SED of SDSS J0306+1853 (archival data from SSDC). The empty circles in the radio band are our VLA data at 1.4 and 5 GHz. The corresponding spectral index is α = 0.88 (F_ν ∝ ν^−α). The solid black line corresponds to the accretion disc, the X-ray corona, and the molecular torus. Left panel: emission from a powerful jet with Γ = 13 (dashed blue line), as would be seen with a viewing angle of 3°. If we interpret the VLA data as the sum of a flat core plus a steep extended component, then both structures should substantially contribute to the flux. This requires the jet to be seen misaligned with θ_v = 13° (solid blue line). The extended structure is assumed to be a lobe with a radius of 10 kpc, in equipartition (namely E_B = E_e; dotted green line). Right panel: emission from a weaker jet with Γ = 2 (dashed blue line), as seen with θ_v = 3°. To contribute to the radio VLA data, θ_v = 30° is required. The extended structure (dotted green line) is the same as in the left panel. The set of parameters is listed in Tables 4 and 5.