Can someone tell me the differnece bewteen RF and IR? I know that IR means infra-red, but what is rf? All of the components I have use an IR remote, but why won't a universal remote work on a Dishnetwork receiver or will it?

RF is radio frequency, it's used when a remote sends a signal over RF, which is then converted to IR, so you don't need to point the remote at the devices, can go through walls, etc.

If the Dishnetwork reciever uses a standard IR remote, then you can use it. If it's one of those "dual tuner" ones, the second TV uses an RF remote. Since remotes do not learn RF signals, you cannot use this TV.

Thank you for your help!