Basil Chupin wrote:

A dog whistle is a dog whistle and you can pick one up any pet shop. But
what good is a whistle in this situation? The dog barks, you blow the
whistle, the dog stops for a second or two thene starts to bark, you
blow the whistle, the dog stops for a second or so and then realises
that everytime it barks he hears a whistle which is rather pleasant so
starts to bark even more just to be able to hear more of the whistle.

I was hoping for a whistle that sounds like your chains idea. It would
be more discrete using a whistle, than a chain.

My neighbours are mostly out, but I would not take the chance of
getting caught chucking chains when they may just be sleeping inside,
and catching me at it.