Angular power spectra of the residual effect of polarization angle uncertainty compared to the foreground spectra at 30GHz and to Planck beam-filtered temperature and polarization spectra at 44 and 70GHz. The blue curve represents the average spectrum, while the grey band is the envelope of all the power spectra calculated from the various realizations of the effect. The theoretical B-mode CMB spectrum assumes a tensor-to-scalar ratio r = 0.1, a tensor spectral index n_T = 0 and has not been beam-filtered. Rows are for 30, 44, and 70GHz spectra, while columns are for TT, EE, and BB power spectra.