A telemetry unit for high speed shafts includes a metallic annular carrier having an inner circumferential surface defining a bore, for receiving a shaft or sleeve to rotatably couple the telemetry unit with the shaft, an outer circumferential surface, opposing axial ends, and interior cavities. An annular insulator formed of an electrically insulative material has an inner circumferential surface disposed about the carrier outer surface, an outer circumferential surface, and opposing axial ends. A generally circular antenna is disposed circumferentially about the insulator outer surface and an annular retainer is disposed about the insulator outer surface such that the antenna is generally sandwiched between the retainer and the insulator to generally fix the antenna relative to the carrier. The carrier engages a portion of the insulator outer surface to prevent radially-outward displacement of the insulator when the telemetry unit rotates about the axis.