In one embodiment of the invention, the mounting assembly includes a channel plate and a bracket for securely receiving the signal testing unit. The channel plate is securely mounted adjacent to a surface of a vehicle and includes a plurality of channels that extend through the plate. The bracket includes a housing for receiving the testing unit and one or more clips. Each clip engages a channel in the channel plate to mount the bracket to the channel plate. In addition, each clip includes at least one finger that includes an engaging portion. The clip is removably engaged into one of the channels by positioning the engaging portion of each finger adjacent the back side of the channel plate such that the bracket is positioned adjacent the front side of the channel plate. In one embodiment, the finger is spring biased.