Normally the higher the better. That’s just the norm of any antennas. Anyways, since the 5th wheel trailer is so high up there already, the Weboost antenna comes in three different/length standing mounts. For example, you can have the antenna standing short, medium, or tall height. Depends on your need. For you since it’s going on the trailer, I would mount the short stand and it should pickup really good signal. The short stand will be sticking up above the trailer about a foot to a foot 1/2. Hope this helps.