Source intrinsic (deconvolved) angular sizes as a function of the measured 150 MHz total flux densities. Deconvolved sizes are defined as the geometric mean of the major and minor FWHM axes, except for well resolved radiogalaxies, which are better described by their major axis. Deconvolved sizes of point sources are set to zero. Raw (▪) and final () catalogs of the LH, Boo and EN1 fields are shown in the top, middle and bottom panels, respectively. The short-long-dashed lines in the three panels define the maximum size (Θ_max) a source can have for a given measured total flux density before dropping below the detection threshold. The solid lines give the minimum size (Θ_min) below which deconvolution is not considered reliable. Both lines have been drawn assuming the median noise in the masked area (see last column of Table 1). The long-dashed lines indicate the Windhorst et al. (1990) median size – flux density relation, converted to 150 MHz, while the dot-dashed lines indicate the median size – 150 MHz flux density relation derived from the simulated T-RECS catalogs directly at 150 MHz (Bonaldi et al. 2019). The filled black-bordered magenta squares and golden circles with error bars represent the median source sizes for the raw and final catalogs respectively. Medians are computed only for those flux density bins where unresolved sources represent less than 50% of the total number of sources.