LCD monitor sensitivity

Can anyone give me some advice on a model of an LCD monitor that does
not humm when you reduce the brightness of the screen? Or does anyone
have advise on a shield that would reduce the brightness?

I did not have problems with an older Dell monitor or an old Fujitsu.
My new dell monitor is very bright as most other new LCDs are. The
brightness causes sunburn and burns that will not go away. Turning the
brightness down, the monitor buzzes. That has led to bad tinnitus.

from my research it appears that most LCD screens buzz when you turn
the brightness down, unless the design is such that the backlight
inverter is shielded. Apparently it is in some models, I don't know
which ones.
from what I have learned, the frequency modulation that the backlight
inverter uses to dimm the brightness is in the hearing range and in
this lies the the origin of the buzzing sound and apparently affects my
ears.

Any comments are welcome.

lena48be wrote:
> Can anyone give me some advice on a model of an LCD monitor that does
> not humm when you reduce the brightness of the screen? Or does anyone
> have advise on a shield that would reduce the brightness?
>

I stopped looking when I got a Planar PL1700
I found the 19 inch and larger (from those I tried) were louder and had
higher emissions.

This might help you: Try changing the screen resolution, and refresh
times. For example, 800x600 comes in 60 Hz, 70 Hz, 72 Hz, and various
numbers in between, depending on the graphics card capability, and what
the display driver allows you to change. At 1024x768, for me and this
hardware, 75 Hz is best.

I recently tried a different graphics card (Nvidia 6200) but it gave mom
a headache upstairs, and was just barely tolerable for me. Rip! out it
went. Back to the Nv FX5200.

Stewart

> I recently tried a different graphics card (Nvidia 6200) but it gave mom
> a headache upstairs, and was just barely tolerable for me. Rip! out it
> went. Back to the Nv FX5200.

Yes, I wonder how much of my "monitor sensitivity" is really due to the video
card or the VGA/DVI cable? I find my sensitivity does change when using
the same monitor, but changing some aspect of the incoming signal (resolution,
refresh rate, type of cable, video card, etc.).

But of course, my sensitivity does change when I change the level of the
backlight as well, so it's certainly a combination of factors involved.

Marc

> I recently tried a different graphics card (Nvidia 6200) but it gave mom
> a headache upstairs, and was just barely tolerable for me. Rip! out it
> went. Back to the Nv FX5200.

Coincidentally, my home computer is also using an NVIDIA GeForce FX 5200
video card! Maybe these are a good model to have with ES...? I'm running
mine at 1360 x 768 pixels...

Marc

So what do we know? Is it the graphics card that can be problematic?
And why? Does it transfer RF to the monitor, or simply emanate from
the computer tower, or...?

Or do some monitors themselves emit something? (And what, and can this
be reduced?) My LCD has an electric and magnetic field at the front,
but you have to touch the meter to the screen to get a reading. It
has no RF between 800 Mhz and 6 Ghz, but of course there are other
frequencies...

And what about DVI cables? I've seen a couple of times here, people
saying that a DVI cable puts out "more EMF" - is that referring to
electric, magnetic, or RF, and can this somehow be changed/improved
upon, without resorting to uber-expensive fibre optics?

Cheers,

R.

Hallo Marc,

it all has to do with the image control signals.

Especially digital signals, which are worked over in the screen do sent very
different frequencies.

I bought an Acer 26"LCD, which I thought was elektrosmog-poor.
I measured it in the store with my VLF Detector with special digital
antenna, which is normally a good indicator for that.
It is rather difficult to measure properly in a large store, not only
because of the public, but also because of the salesmen, who do not like you
to do that. It must be done quick and stealth.

At home, I was able to measure it further with my Spectran NF, and was
shocked to find heavy peaks at round 4.5 MHz.
See the last issue of *het bitje* September 2008.
Later on, I found other spikes at other frequencies.

Lately, many people ask me what LCD monitor or television they should buy,
but I do not dare to give types.

I have a 42" Philips televison, which works fine, but as soon as my digital
satellite receiver is on, my wife waves goodbye.
The modulation (LCD TV+) I have recorded on:
http://www.milieuziektes.nl/Pagina109.html

Greetings,
Charles Claessens
member Verband Baubiologie
www.milieuziektes.nl
www.milieuziektes.be
www.hetbitje.nl
checked by Bitdefender


----- Original Message -----
From: "Marc Martin" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, December 07, 2008 5:34 PM
Subject: Re: [eSens] LCD monitor sensitivity

> I have a 42" Philips televison, which works fine, but as soon as my
> digital satellite receiver is on, my wife waves goodbye.

Charles, do you know if your wife is reacting to the digital satellite
receiver box, or if she is reacting to frequencies emitted from the
cable to the TV, or if she is reacting to the internal processing
inside the TV set?

I presume that the TV set will emit different frequencies depending
on the kind of signal that is being fed into it? That is, processing
an analog RCA/S-Video signal must be quite different than processing
a digital HDMI 1080p signal?

I find that my HDTV LCD TV set is more tolerable if I feed it a 1080i
signal than a 1080p signal. I can't tell the difference between
1080i and 720p. I am using HDMI cables.

Marc

Hello Marc,

no, my LCD is the normal HD Ready, so no 1080, but 1366x768 pixels.

And it is not the receiver, because it is placed inside a metal cabinet.

I recorded the modulation just 10 cm in front of the television, on the
cabonet.

My wife reacted also, when I was looking at the menu of the receiver, where
you may choose which broadcaster you are going to look at.
This menu (on the TV) gives also different frequencies on the TV.
It can also happen, when the contrast is changing with normal cable
television looking.

So, something weird is happening on the screen itsself.

Greetings,
Charles Claessens
member Verband Baubiologie
www.milieuziektes.nl
www.milieuziektes.be
www.hetbitje.nl
checked by Bitdefender

----- Original Message -----
From: "Marc Martin" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, December 07, 2008 9:15 PM
Subject: Re: [eSens] LCD monitor sensitivity

In a message dated 12/7/2008 8:23:50 P.M. GMT Standard Time,
[hidden email] writes:

And it is not the receiver, because it is placed inside a metal cabinet.

I recorded the modulation just 10 cm in front of the television, on the
cabonet.

My wife reacted also, when I was looking at the menu of the receiver, where
you may choose which broadcaster you are going to look at.
This menu (on the TV) gives also different frequencies on the TV.
It can also happen, when the contrast is changing with normal cable
television looking.

So, something weird is happening on the screen itsself.

Greetings,
Charles Claessens
member Verband Baubiologie
www.milieuziektes.ww
www.milieuziektes.ww
www.hetbitje.ww
checked by Bitdefender


Greetings Charles, plese check out the Radio Society Great Britain for all
sorts of info on RF interference concerning Ham Radios, I think we are similar
sensitivity to some of their set-ups. Timebase line harmonics is one thing
that might be applicable for the above

PUK


[Non-text portions of this message have been removed]

Rip out the switching power supply and dimmer crap
all together.

http://www.ahappyhabitat.com/LCDTutorial/LCDTutorial.html

Eli

--- In [hidden email], "lena48be" <lena48be@...> wrote: