Monopole signal in terms of antenna temperature for the two considered extragalactic background models and various estimates of extragalactic source background signal for different assumptions of source contribution subtraction. The labels “Res Back” and “Res Back P(D)” refer to the choice of A = 2.35 and 1.51 mK in Eq. (14), while the additional label “Uncer” includes a reduction by factor of 10. The dashed lines refer to the same estimates, but derived assuming an increase of a factor of 2 in the differential number counts at faint flux densities. See also the legend and the text.