@proceedings {949, title = {Climatology of Large-Scale Traveling Ionospheric Disturbances Observed with 14 MHz Amateur Radio Using a Novel Automated Detection Technique}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

We present a multi-year climatology of Large Scale Traveling Ionospheric Disturbance (LSTID) period oscillations observed using 14 MHz amateur (ham) radio data. Traveling ionospheric disturbances (TIDs) are quasi periodic electron density perturbations in the F region ionosphere that affect radio communications and can help with understanding energy transport throughout the coupled magnetosphere-ionosphere-neutral atmosphere system. These are seen, in daytime, as variations in contact ranges in 14 MHz amateur radio communication reports recorded by automated monitoring systems such as the Weak Signal Propagation Reporting Network (WSPRNet), the Reverse Beacon Network (RBN), and PSKReporter. A new deterministic and fully automated method was developed for identifying and quantifying these disturbances. This technique, which filters for TID wave periods between 1 and 5 hours and curve fits a sinusoidal function to the first hop skip-distance edge of observed communication ranges, provides both TID amplitudes and periods. In this study, we present full year climatologies of LSTID events over the continental United States (CONUS) using RBN, WSPRNet, and PSK observations from 2016- 2021. Results are organized as a function wave period, amplitude, and season. We find that LSTIDs increase in winter and decline during the fall and spring, with slight enhancements in the summer and occasional brief declines in LSTID winter activity. This seasonal pattern shows consistency with previous studies and observations of LSTIDs and medium scale TIDs that suggests this behavior may be associated with neutral wind filtering in the middle atmosphere, sudden stratospheric warming (SSW) events, and multi-step vertical coupling (MSVC) processes. MSVC is a process where gravity waves (GWs) from the lower neutral atmosphere propagate upwards, break, and produce new, higher-order GWs in the thermosphere and TIDs in the ionosphere.

}, author = {Diego Sanchez and Nathaniel Frissell and Mary Lou West and V. Lynn Harvey and Sharon Vadas and Erich Becker and Gareth Perry and William Engelke and Nicholas Callahan and Philip Erickson} } @proceedings {973, title = {Electron thermionic emission and tunneling transport in spherically symmetric charged grains in dusty plasmas}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

Electron emission from charged spherical dusty grains plays a crucial role in plasma environments, influencing charge dynamics and transport properties. This presentation explores thermionic emission and quantum tunneling as potential escape mechanisms for electrons in such systems. Using the Richardson-Dushman equation, we estimate thermionic emission currents at high temperatures, revealing significant electron loss under extreme conditions. Additionally, we analyze the feasibility of quantum tunneling, incorporating Debye shielding effects to assess barrier modifications and electron transmission probabilities. Our findings suggest that while thermionic emission dominates at elevated temperatures, tunneling can contribute non-negligibly in dense plasma conditions, influencing overall charge equilibrium. A promising direction for future probing is the impact of dynamic charge fluctuations on tunneling probabilities, which could further refine our understanding of electron escape processes in fluctuating plasma environments.

}, author = {Rebecca Potter and Nina Tormann and Argyrios Varonides} } @proceedings {975, title = {Incorporating HamSCI Project into a College Physics Course: A Progress Report}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

We report on citizen science activities in a physics course and Space Force ROTC training designed to engage undergraduate students and cadets in the HamSCI Personal Space Weather Station (PSWS) project. The New Jersey Institute of Technology (NJIT) Physics Department offers a senior-level lab course, "Advanced Physics Lab," where students are expected to gain hands-on experience with experimental techniques, instrumentation, theoretical and applied electronics, solid-state electronic devices, and experiments in modern physics by performing quantitative measurements of fundamental physical parameters. In this lab, students work in a largely unstructured environment, where they are provided with equipment and related manuals to conduct experiments with minimal instructor supervision. Traditionally, students have followed preset lab setups, guided by the manuals that accompany the equipment. While this approach helps students relate lab results to established physics theories and principles, its impact has been limited due to a lack of "hands-on" experience and real-world application demonstrations. The HamSCI PSWS project provides an excellent opportunity to address this gap. Through the project, students build and test scientific instruments, using them for investigations that engage them directly in scientific inquiry. This paper presents an evaluation of the impact of this undergraduate class activity on future workforce development, utilizing HamSCI resources.

}, author = {Hyomin Kim and Jeremy McLynch and Joseph Visone and Dominick Santelli and Sergio Santelli and Gareth Perry and Nathaniel Frissell and Gary Mikitin and John Gibbons and David Witten} } @proceedings {972, title = {Investigating January 2016 Traveling Ionospheric Disturbance Causes with SuperDARN}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) are quasi-periodic variations of F-region ionospheric densities that are most often associated with atmospheric gravity waves (GWs) generated in the lower neutral atmosphere. The ionospheric variations caused by MSTIDs can focus and defocus HF radio signals, propagating through the ionosphere, thereby causing changes in the range at which these radio signals are refracted back to Earth. Using this principle, high frequency radars such as those in the Super Dual Auroral Radar Network (SuperDARN) can be used to observe MSTIDs. The SuperDARN MSTID Multiple Signal Classification (MUSIC) Algorithm can be used to determine the period, wavelength, speed, and direction of propagation of the observed MSTIDs. We present SuperDARN observations over the North American continent for the period of 11-16 January 2016 as shown in Vadas et. Al. 2024. \ This period is known to be important in terms of the polar vortex generating GWs that seed MSTID activity through multi-step vertical coupling processes. A period of low MSTID activity is observed from 11-13 January followed by a period of elevated MSTID activity from 14-16 January, which is observed across multiple radar fields of view. For this period of interest, an Investigation of MUSIC{\textquoteright}s radar-by-radar reports of observed MSTID parameters including direction of propagation, speed, and period and their comparison to polar vortex activity level observation is also presented.\ 

}, author = {Michael Molzen and Nathaniel Frissell and Sharon Vadas and Lynn Harvey} } @proceedings {966, title = {Machine learning applied to the ray tracing model of the OTH radar}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

Over-the-horizon skywave radar (OTHR) uses reflections in the Earth{\textquoteright}s ionosphere to detect targets at very long ranges. To achieve detection, the electromagnetic energy emitted by the radar must follow a specific path with the target as its endpoint. This propagation path is strongly dependent on three factors: the direction of emission, the frequency of the electromagnetic wave and the conditions of the propagation medium, in particular the dynamic and complex characteristics of the ionosphere. From the above, it can be concluded that for this type of radar, the prior determination of the wave propagation path is essential for the correct operation of the system. In this work we are presenting the first results of a computational model based on Machine Learning to predict the propagation path of an electromagnetic wave emitted by an OTHR. A variety of ray tracing models are currently available. These models can range from very simple versions using analytical equations to versions that find the propagation path by solving a system of differential equations using numerical integration methods. The proposed model will provide solutions to the main disadvantages of traditional ray tracing models based on systems of differential equations, such as: Speed of response: once trained, the neural network model is able to respond to new queries almost instantaneously; Adaptive capability: unlike traditional models, neural networks can be retrained or adapted to incorporate new data and scenarios, improving accuracy, and, finally Reduced computing resources: optimised neural network models can run on less demanding hardware than numerical integration methods.

