  We report extensive VLA and ATCA observations of the two diffuse radio
sources in the cluster of galaxies Abell 548b, which confirm their
classification as relics. The two relics (named A and B) show similar flux
density, extent, shape, polarization and spectral index and are located at
projected distances of about 430 and 500 kpc from the cluster center, on the
same side of the cluster's X-ray peak. On the basis of spectral indices of
discrete radio sources embedded within the diffuse features, we have attempted
to distinguish emission peaks of the diffuse sources from unrelated sources. We
have found that both relics, in particular the B-relic, show possible fine
structure, when observed at high resolution. Another diffuse source (named C)
is detected close in projection to the cluster center. High-resolution images
show that it contains two discrete radio sources and a diffuse component, which
might be a candidate for a small relic source. The nature and properties of the
diffuse radio sources are discussed. We conclude that they are likely related
to the merger activity in the cluster.
