A method for calibrating an antenna system including a antenna elements connected to signal receiver units at an RF signal input port thereof comprising, generating an RF calibration signal, applying the RF calibration signal to the RF signal input port of the signal receiver units without applying the calibration signal via the antenna elements. The charging switch is coupled between a first supply voltage and a circuit node to selectively couple a sensing capacitor to the first supply voltage through the circuit node. An elevator is coupled with a lower end of the movable pulley block. A carrying ring with bypass ports mounts on the string above the upper bed roof.