Plastic does not make a good RF shield material
RichA
is allowing companies to import shoddy RF-emanating products that are
a problem, from computers with plastic box housings to set-top HDTV
boxes. Plastic and aluminum SUCK as RF shields. Only steel or copper
work well. Below is an example of the problem.
U*U
"RichA" <rande...@gmail.com> wrote in message
news:b1761f8f-dde6-429f...@v25g2000yqk.googlegroups.com...
Wrong Mr. Engineer, aluminum is used in RF shields, as is bronze, stainless
steel, gold, tin and copper. Plastic can be coated with RF paint. So once
again Rich/RichA shows he knows nothing about what he prattles on about.
Eric Stevens
wrote:
Shielding is designed to keep RF in. Your problem is that you cannot
keep RF out. You should know that your shielding will not keep out
X-Rays or Cosmic Rays, either.
Eric Stevens
Doug McDonald
>
> Shielding is designed to keep RF in.
Shielding that keeps RF in will keep it out. In the same frequency range,
of course.
Doug McDonald
John McWilliams
That's why we recommend actual *tin* foil, not the ubiquitius aluminum
foil for protective caps/hats.
--
john mcwilliams
Paul J Gans
Good grief! You've given RichA something new to torment us with!
--
--- Paul J. Gans
John McWilliams
> bands reserved for government use?
>
> http://people.csail.mit.edu/rahimi/helmet/
>
> (Has such a study been done on tin foil hats?)
Dunno. But it's not radio signals he has to be chary of: It's the
controlling brain waves from aliens circling the earth in invisible
space ships....
--
john mcwilliams
RichA
> "RichA" <rander3...@gmail.com> wrote in message
CLUELESS! Steel or other ferrous material or copper is the only sure
way to guard against RF.
RF paint on plastic!!!
Eric Stevens
I wonder how many holes have been punched through his brain while he
has been thinking about this new source of worry?
Eric Stevens
Bristolian
Tut! Tut! You have demonstrated your complete lack of knowledge about
anything to do with materials properties so often on here that it
beggars belief that you would continue in this vein.
For a start you need to define whether you are talking about radiated or
conducted RF because the protection methods needed for both are entirely
different. If radiated interference is the problem then shielding with a
path to ground is the ONLY solution. Any conductive metallic material
(including Aluminium) can be used with pretty much equal effectiveness.
Metallic coatings on plastic are also quite effective for low levels of
interference - a solution widely used in modern airliners and medical
instruments.
Where conducted interference is an issue the parasitic beads around
cables is the widely adopted method but over-all screened cables with
ONE END grounded is the better (but more costly) solution.
For the past ten years (at least) all electrical products manufactured
and/or sold within the EU have had to comply with strict rules about
both radiated and conducted RF emissions - both the levels they give out
and their susceptibility to received interference.
--
Regards
Bristolian
Nervous Nick
So does this mean that that you've finally replaced your aluminum
foil hat with a proper Faraday helmet?
anonymous
>>
>>CLUELESS! Steel or other ferrous material or copper is the only sure
>>way to guard against RF.
>>RF paint on plastic!!!
>
> gather.
The USAF uses "iron ball" paint (likely not iron) on their black airplanes..
anonymous
"Nervous Nick" <nervou...@gmail.com> wrote in message
news:a61defe1-bfcf-4a8e...@k19g2000yqc.googlegroups.com...
Only if Rich's metal chair seat is attached to a proper radio grounding
grid, and the Faraday Helmet is attached to a 100' tower mounted lightning
rod...
Ray Fischer
>CLUELESS! Steel or other ferrous material or copper is the only sure
>way to guard against RF.
Which means that aluminum and magnesium are not, according to you, any
better than plastic at shielding from RF radiation.
Can you tell us how many camera bodies are made with steel or copper?
--
Ray Fischer
rfis...@sonic.net
-hh
> Paul J Gans
>
> >Good grief! You've given RichA something new to torment us with!
>
> I wonder how many holes have been punched through his brain while he
> has been thinking about this new source of worry?
