Angular power spectra for the input H I plus noise signal (black), the GNILC recovered H I plus noise signal (red), and the PCA recovered H I plus noise signal with three modes removed (blue) at ≈1.1 GHz. For this particular channel and configuration (double-rectangular, 28 feeds, one-year observation time, and β = 0.001), N_Rec (GNILC) equals ≈12%. The recovery improvement, due to the increased 1/f noise correlation, is clear.