TY - CONF T1 - Amateur digital mode based remote sensing: FT8 use as a radar signal of opportunity for ionospheric characterization T2 - HamSCI Workshop Y1 - 2020 A1 - P. J. Erickson A1 - W. Liles A1 - E. S. Miller AB -

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.

JF - HamSCI Workshop PB - HamSCI CY - Scranton, PA ER - TY - CONF T1 - HamSCI Distributed Array of Small Instruments Personal Space Weather Station (DASI-PSWS): Architecture and Current Status (Invited) T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2020 A1 - N. A. Frissell A1 - D. Joshi A1 - K. Collins A1 - A. Montare A1 - D. Kazdan A1 - J. Gibbons A1 - S. Mandal A1 - W. Engelke A1 - T. Atkison A1 - H. Kim A1 - A. J. Gerrard A1 - J. S. Vega A1 - S. H. Cowling A1 - T. C. McDermott A1 - J. Ackermann A1 - D. Witten A1 - H. W. Silver A1 - W. Liles A1 - S. Cerwin A1 - P. J. Erickson A1 - E. S. Miller 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) CY - Santa Fe, NM (Virtual) UR - http://cedarweb.vsp.ucar.edu/wiki/index.php/2020_Workshop:MainVG ER - TY - CONF T1 - Initial Results of HamSCI Ham Radio 21 August 2017 Eclipse Ionospheric Experiments T2 - American Meteorological Society Annual Meeting Y1 - 2018 A1 - N. A. Frissell A1 - J. R. Ackermann A1 - D. Bern A1 - F. Ceglia A1 - G. D. Earle A1 - P. J. Erickson A1 - A. J. Gerrard A1 - R. Gerzoff A1 - P. Gladstone A1 - S. W. Gunning A1 - J. D. Huba A1 - J. D. Katz A1 - E. S. Miller A1 - M. L. Moses A1 - S. E. Reyer A1 - S. W. Rose A1 - A. Shovkoplyas A1 - H. W. Silver A1 - P. Smith A1 - J. S. Vega A1 - M. L. West A1 - R. Williams AB -

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’ 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.

JF - American Meteorological Society Annual Meeting PB - American Meteorological Society CY - Austin, TX UR - https://ams.confex.com/ams/98Annual/webprogram/Paper337094.html ER - TY - JOUR T1 - Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse JF - Geophysical Research Letters Y1 - 2018 A1 - N. A. Frissell A1 - J. D. Katz A1 - S. W. Gunning A1 - J. S. Vega A1 - A. J. Gerrard A1 - G. D. Earle A1 - M. L. Moses A1 - M. L. West A1 - J. D. Huba A1 - P. J. Erickson A1 - E. S. Miller A1 - R. B. Gerzoff A1 - W. Liles A1 - H. W. Silver AB -

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 ±0.3 hr on 1.8 MHz, ±0.75 hr on 3.5 and 7 MHz, and ±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°, while 14 MHz signals refracted at h < 125 km with elevation angles θ < 10°.

VL - 45 UR - https://doi.org/10.1029/2018GL077324 ER - TY - CONF T1 - Fitting Ionospheric Models Using Real-Time HF Amateur Radio Observations T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2017 A1 - J. D. Katz A1 - N. A. Frissell A1 - J. S. Vega A1 - A. J. Gerrard A1 - R. B. Gerzoff A1 - P. J. Erickson A1 - E. S. Miller A1 - M. L. Moses A1 - F. Ceglia A1 - D. Pascoe A1 - N. Sinanis A1 - P. Smith A1 - R. Williams A1 - A. Shovkoplyas JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) CY - Keystone, CO ER - TY - CONF T1 - HamSCI and the 2017 Total Solar Eclipse T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2017 A1 - N. A. Frissell A1 - J. R. Ackermann A1 - G. D. Earle A1 - P. J. Erickson A1 - A. J. Gerrard A1 - R. B. Gerzoff A1 - S. W. Gunning A1 - M. Hirsch A1 - J. D. Katz A1 - S. R. Kaeppller A1 - R. W. McGwier A1 - E. S. Miller A1 - M. L. Moses A1 - G. Perry A1 - S. E. Reyer A1 - A. Shovkoplyas A1 - H. W. Silver A1 - J. S. Vega A1 - RBN Team JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) CY - Keystone, CO ER - TY - CONF T1 - HamSCI and the 2017 Total Solar Eclipse T2 - American Geophysical Union Fall Meeting Y1 - 2017 A1 - N. A. Frissell A1 - J. D. Katz A1 - S. W. Gunning A1 - J. S. Vega A1 - A. J. Gerrard A1 - M. L. Moses A1 - G. D. Earle A1 - M. L. West A1 - P. J. Erickson A1 - E. S. Miller A1 - R. Gerzoff A1 - H. Ward Silver JF - American Geophysical Union Fall Meeting PB - American Geophysical Union CY - New Orleans, LA ER - TY - CONF T1 - HamSCI and the 2017 Total Solar Eclipse (Experiment Description) T2 - ARRL and TAPR Digital Communications Conference Y1 - 2017 A1 - N. A. Frissell A1 - J. S. Vega A1 - J. D. Katz A1 - S. W. Gunning A1 - A. J. Gerrard A1 - M. L. Moses A1 - G. D. Earle A1 - E. S. Miller A1 - J. D. Huba A1 - M. Hirsch A1 - H. W. Silver A1 - S. E. Reyer A1 - J. R. Ackermann A1 - M. D. Suhar A1 - D. Bern AB -

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

JF - ARRL and TAPR Digital Communications Conference CY - St. Louis, MO UR - https://www.tapr.org/pub_dcc.html ER - TY - CONF T1 - HamSCI: The Ham Radio Science Citizen Investigation (Banquet Presentation) T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2017 A1 - N. A. Frissell A1 - J. R. Ackermann A1 - J. Dzekevich A1 - G. D. Earle A1 - P. J. Erickson A1 - A. J. Gerrard A1 - R. B. Gerzoff A1 - S. W. Gunning A1 - M. Hirsch A1 - J. D. Katz A1 - S. R. Kaeppler A1 - R. W. McGwier A1 - E. S. Miller A1 - M. L. Moses A1 - G. Perry A1 - S. E. Reyer A1 - A. Shovkoplyas A1 - H. W. Silver A1 - J. S. Vega A1 - RBN Team JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) CY - Keystone, CO ER - TY - CONF T1 - Ionospheric Simulations of the 2017 Solar Eclipse QSO Party T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2017 A1 - N. A. Frissell A1 - J. S. Vega A1 - J. D. Katz A1 - M. L. Moses A1 - G. D. Earle A1 - S. W. Gunning A1 - A. J. Gerrard A1 - E. S. Miller A1 - M. L. West A1 - F. Ceglia A1 - D. Pascoe A1 - N. Sinanis A1 - P. Smith A1 - R. Williams A1 - A. Shovkoplyas A1 - H. W. Silver JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) CY - Keystone, CO ER -