Yesterday I spent ages on a roof tweaking an aerial to Optus D1 and could not believe the receiver was getting no signal. My meter was telling me it was aligned but the receiver was getting nothing.
LNB have different LNB frequency and these need to be set in receiver. The previous LNB had LNB low: 9750 LNB high:10600. New LNB is low:11300 high:11300. These figures differ depending on LNB.
Tip - if you have the box for the LNB it usually has the specification on it, and/or its printed on the LNB.
Step 1 - check the receiver aerial setting matches the LNB that you are installing.
Step 2 - align the dish
Step 3 - fine tune the dish with receiver meter if no other available.
Hope this helps someone!