Episodic radio galaxies J0116$-$4722 and J1158+2621: can we constrain
  the quiescent phase of nuclear activity?
  We present multifrequency radio observations of two well known episodic
FR\,II radio galaxies (J0116$-$4722 and J1158+2621) and a detailed
investigation of the life-cycle of episodic radio galaxies from their spectral
and radiative properties. Combining our previous work with the present results,
we either constrain or place very good limits on the active and quiescent
phases of a small sample of episodic FR\,II radio galaxies. The duration of the
quiescent phase can be as small as the hotspot fading time of the previous
episode, and as high as a few tens of Myr; however, for none of the sources in
our sample is it close to the duration of the active phase of the previous
episode. We also find that for many episodic radio galaxies, the nucleus is
variable at radio wavelengths. For our small sample of 7 episodic radio
galaxies, we find 4 to have strongly variable cores, a much larger proportion
than is generally found in samples of normal FR\,II radio galaxies. Studies
with larger samples will be required to establish a statistical association
between core variability and episodic radio activity.