}, author = {Zenon Saavedra and Alexis Vale and Ana Georgina Elias} } @proceedings {820, title = {Citizen Science: Development of a Low-Cost Magnetometer System for a Coordinated Space Weather Monitoring}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

As part of Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project, a low-cost, commercial off-the-shelf magnetometer has been developed to provide quantitative and qualitative measurements of the geospace environment from the ground for both scientific and operational purposes at a cost that will allow for crowd-sourced data contributions. The PSWS magnetometers employ a magneto-inductive sensor technology to record three-axis magnetic field variations with a field resolution of ~3 nT at a 1 Hz sample rate. Crowd-sourced data from the PSWS systems will be collected into a central archive for the purpose of public access and analyzation along with space weather research. Ultimately, data from the PSWS network will combine the magnetometer measurements with high frequency (HF, 3-30 MHz) radio observations to monitor large scale current systems and ionospheric disturbances and events due to drivers from space and the atmosphere alike. A densely-spaced magnetometer array, once established, will demonstrate their space weather monitoring capability to an unprecedented spatial extent. Magnetic field data obtained by the magnetometers installed at various locations in the US are presented and compared with the existing magnetometers nearby, demonstrating that the performance is entirely satisfactory for scientific investigations.

}, author = {Joseph Visone and Hyomin Kim and David Witten and Julius Madey and Nathaniel A. Frissell and John Gibbons and William D. Engelke and Anderson Liddle and Nicholas Muscolino and Zhaoshu Cao} } @article {913, title = {Citizen science: Development of a low-cost magnetometer system for a coordinated space weather monitoring}, journal = {HardwareX}, volume = {20}, year = {2024}, month = {Jan-12-2024}, pages = {e00580}, abstract = {
As part of Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project, a low-cost, commercial off-the-shelf magnetometer has been developed to provide quantitative and qualitative measurements of the geospace environment from the ground for both scientific and operational purposes at a cost that will allow for crowd-sourced data contributions. The PSWS magnetometers employ a magneto-inductive sensor technology to record three-axis magnetic field variations with a field resolution of\ 3 nT at a 1 Hz sample rate. The measurement range of the sensor is\ \ nT) and is valid over a temperature range of -40 {\textdegree}C to +85 {\textdegree}C. Data from the PSWS network will combine these magnetometer measurements with high frequency (HF, 3{\textendash}30 MHz) radio observations to monitor large-scale current systems and ionospheric disturbances due to drivers from both space and the atmosphere. A densely-spaced magnetometer array, once established, will demonstrate their space weather monitoring capability to an unprecedented spatial extent. Magnetic field data obtained by the magnetometers installed at various locations in the US are presented and compared with the existing magnetometers nearby, demonstrating that the performance is very adequate for scientific investigations.
}, keywords = {magnetometer}, issn = {24680672}, doi = {10.1016/j.ohx.2024.e00580}, url = {https://www.sciencedirect.com/science/article/pii/S2468067224000749}, author = {Kim, Hyomin and Witten, David and Madey, Julius and Frissell, Nathaniel and Gibbons, John and Engelke, William and Liddle, Anderson and Muscolino, Nicholas and Visone, Joseph and Cao, Zhaoshu} } @proceedings {863, title = {University of Michigan Space Weather Sensor Package}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

Ground magnetometer and dual frequency GPS systems are used to measure space weather effects observed in geomagnetic disturbances and variations in Total Electron Content (TEC). However, such systems are usually cost-prohibitive, susceptible to noise from human infrastructure, and difficult to deploy and maintain. Our team has been working on a low-cost space weather sensor package that can be easily deployed and requires low maintenance while having good magnetic and TEC data accuracy. The system has multiple options with respect to power (e.g., AC powered or solar panel and battery system), communication (Cat5 internet, Wi-Fi, Cellular or satellite modem), and sensors (use of network protocol time, single frequency GPS time stamping, or dual frequency GPS for both time and TEC). This presentation describes the low-cost magnetometer sensor package, the simple user interfaces, and design of the electrical and structural components for ease of manufacturing. We have developed a prototype for a system that is much cheaper and easier to mass-produce and install than current commercial systems, and real-world testing has shown that these systems function reliably.

}, author = {Theodore Masterson and Mark B. Moldwin and Lauro Ojeda and Julio Vata and Isaac Fertig and Alex Hofmann and Brian Tsang} } @proceedings {742, title = {Electrostatic and Quantum Size Effects in Short Channel MOSFETs}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {
Two dimensional electrostatics and quantum size effects have become important features of modern short channel MOSFET device design where the surface potential becomes spatially dependent affecting the threshold voltage Several nanometer channel lengths between Source and Drain cause quantum effects that need to be addressed in modern MOSFET design. We present a model of electron transport in the 2D inversion layer, where (a) electrostatic and (b) quantum size effects are pointed out.
}, author = {Robert Troy and Aidan Szabo and Argyros Varonides} } @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 {757, title = {PyLap: An Open Source Python Interface to the PHaRLAP Ionospheric Raytracing Toolkit}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

PyLap is a Python interface to the ionospheric ray tracing toolkit PHaRLAP. The software allows users to generate accurate models of the ionosphere and ray tracing to make plots of radio propagation through the ionosphere. Not only does this software look, feel, and operate very similarly to how the MATLAB interface is currently used, it is also completely free alternative to the current MATLAB interface.

}, author = {Devin Diehl and Gerard Piccini and Alexander Calderon and Joshua Vega and William Liles and Nathaniel A. Frissell} } @proceedings {751, title = {Toward Developing an Algorithm for Separation of Transmitters of High Frequency Chirp Signals of Opportunity for the Purpose of Ionospheric Sounding}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, author = {Simal Sami and Nisha Yadav and Nathaniel A. Frissell and Robert Spalletta and Declan Mulhall and Dev Raj Joshi and Juha Vierinen} } @article {802, title = {Validating Ionospheric Models Against Technologically Relevant MetricsAbstractPlain Language SummaryKey Points}, journal = {Space Weather}, volume = {21}, year = {2023}, month = {Jan-12-2023}, abstract = {

New, open access tools have been developed to validate ionospheric models in terms of technologically relevant metrics. These are ionospheric errors on GPS 3D position, HF ham radio communications, and peak F-region density. To demonstrate these tools, we have used output from Sami is Another Model of the Ionosphere (SAMI3) driven by high-latitude electric potentials derived from Active Magnetosphere and Planetary Electrodynamics Response Experiment, covering the first available month of operation using Iridium-NEXT data (March 2019). Output of this model is now available for visualization and download via\ https://sami3.jhuapl.edu. The GPS test indicates SAMI3 reduces ionospheric errors on 3D position solutions from 1.9\ m with no model to 1.6\ m on average (maximum error: 14.2\ m without correction, 13.9\ m with correction). SAMI3 predicts 55.5\% of reported amateur radio links between 2{\textendash}30\ MHz and 500{\textendash}2,000\ km. Autoscaled and then machine learning {\textquotedblleft}cleaned{\textquotedblright} Digisonde NmF2 data indicate a 1.0\ {\texttimes}\ 1011\ el. m3\ median positive bias in SAMI3 (equivalent to a 27\% overestimation). The positive NmF2 bias is largest during the daytime, which may explain the relatively good performance in predicting HF links then. The underlying data sources and software used here are publicly available, so that interested groups may apply these tests to other models and time intervals.

