  We discuss the possibility of obtaining Fast Radio Bursts (FRBs) from the
interior of supernovae, in particular SN 1986J. Young neutron stars are
involved in many of the possible scenarios for the origin of FRBs, and it has
been suggested that the high dispersion measures observed in FRBs might be
produced by the ionized material in the ejecta of associated supernovae. Using
VLA and VLBI measurements of the Type IIn SN 1986J, which has a central compact
component not so far seen in other supernovae, we can directly observe for the
first time radio signals which originate in the interior of a young (~30 yr
old) supernova. We show that at age 30 yr, any FRB signal at ~1 GHz would still
be largely absorbed by the ejecta. By the time the ejecta have expanded so that
a 1-GHz signal would be visible, the internal dispersion measure due to the SN
ejecta would be below the values typically seen for FRBs. The high dispersion
measures seen for the FRBs detected so far could of course be due to
propagation through the intergalactic medium provided that the FRBs are at
distances much larger than that of SN 1986J, which is 10 Mpc. We conclude that
if FRBs originate in Type II SNe/SNRs, they would likely not become visible
till 60 ~ 200 yr after the SN explosion.
