Difference maps between the Planck 30 GHz and WMAP K-band maps for Planck 2018 (first row), Planck PR4 (second row), and BEYONDPLANCK (third row). All maps have been smoothed to a common angular resolution of 3° FWHM before evaluating the differences. The WMAP K-band map has been scaled by a factor of 0.495 to account for different center frequencies, assuming a synchrotron spectral index of β_s = −3.1. Bottom row shows one of the WMAP K-band transmission imbalance templates discussed by Jarosik et al. (2007), which accounts for known poorly measured modes in the WMAP data.