}, issn = {1542-7390}, doi = {10.1029/2023SW003590}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023SW003590https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023SW003590https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023SW003590}, author = {Chartier, A. T. and Steele, J. and Sugar, G. and Themens, D. R. and Vines, S. K. and Huba, J. D.} } @proceedings {747, title = {Web-Based Application for the Visualization and Analysis of Ionogram Data Observed by GNU Chirpsounder2}, year = {2023}, month = {03/2022}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

The focus of my system is to develop a web-based application for the visualization and analysis of data observed by GNU Chirpsounder2. We receive many ionograms each day from different transmitters around the world. Currently, data is in an unsorted format, so my initial task is to classify ionograms by chirp-rate and distance of the transmitter from the receiver. Once these two parameters are identified, it is necessary to have a method for sorting, analyzing, and visualizing the collected ionograms to conduct scientific studies or make the observations useful for radio communications operations.

}, author = {Nisha Yadav and Simal Sami and Dev Raj Joshi and Nathaniel A. Frissell and Robert A. Spalletta and Paul M. Jackowitz and Juha Vierinen} } @proceedings {619, title = {Mid-latitude Irregularities Observed by the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

The spread in the echoes of high-frequency (HF, 3-30 MHz) radio waves from the F-region of the ionosphere was one of the earliest indications of plasma density irregularities in the mid-latitude F region ionosphere. Although mid-latitude spread F has been widely studied, the plasma instability mechanisms that create these irregularities are still largely unknown. This phenomenon can cause radio wave scintillation effects that degrade the performance of human-made technologies such as satellite communications and Global Navigation Satellite Systems (GNSS). Here, we present signatures of mid-latitude irregularities observed in oblique ionograms received near Scranton, PA transmitted by the Relocatable Over-the-Horizon Radar (ROTHR) in Chesapeake, Virginia. These observations are collected with the GNU Chirpsounder2 software, an open source software package capable of creating ionograms from frequency modulated (FM) chirp ionosondes. This ionospheric sounding mode will be implemented in the currently under-development Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), a ground-based multi-instrument system designed to remote-sense the ionosphere using signals of opportunity. Using the data from the oblique ionograms, we generate the Range Time Intensity (RTI) plots that show ionospheric dynamics through measured path length variations as a function of time. We also compare the RTI plots with Range-Time-Parameter (RTP) plots from the SuperDARN HF\  radar in Blackstone, Virginia which commonly observes direct backscatter from decameter-scale irregularities within the region of ionosphere traversed by the ROTHR signal. We also investigate the dependence of the occurrence of the mid-latitude irregularities on the level of the geomagnetic activity.

}, author = {Dev Raj Joshi and Nathaniel A. Frissell and Juha Vierinen} } @proceedings {644, title = {An Overview of Oblique Soundings from Chirp Ionosondes}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

An ionospheric sounder, typically known as an ionosonde, is a radar device which is used to make observations of the ionized layer of the Earth{\textquoteright}s upper atmosphere known as the ionosphere. The ionosonde works by transmitting high frequency (HF, 3-30 MHz) radio waves and observing the time delay of the ionospheric echoes. Ionosondes play an especially crucial role in our understanding both ionospheric dynamics and how radio wave propagation is impacted by the ionosphere. The data from an ionosonde is displayed in a type of plot known as an ionogram. A chirp ionosonde is a type of ionospheric sounder that produces ionograms by transmitting an HF signal that changes linearly in frequency with time. Conventional chirp ionosondes are used in a vertical sounding mode, in which signals are transmitted directly up to the ionosphere. This allows for measurements of electron density as a function of height for the bottomside ionosphere. Chirp ionosondes may also be used in an oblique sounding configuration, in which the transmitter and receiver are separated by a significant geographic distance. While the measurements of an oblique sounder are more complicated to interpret than a vertical sounder, a single transmitter can be used simultaneously by receivers in many different locations, thus allowing for a cost-effective increase in the number of ionospheric sampling points. The HamSCI Personal Space Weather Station plans to take advantage of this fact by using signals-of-opportunity from the global network of pre-existing chirp ionosonde transmitters. In this presentation, we give a brief overview of chirp ionosondes and their uses in studying ionospheric dynamics.

}, author = {Simal Sami and Nathaniel A. Frissell and Mary Lou West and Dev Raj Joshi and Juha Vierinen} } @proceedings {641, title = {Ray Tracing in Python Utilizing the PHaRLAP Engine}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

Provision of High-Frequency Raytracing Laboratory for Propagation (PHaRLAP) is an ionospheric ray tracing library developed by the Australian Department of Defence (DOD). PHaRLAP is freely available as a MATLAB toolbox downloadable from an Australian DOD website. PHaRLAP is capable of numerically ray tracing radio propagation paths using 2D and 3D algorithms through model ionospheres, most typically the International Reference Ionosphere (IRI). In an effort to make PHaRLAP available to a wider user community we are porting the PHaRLAP MATLAB toolbox to the open source Python 3 language while retaining the original core PHaRLAP computational engine. In this presentation, we describe the architecture of the new Python 3 PHaRLAP interface and demonstrate examples of 2D ray traces using the new interface.

}, author = {Alexander Calderon and William Liles and Nathaniel Frissell and Joshua Vega} } @proceedings {475, title = {Beacon Programme to study inland Tropo in South Africa}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

On the West Coast of South Africa contacts via Tropospheric ducting with St Helena Island occur regularly and are generally well predicted on the Hepburn charts. While some sporadic tropospheric conditions inland have resulted in long distance two metre contacts they mostly occurred by accident, someone just happens to be on the air. A few years ago, the South African Radio League (SARL) embarked on a beacon programme with the aim to study Tropospheric and other propagation modes on VHF. It was planned to link the beacon programme with a reverse beacon monitoring system. It turned out that\ CW beacons are not particularly useful as the reverse beacon monitoring system requires a fairly strong signal to identify the beacon signal. This defeated the objective of the study.\ The SARL has now opted for a next generation beacon system of which the first one will go on the air during March 2021. AMSAT SA is partnering with the SARL and has launched a crowd funding initiative to generate more funding to accelerate the process and erect more beacons and expedite a reverse beacon network. The paper will introduce the objectives of the programme, the challenges of being at the southern point of Africa, details of the next generation beacon system and the development of a reverse beacon monitoring system.

