Normally I find LNBs are interchangeable without problem. However with the quad LNB you have sent me, when I connect it I find either no signal or on some channels a different station to the one that should be being received. I presume the LNB is converting to a different frequency to normal. Can you explain why this is happening and what is the solution? Also why are the outputs on the LNB labelled 'high' and 'low'. What is this referring to?