I wonder how feasible it is to build something like this for back yard scale? I just want to fry the drones my neighbor flies crossing my yard. Is there some kind of distance squared dynamic going on? That would imply I could run a small device off a car battery right?

Netting spread across tall poles are about the only thing that is not outright illegal. HOA's and some towns will throw a fit about the netting. Using radio weapons outside of a war-zone will likely result in fines if it interferes with anything revenue generating and possibly even arrest.