  A complete sample of 18 X-ray selected clusters of galaxies belonging to the
ROSAT North Ecliptic Pole (NEP) survey has been observed with the Very Large
Array at 1.4 GHz. These are the most distant clusters in the X-ray survey with
redshift in the range 0.3 < z < 0.8.Seventy-nine radio sources are detected
within half an Abell radius with an observed peak brightness >=0.17 mJy/beam,
except for three sources, belonging to the same cluster, which have a higher
peak brightness limit of 0.26 mJy/beam. The NEP field source counts are in good
agreement with the source counts of a comparison survey, the VLA-VIRMOS deep
field survey, indicating that the NEP sample is statistically complete.
Thirty-two out of the 79 sources are within 0.2 Abell radii, twenty-two of them
are considered cluster members based on spectroscopic redshifts or their
optical magnitude and morphological classification. The cluster radio galaxies
are used to construct the Radio Luminosity Function (RLF) of distant X-ray
selected clusters. A comparison with two nearby cluster RLFs shows that the NEP
RLF lies above the local ones, has a steeper slope at low radio powers (<=
10^(24) W/Hz) and shows no evidence for a break at about 6 X 10^(24) W/Hz which
is observed in the nearby cluster RLFs. We discuss briefly the origin and
possible explanations of the differences observed in the radio properties of
nearby and distant clusters of galaxies. The main result of this study is that
the RLF of the distant X-ray clusters is very different from that of the local
rich Abell clusters.
