@proceedings {1042, title = {An Amateur Radio HF Channel Sounder}, year = {2026}, month = {03/2026}, publisher = {HamSCI}, address = {Newington, CT}, abstract = {This presentation will provide a description of a channel sounding architecture that is accessible to the amateur radio community. It is used to study selected radio channels between an HF transceiver and a remote software-defined radio receiver. A system has been implemented that employs a combination of a Flex 6700 SDR transceiver and a remote Kiwi SDR. An audio file containing a series of a repeated maximum-length sequence is transmitted over the air by a Flex 6700 transceiver to a selected Kiwi SDR that generates an audio recording of the received signal. The recording is sent back to the transmitting station over the Internet for post processing. A software analysis tool is used to cross correlate the original transmitted audio file with the received signal recording. This process generates a multiple-period channel impulse response, which is used to construct a channel impulse response matrix. The channel impulse response matrix provides the basis for quantifying channel characteristics such as delay, Doppler, and time variability. This system has been used to perform a series of over-the-air tests in the 60 m amateur band and selected Kiwi SDRs. This presentation will describe the system architecture, signal generation and processing, validation using audio baseband channel simulators, and over-the-air measurements. Measurement results from a sporadic-E event that occurred on June 21, 2025 will be highlighted. This system should be useful for citizen science efforts to study solar events and for intercomparisons with other measurement techniques. The waveforms developed in this effort might be highly useful for incorporation into the WWV special tests waveform, and it might facilitate some very interesting propagation measurements and studies.}, author = {Robert Johnk} } @proceedings {940, title = {Effect of the equatorial plasma bubbles on amateur radio communication: Full-wave simulation Study}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

We present the impact of equatorial plasma bubbles (EPB) on high-frequency (HF) wave propagation, such as amateur (ham) radio communications, in the ionosphere. Ionospheric density irregularities occur over a wide range of latitudes from the equator to the polar region and local times. Many numerical efforts have been made to study wave propagation in the ionosphere; however, several challenges arise in modeling the propagation of HF waves. For example, the wavelength of radio waves in the ionosphere is much shorter than the ray path and the thickness of the ionosphere; thus, simulating these waves requires high-performance computing resources. This challenge is one reason why previous research has predominantly focused on ray tracing and analytical calculations. For such reasons, the properties of HF waves{\textemdash}such as reflection, refraction, scattering, and scintillation{\textemdash}are not fully understood in the context of density irregularities. This presentation introduces the state-of-the-art full-wave simulation code, Petra-M. \ We then conduct numerical examinations of how the EPB affects HF wave propagation. We utilize density irregularity structures, such as EPBs, derived from other simulations as background ionospheric density structures. Due to the small-scale density fluctuations in the EPB, HF waves can reach higher altitudes with scattering and trapping in the density structure. Mode conversion from the incoming HF wave to the electrostatic waves, which are localized waves in the ionosphere, also occurs. Such effects can lead to failed wave detection at the receiver since the wave power reaches a broader area near the receiver due to scattering, and wave power can decrease because of the wave mode conversion.

}, author = {Eun-Hwa Kim and S. Shiraiwa and J. R. Johnson and J. Huba and K Hozumi and S. Wing and N. Bertelli} } @proceedings {953, title = {Integration \& Validation of a Standardized Library \& File Format for PyDARNMUSIC \& DARNtids: Migrating From Legacy Pickle Files to HDF5 \& Implementing a Comprehensive Testing Suite}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

