@proceedings {606, title = {Contrasting effects of the 3-5 November 2021 geomagnetic storm on reception in Colorado of WSPR transmissions from North-Eastern North America with those from Australia}, year = {2022}, month = {03/2022}, publisher = {HamSCI}, address = {Huntsville, AL}, abstract = {

Solar wind particles from three M-class flares hit the Earth{\textquoteright}s magnetic field around 19:30 UTC on 3 November 2021. The planetary geomagnetic disturbance index (Kp) peaked at 7 that evening and the following morning. At the USGS Boulder Geomagnetic Observatory, Colorado the vertical magnetic field anomaly was below -40 nT between 07:38 UTC and 12:56 UTC on 4 November, dipping briefly to -75 nT. These dramatic space weather events are examined using WSPR spots at N6GN, near Fort Collins, Colorado. Between 10:30 UTC and 11:00 UTC the 7 MHz WSPR spot count showed a ~90\% drop compared with previous days at that time interval. Second, the median distance for remaining spots increased to 7089 km from ~2500 km of previous days. Furthermore, the noise level dropped about 4 dB. At that time of day the noise at N6GN{\textquoteright}s remote receiver is limited by propagated-in noise rather than local or receiver noise. Central to the observed spot count decrease and median distance increase was a 98\% reduction in spots received from grid FN, North Eastern North America: down to 5 spots from a typical 245 on other days in the same interval. But what caused that precipitous drop? We look at signal levels of individual transmissions to try and understand whether received signal levels dropped below the noise or whether Doppler flutter spread the signals beyond the bandwidth of the WSPR decoder. We also seek to understand the increase in spots from Australia compared with previous days. During the storm itself, signal levels from Australia were unchanged; it was not until the following day that levels and the number of spots decreased. We caution and investigate that the very narrow band transmissions may not be decoded more due to spectral distortion and spreading rather than the more usual lack of signal to noise ratio. This analysis provides a valuable use case for WSPR transmissions, reporting via wsprnet.org, augmented with noise estimates and on-line access via the WsprDaemon database with quick-look Grafana and animated Octave visualizations.

}, author = {Gwyn Griffiths and Glenn Elmore} } @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} } @conference {400, title = {Patterns in Received Noise: Methods, Observations and Questions (ePoster)}, booktitle = {HamSCI Workshop 2020}, year = {2020}, month = {03/2020}, publisher = {HamSCI}, organization = {HamSCI}, address = {Scranton, PA}, abstract = {

There are valid concerns that local noise, often as common mode, is an increasing problem for radio amateurs. By adding two noise measurement algorithms to a robust Weak Signal Propagation Reporter (WSPR) processing and reporting package\ -\ wsprdaemon\ -\ we now have the capability to record and share noise level measurements from over twenty amateur stations. With locations from Maui to Moscow, and ranging from very quiet rural Northern California, Utah, and Austria to more typical suburban noise environments we have observed a multitude of patterns in received noise on the LF to HF bands (136 kHz to 28 MHz). These patterns show clearly where and when the local noise floor becomes a limiting factor. More intriguingly, we have observed coherent fluctuations in the noise over periods of hours at a pair stations 1000 km apart. Now with observations from a {\textquoteright}diamond{\textquoteright} of four stations we can look in more detail at the timing of these coherent fluctuations. With over six months of observations every two minutes from several stations we can show systematic seasonal variations in the daily noise patterns. We think we understand the root causes of some of the features, such as the local noon minimum and the post-sunset maximum in late spring and summer. However, we have yet to reach a satisfactory understanding for some patterns, including a transition to a daytime noise maximum in autumn. The challenging task of calibration to a field strength in free space will not be ignored, but for this presentation it will be set aside as we concentrate on patterns and not absolute noise levels. This presentation will outline the noise measurement methods, show examples of noise patterns from several stations, introduce the on-line database and its Grafana interface that delegates will be able to explore, and we will seek comments, insights and suggestions as to causes for the patterns and next steps for this collaborative effort.

}, author = {Gwyn Griffiths and Rob Robinett and Glenn Elmore and Clint Turner and Tom Bunch and Dennis Benischek} }