Obviously, however many holes his head currently has, its not enough
holes.
-hh
Paul Furman
The problem seems to be with the remote flash trigger's design.
--
Paul Furman
www.edgehill.net
www.baynatives.com
all google groups messages filtered due to spam
Alan Browne
> "RichA"<rande...@gmail.com> wrote in message
> news:b1761f8f-dde6-429f...@v25g2000yqk.googlegroups.com...
>> Once again, plastic falls short. Lack of oversight of products today
>> is allowing companies to import shoddy RF-emanating products that are
>> a problem, from computers with plastic box housings to set-top HDTV
>> boxes. Plastic and aluminum SUCK as RF shields. Only steel or copper
>> work well. Below is an example of the problem.
>>
>> http://forum.getdpi.com/forum/showthread.php?t=12869
Gee whiz. Has RichA actually stumbled onto a real problem?
I have had two Cactus wireless triggers (one since sold), but I have had
the problem illustrated in the link. This _might_ be because my cameras
are metal body.
Such interference from the triggers might be conducted interference
(rather than radiated) down the shield or sync lines themselves from the
trigger into the camera. I have no idea if the cactus triggers filter
those lines appropriately to reduce outgoing conducted emissions, nor
whether my cameras filter those lines coming into the camera body.
It may even be a poor connection between the trigger and the camera
resulting in a capacitance in turn oscillating in the presence of the DC
flow from the trigger towards the camera being interrupted by the shutter.
IOW, plastic is not necessarily the culprit.
Alan Browne
> news:b1761f8f-dde6-429f...@v25g2000yqk.googlegroups.com...
>> Once again, plastic falls short. Lack of oversight of products today
>> is allowing companies to import shoddy RF-emanating products that are
>> a problem, from computers with plastic box housings to set-top HDTV
>> boxes. Plastic and aluminum SUCK as RF shields. Only steel or copper
>> work well. Below is an example of the problem.
>>
>> http://forum.getdpi.com/forum/showthread.php?t=12869
Gee whiz. Has RichA actually stumbled onto a real problem?
I have had two Cactus wireless triggers (one since sold), but I have
_not_ had the problem illustrated in the link. This _might_ be because
my cameras are metal body.
(correction above).
Such interference from the triggers might be conducted interference
(rather than radiated) down the shield or sync lines themselves from the
trigger into the camera. I have no idea if the cactus triggers filter
those lines appropriately to reduce outgoing conducted emissions, nor
whether my cameras filter those lines coming into the camera body.
It may even be a poor connection between the trigger and the camera
resulting in a capacitance in turn oscillating in the presence of the DC
flow from the trigger towards the camera being interrupted by the shutter.
IOW, plastic is not necessarily the culprit.
(Prev. v. of this post deleted, but likely viewable).
isw
<b1761f8f-dde6-429f...@v25g2000yqk.googlegroups.com>,
RichA <rande...@gmail.com> wrote:
> Once again, plastic falls short. Lack of oversight of products today
> is allowing companies to import shoddy RF-emanating products that are
> a problem, from computers with plastic box housings to set-top HDTV
> boxes. Plastic and aluminum SUCK as RF shields. Only steel or copper
> work well.
Steel is effective against magnetic fields, but not so much for electric
fields. Electric fields are suppressed by anything that's conductive;
the better the conductivity, the more the suppression. (Which is why
silver, copper, and aluminum work better than steel for that.)
Plastics by themselves are not good for either electric or magnetic
fields, but with the proper materials embedded in them (which can be
difficult to discern), they can be very effective.
Further, *every* "RF-eminating product" on the market is required by law
to pass the FCC's rather stringent emission regulations -- basically,
any digital device that has a clock frequency over 10 kHz is subject to
the rule, and that would include settop boxes, computers, cameras,
cellphones, ...
I've performed those tests on consumer products; it can be quite
difficult to achieve a passing score.
Isaac
Twibil
>
>
> Obviously, however many holes his head currently has, its not enough
> holes.
An argument with a certain degree of caliber.