> BUT has anyone had any practical experience in successfully
> using ultrasonic energy to repell / kill / destroy /  ... anything.

I believe electronic mosquito repellers are rubbish. SPCA advises
not to willy-nilly use ultrasonic devices on dogs, but posties etc do
have them as irritants. So, when you're trying to get to the mailbox
and that pit bull isn't quite pissed off enough .....

Short of dropping it in an ultrasonic bath (and drowning it) I can't
imagine anything being physically harmed in normal circumstances
when the pest has the freedom to escape

As Doug says, familiarity breeds contempt. Or de-sensitisation. A
variable warble with unexpected events would probably work better
than a continuous tone (cf burglar alarms)

Joe
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