Hello, I am working on an unknown thru calibration outside of the VNA. I am having trouble calculating correct load match and transmission tracking terms ( I am comparing my calculated terms to the terms computed by the VNA). In my reading I have found that the 8-term error model is used for unknown thru calibration. The 8-term model requires that the measured s-params be switch corrected. How do I go about measuring the switch terms or calculating them? Thank you for your time.