Re: Steel Balls vs. Chickens

[Ralph Cameron]

RE: Steel Balls vs. ChickensNational Research Council in Canada has used 
chiekens in conjunction with their wind tunnel tests for airworthiness of 
aircraft designs for at least 25 years. 

Ralph Cameron

EMC Consulting and Suppression of Consumer Electronics 
(after sale)


  - Original Message - 
  From: Gary McInturff 
  To: 'k.macl...@aprel.com' ; mtay...@hach.com ; geor...@lexmark.com ; 
emc-p...@ieee.org 
  Sent: Thursday, September 27, 2001 2:14 PM
  Subject: RE: Steel Balls vs. Chickens


  You can find similar data by going through commercial aircraft test 
procedures. I've seen the video from Boeing of chickens going through turbine 
blades, cockpit deflections etc. Don't have a contact for you but its not a 
super secret military idea - and it the turbine test makes tasty sliced chicken 
for sandwiches.
  Gary
-Original Message-
From: k.macl...@aprel.com [mailto:k.macl...@aprel.com]
Sent: Thursday, September 27, 2001 7:30 AM
To: mtay...@hach.com; geor...@lexmark.com; emc-p...@ieee.org
Subject: RE: Steel Balls vs. Chickens


Then, of course, there is the (apocryphal?) story of the Brits forgetting 
to defrost the chickens in their tests...  just goes to say that those dreally 
etailed test procedures can come in handy...

Kathy M. MacLean 
President, APREL Laboratories 
-EMC-RF Safety-Antenna Design/Test-SAR/MPE-SAR/Near-Field 
Tools-Acoustics-Wireless- 
51 Spectrum Way, Nepean, Ontario K2R 1E6 
(613) 820-2730 fax (613) 820-4161 
cell (613) 791-3777 
Web site:  http://www.aprel.com - watch for our new web site coming soon! 

  -Original Message-
  From: Michael Taylor [mailto:mtay...@hach.com]
  Sent: September 26, 2001 3:52 PM
  To: 'geor...@lexmark.com'; emc-p...@ieee.org
  Subject: RE: Steel Balls vs. Chickens


  A really trick cannon was used at China Lake-NWTC  Edwards-AFB to test 
the impact resistance on All Weather Aircraft wind screens  canopy's.  Fresh 
Frozen chickens were defrosted the day before and shot out of a high pressure 
tube at the subject wind screens  canopy's simulating bird impact in flight.  
At the end of the test you could not imagine the carnage unless you saw it.  
What a mess.  Many times I wished I was able to photograph the scene - but no 
cameras allowed.

  Michael Taylor. 

  -Original Message- 
  From: geor...@lexmark.com [mailto:geor...@lexmark.com] 
  Sent: Wednesday, September 26, 2001 12:51 PM 
  To: emc-p...@ieee.org 
  Subject: Steel Balls vs. Chickens 






  In the late 1960's I was working on what became IBM's first copier. 
  We made frequent use of NESA glass, a PPG product.  This consisted 
  of an ultra-thin gold layer deposited on glass sheets.  We could perform 
  photoconductor light-discharge experiments by coating the PC on the 
  gold surface, and expose from the opposite side. 

  I was told that the NESA glass concept was developed during WWII to 
  defrost bomber windshields.  These were typically made of plexi-glass, 
  and would not thermally conduct sufficient heat from within the cockpit 
to 
  defrost the exterior.  The gold coating was placed on the outside of the 
  windshield, and DC current passed across the surface to create enough 
  heat to melt frost. 

  The question of durability of the gold coating to birds striking the 
surface 
  was established by firing dead chickens at test surfaces.  I often 
kidded 
  one of my mechanical engineering friends that he could  and should design 
  a top-of-the-line chicken cannon, with variable muzzle velocity, 
variable 
  bores for using birds of different sizes, etc. 

  As you know, jet airplane engines are still tested for their resiliency 
to birds 
  both small (near airport ground level) and large (those ecountered at 
high 
  altitudes) by similar methods. 

  George Alspaugh 




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Re: 134kHz transmitter in the U.K.

[Ralph Cameron]

In Canada  there is licenced operation on 137.1Khz  and I understand FCC
just released a small segment for use on 433Khz on an experimental basis.


Ralph Cameron

- Original Message -
From: Jacob Schanker j.schan...@worldnet.att.net
To: Sykes, Bob bob.sy...@marconi.com; emc-p...@ieee.org
Sent: Wednesday, September 19, 2001 4:07 PM
Subject: Re: 134kHz transmitter in the U.K.



 Bob:

 You should be aware that there is a UK amateur radio band at 135.7 - 137.8
 kHz. Please keep that in mind both from an interference and from an
immunity
 standpoint. You'll need to check the RA's website for technical
limitations.
 Another resource is the RSGB's website at www.rsgb.org.uk.

