@conference {381, title = {Amateur digital mode based remote sensing: FT8 use as a radar signal of opportunity for ionospheric characterization}, booktitle = {HamSCI Workshop}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

The K1JT / WSJT suite of digital modes for amateur QSOs, provided to the community by Joe Taylor K1JT and Steve Franke K9AN, has revolutionized the use of weak signal HF propagation to carry short digital messages. Traffic on the FT8 mode has become a large fraction of all digital transmissions by amateurs since its introduction in 2017 near solar minimum. FT8 is a 15 second cadence, 8-tone FSK mode using a sophisticated combination of stacked low-density parity coding (LDPC) and cyclical redundancy check (CRC) codes. Combined with a deep search retrieval algorithm that takes advantage of the sparse information for messages within typical QSOs, the effective FT8 communications detection threshold is considerably lower than other traditional modes such as CW.

FT8 signals undergo changes on reception caused by ionospheric refraction. Observational study of this feature opens up compelling avenues for research into the time and space dependent behavior of ionospheric variations. A technique long known to the passive radio remote sensing community involves intercepting transmissions of opportunity and processing them to yield information on reflecting targets on the transmit-to-receive path. We present initial simulations and studies of the use of FT8 in this manner as an ionospheric range-Doppler passive radar, and will discuss the qualities of these signals for crowdsourced upper atmospheric research, including an explanation and examples of their effective range-Doppler ambiguity in typical QSO exchanges. Also discussed will be the particular effectiveness for radar applications of the three Costas array frequency/time synchronization sequences used by FT8 in the start, middle, and at the end of transmissions.

}, author = {P. J. Erickson and W. Liles and E. S. Miller} } @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 {390, title = {Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, 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 observations made by Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporting Network (WSPRNet) for the first time. The RBN and WSPRNet are two large-scale High Frequency (HF, 3-30 MHz) amateur (ham) radio observing networks that provide data to the Ham Radio Science Citizen Investigation (HamSCI). The LSTIDs were observed on the 7 and 14 MHz amateur radio bands, and are detected by observing changes in average propagation path length with time. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. Simultaneous LSTID signatures were present in ham radio observations over the continental United States, the Atlantic Ocean, and Europe. LSTIDs observed with amateur radio were consistent with LSTIDs observed by the Blackstone SuperDARN HF radar and in differential GNSS Total Electron Content (TEC) measurements. GNSS TEC maps were used to estimate LSTID parameters: horizontal wavelength 1100 km, phase velocity 950 km/hr, period 70 min, and propagation azimuth 135{\textdegree}. The LSTID signatures were observed throughout the day following ~800 nT surges in the Auroral Electrojet (AE) index at 00 and 12 UT. We will discuss potential generation hypotheses for the observed LSTIDs, including atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications
and associated Joule heating.

}, author = {D. Sanchez and N. A. Frissell and G. Perry and W. D. Engelke and A. Coster and P. J. Erickson and J. M. Ruohoniemi and J. B. H. Baker} } @conference {425, title = {Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, GNSS TEC, and Ionosondes}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2020}, month = {06/2020}, address = {Santa Fe, NM (Virtual)}, url = {http://cedarweb.vsp.ucar.edu/wiki/index.php/2020_Workshop:MainVG}, author = {D. F. Sanchez and N. A. Frissell and G. W. Perry and W. D. Engelke and A. Coster and P. J. Erickson and J. M. Ruohoniemi and J. B. H. Baker and R. C. Luetzelschawb} } @conference {382, title = {Update on the Golden Ears Project}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

The Radio Receiver Instrument (RRI), part of the Enhanced Polar Outflow Probe (e-POP) science payload on the Cascade, Smallsat and Ionospheric Polar Explorer (CASSIOPE) spacecraft, has recorded continuous wave (CW; Morse code) transmissions during the American Radio Relay League (ARRL) Field Day exercises since 2015. Perry et al. (2018) demonstrated the value of such transmissions to radio science. By identifying a handful of hams in the RRI data collected during the 2015 Field Day and inputting their transmitting locations into a high frequency (HF) ray tracing model, Perry et al. were able to accurately estimate foF2 over a portion of the midwestern United States. They were also able to diagnose the periodic fading in the amplitude of one ham{\textquoteright}s transmission as a multipath propagation effect unique to transionospheric propagation.

One lesson from the Perry et al. analysis was that decoding the transmissions using CW {\textquotedblleft}skimmers{\textquotedblright}, software capable of decoding large bands of CW signal, was not feasible with the RRI data. This is likely due to the fact that the signals disperse and degrade as they transit from the ground, through the ionosphere, and up to the spacecraft. As a result, the Perry et al. transmissions had to be decoded aurally by the article{\textquoteright}s co-authors. Since 2015, RRI has collected several hours of ARRL Field Day transmissions, necessitating a more organized decoding effort, rather that the ad hoc methodology employed thus far.

