On a PC, go into Device Manager and verify if the PC is detecting the NanoVNA port when the connected NanoVNA is powered on.
You should see something like “USB Serial Device (COMx)” where x will be the COM port number.
If you do not see a the above message, try another USB port and also another USB cable.
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Bernie Murphy, VE3FWF
*Real* radios glow in the dark
Ham Radio