Important observations regarding the ultrasound's OFF pulse used for lift. It adds to the TC's 2nd harmonic (1.4MHz) when the US is tuned properly. OFF Pulse also seems to sync up the signals between the TC / US.

7:40 TC ON
14:24 OFF Pulse on Spectrum analyzer. US spikes change freq for about 2sec following holding down the OFF button
19:04 Demonstrate TC/US interactions on oscilloscope