Dr. Kirkby is right, as I can confirm from my own experience. Last year I wanted to do a RL measurement o find the losses of several lengths (up to 25 m) of leftover coaxial cables on all amateur bands from 2 m up to 13 cms IN ONE GO. So I set my HP8753C to a span of something like 100 to 2500 MHz and measured the RL of each cable on one end while leaving the other end open (or shorting it), with default settings of the 8753. Or maybe I used 401 iso 201 points. Anyway, I then noticed unexplainable steps along the way in the measured RL curves. This turned out to be simply a matter of the default sweep time being too short. I haven't tried a similar thing with my NanoVNA-F up to 1.5 GHz, and maybe I will just for curiosity. But you can't change the sweep time of a NanoVNA anyway, to my early knowledge of the device.
73's Hans PA3AZA
