"Dave W." wrote in message
...
This is only 90% OT ! I wonder if anyone has any idea what one of my close
neighbours has in his/her bedroom which whines at high pitch for minutes
on
end most evenings. Once while lying in bed with the windows in summer
mode,
I thought I was suffering from tinnitus. It isn't loud, but it is ...
penetrating. Very constant, finally winding down in pitch then off. Any
ideas?

Dave W.

Exhaust fan in a toilet? Usually they're on a timer connected to the light
switch. Once the light's out they shut themselves off after 5 minutes or so.