Uncomfortable high frequency noise on CP Road

[AmazingDancingBear]

Just a quick question-

We’re on Crystal Palace Road, backing onto Darrell Road, about midway between The Great Exhibition and The Actress, and both my daughters (late teens/early twenties) are complaining about an intermittent, very high frequency noise that they find very uncomfortable. It’s worse for the older one as she’s trying to study for the finals of her degree coming up in May, and she’s already having hospital treatment for an ear condition. The sound can even be heard from indoors with the windows closed.

Neither my wife or I can hear it but it’s been going on for a few days now and I wonder if it’s one of those ultrasonic cat/dog/fox repellents, maybe connected to a movement sensor, that only registers with animals and younger people with much more sensitive hearing? 
 

If that is the case would you mind turning it off please as it’s causing a very real problem. 
 

Many thanks.

[se22cat]

My wife has been complaining about this actually; we are on Crawthew Grove, it started a few years back, then seemed to stop, starting up again circa last September. I'm normally at work around the time she hears it most - between 11pm and 2AM, but even when I'm home I just can't hear it, which she just can't believe, so I guess it depends how sensetive your hearing is...

Would love to get to the bottom of it too!

[Alec1]

Had this problem a few years back.  I can hear high-pitched sounds easily.  I can't find my original post, but it was likely a faulty boiler cycling on and off as they do. It stopped not long after I posted!  Quick search on here pulled up lots of posts about similar.  https://www.eastdulwichforum.co.uk/search/?q=boiler noise&quick=1

[LdnLife]

I’m on Darrell Road and have noticed this recently - your daughters are not alone! It seems to only be at night. Would you agree? High pitched and consistent. I’ve been wondering if it’s a street lamp, or a fox deterrent system.