Interestingly enough, this project was originally licensed under the MIT license, but Motti was advised that said license does not protect physical hardware, so it changed to the CERN-OHL-PT license. Should you elect to build your own unit, be aware that the frequencies it operates in are almost assuredly highly regulated in your legal jurisdiction.
Also be aware of anti radiation munitions if you decide to operate one of these in a warzone. Radarmen have very short battlefield lifetimes because turning on a radar without lots of electronic countermeasures (hell even with countermeasures) is basically like turning on a spotlight that says “blow me up”.
Neat but 3 hours of loitering is nothing for a fixed wing drone. We have drones that stay in flight for a month or more.