Paper on Grape Personal Space Weather Station HF Doppler Observations Published

Dr. Kristina Collins, KD8OXT, is the lead author on a new paper published in the peer-reviewed journal Earth System Science Data entitled Crowdsourced Doppler measurements of time standard stations demonstrating ionospheric variability. The Grape Personal Space Weather Station is a low-cost, high frequency (HF) receiver designed to make precision measurements of signals received from frequency standards stations such as WWV, WWVH, and CHU. Because these standards stations transmit carriers with atomic-clock grade frequency stability, and the Grape receiver achieves similar frequency stability through the use of a GNSS Disciplined Oscillator, variations in the received signal can be attributed to changes in the ionosphere. The new paper demonstrates this in multiple ways, including showing changes in Doppler frequency due to the dawn and dusk terminators, seasonal variations, wave signatures with Medium Scale Traveling Ionospheric Disturbance periods, and the ionospheric response to solar flares. The paper also explains how to access Grape data and the open-source software used to conduct the analysis. The co-author team consists of professionals, students, and HamSCI volunteers, including Kristina Collins KD8OXT, John Gibbons N8OBJ, Nathaniel Frissell W2NAF, Aidan Montare KB3UMD, David Kazdan AD8Y, Darren Kalmbach KC0ZIE, David Swartz W0DAS, Robert Benedict KD8CGH, Veronica Romanek KD2UHN, Rachel Boedicker AC8XY, William Liles NQ6Z, William Engelke AB4EJ, David G. McGaw N1HAC, James Farmer K4BSE, Gary Mikitin AF8A, Joseph Hobart W7LUX, George Kavanagh KB1HFT, and Shibaji Chakraborty KN4BMT. The Grape receivers are the focus of an NSF-funded experiment to study the upcoming 2023 annular and 2024 total solar eclipses. More information on building your own Grape receiver is available at hamsci.org/grape.

Figure from Paper: Heat maps of frequency (a) and amplitude (b) of 10 MHz WWV received by N8OBJ in Macedonia, OH. Each day represents a line of pixels from top to bottom, with corresponding UTC times lined up across the plots horizontally. Diel variation, and the seasonal shift of sunrise and sunset times per Fig. 7, is clearly visible in both plots. A new antenna and preamplifier were installed on 26 August 2021, resulting in higher received power.

Collins, K., Gibbons, J., Frissell, N., Montare, A., Kazdan, D., Kalmbach, D., Swartz, D., Benedict, R., Romanek, V., Boedicker, R., Liles, W., Engelke, W., McGaw, D. G., Farmer, J., Mikitin, G., Hobart, J., Kavanagh, G., and Chakraborty, S.: Crowdsourced Doppler measurements of time standard stations demonstrating ionospheric variability, Earth Syst. Sci. Data, 15, 1403–1418, https://doi.org/10.5194/essd-15-1403-2023, 2023.