Comparison with other AGN sources. Left: comparison of the jet radius of 1928+738 in the collimation zone as a function of deprojected distance from the black hole with M 87, NGC 315 and 1H 0323+342 in units of R_g. For 1H 0323+342, M_• = 2 × 10⁷ M_⊙ and θ_v = 8° are assumed in this plot. The M 87 data have been compiled from numerous previous studies (see Nakamura et al. 2018, and references therein). The data for NGC 315 and 1H 0323+342 are from Park et al. (2021) and Hada et al. (2018), respectively. Their best-fit power-law scaling relations R ∝ z^0.58 are indicated by dashed lines. Right: comparison of the jet velocity field (Γβ) in the acceleration zone as a function of deprojected distance from the black hole in units of R_g of 1928+738 with those of M 87 and NGC 315. The M 87 data have been compiled from numerous previous studies (see Park et al. 2019a, and references therein), and the NGC 315 data are from Park et al. (2021). The black dashed horizontal line indicates Γ = 2 for illustration. The best-fit jet acceleration profiles of NGC 315 (Park et al. 2021) and 1928+738 (Sect. 3.5) are also presented with colored dashed lines for comparison.