  We report the results of 15 years of radio observations of the six historical
supernovae (SNe) in M83 using the Very Large Array. We note the near linear
decline in radio emission from SN 1957D, a type II SN, which remains a
non-thermal radio emitter. The measured flux densities from SNe 1923A and 1950B
have flattened as they begin to fade below detectable limits, also type II SNe.
The luminosities for these three SNe are comparable with the radio luminosities
of other decades-old SNe at similar epochs. SNe 1945B, 1968L, and 1983N were
not detected in the most recent observations and these non-detections are
consistent with previous studies. We report the X-ray non-detections of all six
historical SNe using the Chandra X-ray Observatory, consistent with previous
X-ray searches of other decades-old SNe, and low inferred mass loss rates of
the progenitors.