The PyDARN Multiple Signal Classification (PyDARN-MUSIC) algorithm is a general, widely used sign processing algorithm for determining the parameters of multiple wavefronts arriving at an antenna array from measurements made on the signals received at the array elements. It has been used in previous Super Dual Auroral Radar Network (SuperDARN) studies to determine the size, strength, speed, and direction of Medium Scale Traveling Ionospheric Disturbances (MSTIDs). DARNtids (Dual Auroral Radar Network Traveling Ionospheric Disturbances) is a python-based open-source software toolkit that first detects level of MSTID activity in SuperDARN data and then runs the MSTID MUSIC analysis software on event periods with significant MSTIDs. DARNtids can run the SuperDARN MUSIC algorithm automatically on thousands\  individual analysis periods. Both PyDARN-MUSIC and DARNtids use pickle files for storing Python objects\  byte streams. Pickle files are fragile and cannot be easily manipulated and used on modern systems. They are specific to Python, produce massive serialized values, and are slower than alternative options. As result, both repositories have experienced software engineering challenges related to portability, interoperability, testability, and maintainability, thereby forcing runs to take significantly longer than necessary, data to be stored inefficiently, and the debugging process to be difficult. We present the methodology taken to seamlessly replace dependencies on pickle files in PyDARN-MUSIC and DARNtids integrating the Hierarchical Data Format Version 5 (HDF5) file format and library. We further discuss validation techniques via the newly implemented PyDARN-MUSIC test suite to ensure numerical data accuracy between existing pickle file results and new HDF5 result.

}, author = {Nicholas Guerra and James Fox and Thomas Pisano and Michael Molzen and Nathaniel Frissell and Paul Jackowitz and Joseph B. H. Baker and J. Michael Ruohoniemi} } @proceedings {828, title = {EclipseNB: A network of low-cost GNSS receivers to study ionospheric response to April 2024 solar eclipse}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

EclipseNB is an initiative of the Radio and Space Physics Lab (RSPL) at the University of New Brunswick (UNB) that enables high-impact scientific research and unique educational opportunities for High School students during the once-in-a-lifetime solar eclipse event over New Brunswick (NB) on April 8, 2024. This project will install state-of-the-art scientific infrastructure at a number of NB schools to monitor the dramatic and sudden modifications to the upper atmosphere associated with the eclipse. These high-value atmospheric measurements will provide rare insight into many open-ended scientific questions pertaining to eclipse-induced atmospheric modifications, while students throughout NB will have an exciting opportunity to participate in numerous EclipseNB activities such as infrastructure installation, data analysis, and scientific research. The infrastructure of EclipseNB is a provincial network of Global Navigation Satellite System (GNSS) receivers to monitor the electrically charged plasma of the upper atmosphere during the April 8, 2024 solar eclipse. A solar eclipse is a both a stunning celestial phenomenon and a rare opportunity to study numerous fundamental physical processes in the atmosphere and near-Earth space that are activated by a sudden and localized reduction in solar radiation. EclipseNB is ideally situated along the eclipse totality path to provide valuable measurements for ground-breaking scientific research, and to garner interest in young New Brunswickers in space physics, technology and engineering. EclipseNB installations are designed to be non-intrusive, with minimal impact on the sites involved. Installations include a self-contained enclosure that houses the GNSS receiver, a small single-board computer, and a cellular modem, as well as a receiving antenna mounted on a small pole with a clear view of the sky. The outdoor antenna is connected to the receiver with a low-loss RF cable. The sole requirement of hosting sites is electrical power, an indoor location to house the equipment enclosure, and an outdoor location to mount the antenna. Data collected by EclipseNB instruments will be stored on servers at UNB RSPL. The instrument will remain running after the solar eclipse in April 2024 and allow facilitating further research and education.

}, author = {Anton Kashcheyev and Chris Watson and P. T. Jayachandran} } @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 {703, title = {Observing Auroral Radio Emissions in Conjugate Hemispheres}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

