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The continuum data calibration was obtained with the following procedure: First, baselines were subtracted, being defined by the lengths of the continuum scans avoiding the source itself at $\pm$ 1.5$\times$HPBW (half power beam width), relative to the center of the scan. Second, Gaussian profiles were fitted to obtain the position offset between the real position of the source and the center of the cross scans. Then, the obtained amplitude was corrected for the pointing error, adopting a two-dimensional Gaussian intensity profile, using the formula: $$T_A^{*'} = T_A^*/Pointing,$$ where $Pointing = exp(-4 \times ln2 \times (offset/HPBW)^2)$. Finally, the antenna temperature has been corrected for the elevation-dependent gain, defined by the parabolic equation: $$T = T_A^{*'} / Gain,$$ where $Gain = A \times Elevation^2 + B \times Elevation + C$. A, B, C are the coefficients of a 2nd order polynomial fit, obtained from “$T/T_{max} - Elevation$” plots of well-known stable calibrators (e.g. 3C286, 3C123 and 3C48). For Ku-band observations the last step of the data reduction was omitted because of an absence of a gain curve equation for this band, which provides up to $10\%$ of uncertainty. The resulting measured amplitude of each source is an average from 