Trying to catch Bell Exp 82 and 91 birds on Channel Master

[CoolDmitriy]

Trying to catch Bell Express 82 bird on Channel Master Gainmaster dish 36 x 24 dish.
Get 91 bird without any problem, but 82 is pain in the butt. I get no signal at all.

Does the mast have to be plum at 90 degrees? Because, it not due to wall location nearby.
Does anyone have Channel Master Gainmaster set up to catch both Bel Express birds.

Thanks