I have a continual high pitch (2645 Hz), sharp (25 ms), loud beep which sounds every 43.145 seconds. It has been going on for over a year now, and after spending considerable time then trying to find it and giving up, I've come back to treating it like a puzzle. It really has me befuddled.
It is in a the dining room next to the kitchen. I can close all the doors and the sound is definitely in this room. I cannot locate it by ear as every time I think I've got it, it seems to move. So I recorded a WAV file (this is where I got the above stats from) of it last night placing the microphone in 4 corners of the room, and it is definitely stronger in the corner I suspected. The amplitude goes up and down a bit.
It is not a smoke or CO2 alarm, as I have removed the only one I can see in the room (unless it is hiding inside the wall, who would do that??).
Does anyone have any ideas?