In addition to its beautiful optical displays, the aurora produces radio emissions of various types, including cyclotron harmonic emissions, auroral hiss, medium frequency burst (MFB), and auroral kilometric radiation (AKR). These emissions enable remote sensing of ionospheric processes and provide a natural laboratory for studying physics of radio emissions that also occur in planetary, solar, and astrophysical environments. Similar to the optical aurora, these radio emissions are generated separately in the northern and southern hemispheres. Nevertheless, optical aurora sometimes exhibit similar features simultaneously in the two hemispheres because aurora in both hemispheres are ultimately driven by the interaction between the solar wind and the magnetosphere. The same should be true of radio emission. At very low frequencies (VLF), auroral hiss has previously been detected at conjugate observatories in Iceland and Antarctica, and satellite-borne radio receivers have observed AKR simultaneously emanating from conjugate sources; however, the other types of radio emission have never been studied at both ends of a magnetic field line. To accomplish this, LF/MF/HF radio receivers have recently been installed at Qikiktarjuaq and Iqaluit, Nunavut, observatories of the Canadian High Arctic Ionospheric Network (CHAIN) which straddle the nominal magnetic conjugate point of South Pole Station, Antarctica, where Dartmouth College operates LF/MF/HF receivers. The Arctic observations employ a dedicated 10-m^2 magnetic loop antenna with active preamp, and a feed from the horizontal linear dipole antennas used for reception of CHAIN ionosonde signals. The Antarctic observations use magnetic loops of areas 2.5-40 m^2 depending on frequency range. Both systems have collected data since October, 2022. Conjugate auroral hiss events have been detected in both equinoctial and solstice conditions. In the latter case, the hiss observed in the daylit hemisphere was weaker than that in the dark ionosphere. Based on initial data, the characteristics and seasonal dependence of conjugate LF auroral hiss appears consistent with previous observations at VLF. Many hiss and cyclotron harmonic emissions have been observed in one hemisphere but not the other. Upcoming 2023 Spring equinox will bring a period of simultaneous darkness at South Pole and Qikiktarjuaq ideal for conjugate medium frequency burst and cyclotron harmonic emissions.

}, author = {James LaBelle and David McGaw and T. Kovacs and A. Kashcheyev and P.T. Jayachandran} } @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} } @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 {645, title = {An Algorithm for Determining the Timing of Components within the HamSCI-WWV/WWVH Scientific Test Signal}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

Beginning in November 2021, WWV and WWVH radio stations have been broadcasting a test signal developed by a Ham Radio Science Citizen Investigation (HamSCI) working group to study what additional ionospheric measurements can be gleaned from the WWV/WWVH transmitter beyond carrier Doppler shift and time-of-flight of standard timing pulses. The signal consists of various individual components including tones, chirps, and Gaussian noise bursts [1]. Interested operators record the signal data at their location, providing researchers with the data naturally manipulated in many different ways [2]. This project seeks to precisely identify the timing of each signal component in the recorded data. The algorithm involves passing the data through various software filters to remove unwanted elements such as frequencies outside of range of interest, DC offset, and so on. Correlation is then performed between the recorded data and each original component to produce their timing. The performance of the algorithm itself is estimated by calculating the SNR of each received signal and the corresponding confidence interval of the algorithm. The results can help to explain the broken symmetry between the transmitted signal and the received signal.

References
[1] Lombardi. {\textquotedblleft}Radio Station WWV.{\textquotedblright} NIST, 16 Nov. 2021, https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwv.
[2] Pamela.corey@nist.gov. {\textquotedblleft}WWV/WWVH Scientific Modulation Working Group.{\textquotedblright} NIST, 5 Nov. 2021, https://www.nist.gov/pml/time-and-frequency-division/time-services/wwvwwvh-scientific-modulation-working-group.

}, author = {Cuong Nguyen and Tyler Jordan and Joseph Tholley and Vaibhavi Patel} } @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} } @conference {586, title = {Amateur Radio Communications as a Novel Sensor of Large Scale Traveling Ionospheric Disturbances (Invited)}, booktitle = {American Geophysical Union Fall Meeting}, year = {2021}, month = {12}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, abstract = {

Amateur (ham) radio high frequency (HF) communications are routinely observed by automated receiving systems on a quasi-global scale. As these signals are modulated by the ionosphere, it is possible to use these observations to remotely sense ionospheric dynamics and the coupled geospace environment. In this presentation, we demonstrate the use of these data to observe Large Scale Traveling Ionospheric Disturbances (LSTIDs), which 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 simultaneously over the continental United States in observations made by global HF amateur 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 discuss possible reasons why LSTIDs were observed in November but not May.

