I cannot get the RF feature to work on the R15. I do have an RF antenna connected to the RF antenna input. I've tried both the RC24 and RC32RF remotes, and cannot get it to work. I can put the remote in RF mode, but as soon as I do, it stops controlling the receiver, and I have to put the remote back in IR mode. Even tried it with both. Put the RC32RF into RF mode, and then tried to control the R15 with the RC24 remote in IR mode, and it responded. How do I put the receiver in RF mode? It's not just the one downstairs either. I've also tried the same steps with my Mother's R15, and can't get hers to accept RF commands either.