@joeqsmith
Although I could do a one port calibration on the NanoVNA, doing a "full" 2 port is not much more work. But, as you say, my problem is just with S11.
Of course, home made SOL, even made with high quality parts and precise construction are not usable at higher frequencies. However, at frequencies below 500MHz, they work well enough for less critical measurements. For critical measurements, much greater care in calibration is needed and more than just the impedance of each standard is important, as you know.
This is why that less expensive tools are good only for less critical activities. Your comparisons of the NanoVNA V2 to a HP 8753E are interesting and illustrate the "good enough" nature of the NanoVNA V2. For measuring the SWR or complex impedance of an antenna up to 450MHz, it is fine and much better than the original NanoVNA. Another problem with Tools like the NanoVNA is the wide variation in quality of items labeled as NanoVNA or NanVNA V2. A friend bought one of the NanoVNAs and it was a very poor example with sloppy parts placement, cold solder joints and questionable components.
It would be interesting if someone was local to me in Southern California that would like to look at the apparently defective unit with me. Not really interested in sending it anywhere. If it is disassembled, I'll take some pictures and post them here.
I did receive my NanoVNA V2. it does fairly well and does not have the incorrect open impedance measurement issue. However, it measures the 150 ohm leaded resistor as 140 ohms at 146 MHz. Other tooling, including the 8753 measures 150 +/- 1 ohm. Not saying this is an issue, just interesting. My use for the V2 is the same as the V1, casual measurements of antennas and feed lines. Also, measurements of swap meet items like attenuators, coax switches, etc. Portability and ease of use are key for my uses.
Need to get a more precise understanding of the NanoVNA V2 limits, but it is good enough for now,