Radio SED of RxAGN as normalized log-flux density vs. rest-frame frequency for z ∈ [0, 4] and log L_1.4 [W Hz⁻¹] ∈ [24, 26]. A single power-law (left panel) and a broken power-law (right panel) model of the radio SED are shown as red lines with red confidence intervals. Detections are shown as gray points, upper limits as yellow arrows, bins without upper limits as green points and bins with upper limits as magenta points. The plots show the best fitting power-law (0.64 ± 0.07) and broken power-law (α₁ = 0.28 ± 0.03, α₂ = 1.16 ± 0.04 and ν_b = (4.1 ± 0.2) GHz) models.