TY - Generic T1 - Estimation of Ionospheric Layer Height by Measuring the Time Difference of Arrival (TDOA) Between 1 and 2 Hop Propagation Modes. 2023 Annular Eclipse Observations T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Steven A. Cerwin A1 - Paul Bilberry A1 - Sam Blackshear A1 - Jesse T. McMahan A1 - Kristina V. Collins A1 - Nathaniel A. Frissell AB -
A HamSCI science objective for the 2023 and 2024 eclipses is to use amateur radio stations to measure how the ionosphere changes with eclipse passage. Of particular interest is the change in effective ionization layer height caused by the momentary blockage of solar radiation. Layer height between two stations can be deduced from a Time of Flight (TOF) measurement but doing so requires complexity beyond the capability of most amateur radio stations. Particularly difficult requirements are precision absolute time references for both stations and calibration of the lengthy time delays incurred in modern DSP based transceivers. A simpler method that can be just as effective is to measure the Time Difference of Arrival (TDOA) between the 1- and 2- hop modes over paths and frequencies that support both modes. The 1-hop mode is shorter and arrives first, followed by the longer 2-hop mode. Geometric models based on virtual height or refractive ray tracing can be used to mathematically relate 1-2 hop TDOA to layer height. The measurement can be implemented by transmitting audio signals that are sensitive to a time delay when summed together, as happens in the receiver during simultaneous 1 and 2 hop propagation. Suitable audio waveforms include a 1-cycle audio burst, audio chirps of controlled sweep rate, and a pseudorandom noise burst. The TDOA measurement using the short pulses is performed by directly measuring the time difference between the two received pulses. The summation of a chirp waveform with a delayed copy of itself produces a beat note equal to the product of the sweep rate and the time delay that can be used to calculate TDOA. The TDOA can be extracted from both the PN bursts and chirps through an autocorrelation technique. The audio signals can simply be fed to the microphone input and recovered from the speaker output of ordinary SSB amateur radio equipment using audio .wav programs. This paper gives details of the method and of on-air experiments both before and during the 2023 Annular Eclipse.
JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - Generic T1 - Reexamining the Characteristics of Flare-Driven Doppler Flash using multipoint HF Observations T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Shibaji Chakraborty A1 - Kristina V. Collins A1 - Nathaniel A. Frissell A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -Sudden enhancement in the ionospheric electron density following a solar flare causes disruption in the transionospheric high frequency (HF: 3-30 MHz) communications, commonly referred to as Shortwave Fadeout (SWF). This disruption is also recorded as a sudden enhancement in Doppler frequency in the received HF signal, referred to as Doppler Flash. This phenomenon was recorded and reported by the SuperDARN HF radar network. Previous investigations have suggested that among various phases of flare-driven SWFs observed by HF radars Doppler Flash is the first to observe, and there are no significant trends in Doppler Flash with location, operating frequency, or flare intensity. Recent development showed that Doppler observations from the distributed HamSCI Personal Space Weather Station (PSWS) can provide insight into the physics behind changes in phase path length of the trans ionospheric radio signals. Unlike SuperDARN, HamSCI PSWS can record the full phase of the Doppler Flash, provide an edge to revisit the characterization study and compare with existing dataset. In this study, we demonstrate how HamSCI observations can be used to infer flare-driven changes in ionospheric properties. We found: (1) HamSCI PSWS has higher dynamic range than SuperDARN during flare making it less susceptible to SWF, thus it can record the full Doppler Flash; (2) data from HamSCI PSWS shows a strong function trend with flare strength, operating frequency, and location on the Earth; and (3) HF rays traveling longer distances experienced statistically higher Doppler. We understand that, while instantaneous Doppler realized by the HF signal is proportional to the rate of change in solar irradiance, the total Doppler realized is proportional to the total flare-deposited energy in the ionosphere.
JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - JOUR T1 - Amateur Radio: An Integral Tool for Atmospheric, Ionospheric, and Space Physics Research and Operations JF - White Paper Submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 Y1 - 2022 A1 - Nathaniel A. Frissell A1 - Laura Brandt A1 - Stephen A. Cerwin A1 - Kristina V. Collins A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Rachel M. Frissell A1 - Robert B. Gerzoff A1 - Stephen R. Kaeppler A1 - Vincent Ledvina A1 - William Liles A1 - Michael Lombardi A1 - Elizabeth MacDonald A1 - Francesca Di Mare A1 - Ethan S. Miller A1 - Gareth W. Perry A1 - Jonathan D. Rizzo A1 - Diego F. Sanchez A1 - H. Lawrence Serra A1 - H. Ward Silver A1 - David R. Themens A1 - Mary Lou West ER - TY - JOUR T1 - Fostering Collaborations with the Amateur Radio Community JF - White Paper Submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 Y1 - 2022 A1 - Nathaniel A. Frissell A1 - Laura Brandt A1 - Stephen A. Cerwin A1 - Kristina V. Collins A1 - Timothy J. Duffy A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Rachel M. Frissell A1 - Robert B. Gerzoff A1 - Stephen R. Kaeppler A1 - Vincent Ledvina A1 - William Liles A1 - Elizabeth MacDonald A1 - Gareth W. Perry A1 - Jonathan D. Rizzo A1 - Diego F. Sanchez A1 - H. Lawrence Serra A1 - H. Ward Silver A1 - Tamitha Mulligan Skov A1 - Mary Lou West ER - TY - Generic T1 - HF Doppler Observations of Traveling Ionospheric Disturbances in a WWV Signal Received with a Network of Low Cost HamSCI Personal Space Weather Stations T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Veronica Romanek A1 - Nathaniel A. Frissell A1 - William Liles A1 - John Gibbons A1 - Kristina V. Collins AB -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. The authors present an analysis of observations of TIDs made with Ham Radio Science Citizen Investigation ( HamSCI ) Low Cost Personal Space Weather Stations (PSWS) located in Northwestern New Jersey and near Cleveland, 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.
JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - WWV/H Scientific Modulation Working Group: Designing for Citizen Science T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Kristina V. Collins AB -Time standard stations WWV and WWVH have served the National Institute of Standards and Technology’s time dissemination needs for the past century. Because of the stations’ dependability and the precision of their frequency control, their carriers have served as a measurement signal in ionospheric sensing work for over half that time. Until now, however, the possibilities for additional science-driven modulations have not been fully explored. Here, we report a characterization signal which is currently being broadcast at 8 minutes past the hour on WWV and (44) minutes past the hour on WWVH from 15 November, its design process, and initial measurements made of that signal. (www.hamsci.org/wwv). This signal serves dual purpose: to characterize the stations’ transmitters and to prototype waveforms that can be incorporated into the existing broadcast schedule for citizen science measurements in the future. We discuss opportunities for this signal as a citizen science tool and introduce a planned campaign of measurements April 30-May 1 2022 (www.hamsci.org/sunrisefest).
JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - Data Collection from WWV, WWVH, and WWVB: A Histoanatomy of NIST's Radio Beacon Transmissions T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - David Kazdan A1 - Kristina V. Collins AB -Beacon radio stations WWV, WWVH, and WWVB are maintained by the National Institute of Standards and Technology for frequency and time of day distribution. Their accuracy and power level are adequate to make the stations suitable for use as passive beacons in ionospheric sounding. The signals' carriers are useful in measurements, and each of the modulation components has its own separate utility, as well. This poster describes several approaches to determining total path length rate of change from the stations to distant receivers through measurements of various signal parts. Tradeoffs for the several approaches in signal strength to noise ratio, ability to distinguish signals from multiple time standard stations, and other factors are discussed.
JF - HamSCI Workshop 2021 UR - https://hamsci2021-uscranton.ipostersessions.com/?s=65-9B-EB-D7-81-ED-65-2D-38-C6-5F-CB-F3-ED-B2-B0 ER - TY - Generic T1 - Estimation of Ionospheric Layer Height Changes From Doppler Frequency and Time of Flight Measurements on HF Skywave Signals T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Steven Cerwin A1 - Kristina V. Collins A1 - Dev Joshi A1 - Nathaniel A. Frissell AB -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.
JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - MGZN T1 - Ham Radio Creates a Planet-Sized Space Weather Sensor Network Y1 - 2021 A1 - Kristina V. Collins A1 - David Kazdan A1 - Nathaniel Frissell JF - QST VL - 105 UR - https://www.arrl.org/qst IS - 8 ER - TY - CONF T1 - HamSCI Campaign Co-Design (Panel Discussion) T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Kristina V. Collins A1 - Nathaniel A. Frissell A1 - Philip J. Erickson A1 - Laura Brandt A1 - Elizabeth MacDonald A1 - Michael Black A1 - Gareth Perry JF - HamSCI Workshop 2021 PB - HamSCI CY - Virtual ER - TY - CONF T1 - HamSCI Personal Space Weather: Architecture and Applications to Radio Astronomy T2 - Annual (Summer) Eastern Conference Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Typinski A1 - William D. Engelke A1 - David R. Larsen A1 - David G. McGaw A1 - Hyomin Kim A1 - David M. Witten, II A1 - Julius M. Madey A1 - Kristina V. Collins A1 - John C. Gibbons A1 - David Kazdan A1 - Aidan Montare A1 - Dev Raj Joshi A1 - Veronica I. Romanek A1 - Cuong D. Nguyen A1 - Stephen A. Cerwin A1 - William Liles A1 - Jonathan D. Rizzo A1 - Ethan S. Miller A1 - Juha Vierinen A1 - Philip J. Erickson A1 - Mary Lou West AB -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.
JF - Annual (Summer) Eastern Conference PB - Society of Amateur Radio Astronomers (SARA) CY - Virtual UR - https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference ER - TY - CONF T1 - HamSCI Personal Space Weather Station (PSWS): Architecture and Current Status T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Dev Joshi A1 - Veronica I. Romanek A1 - Kristina V. Collins A1 - Aidan Montare A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Travis Atkison A1 - Hyomin Kim A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Witten A1 - Julius Madey A1 - H. Ward Silver A1 - William Liles A1 - Steven Cerwin A1 - Philip J. Erickson A1 - Ethan S. Miller A1 - Juha Vierinen AB -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.
JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - CONF T1 - HF Doppler Observations of Traveling Ionospheric Disturbances in a WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations T2 - Annual (Summer) Eastern Conference Y1 - 2021 A1 - Veronica I. Romanek A1 - Nathaniel A. Frissell A1 - Dev Raj Joshi A1 - William Liles A1 - Claire C. Trop A1 - Kristina V. Collins A1 - Gareth W. Perry AB -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.
JF - Annual (Summer) Eastern Conference PB - Society of Amateur Radio Astronomers (SARA) CY - Virtual UR - https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference ER - TY - Generic T1 - PSWS Grape Hardware: Version 1.0 and Pilot Experiments T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Kristina V. Collins A1 - John Gibbons A1 - David Kazdan AB -One year into our NSF grant, HamSCI's Low-Cost Personal Space Weather Station is undergoing rapid development. Like its namesake, the "Grape" does its best work in bunches, and several early prototypes are already deployed and collecting Doppler data. This talk will present the Grape 1.0 hardware, the data collected by pilot stations, and the lessons this platform has taught us as we move to Grape 2.0.
JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - Generic T1 - W8EDU: Case Amateur Radio Club from 2010 to 2021 T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Kristina V. Collins A1 - Aidan Montare A1 - David Kazdan AB -W8EDU, 2010-2021: In ten years, the Case Amateur Radio Club has grown from a small alumni-based group to a large student organization with extensive curricular and research involvement. This poster shows some of our successful efforts in that time, and highlights how our operating, licensing, curricular and research efforts support one another.
JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) UR - https://hamsci2021-uscranton.ipostersessions.com/?s=B5-39-13-BC-26-3A-2E-F1-35-30-97-99-27-96-4D-CD ER -