There is no separate LNB whatsoever. On some satellites , mostly Russians, they employ R/C and L/C ( Right Circling and Left Circling). Practically the only difference is that you have to use an LNB with the TEFLON Strip in it. It is a hard material, non-metalic and almost all C band LNB boxes have it. In case of strong signals you dont need it . In case of weaker signals it helps really.