I did this very test with an aluminum box made from rolled aluminum flashing. I took the get up and my son to a street where I placed the aluminum box on a corner post at the curve along with my son. Using our phones about every 20 feet I would say up-down and he'd reply yep. There was a pushrod pointing out of the top with a square piece of balsa on it. I did this for one mile, at which point I could not see the pole or him. I cover numerous planes with this same aluminum, wrapping the forward fuse totally encasing the equipment and have not had a single issue. This is with Futaba 2.4ghz.