The author upgraded an obsolete and failing Narco 50A transponder to a new Stratus ESG transponder system in their airplane.
The installation involved replacing the old rack and encoder with a new, more accurate encoder (25 ft accuracy), and drilling a new hole in the fuselage for a dedicated GPS antenna.
New antenna cables were carefully routed, and the Stratus 2S unit now integrates with the external GPS antenna, eliminating the need for a sky view.