  We present multifrequency VLA and VLBA observations at 8.4 GHz of the RS CVn
system AR Lac, that were performed in autumn 1997 simultaneously with X-ray
observations obtained from Rodono` et al. (1999). Our VLBA data indicate a
resolved source with dimension close to the system separation, while the study
of the flux density curve evidences a small amplitude outside of the eclipse
variability. The derived five-frequencies spectra, combined with the size
information from VLBA data, are compared with gyrosynchrotron emission from a
two component structured source. A comparison with the results of the X-ray
observations allow us to exclude the possibility that thermal gyrosynchrotron
is responsible for the radio emission, but it is compatible with the hypothesis
of co-spatial X-ray and radio emitting sources.
