Representative stages in the data reduction pipeline. In each panel, the horizontal axis is frequency, covering approximately 1 MHz, and the vertical is time, increasing downward and covering approximately 1 h. The grey-scale is the cross-power spectral density. The top row is the C0–C8 baseline and the bottom row the C0–W4 baseline, which are approximately 560 and 9400 m, respectively. The large bright patches indicate broad-band RFI, and the vertical lines indicate line RFI. The first panel in each row is the initial input data. The second is after the initial 8σ mask, with most interference still visible. The third panel is after removing the largest eigenvalues in the SVD. The broad-band interference is no longer visible. The last panel shows the final 3σ mask removing the line RFI, leaving a nearly uniform image.