 Regards,

 Jack

 Jacob Z. Schanker, P.E.
 65 Crandon Way
 Rochester, NY 14618
 Phone: 716 442 3909
 Fax: 716 442 2182
 j.schan...@ieee.org


 - Original Message -
 From: Sykes, Bob bob.sy...@marconi.com
 To: emc-p...@ieee.org
 Sent: Wednesday, September 19, 2001 10:49 AM
 Subject: 134kHz transmitter in the U.K.


 
 
  Greetings,
 
  We are looking at providing a short range RFID system to the U.K., and I
 am
  tasked with
  determining the regulatory requirements for this system.  It
incorporates
 a
  low power
  transmitter/receiver operating at 134kHz.  I am familiar with the LVD
and
  EMCD requirements,
  but unable to determine RTTE applicability, or whether U.K. National
  regulations apply.
 
  Any help would be most appreciated.
 
  adTHANKSvance,
 
  -Bob Sykes
  Marconi Commerce Systems
 
 
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Re: CE Mark

[Ralph Cameron]

Chris:
Thanks for your intelligent reply and a little needed humor too. In my days
of paid employment CSA electrical safety was where it was at. Nowdays I
think they need Compliance Engineers to be able to determine which standard
applies.  I guess there could be two approaches, generic immunity or the way
it is now. Either way, it seems to present as many problems.

By the way, I'll endorse your cheques with CE, but only from my basement.

Regards,


Ralph Cameron

- Original Message -
From: Chris Chileshe chris.chile...@ultronics.co.uk
To: emc-p...@majordomo.ieee.org
Sent: Thursday, September 13, 2001 12:37 PM
Subject: RE: CE Mark



 Hi Ralph,

 The CE mark is not exclusive to EMC. Indeed, it refers to compliance with
 all directives relevant to the product, so a teddy bear will be CE marked
if
 it meets the requirements of the toy directive and all relevant safety
directives.

 Pressure vessels will have to meet the requirements of the pressure
directive
 and so on, and if any product crosses boundaries, it has to meet all the
applicable
 directives.

 However, the CE mark is a declaration of conformity and you can self
certify.
 This means I can disappear into my garage for a few weeks and emerge with
 a CE marked product - and it would be perfectly legal - as long as the
declaration
 is true i.e. I have done what needs to be done to prove compliance, and
one way
 to do this would be to test to applicable harmonised standards. Validity
of self
 certification may change in due course but at the moment, that is how it
is.

 I like Chris Maxwell's spin on the meaning of CE, and it would be true if
 every firm made a distinction between the compliance engineer and the
 designer. In all the companies I have worked for - we do it all i.e. the
designer
 designs to spec, takes the product through type approval tests, then
through
 precompliance and then through full compliance. So the electronics
designers
 are responsible for meeting all the applicable directives (EMC, electrical
safety)
 and functional type approval and they do so by product proving and EMC
testing
 the product themselves - to the applicable standard. They are also
responsible for
 the technical documentation for the electrical aspects of the product. The
 mechanical engineers and hydraulics engineers do likewise and when it's
all done,
 the fall guy (engineering director) puts his signature on the declaration
of conformity.
 What this means is that if the declaration should subsequently be proven
false, he
 is the one who goes to the gallows.

 Wait a minute! I used to think everyone worked that way, but I get the
feeling
 I may be doing too much! That does it! I am off to see the payroll people
soon
 after sending this e-mail and hopefully will emerge with a CE marked
cheque -
 or CE marked letter of dismissal!! You can never be too sure with these
 accounts people.

 Regards y'all

 - Chris Chileshe


 -Original Message-
 From: Ralph Cameron [SMTP:ral...@igs.net]
 Sent: Thursday, September 13, 2001 4:57 PM
 To: Chris Chileshe; emc-p...@majordomo.ieee.org
 Subject: Re: CE Mark

 I think its fair to state that CE also equates to designed in level of
 immunity to electromagnetic interference, i.e.  reduced sensitivity or
 susceptibility.  In my view , a highly desireable because it prevents a
lot
 of what's out there from coming in and conversely a lot of what's inside
 from coming out.

 It's a compromise but better than nothing.

 Ralph cameron
 EMC Consulting and Suppression of Consumer Electronics
 (after sale)

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 majord

Re: CE Mark

[Ralph Cameron]

I think its fair to state that CE also equates to designed in level of
immunity to electromagnetic interference, i.e.  reduced sensitivity or
susceptibility.  In my view , a highly desireable because it prevents a lot
of what's out there from coming in and conversely a lot of what's inside
from coming out.

It's a compromise but better than nothing.

