  We aim to test the model proposed to explain the correlation between the flux
density at 15 GHz of a stationary component in the parsec-scale jet and the
optical continuum emission in the radio galaxy 3C~390.3. In the model, the
double-peaked emission from 3C~390.3 is likely to be generated both near the
disk and in a rotating subrelativistic outflow surrounding the jet, due to
ionization of the outflow by the beamed continuum emission from the jet. This
scenario is chosen since broad-emission lines are observed to vary following
changes in the inner radio jet. For recent epochs we have imaged and modelled
the radio emission of the inner jet of 3C~390.3, which was observed with very
long baseline interferometry at 15 GHz, 22 GHz and 43 GHz, to image the inner
part of the parsec-scale jet, locate the exact region where the bulk of the
continuum luminosity is generated and search for the mechanism that drives the
double-peaked profile emission. We present the preliminary results of testing
the model using data from 11 years of active monitoring of 3C~390.3.
