Hello,
I am interested in purchasing a couple of Dish DVR 721's to replace my existing 4700 and 2800 Dish receivers. I have a DISH 500 with 2 Dual-Output LNBF's (legacy) linking to 2 SW21's. I understand that I will have to do some modifications to my dish or LNBF's (since the 721's need 2...