Your HR20 should work fine with that existing "4-coax dish". Do you know if it's an older "Phase III" SD dish, or a newer "Slimline HD Dish"? If you can, post a photo. Or compare it with the photos here ....
http://www.solidsignal.com/p/?p=2709&d=directv-dish-antenna-types&mc=02
Once you know the exact dish type, just connect one or two of that dish's four coax cables to your HR20's SAT IN jacks. No SWM is required. But if it's an HD Slimline dish and you want any HD channels, you will need a B-Band Converter (BBC) module for each SAT INPUT jack. They're free by calling DirecTV.
Once you've connected the HR20 to that dish, power it up and perform the "Satellite Setup" process. Follow the on-screen instructions to select "Multiswitch" and the appropriate dish type. Assuming that dish is still properly aligned, you should be good to go.
http://www.solidsignal.com/p/?p=2709&d=directv-dish-antenna-types&mc=02
Once you know the exact dish type, just connect one or two of that dish's four coax cables to your HR20's SAT IN jacks. No SWM is required. But if it's an HD Slimline dish and you want any HD channels, you will need a B-Band Converter (BBC) module for each SAT INPUT jack. They're free by calling DirecTV.
Once you've connected the HR20 to that dish, power it up and perform the "Satellite Setup" process. Follow the on-screen instructions to select "Multiswitch" and the appropriate dish type. Assuming that dish is still properly aligned, you should be good to go.
