@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 {700, title = {Viability of Nowcasting Solar Flare-Driven Radio-Blackouts Using SuperDARN HF Radars}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

The first space weather impact of a solar flare is radio blackout across the dayside of the Earth. At a delay of just 8 minutes, the arrival of enhanced X-ray and EUV radiation leads to a dramatic increase in ionization density in the lower ionosphere. Operation of HF systems are often completely suppressed due to anomalous absorption, while many RF systems suffer some degradation. While the onset of blackout is very rapid (~1-minute), the recovery takes tens of minutes to hours. Furthermore, severe solar flares can disrupt emergency HF communications that support humanitarian aid services, including amateur radio and satellite communication systems. Our current monitoring capability is based on modeling the ionospheric impacts based on GOES satellite observations of solar fluxes. We present a technique to characterize radio blackout following solar flares using HF radar. The future extension of this work is to develop an now-casting system to identify and monitor radio blackouts using HF radars currently deployed to support space science research. Networks of such radars operate continuously in the northern and southern hemisphere as part of the SuperDARN collaboration. Recent studies have shown that radio blackout (also known as shortwave fadeout) is easily detected and characterized using radar observations. We will combine real-time observations from the North American suite of SuperDARN radars to specify the occurrence of radio blackouts in near real-time.

}, author = {Shibaji Chakraborty and J. Michael Ruohoniemi and Joseph B. H. Baker} } @proceedings {618, title = {Viability of Nowcasting Solar Flare-Driven Radio-Blackouts Using SuperDARN HF Radars}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

The first space weather impact of a solar flare is radio blackout across the dayside of the Earth. At a delay of just 8 minutes, the arrival of enhanced X-ray and EUV radiation leads to a dramatic increase in ionization density in the lower ionosphere. Operation of HF systems are often completely suppressed due to anomalous absorption, while many RF systems suffer some degradation. While the onset of blackout is very rapid (1-minute), the recovery takes tens of minutes to hours. Furthermore, severe solar flares can disrupt emergency HF communications that support humanitarian aid services, including amateur radio and satellite communication systems. Our current monitoring capability is based on modeling the ionospheric impacts based on GOES satellite observations of solar fluxes. We present a technique to characterize radio blackout following solar flares using HF radar. The future extension of this work is to develop an now-casting system to identify and monitor radio blackouts using HF radars currently deployed to support space science research. Networks of such radars operate continuously in the northern and southern hemisphere as part of the SuperDARN collaboration. Recent studies have shown that radio blackout (also known as shortwave fadeout) is easily detected and characterized using radar observations. We will combine real-time observations from the North American suite of SuperDARN radars to specify the occurrence of radio blackouts in near real-time.

}, author = {Shibaji Chakraborty and J. Michael Ruohoniemi and Joseph B. H. Baker} } @proceedings {626, title = {VLF LEAF Module for the Tangerine SDR HamSCI Workshop 2022 Progress Update}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

Development of the VLF LEAF Module continues despite the global electronic component shortage. Since the Tangerine SDR cannot be built currently due to long lead times of the Intel Max 10 FPGA, the Max 10 FPGA development board was repurposed for Tangerine SDR Development. An adapter board was designed that allows the Clock Module and RF Module to be interfaced to the Max 10 development board for Verilog development of the Tangerine SDR. Since the LEAF module is too large for the adapter board, the adapter board will include a connector to interface the TI TLV320ADC6140 Evaluation (DUT) board. The DUT board includes the TLV320ADC6140 and all supporting circuitry to spearhead Verilog development of the VLF LEAF module. The FPGA will add GPS timestamping to the recorded samples and reformat the stream to be compatible with vlfrx-tools, an open source signal processing tool set with many applications, including VLF/ULF signal processing.\ 

}, author = {Jonathan Rizzo} } @proceedings {469, title = {Viability of nowcasting solar flare-driven radio-blackouts using SuperDARN HF radars}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, abstract = {

The first space weather impact of a solar flare is radio blackout across the dayside of the Earth. At a delay of just 8 minutes, the arrival of enhanced X-ray and EUV radiation leads to a dramatic increase in ionization density in the lower ionosphere. Operation of HF systems are often completely suppressed due to anomalous absorption, while many RF systems suffer some degradation. While the onset of blackout is very rapid (~ minutes), the recovery takes tens of minutes to hours. Furthermore, severe solar flares can disrupt emergency HF communications that support humanitarian aid services, including amateur radio and satellite communication systems. Our current monitoring capability is based on modeling the ionospheric impacts based on GOES satellite observations of solar fluxes. We present a technique to characterize radio blackout following solar flares using HF radar. The future extension of this work is to develop an early warning system to identify \& monitor radio blackouts using HF radars currently deployed to support space science research. Networks of such radars operate continuously in the northern and southern hemisphere as part of the SuperDARN collaboration. Recent studies have shown that radio blackout (also known as shortwave fadeout) is easily detected and characterized using radar observations. We will combine real-time observations from the North American suite of SuperDARN radars to specify the occurrence of radio blackouts in near real-time. In this study, however, we present investigation and recognition techniques of shortwave fadeouts in SuperDARN HF radar.

