qrp.ddc,
The plot I attached was for a scan I had on hand called "rg316-rg6u-rg58-50R.s1p", sorry for the confusion. The plots for the two files in your original message are attached. They don't seem to show the clearly defined impedance steps you are looking for. Salil Tembe downloaded your files and may be able to give an explanation of the step data shown.