}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=74-34-37-9E-AA-7E-F5-CF-CF-FD-00-3F-96-71-A9-0E}, author = {Hans van de Groenendaal and Brian Jacobs} } @conference {557, title = {Early Results from the Ionospheric Sounding Mode Using Chirp Ionosondes of Opportunity for the HamSCI Personal Space Weather Station}, booktitle = {2021 XXXIVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS)}, year = {2021}, abstract = {

The objective of the Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is to develop a distributed array of ground-based multi-instrument nodes capable of remote sensing the geospace system. This system is being designed with the intention of distribution to a large number of amateur radio and citizen science observers. This will create an unprecedented opportunity to probe the ionosphere at finer resolution in both time and space as all measurements will be collected into a central database for coordinated analysis. Individual nodes are being designed to service the needs of the professional space science researcher while being cost-accessible and of interest to amateur radio operators and citizen scientists. At the heart of the HamSCI PSWS will be a high performance 0.1{\textendash}60 MHz software defined radio (SDR) [1] with GNSS-based precision timestamping and frequency reference. This SDR is known as the TangerineSDR and is being developed by the Tucson Amateur Packet Radio (TAPR) amateur radio organization. The primary objective of PSWS system is to gather observations to understand the short term and small spatial scale ionospheric variabilities in the ionosphere-thermosphere system. These variabilities are important for understanding a variety of geophysical phenomena such as Traveling Ionospheric Disturbances (TIDs) [2], Ionospheric absorption events, geomagnetic storms and substorms. We present early results suggesting signature of Traveling Ionospheric Disturbances (TIDs) from an ionospheric sounding mode that we intend to implement on the PSWS system, currently implemented on an Ettus N200 Universal Software Radio Peripheral (USRP) using the open source GNU Chirpsounder data collection and analysis code.

}, doi = {10.23919/URSIGASS51995.2021.9560441}, author = {Joshi, Dev and Frissell, Nathaniel and Liles, William and Vierinen, Juha and Miller, Ethan S.} } @conference {544, title = {HamSCI Personal Space Weather: Architecture and Applications to Radio Astronomy}, booktitle = {Annual (Summer) Eastern Conference}, year = {2021}, month = {07/2021}, publisher = {Society of Amateur Radio Astronomers (SARA)}, organization = {Society of Amateur Radio Astronomers (SARA)}, address = {Virtual}, abstract = {

The Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is a citizen science initiative to develop a new modular set of ground-based instrumentation for the purpose of studying the structure and dynamics of the terrestrial ionosphere, as well as the larger, coupled geospace system. PSWS system instrumentation includes radio receivers sensitive to frequencies ranging from the very low frequency (VLF) through very high frequency (VHF) bands, a Global Navigation Satellite System (GNSS) receiver to provide Total Electron Content (TEC) measurements and serve as a precision time and frequency reference, and a ground magnetometer sensitive to ionospheric and geospace currents. Although the PSWS is designed primarily for space weather and space science, its modular and open design in both hardware and software allows for a variety of use cases. The core radio instrument of the PSWS, the TangerineSDR, is a wideband, direct sampling 100~kHz to 60~MHz field programmable gate array (FPGA)-based software defined radio (SDR) receiver with direct applicability to radio astronomy. In this paper, we describe the PSWS and TangerineSDR architecture, show examples of how the TangerineSDR could be used to observe Jovian decametric emission, and discuss the applicability of the TangerineSDR to radio astronomy in general.

}, url = {https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference}, author = {Nathaniel A. Frissell and Scott H. Cowling and Thomas C. McDermott and John Ackermann and David Typinski and William D. Engelke and David R. Larsen and David G. McGaw and Hyomin Kim and David M. Witten, II and Julius M. Madey and Kristina V. Collins and John C. Gibbons and David Kazdan and Aidan Montare and Dev Raj Joshi and Veronica I. Romanek and Cuong D. Nguyen and Stephen A. Cerwin and William Liles and Jonathan D. Rizzo and Ethan S. Miller and Juha Vierinen and Philip J. Erickson and Mary Lou West} } @conference {540, title = {HamSCI Personal Space Weather Station (PSWS): Architecture and Current Status}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2021}, month = {06/2021}, publisher = {CEDAR}, organization = {CEDAR}, address = {Virtual}, abstract = {

Recent advances in geospace remote sensing have shown that large-scale distributed networks of ground-based sensors pay large dividends by providing a big picture view of phenomena that were previously observed only by point-measurements. While existing instrument networks provide excellent insight into ionospheric and space science, the system remains undersampled and more observations are needed to advance understanding. In an effort to generate these additional measurements, the Ham Radio Science Citizen Investigation (HamSCI, hamsci.org) is working with the Tucson Amateur Packet Radio Corporation (TAPR, tapr.org), an engineering organization comprised of volunteer amateur radio operators and engineers, to develop a network of Personal Space Weather Stations (PSWS). These instruments that will provide scientific-grade observations of signals-of-opportunity across the HF bands from volunteer citizen observers as part of the NSF Distributed Array of Small Instruments (DASI) program. A performance-driven PSWS design (~US$500) will be a modular, multi-instrument device that will consist of a dual-channel phase-locked 0.1-60 MHz software defined radio (SDR) receiver, a ground magnetometer with (~10 nT resolution and 1-sec cadence), and GPS/GNSS receiver to provide precision time stamping and serve as a GPS disciplined oscillator (GPSDO) to provide stability to the SDR receiver. A low-cost PSWS (\< US$100) that measures Doppler shift of HF signals received from standards stations such as WWV (US) and CHU (Canada) and includes a magnetometer is also being developed. HF sounding algorithms making use of signals of opportunity will be developed for the SDR-based PSWS. All measurements will be collected into a central database for coordinated analysis and made available for public access.

}, author = {Nathaniel A. Frissell and Dev Joshi and Veronica I. Romanek and Kristina V. Collins and Aidan Montare and David Kazdan and John Gibbons and William D. Engelke and Travis Atkison and Hyomin Kim and Scott H. Cowling and Thomas C. McDermott and John Ackermann and David Witten and Julius Madey and H. Ward Silver and William Liles and Steven Cerwin and Philip J. Erickson and Ethan S. Miller and Juha Vierinen} } @proceedings {561, title = {HamSCI Personal Space Weather Station (PSWS): Fall 2021 Update}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/MHkz7jNynOg?t=1990}, author = {Frissell, Nathaniel A. and Joshi, Dev Raj and Collins, Kristina and Montare Aidan and Kazdan, David and Engelke, William D. and Atkison, Travis and Kim, Hyomin and Cowling, Scott H. and McDermott, Thomas C. and Ackermann, John and Witten, David and Madey, Jules and Silver, H. Ward and Liles, W. and Cerwin, Stephen A. and Erickson, Phillip J. and Miller, Ethan S, and Vierinen, Juha} } @proceedings {458, title = {Mid-latitude Irregularities in the Early Results from the Ionospheric Sounding Mode Using Chirp Ionosondes of Opportunity for the HamSCI Personal Space Weather Station}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

