DirecTV recommends the use of (2) support brackets to secure your DirecTV 5 Phase AT9 and DirecTV 5 Phase AU9S Slimline dish to any wall or roof mount.
There are two sizes available depending on your needs.   This item is the "short" backet which extends from 19 1/2" - 32" long and connects the J-Mount bracket to the wall or roof.
Although these long support brackets are typically recommended... this short brackets can be used where space is limited.

NOTE... these items are sold individually, however most installations require 2 of these brackets for proper support!