The article details the replacement of an obsolete Narco 50A transponder and encoder with a modern Stratus ESG Transponder and Stratus 2S system in an older airplane.
The upgrade involved installing a new rack, a higher-accuracy (25 ft.) encoder, and carefully drilling and mounting a new GPS antenna, along with routing new antenna cables.
The new Stratus system provides enhanced functionality, including improved altitude reporting and the Stratus 2S now receiving GPS data from the newly installed antenna.