The objective of the Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is to develop a distributed array of ground-based multi-instrument nodes capable of remote sensing the geospace system. This system is being designed with the intention of distribution to a large number of amateur radio and citizen science observers. This will create an unprecedented opportunity to probe the ionosphere at finer resolution in both time and space as all measurements will be collected into a central database for coordinated analysis. Individual nodes are being designed to service the needs of the professional space science researcher while being cost-accessible and of interest to amateur radio operators and citizen scientists. At the heart of the HamSCI PSWS will be a high performance 1 {\textendash} 50 MHz software defined radio (SDR) with GNSS-based precision timestamping and frequency reference. This SDR is known as the TangerineSDR and is being developed by the Tucson Amateur Packet Radio (TAPR) amateur radio organization. The primary objective of PSWS system is to gather observations to understand the short term and small spatial scale ionospheric variabilities in the ionosphere-thermosphere system. These variabilities are important for understanding a variety of geophysical phenomena such as Traveling Ionospheric Disturbances (TIDs), Ionospheric absorption events, geomagnetic storms and substorms. We present early results suggesting signatures of Traveling Ionospheric Disturbances (TIDs) from an ionospheric sounding mode that we intend to implement on the PSWS system, currently implemented on an Ettus N200 Universal Software Radio Peripheral (USRP) using the open source GNU Chirpsounder data collection and analysis code.

}, author = {Dev Joshi and Nathaniel A. Frissell and William Liles and Juha Vierinen and Ethan S. Miller} } @conference {536, title = {Observations of Mid-latitude Irregularities Using the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2021}, month = {06/2021}, publisher = {CEDAR}, organization = {CEDAR}, address = {Virtual}, abstract = {

The spread in the echoes of high-frequency (HF, 3-30 MHz) radio waves from the F-region of the ionosphere has been the earliest indication of plasma density irregularities in the mid-latitude F region ionosphere. Although mid-latitude spread F has been widely studied, the plasma instability mechanisms for these irregularities are still largely unknown. This phenomenon can cause radio wave scintillation effects that degrade the performance of man-made technologies such as satellite communications and global navigation satellite systems (GNSS). Understanding these irregularities so that they can be anticipated and mitigated are important aspects of space weather research. The occurrence climatology and variability can also be helpful in modeling efforts of these irregularities. Here, we present signatures of mid-latitude irregularities observed in oblique ionograms received near Scranton, PA transmitted by the Relocatable Over-the-Horizon Radar (ROTHR) in Chesapeake, Virginia. These observations are collected with the GNU Chirpsounder2 software, an open-source software package capable of creating ionograms from frequency modulated (FM) chirp ionosondes. This ionospheric sounding mode will be implemented in the currently under development Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), a ground-based multi-instrument system designed to remote-sense the ionosphere using signals of opportunity.

}, author = {Dev Joshi and Nathaniel A. Frissell and William Liles and Juha Vierinen} } @proceedings {577, title = {Observations of Mid-latitude Irregularities Using the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station (Proceedings)}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/kVY3E3e--_I?t=2542}, author = {Joshi, Dev Raj and Frissell, Nathaniel A. and Liles, William and Vierinen, Juha} } @conference {585, title = {Observations of Mid-latitude Irregularities Using the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station}, booktitle = {American Geophysical Union Fall Meeting}, year = {2021}, month = {12}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, abstract = {

The spread in the echoes of high-frequency (HF, 3-30 MHz) radio waves from the F-region of the ionosphere was one of the earliest indications of plasma density irregularities in the mid-latitude F region ionosphere. Although mid-latitude spread F has been widely studied, the plasma instability mechanisms that create these irregularities are still largely unknown. This phenomenon can cause radio wave scintillation effects that degrade the performance of human-made technologies such as satellite communications and Global Navigation Satellite Systems (GNSS). Understanding these irregularities so that they can be anticipated and mitigated are important aspects of space weather research. The occurrence climatology and variability can also be helpful in validating models of these irregularities. Here, we present signatures of mid-latitude irregularities observed in oblique ionograms received near Scranton, PA transmitted by the Relocatable Over-the-Horizon Radar (ROTHR) in Chesapeake, Virginia. These observations are collected with the GNU Chirpsounder2 software, an open source software package capable of creating ionograms from frequency modulated (FM) chirp ionosondes. This ionospheric sounding mode will be implemented in the currently under-development Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), a ground-based multi-instrument system designed to remote-sense the ionosphere using signals of opportunity. Using the data from the oblique ionograms, we generate the Range Time Intensity (RTI) plots that show ionospheric dynamics through measured path length variations as a function of time. We also compare the RTI plots with Range-Time-Parameter (RTP) plots from the SuperDARN HF radar in Blackstone, Virginia which commonly observes direct backscatter from decameter-scale irregularities within the region of ionosphere traversed by the ROTHR signal.

}, url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/875589}, author = {Joshi, Dev Raj and Frissell, Nathaniel A. and Sarwar, M. Shaaf and Sami, Simal and Ruohoniemi, J. Michael and Baker, Joseph B. H. and Coster, Anthea J. and Erickson, Philip J. and Liles, William and Vierinen, Juha and Groves, Keith} } @proceedings {487, title = {Plasma Bubble and Blob Events in the F-region Ionosphere}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

The equatorial plasma bubbles (EPBs) and plasma blobs (enhancements) are, in general, the nighttime phenomena of ionospheric plasma irregularities in the F-region ionosphere. This study presents plasma bubble and blob events identified from the SWARM satellite constellation when it flies above the American continent. We have also simultaneously examined the behavior of total electron content (TEC), its depletions, and enhancements in the equatorial/low/mid-latitude F-region ionosphere detected from ground-based Global Positioning System (GPS) receivers in the American sector. The in situ observations of bubble and blob events are concurrently supported by GPS-TEC measurement from the ground. Additionally, the coordinated ground- and satellite-based observations indicate that the ground-based data show the variability of the background ionosphere prior, during, and later than the development time of the EPBs as seen by the SWARM. For this limited analysis, the plasma blob events are mostly seen at/nearby mid-latitude regions. Finally, we discuss the possible mechanism of the generation, evolution, and relationship between EPBs and plasma blobs in the F-region ionosphere.

}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=51-F0-AC-9D-0C-7E-D9-A3-FC-F1-2E-13-F2-6E-34-90}, author = {Sovit Khadka and Cesar Valladares and Andrew Gerrard} } @proceedings {556, title = {Simultaneous observations of mid-latitude Ionospheric Irregularities in HamSCI Personal Space Weather Station and SuperDARN radar}, year = {2021}, month = {05/2021}, publisher = {SANSA}, address = {Virtual}, url = {https://www.sansa.org.za/events-outreach/superdarn-workshop-2021/}, author = {Joshi, Dev Raj and Frissell, Nathaniel A. and Liles, William and Vierinen, Juha} } @proceedings {501, title = {The Sun and the Earthquakes}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

Since 2017 I have been studying and contrasting the turbulence and solar wind data, observing the close relationship between the two, I currently have a YouTube channel where I am dedicated to forecasting these seismic events based on the heliospheric graphs provided by NOAA, the Space weather influences volcanic activity, earthquakes and the climate on earth, I could also observe the negative impact on people, the prolonged zero magnetic index or geomagnetic storms.

