The ionosonde data that feeds this site is provided by the Global Ionospheric Radio Observatory who have graciously offered free access for that purpose. Thanks are given to all of the ionosonde stations participating in that network.
The World Wide Radio Operators Foundation is a foundation created by amateur radio operators in 2009 to advance the state of the art in radio operating. They cover the ongoing cost of server colocation for the site, and in March 2022, they funded a $10,000 grant to purchase a new server to run the numerical models and host the prop.kc2g.com website.
This site began as a fork of Matt Smith AF7TI's "giroapp" and "giroviz", for which we are grateful, and all of the code for the site is provided under open-source licenses.
In addition, the site would never have been possible without dozens of other open-source projects, including Python, Perl, NumPy, SciPy, pandas, matplotlib, cartopy, george, Flask, IRI-2020, IGRF-13, WMM2020, the space-physics packages iri2016, igrf, and wmm2020, Mojolicious, Minion, PostgreSQL, Podman, and many more.