Hello S+13: This is the simplest SWR Meter to use. You just transmit with no modulation, adjust the knob for full deflection on the left meter, manual. You can buy an SWR meter separately or have your antenna checked by your Midland CB. Dealer's service department. Factors affecting CB and Weather used, refer to the antenna manufacturer's installation manual. You can buy an SWR meter separately or have your antenna checked by your Midland CB Dealer's.installation manual. You can buy an SWR meter separately or have your antenna checked by your Midland. CB Dealer's service department.