Accordingly, the {\textquotedblleft}Golden Ears Project{\textquotedblright} was initiated following the RRI operations for the 2019 ARRL Field Day. The goal of the project is straightforward: use members of the ham community with a distinct aptitude for aurally decoding CW signals (i.e., individuals with {\textquotedblleft}Golden Ears{\textquotedblright}) to decode data collected by RRI in thorough and organized way. In this presentation we will disseminate the first project{\textquoteright}s first results from 2019 Field Day operations. We will describe the experimental setup, methodology used to prepare the data from the decoders, discuss their results, and outline the future directions of the project.

Perry, G. W., Frissell, N. A., Miller, E. S., Moses, M., Shovkoplyas, A., Howarth, A. D., \& Yau, A. W. (2018). Citizen Radio Science: An Analysis of Amateur Radio Transmissions With e-POP RRI. Radio Science, 933{\textendash}947. https://doi.org/10.1029/2017RS006496

}, author = {G. Perry and P. J. Erickson and B. D. Blain and R. Reif and N. A. Frissell} } @conference {274, title = {HamSCI Personal Space Weather Station: A New Tool for Citizen Science Geospace Research}, booktitle = {USNC{\textendash}URSI National Radio Science Meeting}, year = {2019}, month = {01/2019}, publisher = {U.S. National Committee for URSI}, organization = {U.S. National Committee for URSI}, address = {Boulder, CO}, abstract = {

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

}, url = {https://nrsmboulder.org/}, author = {J. S. Vega and N. A. Frissell and P. J. Erickson and A. J. Gerrard} } @conference {236, title = {Initial Results of HamSCI Ham Radio 21 August 2017 Eclipse Ionospheric Experiments}, booktitle = {American Meteorological Society Annual Meeting}, year = {2018}, month = {01/2018}, publisher = {American Meteorological Society}, organization = {American Meteorological Society}, address = {Austin, TX}, abstract = {

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

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

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

}, issn = {1944-8007}, doi = {https://doi.org/10.1029/2018GL077324}, url = {https://doi.org/10.1029/2018GL077324}, author = {N. A. Frissell and J. D. Katz and S. W. Gunning and J. S. Vega and A. J. Gerrard and G. D. Earle and M. L. Moses and M. L. West and J. D. Huba and P. J. Erickson and E. S. Miller and R. B. Gerzoff and W. Liles and H. W. Silver} } @conference {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 {176, title = {Fitting Ionospheric Models Using Real-Time HF Amateur Radio Observations}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {J. D. Katz and N. A. Frissell and J. S. Vega and A. J. Gerrard and R. B. Gerzoff and P. J. Erickson and E. S. Miller and M. L. Moses and F. Ceglia and D. Pascoe and N. Sinanis and P. Smith and R. Williams and A. Shovkoplyas} } @conference {175, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {N. A. Frissell and J. R. Ackermann and G. D. Earle and P. J. Erickson and A. J. Gerrard and R. B. Gerzoff and S. W. Gunning and M. Hirsch and J. D. Katz and S. R. Kaeppller and R. W. McGwier and E. S. Miller and M. L. Moses and G. Perry and S. E. Reyer and A. Shovkoplyas and H. W. Silver and J. S. Vega and RBN Team} } @conference {230, title = {HamSCI and the 2017 Total Solar Eclipse}, booktitle = {American Geophysical Union Fall Meeting}, year = {2017}, month = {12/2017}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, author = {N. A. Frissell and J. D. Katz and S. W. Gunning and J. S. Vega and A. J. Gerrard and M. L. Moses and G. D. Earle and M. L. West and P. J. Erickson and E. S. Miller and R. Gerzoff and H. Ward Silver} } @conference {174, title = {HamSCI: The Ham Radio Science Citizen Investigation (Banquet Presentation)}, booktitle = {NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions)}, year = {2017}, month = {06/2017}, address = {Keystone, CO}, author = {N. A. Frissell and J. R. Ackermann and J. Dzekevich and G. D. Earle and P. J. Erickson and A. J. Gerrard and R. B. Gerzoff and S. W. Gunning and M. Hirsch and J. D. Katz and S. R. Kaeppler and R. W. McGwier and E. S. Miller and M. L. Moses and G. Perry and S. E. Reyer and A. Shovkoplyas and H. W. Silver and J. S. Vega and RBN Team} }