You can try going to the: Menu / System Setup /
Installation / Point Dish
(or something like that .. in Your receiver's menu - and then when there - try to choose 105 and 121 (one by one maybe) .. and see if you are getting a signal on the bottom there...
Also...
( And you can verify this here:
http://ekb.dbstalk.com/dishlist.htm )
You can press channels 900 and 7000 (one by one) with your remote.. and see which one of those you can get... (By the way.. - at the Link above you can see that ch 900 = "You have a SuperDISH @ 121, D121" and ch 7000 = "You have a SuperDISH @105, D105")
