You can always access the source code and compile for free.
But, if you want to try it out compiled on a Windows device free for 7 days check out the Microsoft Store. If you like it please purchase to help support development. The Microsoft Store version will continue to be the latest stable branch of the project.
You will need an external antenna like the BU-353 S4 (know for sure this one works).
Want to support the project? Try bitcoin: bc1qzcp55j36mj84wxc5ytpgyx75re0ymg5j5sjc09