Minimum distance to Eq. (5) for each source as calculated in log space (see Eq. (6)). Red circles represent our sources while black squares represent literature sources listed in Table A.1. Arrows indicate lower limits for unresolved sources and black circles indicate sources with unknown redshifts (set to 1 for this plot). Note that the thick spectral indices of our sources with spectral peaks between 72 and 230 MHz are less reliable since their spectra were only sampled at < 12 frequencies below the spectral turnover.