A wellbore apparatus may include first and second tubular members aligned in end-to-end relation, and an antenna assembly coupled to at least one of the first and second tubular members. The antenna assembly may include a cylindrical housing having a circumferential recess therein, a rigid insulating support ring carried by the cylindrical housing in the circumferential recess, an antenna coil carried by the rigid insulating support ring, and an electrical connector coupled to the antenna coil. The wellbore apparatus may include resistivity processing circuitry coupled to the electrical connector to determine an electrical resistivity of a wellbore based upon the antenna coil.