[PaulHoule]

In larger scale systems (say ham radio or commercial radio or cellular telephone) there is some network planning involved. A ham radio repeater on a mountaintop can “network” with another repeater 70 miles away if there is a good line of sight. Similarly cell phone towers use millimeter wave and other radio backhaul but once more there is a carefully planned line of site. That isn’t what is happening with mesh WiFi.

[thfuran]

Sure, they don't use bands requiring line of sight (though you can buy relatively cheap fast point to point wireless that's line of sight), but a mesh WiFi router that has 2.4, 5, and 6 GHz can reserve one for back haul.