just found this
The correct answer Is given to you by John C however he has put it in rather complicated terms for the layman to understand . So this is it in basic terms . On the Dish you have a device called an LNB it is basically a microwave receiver , now some signals are vertical and some are horizontal , now what this means is inside the LNB there is a component that electronically changes its direction to collect the signals Ie: Vertical or Horizontal . to do this it applies either an 18volt positive to negative voltage or a 13 volt negative to positive voltage . now in the end of the sky LNB there are two LNB's joined together one for each tuner hence two cables. applying a different voltage for each channel .
and btw i definatley have a twin lnb and not a quad.