}, author = {Edmondo Manuel Vasiu Vasiu} } @conference {424, title = {HamSCI Distributed Array of Small Instruments Personal Space Weather Station (DASI-PSWS): Architecture and Current Status (Invited)}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2020}, month = {06/2020}, address = {Santa Fe, NM (Virtual)}, abstract = {

Recent advances in geospace remote sensing have shown that large-scale distributed networks of ground-based sensors pay large dividends by providing a big picture view of phenomena that were previously observed only by point-measurements. While existing instrument networks provide excellent insight into ionospheric and space science, the system remains undersampled and more observations are needed to advance understanding. In an effort to generate these additional measurements, the Ham Radio Science Citizen Investigation (HamSCI, hamsci.org) is working with the Tucson Amateur Packet Radio Corporation (TAPR, tapr.org), an engineering organization comprised of volunteer amateur radio operators and engineers, to develop a network of Personal Space Weather Stations (PSWS). These instruments that will provide scientific-grade observations of signals-of-opportunity across the HF bands from volunteer citizen observers as part of the NSF Distributed Array of Small Instruments (DASI) program. A performance-driven PSWS design (~US$500) will be a modular, multi-instrument device that will consist of a dual-channel phase-locked 0.1-60 MHz software defined radio (SDR) receiver, a ground magnetometer with (~10 nT resolution and 1-sec cadence), and GPS/GNSS receiver to provide precision time stamping and serve as a GPS disciplined oscillator (GPSDO) to provide stability to the SDR receiver. A low-cost PSWS (\< US$100) that measures Doppler shift of HF signals received from standards stations such as WWV (US) and CHU (Canada) and includes a magnetometer is also being developed. HF sounding algorithms making use of signals of opportunity will be developed for the SDR-based PSWS. All measurements will be collected into a central database for coordinated analysis and made available for public access.

}, url = {http://cedarweb.vsp.ucar.edu/wiki/index.php/2020_Workshop:MainVG}, author = {N. A. Frissell and D. Joshi and K. Collins and A. Montare and D. Kazdan and J. Gibbons and S. Mandal and W. Engelke and T. Atkison and H. Kim and A. J. Gerrard and J. S. Vega and S. H. Cowling and T. C. McDermott and J. Ackermann and D. Witten and H. W. Silver and W. Liles and S. Cerwin and P. J. Erickson and E. S. Miller} } @conference {408, title = {The Language of Amateur Radio (ePoster)}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

The survival of Amateur Radio demands big changes in the Language of Amateur Radio. Radio Amateurs must think and speak in terms of Science, Technology, Engineering and Math\ \ (STEM) educational concepts that appeal to school and college students. STEM educated young people are critically important in maintaining our country{\textquoteright}s global competitiveness. Another aspect of the Language of Amateur Radio is to reconsider use of the word "hobby" in favor of stronger concepts such as "Enterprise." Amateur Radio in total generates a small but substantial economic impact and provides public service too. No other endeavor touches upon all aspects of STEM subjects so use of the word "hobby" to describe Amateur Radio may be misleading to many people.

}, author = {David Vine} } @conference {274, title = {HamSCI Personal Space Weather Station: A New Tool for Citizen Science Geospace Research}, booktitle = {USNC{\textendash}URSI National Radio Science Meeting}, year = {2019}, month = {01/2019}, publisher = {U.S. National Committee for URSI}, organization = {U.S. National Committee for URSI}, address = {Boulder, CO}, abstract = {

Recent advances in geospace remote sensing have shown that large-scale distributed networks of ground-based sensors pay large dividends by providing a big picture view of phenomena that were previously observed only by point-measurements. Notable examples include the improved understanding of traveling ionospheric disturbance (TID) sources based on observations from the high frequency (HF) Super Dual Auroral Radar Network (SuperDARN) radars and GNSS-based total electron content remote sensing networks. While these existing networks provide excellent insight into TID science, the system remains undersampled (especially at HF) and more observations are needed to advance understanding. Additionally, previous measurements have revealed that characteristics of medium scale traveling ionospheric disturbances (MSTIDs) observed on the bottomside ionosphere using oblique HF sounding by SuperDARN differ from integrated ionospheric measurements of MSTIDs made using GNSS-TEC. These differences have yet to be accounted for, and additional observations could aid in understanding the propagation of MSTIDs from the bottom to the top of the ionosphere. In an effort to generate these additional measurements, the Ham Radio Science Citizen Investigation (HamSCI, hamsci.org) is working with the Tucson Amateur Packet Radio Corporation (TAPR, tapr.org), an engineering organization comprising of volunteer amateur radio operators and engineers, to develop a network of Personal Space Weather Stations that will provide scientific-grade observations of signals-of-opportunity across the HF bands from volunteer citizen observers. These measurements will play a key role in the characterization of ionospheric variability across the geographic regions in which these stations are deployed. We will describe concepts, key software patterns for radio science, and proposed timelines for the Personal Space Weather Station project. A particular focus will be assembling the proper metadata for science grade observations, and strategies for lightweight calibration of radio sensors. Initial project efforts concentrate on a wideband receiving station and backing software data distribution system.

}, url = {https://nrsmboulder.org/}, author = {J. S. Vega and N. A. Frissell and P. J. Erickson and A. J. Gerrard} } @article {275, title = {High Frequency Communications Response to Solar Activity in September 2017 as Observed by Amateur Radio Networks}, journal = {Space Weather}, year = {2019}, month = {2019/01/11}, abstract = {

Abstract Numerous solar flares and coronal mass ejection (CME) induced interplanetary shocks associated with solar active region AR12673 caused disturbances to terrestrial high frequency (HF, 3--30 MHz) radio communications from 4-14 September 2017. Simultaneously, Hurricanes Irma and Jose caused significant damage to the Caribbean Islands and parts of Florida. The coincidental timing of both the space weather activity and hurricanes was unfortunate, as HF radio was needed for emergency communications. This paper presents the response of HF amateur radio propagation as observed by the Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporting Network (WSPRNet) to the space weather events of that period. Distributed data coverage from these dense sources provided a unique mix of global and regional coverage of ionospheric response and recovery that revealed several features of storm-time HF propagation dynamics. X-class flares on 6, 7, and 10 September caused acute radio blackouts during the day in the Caribbean with recovery times of tens of minutes to hours, based on the decay time of the flare. A severe geomagnetic storm withKpmax\ =\ 8\ +\ and?SYM\ ?\ Hmin\ =\ \ ?\ 146?nT occurring 7-10 September wiped out ionospheric communications first on 14 MHz and then on 7 MHz starting at~1200 UT 8 September. This storm, combined with affects from additional flare and geomagnetic activity, contributed to a significant suppression of effective HF propagation bands both globally and in the Caribbean for a period of 12 to 15 days.

