...
The most effective installation method we recommend is to connect the CTM-ONE to power via the vehicle’s OBDII or J1939, place the CTM-ONE on the dashboard, under the seat, on the window, or any other suitable position, and attach an external antenna to a window. This installation can be completed in roughly five minutes with the wires hidden.
Please find a graphical illustration of the use of internal vs. external antennas belowrefer to the CTM-ONE installation overview here.
Use of Internal Antennas
...