In Afghanistan, I used an old fashioned DDWRT router with the transmission power turned up to 125milliwatts IIRC? No special antennas like a high gain one. The distance was a backhaul link between routers so we could have civilian internet at the office. There was no regulatory domain other than not interfering with the signals guys or messing up radar returns.

My FPOV drone was in the 5Ghz band and I could go for about 1.5 miles before a tree limb would cause significant interference.