  The Seyfert 2 galaxy NGC3079 is one of the nearest radio-weak AGN. We have
carried out multi-frequency, multi-epoch VLBI observations of this object and
detected new components, proper motion of the order of 0.1 c, strong spectral
variability, and free-free absorption. Based on phase-referenced astrometry, we
suggest a new identification of components seen at 1.7 GHz. Our results suggest
that the nucleus in NGC3079 is embedded in a dense medium which strongly
affects the radio appearance of the AGN ejecta. We supplement our work with
Seyfert VLBI observations taken from the literature.
