Since nobody responded, I'll do it.
The Oppo 105 does not have any sort of analog inputs. It does have digital inputs. So, if you really want to hook up your analog tuner to the Oppo, you will need some sort of "analog-to-ditial" converter.
You can get something really cheap (crappy) for less than $20. Just search for:
Cingk RCA L/R Analog to Digital
Or if you are willing to spend more, go on ebay and search for "ad converter". There's everything from $100 on up to $1000 (such as an "RME ADI 2").
You'll need to connect this to one of the Oppo digital inputs (such as COAX or Toslink).