Radio light curves at ν = 4.86 GHz for one-dimensional simulations using the fallback-powered jet luminosities and circumnuclear density profiles shown in Figure 1 for 10⁶ and 10⁷ M_⊙ black holes. The black curve corresponds to the fiducial 10⁷ M_⊙ model. The gray curves correspond to models with a 10⁶ M_⊙ black hole that adopt the fiducial density profile shown in Figure 1 and an ambient density profile enhanced by a factor of 10. Although the external density modifies the deceleration time and peak luminosity, the delayed radio evolution produced by sustained energy injection persists across the full range of environments considered.