Can anyone else hear Bluetooth transmissions? :)

Hi Folks,

A curious one.

I have a couple Bluetooth dongles made by different manufacturers, and a
couple of Bluetooth devices namely PDA and a Bluetooth gps.

Whenever I establish a Bluetooth link I can distinctly hear the high pitched
transmissions throughout the duration of the link.

I' remember in the past there was a PC in my workplace with a serial card
installed, which linked to and controlled a swipe card system. Again I could
always distinctly hear the high pitched serial transmissions from rear of
the PC whenever I passed near it. No one else could hear them however.

Has anyone else come across the same phenomenon? I'm wondering whether it
has something to do with my fillings.

--
Peter <X-Files Fan>
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Trust No One®

Trust No One® wrote:
> I' remember in the past there was a PC in my workplace with a serial card
> installed, which linked to and controlled a swipe card system. Again I could
> always distinctly hear the high pitched serial transmissions from rear of
> the PC whenever I passed near it. No one else could hear them however.
>
> Has anyone else come across the same phenomenon? I'm wondering whether it
> has something to do with my fillings.
>

"Got to break this information to you gently. Sit down.

"Over the last 30 something years you have been bought up to believe
that you are of human origin. Dedicated teams of support personal have
been working 24/7 to paper over the cracks, and to some degree it has
been of success... but sadly, due to the company folding (and no
government assistance to keep it going), the deception cannot continue.

"You are in-fact alien. In ten seconds there will be a knock at the
door. Your best route is out of the window....

"Trust No One®" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi Folks,
>
> A curious one.
>
> I have a couple Bluetooth dongles made by different manufacturers, and a
> couple of Bluetooth devices namely PDA and a Bluetooth gps.
>
> Whenever I establish a Bluetooth link I can distinctly hear the high
> pitched transmissions throughout the duration of the link.
>
> I' remember in the past there was a PC in my workplace with a serial card
> installed, which linked to and controlled a swipe card system. Again I
> could always distinctly hear the high pitched serial transmissions from
> rear of the PC whenever I passed near it. No one else could hear them
> however.
>
> Has anyone else come across the same phenomenon? I'm wondering whether it
> has something to do with my fillings.

Yes, I have, in a few situations, but not with Bluetooth. One cause is an
inductor or transformer somewhere, with a signal that has a frequency
component in the audible range. For example, although the data rate may be
too high to hear, transmission may occur in bursts with the burst frequency
audible.

BTW, I have no fillings .

Alex

I used to be able to hear if monitors were on years ago lol

Gordy

Gordy wrote:
> I used to be able to hear if monitors were on years ago lol

I can hear the irritating high-pitched sound my TV gives off.

Alex Fraser wrote:
>
> Yes, I have, in a few situations, but not with Bluetooth. One cause
> is an inductor or transformer somewhere, with a signal that has a
> frequency component in the audible range. For example, although the
> data rate may be too high to hear, transmission may occur in bursts
> with the burst frequency audible.
>
> BTW, I have no fillings .
>
Your theory re the inductor or transformer sounds feasible, though with the
Bluetooth transmissions I can hear them in the house, in my car (when using
the GPS) and in my workplace. Also no one else appears to be able to hear
the noise. The noise sounds like an extremely high pitched version of Morse
code.

Another poster made reference to a whining monitor. I'm afraid I've also
been there done that. Again at one of my work sites a monitor was making an
extremely high pitched whining noise from the rear. A couple of my
colleagues had a listen (one with his ear right next to the case) and swore
they could not hear a thing.

I made reference to fillings as I'd read somewhere that loose fillings can
pick up radio stations? About 15 years back I worked on the 8th floor of a
building. For ages I was being driven to distraction by what sounded like a
radio playing at very low volume. My colleagues all sat in my chair and
listened but could not hear a thing. It was extremely annoying. One day when
I was outside the building I noticed that someone in a block of flats across
the road about 70 metres away from my building kept their radio on
constantly during the day.

Now the block of flats were 70 metres or so away across the road and I was
on the 8th floor of my building, which had thick glass panes which could not
be opened. There was no way that the radio could be heard through normal
human hearing.

As regards the Bluetooth/serial stuff the audible transmissions (however
they are generated) must probably be right on the edge of human hearing,
meaning that some people can hear them while most cant. It is annoying at
times though.

--
Peter <X-Files Fan>
Please Note: Emailed replies cc'd / bcc'd , containing HTML or attachments
auto-binned as spam

"Trust No One®" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Alex Fraser wrote:
> > Yes, I have, in a few situations, but not with Bluetooth. One cause
> > is an inductor or transformer somewhere, with a signal that has a
> > frequency component in the audible range. For example, although the
> > data rate may be too high to hear, transmission may occur in bursts
> > with the burst frequency audible.
> >
> > BTW, I have no fillings .
>
> Your theory re the inductor or transformer sounds feasible, though with
> the Bluetooth transmissions I can hear them in the house, in my car (when
> using the GPS) and in my workplace.

I meant somewhere in the devices themselves.

[snip]
> Another poster made reference to a whining monitor. I'm afraid I've also
> been there done that.

AIUI, the cause in CRTs is "magnetostriction" at the line scan (or
horizontal) frequency. For PAL TVs the frequency is 15.625kHz; audible if
you have good hearing - normal hearing for a young person. I think it's this
magnetostriction that has been the cause in cases where I've heard data
transmissions.

Monitors normally use much higher scanning frequencies which are not
audible, but perhaps you sometimes get lower frequency (mechanical)
resonance at certain frequencies (ie resolution/refresh rate combinations)
which is in range.

As for hearing radio stations through your fillings, I've heard of it, but
don't know any more. In the case of hearing Bluetooth I'd have thought that
real sound (ie something physically moving or changing shape) is a more
likely explanation.

Alex

On Fri, 15 Apr 2005 22:59:46 +0100, Anton Gÿsen
<(E-Mail Removed)> wrote:

>Gordy wrote:
>> I used to be able to hear if monitors were on years ago lol
>
>I can hear the irritating high-pitched sound my TV gives off.

Oh yes its dreadful, and one of the reasons I hate watching TV. I can
also hear low res monitors on older machines as well. As for
Bluetuth, however, I haven't ever heard that, although I don't use it
often!

Andrew.
--
Andrew Hodgson in Bromyard, Herefordshire, UK.
My Email: use <andrew at hodgsonfamily dot org>.

Trust No One® wrote:
> Hi Folks,
Hi!
> Whenever I establish a Bluetooth link I can distinctly hear the high pitched
> transmissions throughout the duration of the link.

I cant hear Bluetooth, but the backlight on my iPaq h2210 gives off an
annoying high pitch noise, it does on my new iPaq h5550 too.
A mate reckons he can hear his WiFi though!
I can hear when monitors are on, and on my Acorn RISC PC, if you drive
the video resolution high enough, you can hear the VRAM squeal, or the
CPU make noises when processing....
I think Alex's theory sounds about right.

Gordy wrote:
> I used to be able to hear if monitors were on years ago lol

I can hear if one of our OpenBSD boxes is rebooting -- they make a
particularly high-pitched whine as the kernel starts.

- Ian

--
Ian Chard, Unix & Network Administrator | E: (E-Mail Removed)
Systems and Electronic Resources Service | T: 80587 / (01865) 280587
Oxford University Library Services | F: (01865) 204937