John Stumbles wrote:

I know some folks who have used electronic rat repellents that use both
ultrasonic and rf (radio) transmitters. Much to my surprise and some
scepticism they claim they work. I think they said the radio mode was
particularly effective.


Well, a friend had a white rat kept in a wire cage that didn't much like
him running a transmitter on 432MHz for some reason... Used to jump
about a bit!

--
Adrian C