Visual inspection of sources. The distribution in the sky of type I (orange dots), type IIa (green dots), type IIb (blue dots), and unaffected sources (grey dots). The size of the dots is proportional to the ratio between the 2 GHz dropout at minimum solar elongation and the average 2 GHz flux density (Col. 8 and 4, respectively, in Table 3). The magenta line shows the ecliptic, while the red one shows the galactic plane.