Overview of the Lockman Hole/XMM observations. Shown is the Spitzer 3.6 μm image as colour scale in the background. The three circles denote the FWHM of the VLBA antennas’ primary beams. The pointing coordinates have been taken from the VLA observations of this field reported in Ibar et al. (2009). It is also indicated which pointings have been observed in epochs A to D. Crosses indicate radio sources from Ibar et al. (2009) with a flux density of 100 μJy or more, and located within 20 arcmin of a pointing centre.