Morning folks; If I wanted to hook two dish pro recievers to a pair of dish 300 's with dish pro dual LNBF's would I need a pair of SW21's and nothing else? TIA

Hi folks newbie here, I have a dish 300 that has a dish pro lnb and a dish311 reciever, I also have a dish 522 that was given to me. I have heard from several people that a dish 500 loses signal easier than a dish 300, is this true? We get our programming from sat.110, I want to add locals and...