You need short wave radio for low power long haul audio .. otherwise we would need so many cell towers at 5Ghz every few blocks or 1 to 0.5 km depending on tower size and terrain.
I can hear the ISS on a walkie talkie when it passes overhead, that's about 405Km distance. Line of sight makes it easy so beware of claims of long range. You might cover 3-5Km line of sight but not be heard in the next room.