@proceedings {1044,
	title = {A Python data analysis and synthesis toolbox for PSWS Doppler data:  A time-of flight case study},
	year = {2026},
	month = {03/2026},
	publisher = {HamSCI},
	address = {Newington, CT},
	abstract = {A prototype Python toolbox is available to aid HamSCI Personal Space Weather Station (PSWS) data interpretation1. The toolbox currently has two themes. First, a set of frequency- (FFT) and time-domain (autocorrelation) scripts for estimating and plotting Doppler frequency, Doppler spread and signal level of PSWS digital_RF data. For bimodal spectra an experimental script estimates Doppler of two peaks, assigns to propagation modes and tries to track even if they cross. Second, a set of scripts invoking PyLap 2D and 3D ray tracing to obtain synthetic spectrograms of one- and two-hop E and F region, low and high ray, propagation modes. Time series of take-off angle, reflection apogee and time of flight (ToF) are derived from automated PyLap simulations. Novel ToF measurements between WWV and KD7EFG, Utah, provide an interpretation challenge case study. Apogee height simulation time series show expected propagation modes, importantly showing periods with two co-propagating modes, and, by omission, suggesting when sporadic E (Es) was present. 5 MHz Es propagation, with minimal vertical height variability, and ToF of 2.12 ms, provided the benchmark to show consistent ToF measurements within 60 us. The more dynamic F region gave rise to commensurate variations in ToF. However, ToF estimates became scattered with two co-propagating modes from WWV (e.g. 5 MHz E and F). 15 MHz Es propagation showed consistent ToF of 2.19 ms from a weak signal 50 dB below one-hop F2. Fascinatingly, an interval with ToF of 14 ms reducing to 8 ms from a weak but strengthening signal was attributed, with certainty, to two-hop sidescatter using 3D PyLap simulation. One-hop via F region only occurred briefly, with correct ToF of 2.81 ms. As the 15 MHz path from WWVH opened, with a strong signal seen in Doppler shift, ToF measurements on the path from WWV, of weak two hop sidescatter, became very scattered. This case study shows the importance of being able to use PSWS Doppler analysis to interpret new ToF measurements.  In conclusion, these results herald a significant advance in the HamSCI Community{\textquoteright}s ability to characterize ionospheric propagation channels. },
	author = {Gwyn Griffiths and Scott Newell and Paul Elliott and Clint Turner and Brett Anderson and Michael Hauan and Rob Robinett}
}
@proceedings {926,
	title = {Interim Findings of the HamSCI DASI2 HF Antenna Project},
	year = {2025},
	month = {03/2025},
	publisher = {HamSCI},
	address = {Newark, NJ},
	abstract = {<p>An ad hoc HamSCI DASI2 Antenna Group was tasked in late 2024 with evaluation of antenna options for the DASI2 grant. We present the the materials, methods, and criteria we have so far developed to accomplish this along with preliminary results. \&nbsp;Antenna systems under consideration include DXE-RSEAV-1FVI, N6GN SAS, LZ1AQ loop dipole, and others. \&nbsp;The materials include key elements already intended for use in the grant -- the RX888-SDR and software such as the KA9Q-Radio system, the KA9Q-Web spectrum display, WSPRDAEMON, and spot and noise reception reports to wspr.net, wsprdaemon.org, and pskreporter. \&nbsp;The methods leverage ITU noise figures, known broadcast station locations, significant recent improvements in the spectrum display, and analysis of the local site. \&nbsp;The criteria so far include antenna performance metrics, site evaluation, ease of deployment, support needs, and cost. This effort will enable us to provide good quality information, some of which we present, for selecting an appropriate antenna for the grant. \&nbsp;However, the effort to solve this particular task has also demonstrated the general utility of these tools and methods for the amateur radio community. \&nbsp;A view of the entire HF spectrum enable at-a-glance assessments that can help one more effectively identify and solve problems and optimize reception given the natural limitations of one{\textquoteright}s site. \&nbsp;One can see recognizable patterns suggesting local and propagated noise, overmodulation, aliasing, inadequate front-end gain, ground loops, and more. \&nbsp;One can compare two (or more) antennas or one antenna with itself at different sites or orientations, the effects of feed-line placement, interactions with nearby structures or foliage, and more. \&nbsp;These efforts will inform the choice of an antenna to use for the DASI2 grant but can prove immediately useful for all hams and scientists in understanding and optimizing their receiving systems.</p>
},
	author = {Michael Hauan and Glenn Elmore and Rob Robinett and Gwyn Griffiths and Dve Witten and Ulli Grunow and Clint Turner}
}
