WiFi working with only one cable?

[ArisVer]

I bought a used notebook and when I opened it for a cleaning I have noticed that one cable was missing from the wireless module. So I opened the screen and there is only one antenna installed. No worries I thought, I will just find the part and use a wireless USB until I replace it.
After installing the OS I have noticed that the WiFi is working with only that one cable connected. Nice surprise. But how is that possible?

 

[ch33zw1z]

That's just the antennae. Running on 1 may be running at reduced speeds. So check the connection speed.