Distribution of the radio-loudness parameter (log(R)) value for 1409 objects classified as BLL and 771 objects as FSRQ of the 4LAC catalogue (upper panel) and for the counterparts of UGS1 (lower panel). The empty orange bars represent the upper limits on R for UGS1 without a radio counterpart. The dashed vertical black line represents the radio-loudness parameter value (R = 10) that separates the radio-quiet from the radio-loud sources. Sources with proper motion are excluded from the histograms.