I'm located in the Dallas Texas area.
Your hangar or mine.
Mobile Aircraft Static and Transponder Systems Inspections and
Certifications. 91.411 and 91.413
For IFR, both the altimeter and transponder tests are required every 24
months.
For VFR, the transponder tests are required every 24 months.
These tests are not required as part of an annual.
Let me know if I can help!
Cheers
Dave
FAA CRS# ZG4R818X