Ralph cameron
EMC Consulting and Suppression of Consumer Electronics
(after sale)

- Original Message -
From: Chris Chileshe chris.chile...@ultronics.co.uk
To: emc-p...@majordomo.ieee.org
Sent: Thursday, September 13, 2001 7:52 AM
Subject: RE: CE Mark




 This understanding (appended e-mail below) is correct AFAIK. I also
checked
 out the website http://www.conformance.co.uk and they seem to agree with
 the notion it doesn't really mean anything *any more*. Here is an excerpt
 from
 their site ..

 .

 We quite often get asked what the 'CE' in the CE logo stands for.

 If anything it probably stands for Communitee Europeen being the French
way
 of saying European Community. It could also represent Conformite Europeen.
 However, it is far from certain that whoever invented the mark (some
 bureaucrat in Brussels) had anything particular in mind other than to
 create a logo which would be universally recognised in the European Union,
 and given all the national prejudices about language in the different
 countries of the EU, even if the original inventor had something specific
 in mind, it was probably conveniently forgotten by the time it became
 'official'. So, officially, it's just a logo and has no linguistic
meaning.

 ..

 Best regards

 - Chris

 -Original Message-
 From: wmccaffe...@npeurope.com [SMTP:wmccaffe...@npeurope.com]
 Sent: Tuesday, September 11, 2001 2:44 PM
 To: Jody Leber
 Cc: 'emc-p...@majordomo.ieee.org'
 Subject: Re: CE Mark



 Hi Jody

 According to sources within the European Commission the letters CE now
have
 no
 meaning.  Communitie European seems to have been assumed from the
inception
 of
 the directives but now CE means CE.

 Slaint

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Re: CE Mark

[Ralph Cameron]

The correct French spelling for the English equivalent of community is
communaute with an accent on the last e, according to my French
dictionary.


Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(after sale)


- Original Message -
From: geor...@lexmark.com
To: Jody Leber jle...@ustech-lab.com
Cc: emc-p...@majordomo.ieee.org
Sent: Tuesday, September 11, 2001 8:23 AM
Subject: Re: CE Mark





 Jody,

 I seem to recall that CE is for European Community but in Frech, i.e.
 Communite European.  You can try looking around the EU website:


http://europa.eu.int/comm/enterprise/newapproach/legislation/guide/legislati
on.htm



 George




 Jody Leber jleber%ustech-lab@interlock.lexmark.com on 09/11/2001
07:30:53
 AM

 Please respond to Jody Leber jleber%ustech-lab@interlock.lexmark.com

 To:   'emc-p...@majordomo.ieee.org'
   emc-pstc%majordomo.ieee@interlock.lexmark.com
 cc:(bcc: George Alspaugh/Lex/Lexmark)
 Subject:  CE Mark




 Is there an offcial website that defines what the CE actually stands
for?
  I believe it is Conformite Europeene, however I have seen other
 definitions.  I seached the europa site but did not have any luck.

 Best Regards,

 Jody Leber
 Laboratory Manager

 jle...@ustech-lab.com
 http://www.ustech-lab.com

 U. S. Technologies
 3505 Francis Circle
 Alpharetta, GA 30004

 770.740.0717
 Fax:  770.740.1508



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Re: UL vs CSA (IT product)

[Ralph Cameron]

George:

I don't think what I said differs substantially from what you said other
than I intended to say that where electrical safety of consumer products is
concerned only CSA and c-UL certification is acceptable in Canada.

If you use a consumer product in Canada  not so approved to CSA or c-UL,
you'll have a problem with insurance. . In fact Ontario Hydro(now Hydro One)
have authority to prevent you from using the product.

Its amazing how many products enter the country without any certification
because this is not examined at entry.

Ralph Cameron

- Original Message -
From: geor...@lexmark.com
To: emc-p...@ieee.org
Sent: Monday, September 10, 2001 11:21 AM
Subject: UL vs CSA (IT product)




 Amund,

 I believe some additional clarification is warranted.
 UL and CSA are private agencies and do not determine what is
 acceptable to market goods (ITE) in their respective countries.
 This is determined by government bodies.

 The U.S. OSHA has approved multiple Nationally Recognized
 Testing Laboratories to (NRTLs) to perform testing to the UL
 standards for ITE.  These include UL and CSA. See:
 http://www.osha-slc.gov/dts/otpca/nrtl/index.html

 The Standards Council of Canada has approved multiple Certification
 Bodies to perform testing to the CSA standards for ITE.  These
 include UL and CSA.  See http://www.scc.ca/certific/colist_e.html

 Neither UL nor CSA is obliged to recognize or accept testing
 performed by the other agency, although their respective governments
 do so.

 Canada requires either CSA, c-UL, or marks of the other listed
 certification bodies.  U.S. requires UL, CSA/NRTL, or marks of the
 other listed NRTLs.

