A SWM system is just a KA/KU dish with either a SWM3 or 5 or a legacy 3 or 5 LNB attached. If you have a legacy system (aka a non-SWM system) than you just need a SWM module in place of your 6X8 switch or 4 way grounding block. You will also need a 29 volt power supply to power the SWM module...
