This article starts with a brief description of historical observations that have been made concerning the effects of solar eclipses on the strengths of distant medium wave signals. It continues with a description of how medium-wave DXers used software defined radios (SDRs) for the first time during the solar eclipse of August 2017 to record the entire AM broadcast band (535-1705kHz) for later analysis. Although no plan had been made to create a formal experiment, it appears to be possible to use the data collected to analyze the effect of the eclipse on radio propagation. An example is presented, derived from recordings made at four different receiver locations in western North America, describing large variations in the signal strength from Salt Lake City's KSL-1160kHz during the course of the eclipse. The times that peak signal strengths occurred at the four locations are then compared relative to the times of eclipse totality along the signal paths.
HamSCI will again be at the Dayton Hamvention as part of the new Ham Radio 2.0: Innovation and Discovery area sponsored by the Yasme Foundation. Come visit the HamSCI Booth and Forum to learn about projects on the cutting edge of ham radio science and engineering research, including new directions in Sporadic E research, causes of F region ionospheric variability, how propagation works on the new 630 and 2200 m bands, the Personal Space Weather Station, and more. Hamvention will be held May 17-19, 2019 at the Greene County Fairgrounds in Xenia, Ohio.
Congratulations to the Case Amateur Radio Club for their second place score (out of 114 entries nation-wide) in the ARRL’s Frequency Measurement Test! The hosts of this year’s HamSCI workshop, W8EDU was able to measure the frequency of one 80 meter and one 40 meter transmission from K5CM to 0.03 and 0.02 Hertz, respectively. First place station W4VU in North Carolina won by only a slight margin of 0.01 Hz on 80 meters (a difference of one part per billion in the measurement).
Plain Language Summary: Radio communications using the high‐frequency (HF) bands (3–30 MHz) is important for emergency communications because it is the only form of electronic communications that can travel over the horizon without relying on man‐made infrastructure such as the Internet, satellite systems, or phone networks. This is possible because HF rays can be bent back to Earth by the ionosphere, an electrically charged layer of the upper atmosphere. Space weather events such as X‐ray flares from the Sun and geomagnetic storms can alter the ionosphere to disrupt these communications. During September 2017, a significant number of solar flares and geomagnetic activity occurred. Simultaneously, major hurricanes, including Hurricane Irma and Hurricane Jose, caused situations in the Caribbean region requiring the use of emergency HF communications, often provided by ham (amateur) radio operators. This paper shows the impacts of these space weather disturbances on HF communications as observed by multiple ham radio monitoring systems.
SEQP logs and data submitted to hamsci.org are now available for download from the Zenodo Data Repository HamSCI Community. This archive contains the locations, logs, and station descriptions submitted by operators to hamsci.org following the SEQP, as well as an aggregated, geolocated archive in CSV format of all Reverse Beacon Network (RBN), WSPRNet, PSKReporter, DXCluster, and SEQP log QSOs. The final rules of the SEQP have also been archived here. More information about the SEQP can be found at http://hamsci.org/seqp, and a published analysis of RBN observations over the United States by Frissell et al. (2018) may be found at https://doi.org/10.1029/2018GL077324.
This week, many HamSCI members are presenting their research at the American Geophysical Union (AGU) Fall Meeting in Washington, D.C. The AGU Fall meeting is one of the largest geoscience meetings in the world, and consists of about 24,000 attendees. The scientific program includes sessions pertaining to all areas of geophysics, including space weather, the solar wind, auroral activity, the ionosphere, and the neutral atmosphere. Below is a list of selected presentations and sessions being given by HamSCI members, or of general interest to ham radio operators. The complete scientific program is available here.
In his recent QEX article, “Ionospheric Disturbances at Dawn, Dusk, and During the 2017 Eclipse,” Steve Cerwin, WA5FRF published his analysis of observations of WWV (5 MHz) and WWVB (60 kHz) transmitters in Ft. Collins, CO as received at his home in San Antonio, TX. Cerwin reports that during the August 21, 2017 eclipse, a definite and measurable enhancement of low frequency (LF) and high frequency (HF) signals from his station. In addition to eclipse observations, Cerwin also examined the dawn and dusk transitions on both frequencies. Notable findings include a propagation null on WWVB that is correlated in time with dusk and dawn, and is consistent with destructive interference from a combination of ionospheric skip and ground-wave multipath propagation. Cerwin also reports on increased frequency jitter at 5 MHz during these times, as well a radical positive frequency swing at dawn and a negative swing at dusk.