On Saturday, May 2, 2020 at 9:41:54 AM UTC-4, Richard Livingston wrote:
Nice demo of cross talk. Last year I fixed a problem in our glider where the microphone wires were not completely shielded, as in your demo, and were picking up signal from the radio speaker wires, also not completely shielded. The result was intermittently the radio would squeal during transmit due to feedback from the speaker back into the microphone. It was intermittent due to the wires shifting slightly every time the canopy opened/closed. Shielding both the speaker and microphone wires fixed the problem.

Rich L.

Such feedback could only occur if the radio had the (mis)feature of echoing the signal from the mic to the speaker. Kind of lets you know you've got the PTT pressed and it's all working, but not really necessary. With that happening, you may also get acoustic feedback, from the speaker back into the mic, even without crosstalk in the wiring. Maybe that feature can be turned off somewhere in the radio's settings?