A distributed smart antenna system including an antenna array having N antenna elements, N radio frequency tranceivers, and feeder cables connecting both. The lid 12 defines a well 13 for receiving a secondary closure 14, with the well providing fining access to the battery box 11. The outer diameter of the sheath portion is smaller than the inner diameter of the spring means, and the sheath portion is disposed within the cylindrical space within the spring means. The second shell comprises at least a second engaging part which is detachably engaged to the first engaging part making the first shell and the second shell form a space, wherein the magnetic unit is disposed inside the space.