This page contains various views of Blue Force Tracker mounted on various M997 Ambulances. The BFT systems shown below were installed in 2011. I believe a different mount/shelf was used in Blue Force Tracker installations in the early 2000's.
Of note is the exterior photos showing two different configurations of the front of the ambulance box and SINCGARs antennae.
The two quarters on the GPS antennae below are there to give you an idea of the size of the GPS antennae.