thanks Jack and Rocky for the suggestions. I will do the tests you suggest. It will be hard to tell because these sounds showed up only occasionally and last year I could not see a trend to when it came up (if they happen only with certain movements, clothing styles, pronunciation styles, etc.). So far, this year it has been a problem only in 2 videos out of 6.
Someone had suggested they could be caused by overmodulation and that the transmitter might be sending in sounds that are overmodulated. I lowered the sensitivity of the transmitter from -6 db to -18db.
