[mjlaupp]

Happy,
The extra wire is a lightning ground conductor. The power for the dish amplifier is carried on the coax cable (the one with the center wire/conductor and the outside braided/foil shield). The center conductor carries the positive DC voltage and the negative is on the shield. The center conductor also carries the digital signal to the converter and the return path is on the cable shield. The DC voltage component is blocked from the receiver by the use of a simple capacitor in the line. The part that is a mystery to me is the statement that someone used a satellite connection to the cable connector and it worked. I can't figure out how it was hooked up unless there is a separate power cable run out to the dish.
MJL