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Note that the menus are different than those I'm seeing on YouTube which aren't for the V2plus4. What's missing is "Isolation" and of course, there is an additional standard for that which is also not included with this device. Specifically, the video says I need two 50 ohm impedance standards. It's $5 so I've ordered these. The menu mystery is what concerns me most. I've already updated the firmware. Is it possible that "Isolation" is not required? Is it possible that they have used a different term to reference "Isolation"? I can't really say that I have a clear grasp of what Isolation is / means.

https://youtu.be/vuxULomtB-4

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According to the NanoVNA V2 documentation, isolation calibration is already done when you calibrate your OPEN and LOAD standard:

Note: on NanoVNA V2 Plus4 and later hardware, isolation calibration is automatically done during OPEN and LOAD steps, and there is no separate ISOLATION calibration step.

It also lists the calibration procedure as follows:

  1. Enter the CAL menu and connect a SMA male-male cable to port 1 of the NanoVNA.
  2. Connect the OPEN standard to the cable end and select "OPEN". Wait for menu highlight.
  3. Connect the SHORT standard to the cable end and select "SHORT". Wait for menu highlight.
  4. Connect the LOAD standard to the cable end and select "LOAD". Wait for menu highlight.
  5. Select "APPLY". Calibration should now be active and you can start performing measurements.

Calibration can also be done directly at port 1 without a cable. Only one 50 ohm load standard is required for the above procedure, and port 2 can be simply left open.

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You can probably get by without it, but very high impedance readings will be less accurate. I think that the V2Plus4 has an older firmware version that doesn't take that measurement.

What "isolation" is in a VNA calibration is how much power bleeds from one port to the other internal to the VNA, without going through the thing you're testing. Ideally, with 50-ohm loads connected to both ports, there would be zero signal on port 1 regardless of the output on port 2. In the real world, there's always some leakage, and the isolation cal measures that, so that it can be subtracted out when taking real measurements.

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  • $\begingroup$ Is it possible that the more expensive, metal covered NanoVNA V2pluss4 does this automagically? $\endgroup$ Feb 12, 2022 at 3:22
  • $\begingroup$ @NonYaBidnezz no, like I said I think it's just an older less-capable firmware. SOLT calibration is the basic for a 2-port device, isolation is an added bonus. $\endgroup$ Feb 12, 2022 at 4:34
  • $\begingroup$ OK. If that is the issue then there should be an update available. I'll check. $\endgroup$ Feb 16, 2022 at 13:23

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