@proceedings {871, title = {Signatures of Space Weather in the NJIT V1 Grape Low-IF Receiver}, year = {2024}, month = {03/2024}, abstract = {

The V1 Grape Low Intermediate Frequency (Low-IF; 10 MHz) Receiver is part of a low-cost Personal Space Weather Station (PSWS) developed by the Ham Radio Science Citizen Investigation (HamSCI) Collective. One of the existing deployed Grapes is located at the New Jersey Institute of Technology (NJIT). The Grape measures the WWV 10 MHz signal originating from Fort Collins, Colorado. Variations in WWV{\textquoteright}s signal intensity and frequency, received by the Grape can be used to investigate\  strong space weather events and their effects on the Earth{\textquoteright}s ionosphere. The Grape data is separated into two parameters, Doppler Shift (Hz) which is a change in frequency introduced by the variability of the ionosphere along the WWV to NJIT link, and Relative Power (dB) which can be used as a proxy for the received signal{\textquoteright}s intensity.\  In this presentation, we will explore the possibility of using the Relative Power parameter for studying ionospheric scintillation due to space weather events.\  We will present several examples of data collected on days with known space weather events to assess the Grape{\textquoteright}s ability to detect the event. We will also discuss our analysis techniques, including our strategies to mitigate the local noise environment at NJIT, and future work.

}, author = {Tiago Trigo and Gareth W. Perry and Sebastian Fernandes and John Gibbons and Nathaniel A. Frissell} } @proceedings {872, title = {Statistical Study of the Magnetospheric Open-Closed Boundary (OCB) using ULF Wave Observations from Antarctic Ground Magnetometers As Compared to the Tsyganenko Model}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

We present a statistical study using ground magnetometer data which are located over extensive latitudes from subauroral to the deep polar cap region. These include the Antarctic Automated Geophysical Observatories (AGOs), McMurdo Station (MCM), and South Pole Station (SPA), to characterize open-closed boundary (OCB) behavior during geomagnetically quiet times. Knowledge of the location and dynamics of the magnetic field line OCB provides insight to space physics processes such as substorms, particle precipitation events, and magnetospheric configuration. Prior studies have shown that determination of the OCB location can be made by examining the ULF wave power in data from a latitudinal chain of ground-based magnetometers extending from the auroral zone into the deep polar cap.

}, author = {Rachel M. Frissell and Hyomin Kim and Andrew Gerrard and Nathaniel A. Frissell} } @proceedings {726, title = {Statistical and Case Studies of Open Closed Boundaries (OCB) using ULF Wave Observations from Antarctic AGOs, McMurdo Station, and South Pole Station}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

We present a statistical study using ground magnetometer data from the Antarctic Automated Geophysical Observatories (AGOs) to characterize open- closed boundary (OCB) behavior during geomagnetically quiet times. Knowledge of the location and dynamics of the magnetic field line OCB provides insight to space physics processes such as sub storms, particle precipitation events, and magnetospheric configuration. Prior studies have shown that determination of the OCB location can be made by examining the ULF wave power in data from a latitudinal chain of ground-based magnetometers extending from the auroral zone into the deep polar cap. In this statistical study, AGOs 1, 2, 3, and 5, along with McMurdo (MCM) and South Pole Station (SPA) were studied. The seasons chosen were centered around the four cardinal dates, March 20th, June 21st, September 22nd, and December 21st. For each season, 60 days were selected centered around the cardinal date; any days with a planetary Ap greater than 30 were discarded. Using the H- component fluxgate data from South Pole Station, McMurdo Station and the AGO systems, an average daily residual power spectra was calculated. The spectrograms for SPA, MCM, and AGO show signatures of whether the station is located in an open or closed magnetic region. We will present case studies of individual days and a climatology of ULF activity as a function of season.

}, author = {Rachel M. Frissell and Andrew J. Gerrard and Hyomin Kim and Nathaniel A. Frissell} } @proceedings {616, title = {Short-Term Variability Associated with 20 Meter Sequential Matched WSPR Observations: A Statistical Exploratory Study}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

Automated amateur radio networks such as the Reverse Beacon Network and WSPRnet record details about hundreds of millions of radio contact contacts that investigators can use to study and ultimately predict HF propagation and its relationship to solar phenomena. However, before researchers can undertake such investigations, it is crucial to understand and document the variability inherent in the measurements provided by these networks. Here, we investigated the short-term variability associated with the signal-to-noise(SNR) reports from WSPRnet. Specifically, we analyzed 2,286,311 pairs of 20 meter WSPR SNR reports observed between Jan 2017 and July 2021. Each pair consisted of two sequential WSPR observations between the same two stations, i.e., the paired observations were separated by a single WSPR time slot of two minutes.\  To describe the SNR variability, we present the SNR distributional characteristics and use Generalized Linear Models (GLMs) to explore the influence of the time of day, the month of the year, and the azimuth between the stations. The models predicted the absolute SNR difference between the sequential observations. Model errors were adjusted to account for multiple observations of pairs of stations. To account for the non-gaussian data distribution, the GLMs assumed a gamma distribution with a log link. Because this study was exploratory, we included all three covariates as categorical variables rather than imposing a particular model form. The three models reported here consist of a fully specified two-way interaction between two of the three covariates, i.e., both main effects and interaction.\  \ Computing resource limitations limited the complexity of the models investigated. Based upon the predicted model averages, two sequential WSPR reports typically vary by 6 dB. Deviations from this average are apparent by month, hour, and azimuth between the reporting stations, and we show those graphically. Future research should increase the complexity of the models to incorporate other covariates, e.g., distance or latitude, ultimately tying these data to solar and atmospheric phenomena.

