This weekend I'll be adding a 72.5 dish to my cabin setup where I currently have an 18x20 dish installed. I'm doing this so I can get the locals as well. I've been doing plenty of reading and most of the guides tell me that I'll need a 6x8 switch to make this happen. Since I'm only using a single cable from the 18x20 dish for one box do I need to hook up all four cables from the 18x20 dish to the 6x8 switch? Can I get a smaller switch if this is the case? What switch should I buy?