It's line of sight only. Think about it like a flashlight. If you have a flashlight (w/power) up on top of a skyscraper roof or a mountainside it can be seen at very long distances. At street level it goes till the next small rise in the ground.
Range for the newly-available parts of the 6 GHz band will not be substantially different from range for the 5 GHz band and the portions of the 6 GHz band that were already available for uses like WiFi.
I am not. Everything above 30 MHz or so is line of sight in the consumer products sense of the word. We can talk about niche modes like tropospheric ducting or super high power troposcatter, but ducting is irregular and unpredictable and tropo scatter requires many kilowatts of power.
Pretty much everything from VHF and up (all of wifi) is line of sight only. Not just the mm-wave stuff. Cell phone networks only work because the telcos pay big money to get their transceivers power/data up on towers high above the terrain.
Store and forward meshes assume the nodes will eventually see each other but down at 5ft above the ground they often won't.
