Similar to Fig. 3, but directly showing the observed rest-frame 5GHz radio luminosity vs. the observable quantities used to compute the expected radio luminosities in Sect. 3.2. In particular, the observed radio luminosities are compared with the broad Hα luminosities (upper left), the linear combination of broad Hα luminosity and M_BH derived from the fundamental plane of Bariuan et al. (2022) (top right), the [O III] λ5007 luminosities (bottom left), and the 4400 Å luminosities (bottom right). Data points for single BLAGN (black) and for their stack (red) are compared to the scaling relations described in Sect. 3.2. In the two top panels we combined the L_Hα, broad vs. L_2−10 keV relation from Jin et al. (2012) with the L_2−10 keV vs. L_radio relation of D’Amato et al. (2022) (top left), and the fundamental plane relation of Bariuan et al. (2022) (top right).