A bracket for releasably mounting an enclosed mobile/transportable motorized antenna system on a vehicle may include a support arm and a mounting assembly. The support arm can include a first end portion configured to secure to a vertically extending member of a vehicle and a second end portion configured to secure a mounting plate assembly. The mounting assembly can be secured to the second end portion of the support arm. The mounting assembly may comprise a generally planar mounting plate having a plurality of apertures defined therein. The apertures may be located within the periphery of the mounting plate and have a size and shape configured to secure a motorized antenna enclosure disposed on the mounting plate assembly. A releasably mountable enclosed mobile/transportable motorized antenna system on a vehicle may include an enclosed mobile/transportable motorized antenna system and a corresponding mounting bracket.