Abstract: When a portable communication equipment such as a cellular telephone is carried inside an automotive vehicle, there is a need for its antenna to be supported exterior to the vehicle frame but at the same time be easily detachable from the vehicle.The invention provides a mounting clamp assembly for removably supporting an antenna on the exterior side of a vehicle window, and includes circuit means extending over the top of the window for sending signals between the antenna and the equipment. The mounting clamp assembly is easily attached to or removed from the window and its operation does not interfere with either the operation of the electrical circuit or the opening or closing of the window.