  Jets, paving their way outward through the inner regions of active nuclei,
Compton-interact with the UV radiation from an accretion disc and broad
emission line region. We calculate the predicted properties of the resulting
spectral signatures of this bulk-Compton process, noting that they are
independent on the fractional proton content or kinetic power of the jet, and
use the presence or absence of such signatures to put constraints on the
structure of jets near their bases.
