wont work with what it sounds like you want to do
a 3x4 will allow you to use 4 recievers off one dual LNB. To use 2 LNB's you need a 4x4 switch (in the 3x4, the 3rd port is an antenna)
If you only hook one line from each LNB you only get one polarity depending on which port you plug it in to.
I actually do this and it does work. I have the cable from my
C-Band dish into the 18v (H) side and a cable from G10 to the 13v (V) side. All 4 boxes can pick either G10V or G4H...the drawback is if I want the opposite polarity it doesn't work