}, keywords = {Amateur Radio, Geomagnetic Storm, Ham Radio, HF Radio Propagation, Radio Blackout, Solar Flare}, issn = {1542-7390}, doi = {10.1029/2018SW002008}, url = {https://doi.org/10.1029/2018SW002008}, author = {Frissell, Nathaniel A. and Vega, Joshua S. and Markowitz, Evan and Gerrard, Andrew J. and Engelke, William D. and Erickson, Philip J. and Miller, Ethan S. and Luetzelschwab, R. Carl and Bortnik, Jacob} } @conference {295, title = {High Frequency Communications Response to Solar Activity in September 2017 as Observed by Amateur Radio Networks}, booktitle = {HamSCI Workshop 2019}, year = {2019}, month = {03/2019}, publisher = {HamSCI}, organization = {HamSCI}, address = {Cleveland, OH}, abstract = {

Numerous solar flares and coronal mass ejection-induced interplanetary shocks associated with solar active region AR12673 caused disturbances to terrestrial high-frequency (HF, 3{\textendash}30 MHz) radio communications from 4{\textendash}14 September 2017. Simultaneously, Hurricanes Irma and Jose caused significant damage to the Caribbean Islands and parts of Florida. The coincidental timing of both the space weather activity and hurricanes was unfortunate, as HF radio was needed for emergency communications. This paper presents the response of HF amateur radio propagation as observed by the Reverse Beacon Network and the Weak Signal Propagation Reporting Network to the space weather events of that period. Distributed data coverage from these dense sources provided a unique mix of global and regional coverage of ionospheric response and recovery that revealed several features of storm time HF propagation dynamics. X-class flares on 6, 7, and 10 September caused acute radio blackouts during the day in the Caribbean with recovery times of tens of minutes to hours, based on the decay time of the flare. A severe geomagnetic storm with Kpmax = 8+ and SYM-Hmin = -146 nT occurring 7{\textendash}10 September wiped out ionospheric communications first on 14 MHz and then on 7 MHz starting at \~{}1200 UT 8 September. This storm, combined with affects from additional flare and geomagnetic activity, contributed to a significant suppression of effective HF propagation bands both globally and in the Caribbean for a period of 12 to 15 days.

}, author = {Nathaniel A. Frissell and Joshua S. Vega and Evan Markowitz and Andrew J. Gerrard and William D. Engelke and Philip J. Erickson and Ethan S. Miller and R. Carl Luetzelschwab and Jacob Bortnik} } @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 {276, title = {High Frequency Communications Response to Solar Activity in September 2017 as Observed by Amateur Radio Networks}, booktitle = {Fall AGU}, year = {2018}, month = {12/2018}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {Washington, DC}, abstract = {

Numerous solar flares and coronal mass ejection (CME) induced interplanetary shocks associated with solar active region AR12673 caused disturbances to terrestrial high frequency (HF, 3{\textendash}30 MHz) radio communications from 4-14 September 2017. Simultaneously, Hurricanes Irma and Jose caused significant damage to the Caribbean Islands and parts of Florida. The coincidental timing of both the space weather activity and hurricanes was unfortunate, as HF radio was needed for emergency communications. This paper presents the response of HF amateur radio propagation as observed by the Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporting Network (WSPRNet) to the space weather events of that period. Distributed data coverage from these dense sources provided a unique mix of global and regional coverage of ionospheric response and recovery that revealed several features of storm-time HF propagation dynamics. X-class flares on 6, 7, and 10 September caused acute radio blackouts during the day in the Caribbean with recovery times of tens of minutes to hours, based on the decay time of the flare. A severe geomagnetic storm withKpmax = 8 + and SYM - Hmin = - 146 nT occurring 7-10 September wiped out ionospheric communications first on 14 MHz and then on 7 MHz starting at\ 1200 UT 8 September. This storm, combined with affects from additional flare and geomagnetic activity, contributed to a significant suppression of effective HF propagation bands both globally and in the Caribbean for a period of 12 to 15 days.

}, keywords = {Amateur Radio, Geomagnetic Storm, Ham Radio, HF Radio Propagation, Radio Blackout, Solar Flare}, url = {https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/419847}, author = {Frissell, Nathaniel A. and Vega, Joshua S. and Markowitz, Evan and Gerrard, Andrew J. and Engelke, William D. and Erickson, Philip J. and Miller, Ethan S. and Luetzelschwab, R. Carl and Bortnik, Jacob} } @conference {236, title = {Initial Results of HamSCI Ham Radio 21 August 2017 Eclipse Ionospheric Experiments}, booktitle = {American Meteorological Society Annual Meeting}, year = {2018}, month = {01/2018}, publisher = {American Meteorological Society}, organization = {American Meteorological Society}, address = {Austin, TX}, abstract = {

On 21 August 2017, a total solar eclipse will cause the shadow of the moon to traverse the United States from Oregon to South Carolina in just over 90 minutes. The sudden absence of sunlight due to the eclipse, especially solar UV and x-rays, provides an impulse function to the upper atmosphere that modifies the neutral dynamics, plasma concentrations, and related properties. Despite more than 60 years of research, questions remain regarding eclipse-induced ionospheric impacts. Ham radio operators{\textquoteright} advanced technical skills and inherent interest in ionospheric science make the amateur radio community ideal for contributing to and and participating in large-scale ionospheric sounding experiments. We present initial results from three amateur radio experiments designed to study the 2017 total solar eclipse: the Solar Eclipse QSO Party (SEQP), the HF Wideband Recording Experiment, and the Eclipse Frequency Measurement Test (FMT). These experiments are coordinated by HamSCI, the Ham Radio Science Citizen Investigation, a citizen science organization that connects the amateur radio community to the professional space science research community for mutual benefit.

}, url = {https://ams.confex.com/ams/98Annual/webprogram/Paper337094.html}, author = {N. A. Frissell and J. R. Ackermann and D. Bern and F. Ceglia and G. D. Earle and P. J. Erickson and A. J. Gerrard and R. Gerzoff and P. Gladstone and S. W. Gunning and J. D. Huba and J. D. Katz and E. S. Miller and M. L. Moses and S. E. Reyer and S. W. Rose and A. Shovkoplyas and H. W. Silver and P. Smith and J. S. Vega and M. L. West and R. Williams} } @article {248, title = {Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse}, journal = {Geophysical Research Letters}, volume = {45}, year = {2018}, month = {05/2018}, type = {Research Letter}, abstract = {

On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium and high frequency radio propagation by the Solar Eclipse QSO Party (SEQP) citizen science experiment organized by the Ham Radio Science Citizen Investigation (hamsci.org). This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed {\textpm}0.3 hr on 1.8 MHz, {\textpm}0.75 hr on 3.5 and 7 MHz, and {\textpm}1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at\ h >= 125 km altitude with elevation angles\ θ >= 22{\textdegree}, while 14 MHz signals refracted at\ h \< 125 km with elevation angles\ θ \< 10{\textdegree}.

