The present invention relates to a method and apparatus for monitoring an antenna system comprising at least two antenna branches providing antenna diversity. At least a first signal branch measure and a second signal branch measure are repeatedly generated in response to a first signal branch and a second signal branch received by a respective one of the at least two antenna branches, thus generating a first plurality of second signal branch measure values in a manner so that the first and second pluralities reflect the quality of the first and second signal branches, respectively, at different points in time. The first and second pluralities are analysed in order to distinguish any differences in the performance of the first and second antenna branches.