  By cross-correlating the 1.4 GHz FIRST catalog of radio sources with the
Abell cluster catalog we have found an excess surface density by a factor ~5 of
radio sources within a projected distance, r_p, of 0.1 Mpc (for h=0.65) from
the cluster center. The profile of the excess density can be described, for r_p
> 0.1 Mpc, by a beta-model with a core radius of ~0.70 Mpc and beta=1.65. The
luminosity function of cluster sources does not show hints of cosmological
evolution over the redshift range (z>~0.4) covered by our cluster sample. The
mean luminosity function is in excellent agreement with the recent
determination by Reddy & Yun (2004) for 7 nearby clusters and extends it by two
orders of magnitude to higher luminosities. Its shape is very similar to that
of the local luminosity function of field galaxies, but the space density is
about 3000 times higher. When extrapolated to 30 GHz, our luminosity function
compares very favourably with an estimate obtained directly from the 30 GHz
observations by Cooray et al. (1998). The antenna temperature contributed by
radio sources within the nominal cluster radius of 1.7 Mpc is estimated to be
\~13.5 microK at 30 GHz for clusters at z~0 and decreases to ~3.4 microK at
z~0.5, in the absence of cosmological evolution; it increases by a factor of
\~1.5 within 0.25 Mpc from the cluster center. If the pure luminosity evolution
models by Dunlop & Peacock (1990) are adopted, the radio source antenna
temperature turns out to be essentially independent of redshift.
