Abstract: An apparatus for reliably conveying real time shaft position information, without cables, between a stationary sensor connected to a reciprocating engine or compressor, or other rotating machinery, and an engine analyzer, in the presence of high energy ignition voltages employs a combination of conventional and non-conventional radio frequency technologies and digital signal processing to both encode and accurately reproduce real time shaft position information. The apparatus provides a safer and more efficient method for an engine maintenance technician to make predictive maintenance measurements on reciprocating engines.