years ago, when I proctored the microwave engineering lab on campus slotted line and the old HP SWR meters were one of the first labs that I would have students do. We had spectrum analyzers and Vector Network analyzers for each student, but nothing gets you a better understanding of wavelength, open and shorted lines then a slotted line. The understanding of the slotted line is a perfect analog for understanding strip line circuits and gaining ability to visualize what's happening in transmission line theory. Dr Pramanick who I worked for always said if you understand transmission line theory everything else is easy.

That thirty-minute lab had the capability to change your life!

Ray F/KA3EKH