My gps is mounted directly on the arm, overlapping the top plate. It rests atop a copper foil rfi shield which itself is grounded. The copper shield serves the same purpose as the stalk. In Naza assistant the Z value in the placement screen is set to 0. From the beginning, when I was deciding what multirotor to buy, the gps placed high up on that flimsy stalk bothered me. I didn't want it.