Ratio of the reconstructed or extracted 21 cm power spectrum, after foreground removal, to the initial 21 cm power spectrum, (transfer function), at z ~ 0.6 for the instrument configuration (a), 11 × 11 packed array interferometer. The effect of a frequency-independent Gaussian beam of  ~ 30′ is shown in black. The transfer function T(k) for the instrument configuration (a), 11 × 11 packed array interferometer, for the GSM/Model-I is shown in red, and in orange for Haslam+NVSS/Model-II. The transfer function for a D = 55 m diameter dish for the GSM model is also shown as the dashed red curve.