I don't know about your cable, but length shouldn't be a problem. Unless you're using RG59! Probably would be a small voltage drop at the point where you have pieced it, but I don't know if it'd be enough to cause those problems. I'm running about 140' RG6 to my cband dishes, and never ran into that problem, using seveal different receivers (including the Mercury 2 in the past). Suggest you take the receiver and tv out to the dish, if possible, using a short coax to connect to lnbf there, see if you can get the lnbf skewed to get both polarities then. If it works out there, then it probably is the cable or connectors.