Page 3-8 GDU 37X Installation ManualRevision C 190-01054-013.4.2 Antenna Installation Instructions1. Refer to Table 3-5 and Figures C-2.X for guidance on selecting the appropriate mounting cutout. Drillor punch the holes to match the mating part (doubler).2. Install a doubler plate to reinforce the aircraft skin, as required. Refer to Section 3.4.1 for doublerpreparation and Table 3-5 for additional guidance on the doubler installation. Dimple aircraft skinwhen the skin thickness is less than 0.051” for installation of flush head rivets. Countersink aircraftskin when the skin thickness is between 0.051” and 0.063” for installation of flush head rivets.3. For the stud mount teardrop footprint antenna, place install gasket on top of aircraft skin using the fourscrew holes to align the gasket.4. Washers and locking nuts are required to secure the antenna. Torque the four #8-32 stainless steellocking nuts 12-15 in-lbs. Torque should be applied evenly across all mounting studs or screws toavoid deformation of the mounting area.5. Ensure that the antenna base and aircraft skin are in continuous contact with the gasket or o-ring, asappropriate to the antenna model.6. Seal the antenna and gasket to the fuselage using Dow Corning 738 Electrical Sealant or equivalent.Run a bead of the sealant along the edge of the antenna where it meets the exterior aircraft skin. Usecaution to ensure that the antenna connectors are not contaminated with sealant.Do not use construction grade RTV sealant or sealants containing acetic acid.These sealants may damage the electrical connections to the antenna. Use ofthese type sealants may void the antenna warranty.3.4.3 Reference FiguresFigure 3-4 Doubler Design, Teardrop Footprint Antenna, Skin Thickness 0.032" to 0.049"CAUTION
