Ultra-sonic cat repellent

[starry]

HAs anyone used those battery operated ultra-sonic cat repellents that let out a noise disliked by cats and hence should stop them pooing in your garden?

Thinking about getting one that costs about £40.00 so any comments/recommendations greatly appreciated.

We bought one and gave it away. Never found out if it worked or not since the sound was terrible!
My guess is that it is probably very effective but make sure you buy one you don't have to have too close to your house (our's had to be plugged in)since you will probably be able to hear it and it is loud!(I thought ultra-sonic meant that humans could not hear it at all, but we certainly could) It was like a TV's high pitched noice, but louder.

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I also thought ultra sonic meant it was at a pitch humans could not hear.....mmmmmm.......It's mainly right at the end of the garden where they or it tends to do it's business, which is about 100ft from the house....a bit far to fire a water pistol from Twiglett

would it not affect the other animals (i.e. your own pets if you have any or any birds etc)?

My research seemed to indicate that they really don't work very well. I found that a combination of chilli powder (unfortunately gets washed away with rain so only good in summer) and mouse traps work the best. Put the mouse traps near where the cats have been digging/pooing. They seem to scare away the cats for several months. If you're worried about the cats, I've yet to actually nip/catch one in a trap...it just scares them.

Chilli powder is really good - put a generous sprinkling all round where they poo and top it up every couple of days.
Once they get used to not going there you'll still need to put some down now and again to deter them from coming back, but its quick, cheap, and above all, silent (apart from the odd feline sneeze).

Orange and lemon peel works fine too, sprinkle it where the cat does it's business and the cat won't come near the place..... until the peelings have disintegrated that is.

My dad has an ultrasonic one starry, and humans can't hear it. It works very well for him.

Thanks everyone. Think I will try a number of things then.
Roisin - do you know what make the one your father has is?

Going to try the chilli powder/lemon peel in the front garden as it is small and they seem to go in a couple of places there but they always do it in different places in the back so will try an ultra sonic one there otherwise I will always wonder.....Getting sick of spending so much money on Scat-A-Cat....