A method for operating an electromagnetic compatibility testing system includes for selected frequencies, adjusting incrementally the lengths of each of the plurality of length-adjustable elements for selected combinations of length ratios between the driven element and other length-adjustable elements, including length ratios where the driven element is longer than the other length-adjustable elements, for each selected frequency storing in a table one of the incremental lengths at one of the selected combinations of length ratios having one of the lowest VSWR and a VSWR lower than a threshold value that has highest signal strength, for each selected frequency adjusting the lengths of each of the length-adjustable elements to the stored lengths, driving RF energy at the selected frequency at a EMC test power level into the EMC antenna generating an e-field in the equipment under test, and measuring behavior of the equipment under test in the presence of the e-field.