Andy G0FTD, for proper calibration, you're needs to use all terminators (open, short and load) with the same geometry and length.If you will try to use different geometry/length load it leads to calibration error.
This is why you're needs to buy calibration kit instead of separate terminators from different sources.
I'm not sure if this cal kit supplied with NanoVNA is precise, but I tested 50 ¦¸ load from NanoVNA cal kit and it looks better than all other 50 ¦¸ loads that I bought on aliexpress before. So, it seems that supplied cal-kit is good enough for NanoVNA. But there are a lot of sellers and no guarantee that other NanoVNA will come with the same cal kit.
