EMI PC monitor mesh and adhesive foil sheet


Conrad, PA5Y
 

Does anyone know where I can find some mesh designed to screen LED/LCD monitor screens, also some self adhesive copper sheet to cover the rear of the monitor. I should add that I am looking for reasonable prices, so far all the places that sell it do not list any prices but will furnish a quote upon enquiry. We all know what that means. Their market is EMC facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors they are relatively short slots and my hope is that the radiation from these gaps is minimal. I am looking for around 20-30dB reduction only. I found that my main monitor that I use for EME radiates like mad on 432 MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen, these stripes are are equivalent to signals of around -26dB in JT65B, a big problem. Because of the 50Hz intervals I suspected the PSU but running it from a battery or clean lab supply makes no difference. When I turn off the screen using the monitor on/off button the traces disappear, in fact in order to work the relatively weak TD9CHR on 432 I had to turn off the monitor during RX periods which was not ideal.  I do not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of monitors before choosing this particular monitor, I just never noticed the 70cms problem before.

I realise that this is not strctly uwave but the people who know live here so I hope that you will indulge me.

73

Conrad PA5Y


John E. Beech
 

Hi Conrad,
                 You could try a Pet Store. They sell fine steel wire mesh for making things like rabbit cages, which might do the trick.
 
de John G8SEQ

  -------Original Message-------
From: Conrad PA5Y g0ruz@... [ukmicrowaves]
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet
Sent: Mar 05 '18 21:11

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y


Conrad, PA5Y
 

I think that such mesh is probably too coarse to allow sufficient transparency, I still need to see what is on the screen. Also the moire effect might be problematical. Whilst I am happy to put up with some optical degradation I would still like to use 'proper' stuff if I can find an affordable source. By affordable I mean 50-60 quid per 24 inch monitor. Of course a lower price is better.

Who sells it in small MOQs?

Regards

Conrad


On 05/03/2018 22:58, john@... [ukmicrowaves] wrote:

Hi Conrad,
                 You could try a Pet Store. They sell fine steel wire mesh for making things like rabbit cages, which might do the trick.
 
de John G8SEQ
  -------Original Message-------
From: Conrad PA5Y g0ruz@... [ukmicrowaves]
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet
Sent: Mar 05 '18 21:11

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y



Neil Smith G4DBN
 

I used some of this stuff before, but I don't know if you'd be able to see through it enough for a PC display.  Search for "metal silk" perhaps? https://www.themeshcompany.com/products/-100-Mesh---0.204mm-Aperture---0.0.05mm-Wire-Diameter---Copper-99.99----Woven-Wire-Mesh-285.html#SID=31

It will probably go manky after a while in the open though. They do stainless mesh https://www.themeshcompany.com/products/-84-Mesh---0.239mm-Aperture---0.063mm-Wire-Diameter---SS304-Grade---Woven-Wire-Mesh-106.html#SID=31, and phosphor bronze, which might be better for your application, but actually you only need maybe 20mm spaced wires to give enough screening, so long as the joints are reasonably reliable.

Neil G4DBN

On 05/03/2018 21:10, Conrad PA5Y g0ruz@... [ukmicrowaves] wrote:

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.



Neil Smith G4DBN
 

Maybe worth a look at this: http://www.opticalfilters.co.uk/emi-mesh.html but no pricing on the site.  It is designed for screens and windows.  Distributor is http://www.visionteksystems.co.uk/emi_mesh.htm

Neil

On 05/03/2018 22:25, Conrad PA5Y g0ruz@... [ukmicrowaves] wrote:

 

I think that such mesh is probably too coarse to allow sufficient transparency, I still need to see what is on the screen. Also the moire effect might be problematical. Whilst I am happy to put up with some optical degradation I would still like to use 'proper' stuff if I can find an affordable source. By affordable I mean 50-60 quid per 24 inch monitor. Of course a lower price is better.

Who sells it in small MOQs?

Regards

Conrad


On 05/03/2018 22:58, john@... [ukmicrowaves] wrote:
Hi Conrad,
                 You could try a Pet Store. They sell fine steel wire mesh for making things like rabbit cages, which might do the trick.
 
de John G8SEQ
  -------Original Message-------
From: Conrad PA5Y g0ruz@... [ukmicrowaves]
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet
Sent: Mar 05 '18 21:11

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y




Neil Smith G4DBN
 

Cheapest source of self-adhesive copper foil is the stuff they sell for slug repellent, but I bought a 300mm x 1m roll of 0.1mm copper self-adhesive foil from China for less than a fiver last year. It got a bit squished in the post, but worked fine.

Neil G4DBN


  -------Original Message-------
From: Conrad PA5Y g0ruz@... [ukmicrowaves]
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet
Sent: Mar 05 '18 21:11

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y




g4bao
 

Perfect timing Neil!

