The ground leg needs to be mounted, physically and electrically, as close as possible to the end rib. Method (1): Before mounting nut plates to the wingtip (or remove them if already done), place the ground leg between the wing tip and the nut plates; match drill wingtip and antenna ground leg at all places. Rivet wingtip - ground leg- nut plate. Remove all paint from the wing under the attaching screws, so there is a good ground leg to wing metal to end rib electrical connection, at many places along the ground leg.