On 9/6/06, Jinx <joecolquitt@clear.net.nz> wrote:
> A friend has been giving me grief for some few weeks about
> noise she says is coming from a microwave tower about 300m
> from her home and keeping her awake in the quiet of the night.
> She describes the sound as a constant high-pitched tone. I have
> every reason to believe she is not crazy, and she assures me she
> has not got tinnitus or any other hearing problems. She may be
> dwelling on the problem (though she says she isn't), which might
> tend to aggravate any auto-suggestion. I'm getting all this from a
> woman who is quite frazzled and cranky after many sleepless night
> but who hasn't lost the plot. She's still quite rational about possible
> causes, but not being technical at all she has a limited number of
> causes to think about. There aren't many houses around where this
> tower was put up so she hasn't neighbours to discuss it with
>
> She reckons she's being fobbed off or stonewalled by the owner
> of the tower (BCL) and the local council and as she doesn't seem
> to be getting anywhere on her own I've offered to try and gather
> evidence. Including, if I have to, trying to record the noise to
> present to someone as hard evidence. What she has so far are
> just opinion and supposition.
>
> I haven't heard the noise myself, she's quite some distance away
> and a visit hasn't been possible yet. She said a tech, ISTR, had
> suggested (I don't know the circumstances or context of the
> conversation) it was 15kHz, which made me think perhaps a
> switch-mode with something loose, but the tone she sung over the
> phone is nowhere near 15kHz. Probably more like 3/4 the way up
> a piano, definitely within almost everyone's hearing range, which
> you'd think would be easily heard by anyone. A late-shift engineer
> came to her home and thought he kind of heard something, but
> seems not in the "my god, how do you sleep with that racket ?"
> league or a problem would have been immediately apparent
>
> If the tower is in fact putting out this mysterious tone, I wonder
> about a couple of things
>
> (1) Apparently the sound is no louder at the tower. I would have
> thought it would be, given the sqrt law unless -
>
> (2) there is some beat frequency being created at her home by
> two or more inaudible frequencies, and she just happens to lucky
> enough to be at a place where a combination of beat frequency
> and distance make a node
>
> Any thoughts ? Any similar experiences ?

 You need a spectrum analyzer and a large band antenna.
Perform a check first in her room. If you found energy levels bigger
than -30dBm or so, it's possible that your friend has a sensitive
detection problem (possible a teeth problem). I know stories in which
the person received the radio program in his head . Almost mad he
finally visit his stomatologist and the problem was solved by a simple
replacement of the material from his damaged tooth.

Vasile
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