Comment by mlfreeman

The visualizer reminds me of my thermal camera.

I have heard claims of devices (mostly TVs) supposedly coming with secret 5G cell uplinks built in [never heard a specific model mentioned though].

If there were more variants covering more commonly-used RF bands, people could walk around and literally check for once.

(incidentally i'm sure three letter agencies have had this sort of tech in their bug-detecting toolkit for a LONG time)