}, author = {Shibaji Chakraborty and J. Michael Ruohoniemi and Joseph B. H. Baker} } @proceedings {473, title = {Visualising propagation to mid-latitudes from a shipboard WSPR transmitter on a passage from 27oN to 70oS using the WsprDaemon database, and how to access the data}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

WSPR transmitters and or receivers on polar research ships provide opportunities for several interesting propagation studies. Such studies include propagation across the Boreal and Austral Auroral Ovals with the ship working in the Polar Regions, or, as in this case, on mid-latitude propagation with the ship on transit. For RV Polarstern{\textquoteright}s voyage from Gran Canaria (27.5oN) to Neumayer III station, Antarctica (70.5oS) from 27 December 2020 {\textendash} 18 January 2021 a WSPR transmitter (DP0POL) operated on all bands 160{\textendash}10 meters. Heatmaps of the number of spots received in Europe and North America each hour, each day, and on each band have been generated from the WSPR data held on the WsprDaemon server. These spot-count heatmaps, proxies for circuit reliability, clearly delineate the diurnal variation in band opening times and how those diurnal variations vary systematically over a 100o span of latitude on the voyage south. However, quantitative assessment of the spot numbers needs care; the number of reporters receiving spots changes with time and distance. Furthermore, there were far fewer distinct reporters for the MF and upper HF bands (11 for 160 m and 14 for 10 m compared with 447 for 40 m and 473 for 20 m). The heatmaps of SNR show several intriguing features, including steps from no decodes to SNRs some 10 dB above the WSPR decoding threshold as bands open and close. A Grafana dashboard is available for all to explore at http://logs1.wsprdaemon.org:3000/d/QGlNSz-Gk_2\  Other ways to obtain WSPR data from the WsprDaemon database are outlined, including using Octave, KNIME, R, Python, PySpark and Clickhouse. A worked example shows how to use Octave to generate a time sequence of great circle maps, as a movie, of where WSPR spots from DP0POL were received on the voyage from 27.5oN to 70.5oS.

}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=57-BC-D3-11-D9-50-97-40-0D-F8-D2-C5-AA-73-79-6A}, author = {Gwyn Griffiths and Rob Robinett} } @proceedings {568, title = {VLF LEAF Module for the Tangerine SDR DCC 2021 Update}, year = {2021}, month = {09/2021}, publisher = {ARRL-TAPR}, address = {Virtual}, url = {https://youtu.be/MHkz7jNynOg?t=10913}, author = {Rizzo, Jonathan} } @proceedings {461, title = {VLF Module for Tangerine SDR Progress Update}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

The VLF Audio Module for the Tangerine SDR has had a design change and now features the TI TLV320ADC6140 4-channel Analog to Digital converter. It features 113dB dynamic range with sampling rates of up to 768kHz. Using a sampling rate of 384kHz, bandwidths of up to 100kHz of VLF spectrum can be captured and will be GPS timestamped by the Tangerine SDR. This design change{\textquoteright}s increase bandwidth capability allows for not only study of natural radio emissions such as whistlers and chorus, but study of the ionosphere with the help of measurements from VLF transmitters in the middle and upper VLF band, such as WWVB.\ \ 

}, author = {Jonathan Rizzo} } @conference {404, title = {Visualizing the Electromagnetic Spectrum in the Time Domain (ePoster)}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

Since the advent of the Software Defined Radio (SDR), the ability to collect raw signal information from the electromagnetic spectrum has become ubiquitous.\ \ Typically, the received Inphase and Quadrature (IQ) data is processed with a Fast Fourier Transform (FFT) algorithm to display the signal information in the frequency domain.\ \ While this has many advantages, to include displaying a waterfall to show the energy per frequency over time, the waterfall visual representation does not visually represent the entire signal.\ \ This work demonstrates a novel method to view the electromagnetic spectrum in the time domain by directly plotting the IQ data in 3- dimensional space.\ \ The Visualization Tool Kit (VTK) is utilized to provide this representation and Paraview is utilized in viewing the 3D data.\ \ The goal is twofold; first to visualize the electromagnetic spectrum for educational use and second to determine if weak signals near strong signals can be visualized where they have traditionally been obscured by the computation of the signal{\textquoteright}s FFT.

}, author = {Stephen Hamilton and Charles Suslowicz} } @conference {311, title = {VLF Sudden Ionospheric Disturbance Receiver (Demonstration)}, booktitle = {HamSCI Workshop 2019}, year = {2019}, month = {03/2019}, publisher = {HamSCI}, organization = {HamSCI}, address = {Cleveland, OH}, author = {Liles, William} } @article {251, title = {A Virtuous Cycle: Hams and Scientists Helping Each Other}, volume = {74}, year = {2018}, month = {05/2018}, pages = {32-35}, issn = {0007-893X}, url = {http://www.cq-amateur-radio.com/}, author = {Rich Moseson} } @conference {164, title = {VLF/LF and the 2017 Total Solar Eclipse}, booktitle = {Dayton Hamvention}, year = {2017}, address = {Xenia, OH}, abstract = {

Previous solar eclipse studies have observed different propagation effects at VLF/LF frequencies (3-300 kHz) compared with those observed at HF (3-30 MHz) frequencies. These differences are primarily due to the much longer wavelengths at lower frequencies in concert with ionospheric D layer interactions. To better understand the unusual eclipse-induced effects at VLF/LF frequencies, we present EclipseMob, a crowdsourced collection effort that will use smart phones as simple VLF/LF software defined radio (SDR) receivers to record changes in propagation from known transmitters during the 2017 Total Solar Eclipse.

}, author = {William Liles and L. Lukes and J. Nelson and K. Kerby-Patel} }