}, issn = {1944-8007}, doi = {https://doi.org/10.1029/2018GL077324}, url = {https://doi.org/10.1029/2018GL077324}, author = {N. A. Frissell and J. D. Katz and S. W. Gunning and J. S. Vega and A. J. Gerrard and G. D. Earle and M. L. Moses and M. L. West and J. D. Huba and P. J. Erickson and E. S. Miller and R. B. Gerzoff and W. Liles and H. W. Silver} } @conference {277, title = {Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse}, booktitle = {Fall AGU}, year = {2018}, month = {12/2018}, publisher = {American Geophysical Union Meeting}, organization = {American Geophysical Union Meeting}, address = {Washington, DC}, abstract = {

On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium- and high-frequency radio propagation by the Solar Eclipse QSO Party citizen science experiment organized by the Ham Radio Science Citizen Investigation (hamsci.org). This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed {\textpm}0.3 hr on 1.8 MHz, {\textpm}0.75 hr on 3.5 and 7 MHz, and {\textpm}1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at h>=125 km altitude with elevation angles θ>=22{\textdegree}, while 14 MHz signals refracted at h \< 125 km with elevation angles θ \< 10{\textdegree}.

}, keywords = {Amateur Radio, Citizen Science, Ham Radio, HF propagation, ionosphere, solar eclipse}, url = {https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/418915}, author = {Frissell, N. A. and Katz, J. D. and Gunning, S. W. and Vega, J. S. and Gerrard, A. J. and Earle, G. D. and Moses, M. L. and West, M. L. and Huba, J. D. and Erickson, P. J. and Miller, E. S. and Gerzoff, R. B. and Liles, W. and Silver, H. W.} } @conference {209, title = {Developing a Solar Eclipse Simulation for Greater Good}, booktitle = {ARRL and TAPR Digital Communications Conference}, year = {2017}, month = {09/2017}, address = {St. Louis, MO}, abstract = {

This paper presents our methodology for simulating the upcoming total solar eclipse that will be taking place on August 21, 2017. By taking advantage of a high-performance distributed computing cluster as well as a number of third-party scientific computing libraries we were able to efficiently simulate a large number of HF amateur radio contacts before, during, and after the upcoming eclipse. The data generated from the simulations allows us to peek into how the amateur radio community and radio propagation as a whole will be affected in preparation for the actual eclipse.

}, url = {https://www.tapr.org/pub_dcc.html}, author = {J. S. Vega and N. A. Frissell and J. D. Katz and J. D. Huba} } @conference {176, title = {Fitting Ionospheric Models Using Real-Time HF Amateur Radio Observations}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {J. D. Katz and N. A. Frissell and J. S. Vega and A. J. Gerrard and R. B. Gerzoff and P. J. Erickson and E. S. Miller and M. L. Moses and F. Ceglia and D. Pascoe and N. Sinanis and P. Smith and R. Williams and A. Shovkoplyas} } @conference {175, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {N. A. Frissell and J. R. Ackermann and G. D. Earle and P. J. Erickson and A. J. Gerrard and R. B. Gerzoff and S. W. Gunning and M. Hirsch and J. D. Katz and S. R. Kaeppller and R. W. McGwier and E. S. Miller and M. L. Moses and G. Perry and S. E. Reyer and A. Shovkoplyas and H. W. Silver and J. S. Vega and RBN Team} } @conference {213, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {HamSCI-UK}, year = {2017}, month = {10/2017}, publisher = {HamSCI-UK}, organization = {HamSCI-UK}, address = {Milton Keynes, UK}, author = {N. A. Frissell and W. Engelke and J. D. Katz and J. S. Vega} } @conference {226, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {2017 Annual Meeting of the APS Mid-Atlantic Section}, year = {2017}, month = {11/2017}, publisher = {American Physical Society}, organization = {American Physical Society}, address = {Newark, NJ}, author = {N. A. Frissell and J. D. Katz and S. W. Gunning and J. S. Vega and M. L. West and G. D. Earle and M. L. Moses and H. W. Silver} } @conference {230, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {American Geophysical Union Fall Meeting}, year = {2017}, month = {12/2017}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, author = {N. A. Frissell and J. D. Katz and S. W. Gunning and J. S. Vega and A. J. Gerrard and M. L. Moses and G. D. Earle and M. L. West and P. J. Erickson and E. S. Miller and R. Gerzoff and H. Ward Silver} } @conference {207, title = {HamSCI and the 2017 Total Solar Eclipse (Experiment Description)}, booktitle = {ARRL and TAPR Digital Communications Conference}, year = {2017}, month = {09/2017}, address = {St. Louis, MO}, abstract = {

On 21 August 2017, a total solar eclipse will cause the shadow of the moon to traverse the United States from Oregon to South Carolina in just over 90 minutes. The sudden absence of sunlight due to the eclipse, especially solar UV and x-rays, provides an impulse function to the upper atmosphere that modifies the neutral dynamics, plasma concentrations, and related properties. In spite of more than 60 years of research, open questions remain regarding eclipse-induced ionospheric impacts. Ham radio operators{\textquoteright} advanced technical skills and inherent interest in ionospheric science make the amateur radio community ideal for contributing to and and participating in large-scale ionospheric sounding experiments. This pa- per describes the Solar Eclipse QSO Party (SEQP), the HF Wideband Recording Experiment, and the Eclipse Frequency Measurement Test (FMT), three amateur radio experiments designed to study the 2017 total solar eclipse. These experi- ments are coordinated by HamSCI, the Ham radio Science Citizen Investigation, a citizen science organization that connects the amateur radio community to the professional space science research community for mutual benefit.

}, url = {https://www.tapr.org/pub_dcc.html}, author = {N. A. Frissell and J. S. Vega and J. D. Katz and S. W. Gunning and A. J. Gerrard and M. L. Moses and G. D. Earle and E. S. Miller and J. D. Huba and M. Hirsch and H. W. Silver and S. E. Reyer and J. R. Ackermann and M. D. Suhar and D. Bern} } @conference {210, title = {HamSCI and the 2017 Total Solar Eclipse (First Results)}, booktitle = {ARRL and TAPR Digital Communications Conference}, year = {2017}, month = {09/2017}, address = {St. Louis, MO}, url = {https://www.tapr.org/pub_dcc.html}, author = {N. A. Frissell and W. Engelke and J. D. Katz and S. W. Gunning and J. S. Vega} } @conference {174, title = {HamSCI: The Ham Radio Science Citizen Investigation (Banquet Presentation)}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {N. A. Frissell and J. R. Ackermann and J. Dzekevich and G. D. Earle and P. J. Erickson and A. J. Gerrard and R. B. Gerzoff and S. W. Gunning and M. Hirsch and J. D. Katz and S. R. Kaeppler and R. W. McGwier and E. S. Miller and M. L. Moses and G. Perry and S. E. Reyer and A. Shovkoplyas and H. W. Silver and J. S. Vega and RBN Team} } @conference {173, title = {Ionospheric Simulations of the 2017 Solar Eclipse QSO Party}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {N. A. Frissell and J. S. Vega and J. D. Katz and M. L. Moses and G. D. Earle and S. W. Gunning and A. J. Gerrard and E. S. Miller and M. L. West and F. Ceglia and D. Pascoe and N. Sinanis and P. Smith and R. Williams and A. Shovkoplyas and H. W. Silver} }