If I need a 2nd receiver for SD only for a second tv in another room, Direct has a D11 on the order details, but their website System Manuals also lists a D12.
Believe me the R15 is better, has more features.But for RF you will need to order the RF Kit through DirecTV.It should cost $30.+tax and you should receive a RC64RB RF remote with back light
and the RF antenna to plug into the back of the R15.It works very good on my R15.