Redshift distribution models, N(z), for the NVSS (top panels) and TGSS catalogs (bottom panels) shown in the range z = [0, 3]. Predictions from the S³ simulator are shown to the left and T-RECS to the right. The thick black histogram in each panel shows the distributions of all sources in the catalog. Histograms with different colors indicate the distribution of each object type identified by the labels.