Just used the last of my Roll of 30mm wide copper adhesive foil that I bought in 1983. No, that's not a typo.... It has "lasted well"

Was wondering where to get more
73

John

On 5 March 2018 at 22:37, Neil neil@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Cheapest source of self-adhesive copper foil is the stuff they sell for slug repellent, but I bought a 300mm x 1m roll of 0.1mm copper self-adhesive foil from China for less than a fiver last year. It got a bit squished in the post, but worked fine.

Neil G4DBN


  -------Original Message-------
From: Conrad PA5Y g0ruz@... [ukmicrowaves]
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet
Sent: Mar 05 '18 21:11

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y





Rex Cameron <cathar.gnostic@...>
 

Don't forget to bring the shield to ground potential, depending on the sheets dimensions it could re-radiate. 

ZL4IV


Conrad, PA5Y
 

Yes common wisdom (nothing common about wisdom - silly phrase) dictates that you have to achieve equal potential on all shields. So this means bonding the edge of the mesh to any foil used and all that to the rear panel metalwork. All the cables have to be properly shielded and the whole lot properly bonded. It is not trivial and you have to start in the knowledge that you might fail. However I am not looking for 100dB here, 30dB is enough and I think that should be achievable.

Shielding the shack is even harder! That's why I dismissed that idea.

Regards

Conrad PA5Y


On 06/03/2018 00:12, Rex Cameron cathar.gnostic@... [ukmicrowaves] wrote:

Don't forget to bring the shield to ground potential, depending on the sheets dimensions it could re-radiate. 

ZL4IV



Eric Schumacher <wb6kcn@...>
 

Hello Conrad

An inexpensive source of EMI mesh is stainless steel silk screen fabric. Put the wires at 45 deg to avoid most moiré interference.  Also makes a great fuel filter. Sorry that you are not local or I would fix you up.

73 WB6KCN

 

From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: Monday, March 05, 2018 1:11 PM
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet

 

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y


Paul G8AQA
 

Hi Conrasd,

There are mesh companies in the uk.  I would telephone them and ask for advice on visibility.

The Mesh Company
Chris Platt
Unit 1
Farrell Street
Warrington
Cheshire
WA1 2WW
United Kingdom
Phone:01925|406602
Fax:01925 444 386
Email:ebay@...

Inoxia Ltd
Steve Hall
45.7 Dunsfold Park
Stovolds Hill
Cranleigh
Surrey
GU6 8TB
United Kingdom
Phone:2032909990
Email:ebay@...

I would be inclined to go for one with a bigger open area.

https://www.ebay.co.uk/itm/Stainless-Steel-woven-wire-mesh-30cm-square-sheet-Fine-Heavy-duty-coarse-/261722409245?_trksid=p2349526.m4383.l4275.c10&var=560592064078

They even do copper and also cut to your size.

Please let us know how you get on.

73
Paul G8AQA




On 06/03/2018 01:03, 'Eric Schumacher' wb6kcn@... [ukmicrowaves] wrote:
 

Hello Conrad

An inexpensive source of EMI mesh is stainless steel silk screen fabric. Put the wires at 45 deg to avoid most moiré interference.  Also makes a great fuel filter. Sorry that you are not local or I would fix you up.

73 WB6KCN

 

From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: Monday, March 05, 2018 1:11 PM
To: ukmicrowaves@...
Subject: [ukmicrowaves] EMI PC monitor mesh and adhesive foil sheet

 

 

Does anyone know where I can find some mesh designed to screen LED/LCD
monitor screens, also some self adhesive copper sheet to cover the rear
of the monitor. I should add that I am looking for reasonable prices, so
far all the places that sell it do not list any prices but will furnish
a quote upon enquiry. We all know what that means. Their market is EMC
facilities and MRI rooms and the military.

I realise that I cannot block any ventilation holes but on my monitors
they are relatively short slots and my hope is that the radiation from
these gaps is minimal. I am looking for around 20-30dB reduction only. I
found that my main monitor that I use for EME radiates like mad on 432
MHz producing slowly wandering 50Hz spaced 'stripes' on my WSJT screen,
these stripes are are equivalent to signals of around -26dB in JT65B, a
big problem. Because of the 50Hz intervals I suspected the PSU but
running it from a battery or clean lab supply makes no difference. When
I turn off the screen using the monitor on/off button the traces
disappear, in fact in order to work the relatively weak TD9CHR on 432 I
had to turn off the monitor during RX periods which was not ideal.  I do
not see a sniff on 6,4,2 or 23, in fact I 'auditioned' quite a number of
monitors before choosing this particular monitor, I just never noticed
the 70cms problem before.

I realise that this is not strctly uwave but the people who know live
here so I hope that you will indulge me.

73

Conrad PA5Y



Virus-free. www.avg.com


mw1fgq
 

Conrad

I thought of Indium Tin oxide coated glass and came across this company:-

John
MW1FGQ