User Defined Info

You can configure the NanoVNA-F V3 to display a custom message — typically your amateur radio callsign — on the boot screen each time the device powers on.

Set your callsign or custom text

1. On your PC, create a plain text file named callsign.txt.
2. Type your callsign or message inside the file (maximum 50 ASCII characters).
3. Save the file.
4. Power off the NanoVNA-F V3.
5. Enter U-disk mode: hold the middle button while powering on.
6. The device appears as a USB drive on your computer.
7. Copy callsign.txt to the root of the USB drive.
8. Safely eject the USB drive.
9. Restart the NanoVNA-F V3.

Your text now appears on the boot screen during startup.

Update or remove the callsign

To change the text: Edit callsign.txt with the new content, enter U-disk mode again, and copy the updated file to the device.

To remove it: Delete callsign.txt from the USB drive while in U-disk mode, then restart.

Caution

The file must be named exactly callsign.txt (all lowercase). The content is limited to 50 ASCII characters — special characters and non-ASCII text may not display correctly.

Tip

This is a good way to identify your device if you have multiple NanoVNAs, or to display contact information in case the device is misplaced at a hamfest or field day event.