A method and apparatus for providing an air bearing pad having improved roll angle sigma is disclosed. An emitting region of the antenna is exposed to a plurality of calibration standards each having a different complex impedance at the treatment frequency. Depending upon authorization, the user can access the entire command set or only certain commands. The filling member covers at least a portion of an outer circumferential surface of a rear trunk portion of the insulator along the entire circumference and the entirety of a rear end surface of the metallic shell, which is a portion of the outer surface of the crimped portion and is visible from the rear side with respect to the direction of an axial line CL1. The bias voltage can be set to a level that is above the sum of a DC voltage differential between positive and negative signal lines and the maximum signal voltage. The rotary sprinkler also includes a rotor axle seat member engageable and disengageable with the rotor’s axle and with the ring facilitating, upon disengagement of the seat member from the ring, axial retrieval of the rotor member through the ring.