NanoVNA - Calibration:

[last updated: 2022-12-20]
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• Calibration:
  • The First Step: before doing any calibration, is to set your frequency range.
    menu > STIMULUS >
    enter desired freq band using your preference of Start, Stop, Center & Span.
    eg: to set a start freq of 14 MHz, press: Start ... 1 ... 4 ... M
    You will see the new start freq listted at lower left of the screen.
    A given calibration setting is only good for the band used during the calibration.

  • There are 3 Calibration Standards included with the kit: Open, Short, and 50-ohm Load.
    
    
  • Calibration Selected:
    There are 5 memory locations with saved cal settings. They are numbered 0 - 4.
    On the far left side of the screen will be a vertical column of white letters: "Cx, D, R, S, T, X"
    On power up, Cx will be "C0", which is the default cal settings #0. If you have saved a calibration to a different memory location, you can select it:
    menu > RECALL
    press the saved cal you want to use, eg. "RECALL 1"
    (If nothing happens when you select a RECALL #, that indicates you haven't saved a cal setting for that memory location.)
    The top element in the left-hand vertical column will change to "C1"
  • Clear Calibration:
    From nanoVNA menu: CAL > RESET > RESET
    The first Reset clears the [Cx, D, R, S, T, X] readout on the far left of the screen. The second Reset clears "Correction" so it's no longer highlighted.
  • Calibrate OPEN:
    You can connect the "Open" cal standard to CH0, or just leave it off, however one source said leaving it off gives a slight error for the loss of length.
    From nanoVNA menu: CAL > CALIBRATE > OPEN (it will highlight)
  • Calibrate SHORT:
    Connect Shorted standard to CH-0.
    Press: SHORT (it will highlight)
  • Calibrate LOAD:
    Remove Shorted standard, and connect the 50-ohm Load standard.
    Press: LOAD (it will highlight)

    
    Stop here if you're just using a single channel/port (CH0). However if you're going to use CH1 for "through" measurements, continue to cal the Isolation and Through parameters.
    Finish with Done and Save.

  • Calibrate ISOLATION:
    Not sure about this one. One ref said both channels should have a 50 ohm load attached, but another said that ch1 has an internal 50 ohm load, so just leave the load standard connected to ch0 and...
    Press ISOLN
  • Calibrate THROUGH:
    Connect the jumper between Ch-0 & Ch-1 and press THRU

  • Press: DONE
    Press: SAVE [to whichever you prefer]
  • Remove the jumper if it's installed.

  • Test your calibration by re-installing each cal standard:
    Open: Smith should show point all the way to the right; LOGMAG ~ 0db
    Short: Smith should be all the way to the left; LOGMAG ~ 0db
    Load: Smith should be in center; LOGMAG -50db or below

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