cerwin and Nathaniel A. Frissell} } @proceedings {766, title = {On-Air Multipath TDOA Experiments for Ionospheric Layer Height Measurements Using Amateur Radio Stations}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

}, author = {Steve Cerwin and Paul Bilberry} } @conference {289, title = {Ionospheric Disturbances at Dawn, Dusk, and During the 2017 Eclipse}, booktitle = {HamSCI Workshop 2019}, year = {2019}, month = {03/2019}, publisher = {HamSCI}, organization = {HamSCI}, address = {Cleveland, OH}, abstract = {

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.

}, author = {Steve Cerwin} } @conference {328, title = {Ionospheric Disturbances at Dawn, Dusk, and During the 2017 Eclipse}, booktitle = {Hamvention HamSCI Forum}, year = {2019}, month = {05/2019}, publisher = {Dayton Amateur Radio Association}, organization = {Dayton Amateur Radio Association}, address = {Xenia, OH}, abstract = {

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.

}, author = {Steve Cerwin} } @article {262, title = {Ionospheric Disturbances at Dawn, Dusk, and During the 2017 Eclipse}, journal = {QEX}, year = {2018}, month = {09/2018}, pages = {8-14}, chapter = {8}, abstract = {

The author recently participated in the HamSCI propagation experiments during the August 2017 total solar eclipse, and the ARRL November 2017 Frequency Measuring Test (FMT). This article presents some interesting propagation phenomena observed during both activities. For the eclipse experiment, well-defined propagation enhancements of both 60 kHz WWVB and 5 MHz WWV for a path between Ft. Collins, CO and San Antonio, TX were 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 at night and especially during dawn and dusk. One observed dawn frequency perturbation was particularly interesting because it occurred at a fundamental frequency shift plus two harmonically related overtones, indicating a nonlinear ionospheric response to rapidly increasing solar radiation.

}, issn = {0886-8093}, author = {Steve Cerwin} }