@proceedings {882, title = {High Frequency Raytracing for Studying the Ionosphere and Radio Propagation (Invited Tutorial)}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

High Frequency (HF) raytracing is a tool to study the propagation of HF radio waves through the ionosphere. This presentation will cover the basics of raytracing, including typical inputs and outputs. We will review the different physics that may be included in the raytracer and how changes in the ionosphere may affect the radio wave propagation. A brief description of how to use a raytracer for common applications will be provided. The applicable frequency ranges and limitations of this technique will be also discussed.

}, author = {Katherine Zawdie} } @proceedings {881, title = {Optimizing Location Estimation with Novel Numerical Solution using Real-Time Transmitting Beacons WSPRlive, Weak Signal Propagation Reporter Protocol, and Friis Propagation Model}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

The proliferation of real datasets has become indispensable for implementing various processes in real-time scenarios. Our previous project successfully contributed to expanding data grids aimed at predicting the vertical total electron content (vTEC) for the ionosphere. Leveraging Ham Radio Networks in conjunction with data broadcasted from the International Space Station (ISS), and integrating them into the Galileo-based NeQuickG mathematical model, we developed a web-based application tailored to this purpose. In this study, the focus is on generating new data grids for location estimation within a Radio Frequency (RF) environment, relying solely on transmitter identities and measured received powers. The localization process is divided into two stages. Initially, ideal received powers are computed using the Friis propagation model, resulting in a dataset encompassing over 25,000 locations per received power. To ensure reliability, a hardware implementation of Weak Signal Propagation Reports (WSPR)-based beacons, operational 24/7, is utilized globally. This implementation, facilitated by the IntlWSPR project covering 40 spots, features beacons transmitting at 23 dBm, with maximum gains varying according to antenna types: 7 dBi for Skyloop 80-10, 5 dBi for DX Commander ABV, and 2 dBi for Q-Tek Penetrator antennas. With the ideal dataset established as a reference, location estimation becomes feasible by identifying the best beacon identities per received power for the query receiver. However, numerical solutions for the localization system involve relatively lengthy processing times and exhibit mean square localization errors, motivating the second phase of this work. A novel numerical solution enhancement technique, coupled with a designed radius of convergence, significantly accelerates the convergence of the localization system{\textquoteright}s equations with improved accuracy. Future efforts aim to integrate this enhanced approach into the real-time application, with a focus on estimating the WSPR channel propagation model using additional real data provided by the WSPRnet spot database. Although the WSPRnet spot database offers non-contiguous timed datasets, it serves as a cornerstone for training regression Machine Learning models, facilitating further refinement of the localization process.

}, author = {Gamal Zayed} } @proceedings {875, title = {Wave Activity in Thermospheric Vertical Winds and Temperatures at Subauroral Latitudes}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

The need for high precision measurements of vertical winds with uncertainties less than 3-5 m/s and a temporal cadence of 1-2 min has made it exceedingly difficult to study the response of the thermosphere to gravity wave activity.\  Herein we present subauroral, midlatitude thermospheric wave measurements of 630 nm OI emission from a 15 cm narrow field Fabry Perot Interferometer, named the Hot Oxygen Doppler Imager (HODI).\  These measurements of temperature and vertical wind velocities are from a first light campaign at Jenny Jump Observatory (40.9 N, 74.9 W) located in northwestern New Jersey. The heightened sensitivity of HODI enables analysis of gravity wave behavior with uncertainties of 3-5 m/s for vertical wind speeds and 10-15 K for temperatures for two-minute exposures. Data was collected during periods of geomagnetically quiet and active conditions, and apparent wave structures were seen during both conditions.\  One detailed observation, taken the night of July 25, 2022, enabled the ~90-deg phase shift between vertical winds and temperatures to be inferred, as per standard gravity wave polarization relations with viscous dissipation.\  However, most other observations found to have little correlation between the temperature and vertical winds, which we speculate may be a result of the propagation and interaction of multiple wave events. Traveling ionospheric disturbances (TIDs) are often described as the ionospheric signature of the passage of gravity waves, and we provide comparisons of select wave events to medium scale TIDs using differential total electron count (TEC) maps.

}, author = {Anneliese Schmidt and John W. Meriwether and Matthew B. Cooper and Andrew J. Gerrard and Lindsay V. Goodwin and Shun-Rong Zhang and Gilbert Jeffer and Chris Callie} } @proceedings {690, title = {Evaluation of Global Ionospheric TEC Using Simultaneous Observations from Amateur Radio Networks, International Space Station, and NeQuickG Model for Space Weather Prediction}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

Ionospheric electron density plays a significant role in long-distance communications and sky-wave propagation. Prediction of the accurate state of the ionosphere is necessary to understand the accurate signal perturbations thereby estimating the critical parameters for better signal transmission. The space weather impacts on such trans-ionospheric technological systems are evident. In this work, a web application is developed to represent the global day-to-day electron density variations from the NeQuickG model. Also, the ground-based HAM radio broadcast network hop data with different wavelengths (eg. 10 m and 20 m) and simultaneous top-side electron density with space-based International Space Station (ISS) probe data from floating point measurement units are examined. The electron density variations for the year 2017 are clearly represented. Optimization techniques are necessary to frame a denser spatial grid-based ionospheric electron density map from all the observations. It is essential to estimate the optimal weight function that can distribute the observation influence over empty grid bins with minimum error variance through a probabilistic approach. User-understandable metrics development exclusively for Amateur radio operators and civil aviation sectors is focused. In the near future, the developed web-based application could serve as a better visualization platform for space weather forecasting.

