Started on a mount for the transponder. It will be located in the rear baggage compartment under the “hat box” shelf. I cut some aluminum angles to attach between the upper and lower longeron. The upper angle will be attached with c/s rivets under the longeron so that the baggage shelf will fit flush on the longeron. Laid out holes in the angles and match drilled to the longerons with my angle drill. Cut a plate from .040 stock for the mounting plate. Will attach to the angles with nutplates.