When I read about ultrasonic cross-device trackers in advertising [1], I installed "org.woheller69.audio_analyzer_for_android" and "hans.b.skewy1_0" (automatic

When I read about ultrasonic cross-device trackers in advertising [1], I installed "org.woheller69.audio_analyzer_for_android" and "hans.b.skewy1_0" (automatic ultrasonic detection) and started scanning through TV channels after running some test tones. Suffice to say I didn't find any, but the entire process was quite fun. There's also "org.billthefarmer.scope" which is an oscilloscope with a spectrum (not spectrogram). 1. https://arstechnica.com/tech-policy/2015/11/beware-of-ads-that-use-inaudible-sound-to-link-your-phone-tv-tablet-and-pc/ https://arstechnica.com/tech-policy/2015/11/beware-of-ads-th...