Low-frequency radio spectra (pink) in log–log space of galaxy cluster A655 for different-sized apertures compared to the modeled radio SZ effect spectra (green), bremsstrahlung radiation (blue), and sum of the models (red). SZ models were calibrated using the ﹩1{0}^{{\prime} }﹩ aperture using the Planck SZ data (yellow). Radio observations (pink) greatly outshine all modeled effects by multiple orders of magnitude, making radio SZ detection extremely difficult.