I had permission to fly my FC40 over some old smoke stacks that were around 200ft high. Just at the point of getting to the top the FC40 would go into come home mode, yellow light flashing, as it lost contact with the remote. I would think the range of the drone would be greater than any 200ft. So is there anything I should be checking to make sure I am getting maximum range? How can this be tested? I plan to go back soon.