Bandwidth (top) and time (bottom) smearing factors relevant to LOFAR MSSS observations, expressed as percentages and where unity is equivalent to no smearing. These values are calculated for 2′ angular resolution and for sources at the half-power point of the station beam. In the top panel, points are plotted for averaging single subbands to 4 (stars), 8 (diamonds), and 16 (squares) channels. In the bottom panel, the smearing is calculated for visibility time averaging intervals of 1 (squares), 2 (diamonds), and 4 (stars) seconds.