Left panel: spectropolarimetry of the normal plasma jet: (top) integrated total intensity – I, (upper middle) integrated fractional linear polarization – m_l, (lower middle) integrated EVPA – χ, and (bottom) integrated fractional circular polarization – m_c, over the frequency range ν_obs = 86 − 230 GHz. Right panel: corresponding spectropolarimetry of the pair plasma jet. The solid red and dashed red lines in the lower panels highlight theoretical predictions for the frequency dependence of m_c(ν) in the limits of intrinsic emission and emission dominated by Faraday conversion in the high-rotation limit, respectively.