Repeatable reference for positioning sensors and transducers in drill pipe

A drill string comprising a plurality of downhole components, each downhole component having two ends, the plurality of downhole components each detachably joined one to another at their respective ends;

• each downhole component having at least two coupled inductive transmission devices, with at least one transmission device mounted in a reference plane in each end of the downhole component such that the transmission device is paired with and spaced a distance from the adjacent transmission device in the adjacent reference plane in the adjacent joined downhole component, wherein the distance between each set of paired transmission devices is substantially constant, forming a tuned electrical communication system in the plurality of downhole components;
• wherein the downhole components comprise lengths of drill pipe to from a drill string for oil, gas, and geothermal well drilling which are detachably joined one to another with tool joints wherein, when each tool joint is connected under a nominal makeup torque, the distance between an internal shoulder of a box end and an external face of a pin end of the tool joint is between 0.003 and 0.010 inches.