Without getting too tied up in terminology, if you are using a dock (has port replication available on the dock) and not just a cradle (only secures the computer in place) this may be a BIOS setting issue.  If you go into the BIOS, select Connections and then scroll all the way to the bottom, there are check boxes to select if you want to use the system antennae or an external antennae when the computer is docked.  Click to use the system antennae unless you have an external antennae connected to the dock.
when cradled in vehicle the devices lose virtually all connection to the cellular network. we have other devices on the same cellular plan, that will have full bars. when we undock the laptop from the cradle it instantly gains its cellular network back and when we re dock it into the cradle it instantly loses its connections. we have exhausted all of our ideas.
Latitude 5430 Rugged cellular not working when cradled