This project, Fellowship of the Ionosphere,\ is a Global Finalist in the 2022 NASA Space Apps Challenge.\ NASA Space Apps 2022 had 31,400+ registered participants from 162 counties and territories, with\ over 3000 submissions from 5327 teams. Global Finalists are ranked as one of the top 35 projects from all submissions.

}, author = {Gamal Zayed and Marcin Lesniowski and Pasumarthi Babu Sree Harsha and Matthew Downs and Daniel Metcalfe and Sila Kardelen Karabulut} } @proceedings {749, title = {Lunar Dust Particle Simulation in the (12-6) Lennard-Jones Potential Approximation}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

We model lunar dust particles as interacting ellipsoidal dipoles by means of Lennard-Jones potentials (L-J). Lunar surface dust particles are continuously bombarded by plasma charge particles coming from the solar wind. It has been recognized that solar wind bombardment leads to strong intergrain interactions between dust particulates leading to collective effects such as attraction of charged dust particles. Formation of electrostatically ordered dust structures is believed to be due to strong attractive van der Waals-like potentials at distances in the order of interparticle separation. Dust-dust electrostatic interactions and collisions may lead to particle coalescence or dust-lumps kept together due to Coulomb forces. On the other hand, dust ionization occurs after solar wind electrons collide with grains in the plasma sheath formed on the lunar surface. Particle coalescence and to an extent condensation is feasible when an attractive potential is present. Ellipsoidal dipole condensation is possible in the presence of a Lennard-Jones (L-J) potential.

}, author = {Rachel Marie Frissell and Joseph Klobusicky and Argyrios Varonides and Amir Zamanian} } @proceedings {508, title = {Characterization of Sporadic E Propagation in WSPRNet Spot Records}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

WSPRNet is a centralized database that collects spot records from amateur radio stations operating weak digital modes. Each of the spot records provides SNR, transmitting power, and geographic information, which can be used to estimate transmission paths. While WSPRNet has primarily used to study propagation paths for HF bands, putative sporadic E propagations at VHF bands have been reported. This on-going exploratory analysis aims to characterize possible Sporadic E Propagations captured in WSPRNet records and possible correlations with solar and other weather conditions. Preliminary results confirms a lack of correlation between sporadic E propagation and F10.7 indices. The geographic distribution pattern of putative sporadic E propagation and its relationship with other space weather indices will be discussed.

}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=56-9E-0F-03-A5-9D-C6-20-FA-F9-00-80-42-84-4B-EA}, author = {Jeannette Zhou} } @proceedings {493, title = {Introduction of Activities at Berkeley ARC W6BB}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=19-77-7A-A0-7D-FF-C1-D6-16-E8-BE-1F-D6-F8-9E-8F}, author = {Michael Zuerch} } @proceedings {464, title = {Traveling ionospheric disturbances tracked through Doppler-shifted AM radio transmissions}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

A comprehensive understanding of the ionosphere is critical for many technologies, particularly those that rely on the propagation of radio waves. This study shows that traveling ionospheric disturbances (TIDs), dawn and dusk signal divergence (terminators), and spread F\ can be tracked and analyzed using clear channel AM radio transmissions and a set of geographically distributed receivers. Early attempts by our research group to track TIDs by AM radio signals reflected from the F region of the ionosphere generated results in conflict with those derived from GPS/TEC mapping methods [Chilcote et al., 2015]. This study seeks to resolve those conflicts with a more sophisticated array of receivers spread throughout the northeastern United States. Specifically, the receivers form a ring around an 810 kHz AM radio station in Schenectady, New York. A minimum of four receivers have been operational from 3/19/20 to the present and Doppler-shifted signals, attributed to TID events, have been consistently visible across several radio channels with frequencies between 800 to 1600kHz. We have focused our study thus far on the terminator signals which appear to be consistent with photochemistry effects and on TID wave characteristic analysis. We have collected a set of exceptional TID events over the past nine months and have correlated our calculated wave characteristics with the data from GNSS TEC, digisonde, and SuperDARN in general finding good agreement between our technique and these established methods. While our study still seeks to clarify discrepancies in our data similar to those seen by Chilcote in the original study, the consistency with which our data typically agrees with other methods supports the validity of using AM radio transmissions to track TIDs in addition to other ionospheric phenomena such as the terminator.\ 

Reference: Chilcote, M., et al. (2015), Detection of traveling ionospheric disturbances by medium-frequency Doppler sounding using AM radio transmissions, Radio Sci., 50, doi:10.1002/2014RS005617.

}, author = {Claire C. Trop and James LaBelle and Philip J. Erickson and Shunrong Zhang and David McGaw and Terrence Kovacs} }