I have a number of flights now. About half,,, 8-9 from my back yard, out over a large bog which is totally open and then over a number of houses. Most of the houses use CenturyLink set-top wifi boxes for TV. When I get to 1700' I am over the horses and I lose Controller signal. When I fly in a totally open field, no houses, cell towers, etc, I have been to 3250' and feel I could have gone to 4000' no problem. Im not drawing any conclusions but thats what happens. The open field area is about 1 1/2 miles from my home.