}, url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/822746}, author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Kaeppler, Steven R. and Joshi, Dev Raj and Engelke, William and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.} } @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.} } @proceedings {459, title = {Estimation of Ionospheric Layer Height Changes From Doppler Frequency and Time of Flight Measurements on HF Skywave Signals}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

The HamSCI community has been studying apparent frequency shifts in the reception of HF skywave signals from radio station WWV in Ft. Collins, CO. WWV is a standard time and frequency station with atomic clock accuracy. If the receiving station uses a GPS Disciplined Oscillator (GPSDO) for a frequency reference, the atomic clock accuracy on both ends guarantees any observed frequency shifts are attributable only to propagation effects through the ionosphere. Causes for frequency shifts in the received signal are recognized as complex and varied. A leading candidate is Doppler shift resulting from dynamic changes in refraction layer height. These, in turn, are caused by the diurnal transitions between night and day, passage of an eclipse shadow, and ionospheric disturbances originating from solar flares or X-ray events. For the case of changing refraction layer height, an analysis of Doppler frequency and Time of Flight (TOF) data can estimate the changes in skywave path length between the transmitter and receiver.\  This data can be used in conjunction with an assumed geometric model and propagation mode to infer the corresponding height profile over time. This paper postulates one possible mechanism for observed frequency swings and presents supporting experimental evidence. Comparisons between the calculated\  height profile derived from Doppler data and data from ray trace programs and ionosonde measurements are given.

}, author = {Steven Cerwin and Kristina V. Collins and Dev Joshi and Nathaniel A. Frissell} } @proceedings {572, title = {Experimental and Computational Methods to Analyze Complex Doppler Behavior of Ionospherically Induced Doppler Shifts on HF Signals (Proceedings)}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/MHkz7jNynOg?t=18161}, author = {Cerwin, Stephen A. and Collins, Kristina V. and Joshi, Dev Raj and Frissell, Nathaniel A.} } @conference {583, title = {Experimental and Computational Methods to Analyze Complex Doppler Behavior of Ionospherically Induced Doppler Shifts on HF Signals}, booktitle = {American Geophysical Union Fall Meeting}, year = {2021}, month = {12}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, abstract = {

The HamSCI community has been studying apparent frequency shifts in the reception of HF skywave signals from radio station WWV in Ft. Collins, CO. Causes for frequency shifts in the received signal are recognized as complex and varied. Leading candidates are Doppler shifts resulting from dynamic changes in refraction layer height and the behavior of modes at incidence angles at the cusp between escape into space and refraction back to earth. Observations have shown the most radical frequency disturbances occur during the diurnal transitions between night and day, with the morning transitions exhibiting more radical behavior than evening. Other changes in solar radiation such as passage of an eclipse shadow or solar flares produce similar results. In all cases the frequency swings were found to follow the rate of change of propagation path length. Specific behaviors studied include mode splitting, where the Doppler shift diverges into multiple overtone-related tracks, modes that abruptly manifest and disappear during the transition, and asymptotic behavior where Doppler tracks exhibit a rapid frequency change followed by extinction. A morning transition spectrogram showing some of these characteristics is shown in the accompanying figure. This paper describes experiments and analytical procedures devised to better understand these phenomena. They include Time-of-Flight measurements reconciled with a geometric model of the ionosphere to infer propagation modes, use of the geometric model to calculate layer height changes from measured Doppler shifts, and comparison of specific features between spectrogram and ionosonde data sets. Data from two morning transitions and the 2017 total eclipse are given. Plausible explanations for several aspects of observed frequency swings are postulated.

