Sky distribution of 3019 RFC sources shown in Aitoff equal-area projection of the celestial sphere in galactic coordinates and used in the analysis after applying the selection criteria. Open dots represent 2327 sources observed simultaneously at 2 and 8 GHz. Blue solid dots denote the other 692 objects observed at 8 GHz only. The sources shown here exclude those with low-core signal-to-noise ratio or unresolved cores.