Looks Great But Has Flaws
For NanoVNA V2 Plus4
Unit looks like advertised and works with a 5V USB plug, but the battery connection does not work (it will not power up on battery power). Very frustrated with the unit as I wanted to use it without a cord for power.
No documentation with the unit, so you will need to find how to use it on the NET.
Buyer beware!
Response from HCXQS group | Nov. 5, 2020
Hi, you need to plug in USB at least once after connecting the battery to activate the battery management IC.
There is a user guide here: https://nanorfe.com/nanovna-v2-user-guide.html