}, url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/849071}, author = {Cerwin, Stephen A. and Collins, Kristina V. and Joshi, Dev Raj and Frissell, Nathaniel A.} } @proceedings {559, title = {HamSCI: Ham Radio Science Citizen Investigation}, year = {2021}, month = {09/2021}, publisher = {International Space Weather Action Team (ISWAT)}, address = {Virtual}, author = {Frissell, Nathaniel A. and Sanchez, Diego and Perry, Gareth W. and Kaeppler, Stephen R. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H. and Gerzoff, Robert} } @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} } @conference {539, title = {HF Doppler Observations of Traveling Ionospheric Disturbances in a WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2021}, month = {06/2021}, publisher = {CEDAR}, organization = {CEDAR}, address = {Virtual}, abstract = {

Traveling Ionospheric Disturbances (TIDs) are quasi-periodic variations in ionospheric electron density that are often associated with atmospheric gravity waves. TIDs cause amplitude and frequency variations in high frequency (HF, 3-30 MHz) refracted radio waves. We present observations of TIDs made with a network of Ham Radio Science Citizen Investigation (HamSCI) Low-Cost Personal Space Weather Stations (PSWS) with nodes located in Pennsylvania, New Jersey, and Ohio. The TIDs were detected in the Doppler shifted carrier of the received signal from the 10 MHz WWV frequency and time standard station in Fort Collins, CO. Using a lagged cross correlation analysis, we demonstrate a method for determining TID wavelength, direction, and period using the collected WWV HF Doppler shifted data.

}, author = {Veronica I. Romanek and Nathaniel A. Frissell and Dev Joshi and William Liles and Clair Trop and Kristina Collins and Gareth Perry} } @conference {545, title = {HF Doppler Observations of Traveling Ionospheric Disturbances in a WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations}, 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 = {

Traveling Ionospheric Disturbances (TIDs) are quasi-periodic variations in ionospheric electron density that are often associated with atmospheric gravity waves. TIDs cause amplitude and frequency variations in high frequency (HF, 3-30 MHz) refracted radio waves. One way to detect TIDs is through the use of a Grape Personal Space Weather Station (PSWS). The Grape PSWS successfully detected TIDs in the Doppler shifted carrier of the received signal from the 10 MHz WWV frequency and time standard station in Fort Collins, CO. This paper will present an explanation of how the Grape PSWS was used to collect data, and how scientist can use this data to further investigate the ionosphere.

}, url = {https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference}, author = {Veronica I. Romanek and Nathaniel A. Frissell and Dev Raj Joshi and William Liles and Claire C. Trop and Kristina V. Collins and Gareth W. Perry} } @proceedings {578, title = {HF Doppler Observations of Traveling Ionospheric Disturbances in the WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/kVY3E3e--_I?t=3495}, author = {Romanek, Veronica I. and Frissell, Nathaniel A. and Joshi, Dev Raj and Liles, William and Trop, Claire and Collins, Kristina and Perry, Gareth W.} } @conference {580, title = {HF Doppler Observations of Traveling Ionospheric Disturbances in the WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations}, booktitle = {American Geophysical Union Fall Meeting}, year = {2021}, month = {12}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, abstract = {

Traveling Ionospheric Disturbances (TIDs) are quasi-periodic variations in ionospheric electron density that are often associated with atmospheric gravity waves. TIDs cause amplitude and frequency variations in high frequency (HF, 3-30 MHz) refracted radio waves. We present observations of TIDs made with a network of Ham Radio Science Citizen Investigation (HamSCI) Low-Cost Personal Space Weather Stations (PSWS) with nodes located in Pennsylvania, New Jersey, and Ohio. The TIDs were detected in the Doppler shifted carrier of the received signal from the WWV frequency and time standard station near Fort Collins, CO. Using a lagged cross correlation analysis, we demonstrate a method for determining TID wavelength, direction, and period using the collected WWV HF Doppler shifted data.

