External wi-fi antenna on a Raspberry Pi build

Hello there!

I'm enabling a passive external antenna on my Raspberry Pi Compute Module 4 board using its U.FL connector. According to this document I changed the /boot/config.txt file and added the following line:

# Switch to external antenna.

If I have the line above added to the config.txt file but no antenna physically connected to the system, everything behaves the same. Is there a better way to test and check if this antenna is working?