Using Correct LNB's or Are LNB's Equal?

I'm a little (no alot) confused about the type of LNB's to use for the sats out there. Is a LNB for DISH different than one for DirecTV or FTA? I currently am trying to get 148W using a Direct TV dish. Why isnt it working?? It works for 121W. Also what exactly is a Universal LNB, and should (and can) I use it for 61.5,110,119,121,148. We should have some kind of matrix of what to use for a specific sat. Know what I mean Vern????? Im also confused about RHCP/LHCP (right/left hand cicular polarity) vs. Vert / Horz Polarity. Are they the same? LNB FREQ is also a mystery. Does anyone know the LNB Freq for a Direct TV LNB? Since there are so many Direct TV and DISH dishes lying around at flea markets and stuff. Looks like we should be able to use them for everything...Am I wrong? Why.