}, url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/888443}, author = {Romanek, Veronica I. and Frissell, Nathaniel A. and Joshi, Dev Raj and Liles, William and Trop, Clair and Collins, Kristina and Perry, Gareth W.} } @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 {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} } @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 {555, title = {Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC}, year = {2021}, month = {05/2021}, publisher = {SANSA}, address = {Virtual}, url = {https://www.sansa.org.za/events-outreach/superdarn-workshop-2021/}, author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.} } @proceedings {574, title = {Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/MHkz7jNynOg?t=22608}, author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Kaeppler, Stephen R. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.} } @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 {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 {385, title = {A new CHAIN site in New Brunswick: low-cost HF and GNSS instruments for Solar Eclipse 2024}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

The Canadian High Arctic Ionospheric Network (CHAIN) is an array of ground-based radio instruments deployed in the Canadian Arctic and operated by the University of New Brunswick. The network consists of 25 GISTMs/GPS receivers and 9 ionosondes located in Canada at high geographic latitudes spanning between 56{\textdegree} and 80{\textdegree} and has been expanded recently with a new mid-latitude station in New Brunswick, Canada. The coordinates of the new station (Blissville, 45.6 N, 66.54 W) make the station an ideal location to host space weather instrumentation for study of the Solar Eclipse 2024. The predicted path of the total solar eclipse is passing through the site. The Blissville station is equipped with a range of scientific grade instruments, including a multi-constellation GNSS scintillation monitor and CADI ionosonde. Likewise, this station is hosting a low-cost, low-power HF-radar and a low-cost dual frequency GNSS receiver. The ongoing tests are showing good performance with room for potential improvements of the low-cost devices with respect to the citizen science applications. The results of the data comparison of the scientific grade and low-cost space weather instruments will be presented. Possibilities for collaboration with amateur radio community will be discussed.

}, author = {A. Farnham and A. Kashcheyev and T. Kelly and P. T. Jayachandran} } @conference {308, title = {Red Pitaya SDR Recorder for Antarctica (Demonstration)}, booktitle = {HamSCI Workshop 2019}, year = {2019}, month = {03/2019}, publisher = {HamSCI}, organization = {HamSCI}, address = {Cleveland, OH}, author = {Frissell, Nathaniel A. and Melville, Robert and Stillinger, Andrew and Jeffer, Gil} } @conference {219, title = {Anthropogenic Space Weather}, booktitle = {HamSCI-UK}, year = {2017}, month = {10/2017}, publisher = {HamSCI-UK}, organization = {HamSCI-UK}, address = {Milton Keynes, UK}, author = {P. J. Erickson and T. I. Gombosi and D. N. Baker and A. Balogh and J. D. Huba and L. J. Lanzerotti and J. C. Foster and J. M. Albert and J. F. Fennell and E. V. Mishin and M. J. Starks and A. N. Jaynes and X. Li and S. G. Kanekal and C. Kletzing} } @conference {51, title = {e-POP Radio Science Using Amateur Radio Transmissions}, booktitle = {Fall AGU - Poster Presentation}, year = {2015}, month = {12/2015}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {

A major component of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) mission is to utilize artificially generated radio emissions to study High Frequency (HF) radio wave propagation in the ionosphere. In the North American and European sectors, communications between amateur radio operators are a persistent and abundant source source of HF transmissions. We present the results of HF radio wave propagation experiments using amateur radio transmissions as an HF source for e-POP RRI. We detail how a distributed and autonomously operated amateur radio network can be leveraged to study HF radio wave propagation as well as the structuring and dynamics of the ionosphere over a large geographic region. In one case, the sudden disappearance of nearly two-dozen amateur radio HF sources located in the midwestern United States was used to detect a enhancement in foF2 in that same region. We compare our results to those from other more conventional radio instruments and models of the ionosphere to demonstrate the scientific merit of incorporating amateur radio networks for radio science at HF.

}, author = {Nathaniel A. Frissell and Gareth Perry and Ethan S. Miller and Alex Shovkoplyas and Magdalina Moses and H. James and Andrew Yau} }