}, author = {Robert B. Gerzoff and Nathaniel A. Frissell} } @conference {542, title = {Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2021}, month = {06/2021}, publisher = {CEDAR}, organization = {CEDAR}, address = {Virtual}, abstract = {

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasi-periodic variations in F region electron density with horizontal wavelengths \> 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected in simultaneously over the continental United States in observations made by global High Frequency (HF) amateur (ham) radio observing networks and the Blackstone (BKS) SuperDARN radar. The amateur radio LSTIDs were observed on the 7 and 14 MHz amateur radio bands as changes in average propagation path length with time, while the LSTIDs were observed by SuperDARN as oscillations of average scatter range. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. The amateur radio and BKS SuperDARN radar observations corresponded with Global Navigation Satellite System differential Total Electron Content (GNSS dTEC) measurements. dTEC was used to estimate LSTID parameters: horizontal wavelength 1136 km, phase velocity 1280 km/hr, period 53 min, and propagation azimuth 167{\textdegree}. The LSTID signatures were observed throughout the day following ~400 to 800 nT surges in the Auroral Electrojet (AE) index. As a contrast, 16 May 2017 was identified as a period with significant amateur radio coverage but no LSTID signatures in spite of similar geomagnetic conditions and AE activity as the 3 November event. We hypothesize that atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications and associated Joule heating are the source of the LSTIDs, and that seasonal neutral atmospheric conditions may play a role in preventing AGW propagation in May but not in November.

}, author = {Nathaniel A. Frissell and Diego F. Sanchez and Gareth W. Perry and Dev Joshi and William D. Engelke and Evan G. Thomas and Anthea Coster and Philip J. Erickson and J. Michael Ruohoniemi and Joseph B. H. Baker} } @proceedings {478, title = {A Survey of HF Doppler TID Signatures Observed Using a Grape in New Jersey}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=6A-B6-94-74-A1-46-CF-D2-AC-BA-F3-58-2E-71-17-97}, author = {Veronica I. Romanek and Nathaniel A. Frissell and Dev Joshi and William Liles and Kristina Collins and John Gibbons and David Kazdan} } @conference {325, title = {Sounding the Ionosphere with Signals of Opportunity in the High-Frequency (HF) Band}, booktitle = {HamSCI Workshop 2019}, year = {2019}, month = {03/2019}, publisher = {HamSCI}, organization = {HamSCI}, address = {Cleveland, OH}, abstract = {

The explosion of commercial off-the-shelf (COTS) education- and consumer-grade hardware supporting software-defined radio (SDR) over the past two decades has revolutionized many aspects of radio science, bringing the cost and calibration of traditionally complex receiver hardware within the grasp of even advanced amateur experimenters. Transmission has now become the limiter of access in many cases, particularly through spectrum management and licensing considerations. Fortunately, several classes of signals endemic to the HF band lend themselves to processing for ionospheric characteristics: time and frequency standard broadcasters, surface-wave oceanographic radars, amateur radio transmissions, and ionospheric sounders.

This presentation is a tour of these signals of opportunity and techniques for collecting and processing them into ionospheric characteristics, with emphasis on distributed receivers collecting on a small number (four or fewer) of coherent channels. Receiving techniques will be discussed for near-vertical ({\textquotedblleft}quasi-vertical{\textquotedblright}) incidence skywave (NVIS or QVI), long-distance oblique soundings, and transionospheric sounding. Soundings will be demonstrated from space-based, ground-based, and maritime platforms.

Binary, Doppler, delay, cone angle of arrival, and polarization observations will be exploited, depending on the signal type and capability of the collector. Each of these techniques conveys different, but not always {\textquotedblleft}orthogonal,{\textquotedblright} information about the ionospheric skywave channel. The information content of each datum will be discussed with respect to the implications for inverting the local or regional ionosphere from the observations. More importantly than inverting the full ionosphere, some of these techniques are sensitive indicators of ionospheric irregularities, structures, and instabilities, that might otherwise be difficult to study due to limited geographic coverage with larger, more exquisite instrumentation.

}, author = {Ethan S. Miller and Gary S. Bust and Gareth W. Perry and Stephen R. Kaeppler and Juha Vierinen and Nathaniel A. Frissell and A. A. Knuth and Philip J. Erickson and Romina Nikoukar and Alexander T. Chartier and P. Santos and C. Brum and J. T. Fentzke and T. R. Hanley and Andrew J. Gerrard} } @conference {165, title = {The Solar Eclipse QSO Party: Ionospheric Sounding Using Ham Radio QSOs}, booktitle = {Dayton Hamvention}, year = {2017}, address = {Xenia, OH}, abstract = {

The 2017 Total Solar Eclipse is expected to temporarily induce profound changes on ionospheric structure, dynamics, and radio propagation. The ARRL and HamSCI are sponsoring a Solar Eclipse QSO Party (SEQP) that will be used to generate to assist in imaging ionospheric changes before, during, and after the eclipse. Data will be collected through participant submitted logs and the use of automated tools such as the Reverse Beacon Network (RBN), PSKReporter, and WSPRNet. SEQP rules and a prediction of results will be presented.

}, author = {Nathaniel A. Frissell and Joshua D. Katz and Andrew J. Gerrard and Magdalina Moses and Gregory D. Earle and Robert W. McGwier and Ethan S. Miller and Stephen Kaeppler and H. W. Silver} }