  The study of the radio properties of the AMIGA sample is intended to
characterize the radio continuum emission for a sample least affected by local
environment, thus providing a reference against which less isolated and
interacting samples can be compared. Radio continuum data at 325, 1420 and 4850
MHz were extracted from the WENSS, NVSS/FIRST and GB6 surveys, respectively. We
focus on the complete AMIGA subsample composed of 719 galaxies. Comparison
between the NVSS and FIRST detections indicates that the radio continuum is
coming from disk-dominated emission in spiral galaxies, in contrast to the
results found in high-density environments where nuclear activity is more
frequent. The comparison of the radio continuum power with a comparable sample,
which is however not selected with respect to its environment, the Condon et
al. UGC-SF sample of star-forming field galaxies, shows a lower mean value for
the AMIGA sample. We have obtained radio-to-optical flux ratios (R) using the
NVSS radio continuum flux. The distribution of R for the AMIGA galaxies is
consistent with a sample dominated by radio emission from star formation (SF)
and a small number of Active Galactic Nuclei (AGN), with less than 3% of the
sample with R > 100. We derived the radio luminosity function (RLF) and total
power density of the radio continuum emission for the AMIGA sample at 1.4 GHz,
and compared them with results from other low redshift studies. The Schechter
fit of the RLF indicates a major weight of the low-luminosity galaxies. The
results indicate the very low level of radio continuum emission in our sample
of isolated galaxies, which is dominated by mild disk SF. It confirms hence the
AMIGA sample as a suitable template to effectively quantify the role of
interactions in samples extracted from denser environments.
