Location of the sat radio antenna on a R1200RT?

I recently purchased a 2017 R1200RT and like that I can now get Sat Radio. It worked fine till I added a top box. Out here in the Great Plains we have lots of north/south, or east/west roads that go on for miles. Since adding the top box it's become difficult to hold a sat signal while traveling east or west. North and south no problem. I've pulled the top box and the seats and tried to see whats in the tail but can't make out if the antenna is located there. Does anyone know if the antenna for the sat system is located under the top box mount?

The antenna is located in the dash, above GPS mount.

A little rootin' around led me to this-

The antenna is under the front fairing where BMW mounts it ( it is the OEM XM antenna ), same way Honda did theirs. I want to buy a new one and mount it in a open location.

Click to expand...

The next time it's acting up, perhaps turn around and reverse direction and see what changes.......As it may. Antennas are the most important part of any radio system......the satellite system is "line of sight".

OM