[SI-LIST] Re: Traces don't cause EMI - really?

  • From: "Grasso, Charles" <Charles.Grasso@xxxxxxxxxxxx>
  • To: "'james.f.peterson@xxxxxxxxxxxxx'" <james.f.peterson@xxxxxxxxxxxxx>,"'si-list@xxxxxxxxxxxxx'" <si-list@xxxxxxxxxxxxx>
  • Date: Fri, 17 Oct 2003 15:29:24 -0600

Whoa - now when did that rule come about?? :-)

Best Regards
Charles Grasso
Senior Compliance Engineer
Echostar Communications Corp.
Tel:  303-706-5467
Fax: 303-799-6222
Cell: 303-204-2974
Email: charles.grasso@xxxxxxxxxxxx;  
Email Alternate: chasgrasso@xxxxxxxx
 


-----Original Message-----
From: Peterson, James F (FL51) [mailto:james.f.peterson@xxxxxxxxxxxxx] 
Sent: Friday, October 17, 2003 2:13 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Traces don't cause EMI - really?


I've been tracking this thread with more interest than any subject for a
long time - I think a lot of us are.

Could it be that the fate of the EMI rule of NEVER routing on the surface
layer dies the same way as the one about routing with 45 degree corners????
I haven't seen any data from the theorist yet that proves otherwise.

excellent discussion - a classic example of why the SI reflector is so
great.

~jim


-----Original Message-----
From: Chris Padilla [mailto:cpad@xxxxxxxxx]
Sent: Friday, October 17, 2003 3:25 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Traces don't cause EMI - really?


As long as you don't interfere with an FCC antenna out there somewhere or 
your neighbor's don't complain, you should be fine.  How many of us have 
taken apart computers, VCRs, anything electronic in a box and not put it 
back together properly whether accidental or purposely--or even just left 
the lid off altogether?  At most, you would probably only impact your 
television reception or voice quality on the phone possible.  Maybe your 
wireless network would show problems.  Etc.  Is it legal...probably 
not...does anyone care...probably only you....

----->Chris

At 11:31 AM 10/17/2003 -0700, Alex Horvath wrote:
>Probably getting off topic here but my computer which is not a name 
>brand,
>was simply assembled from components and has none of the obvious EMI 
>preventative measures like gaskets, filters etc that you see on a name 
>brand. Also, it was never EMI tested as a unit. So is this unit legal from 
>an FCC emissions standpoint?
>
>Lfresearch@xxxxxxx wrote:
>In a message dated 10/17/2003 1:09:11 PM Central Daylight Time,
>alexh1@xxxxxxxxxxxxx writes:
>Assuming the EMI testing that's done for CISPRB and CE is done
>with a base configuration (no added PCI cards, etc.), the inclosure could
be
>providing a great deal of the necessary shielding. The mother board 
>itself would then not need to be especially clean. This has been an 
>area I've looked at in great depth recently. I have been EMI testing a 
>great many PC Cards, and it took me a long while to find a PC that 
>would comply on it's own. I found only 2 motherboards, both made in the 
>USA, that could pass with no cover on.
>
>The worst motherboard was close to 35 dB over spec when tested with the
>cover off. It was made offshore. The reason this was a problem to the card 
>makers, is that noisy motherboards use plug in cards and their cables for 
>an exit point. So, the performance of the card is often disguised.
>
>Back to my point :-).
>
>The MB performance is often swamped by the plug in cards and
>interconnections that take place to off the boards... So even if the MB is 
>quiet, the rest of the PC isn't. However, what leaves the case raely comes 
>from here anyway, it leaves fom the the leads that leave the case like the 
>mouse and keyboard...
>
>Cheerz,
>
>
>Derek N. Walton
>Owner, L F Research EMI Design and Test Facility
>Poplar Grove,
>IL 61065
>
>
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