 So, you can use either agency to get a mark acceptable in both
 countries.  However, here is the down side of each:

 CSA/NRTL--Not as well known in the U.S. by large corporate customers.
 Requires some selling to convince that it is equal to UL.

 c-UL--OK for both country consumer/business markets, but Canadian
 government tends to give precidence to CSA marked ITE when bidding
 for its own use.

 George Alspaugh
 Lexmark International Inc.




 Ralph Cameron ralphc%igs@interlock.lexmark.com on 09/10/2001
09:33:00 AM

 Please respond to Ralph Cameron ralphc%igs@interlock.lexmark.com

 To:   Horst Haug innova.ps%t-online...@interlock.lexmark.com, Peter
   Merguerian pmerguerian%itl.co...@interlock.lexmark.com,
   amund%westin@interlock.lexmark.com,
   emc-pstc%majordomo.ieee@interlock.lexmark.com
 cc:(bcc: George Alspaugh/Lex/Lexmark)
 Subject:  Re: UL vs CSA  (IT product)










CSA accepts approval by ULC.  The C is indicative of Canadian UL.
UL is normally not accpetable by itself in Canada

Ralph Cameron
EMC Consulting and Suppresion of Consumer Electronics
(after sale)

- Original Message -
From: Horst Haug innova...@t-online.de
To: Peter Merguerian pmerguer...@itl.co.il; am...@westin.org;
emc-p...@majordomo.ieee.org
Sent: Monday, September 10, 2001 5:24 AM
Subject: AW: UL vs CSA (IT product)



 Amund,

 UL accept components approved by CSA and CSA accepts components approved
 by UL.  A CSA approved Power Supply within an end product with UL approval
 is no problem any more (that is my experience).
 The UL PAG practical application guide about is 1.5.002.  I send it to
 you in a separate EMAIL.

 With best regards
 Horst Haug

 -Ursprüngliche Nachricht-
 Von: owner-emc-p...@majordomo.ieee.org
 [mailto:owner-emc-p...@majordomo.ieee.org]Im Auftrag von Peter Merguerian
 Gesendet: Montag, 10. September 2001 09:44
 An: 'am...@westin.org'; emc-p...@majordomo.ieee.org
 Betreff: RE: UL vs CSA (IT product)


 Amend,

 See my answers in body of your message.


 UL and/or CSA certification are mandatory within the electrical safety
area,to have access to the US and Canadian marked. Right ?

 I know there are some differences between them, the certification fee, the
 certification-handling period and the number of audit/year.

 My questions are:
 1.Do they have the same status?

 Peter: Yes, to a certain extent. You must check the scope of their
 acceditations in OSHA's and Standard Council of Canada's websites.


 2.What requirements do the end users/ buyers have, do most of them prefer
 one of the approvals?

 Peter: Depends on the categories. But most end-users are not aware that
 other NRTLs are capable of giving the same Listing service.
 You must educate them.

 3.Do we have to go for both of them?

 Peter: One is enough, but as I said above, you must educate end-users to
 accept and also check if the test house is accredited for the particular
 standards.

 Best regards
 Amund Westin, Oslo/Norway





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To cancel your

Re: UL vs CSA (IT product)

[Ralph Cameron]

CSA accepts approval by ULC.  The C is indicative of Canadian UL.  UL is
normally not accpetable by itself in Canada

Ralph Cameron
EMC Consulting and Suppresion of Consumer Electronics
(after sale)

- Original Message -
From: Horst Haug innova...@t-online.de
To: Peter Merguerian pmerguer...@itl.co.il; am...@westin.org;
emc-p...@majordomo.ieee.org
Sent: Monday, September 10, 2001 5:24 AM
Subject: AW: UL vs CSA (IT product)



 Amund,

 UL accept components approved by CSA and CSA accepts components approved
by
 UL.  A CSA approved Power Supply within an end product with UL approval is
 no problem any more (that is my experience).
 The UL PAG practical application guide about is 1.5.002.  I send it to
you
 in a separate EMAIL.

 With best regards
 Horst Haug

 -Ursprüngliche Nachricht-
 Von: owner-emc-p...@majordomo.ieee.org
 [mailto:owner-emc-p...@majordomo.ieee.org]Im Auftrag von Peter Merguerian
 Gesendet: Montag, 10. September 2001 09:44
 An: 'am...@westin.org'; emc-p...@majordomo.ieee.org
 Betreff: RE: UL vs CSA (IT product)


 Amend,

 See my answers in body of your message.





 UL and/or CSA certification are mandatory within the electrical safety
area,
 to
 have access to the US and Canadian marked. Right ?

 I know there are some differences between them, the certification fee, the
 certification-handling period and the number of audit/year.

 My questions are:
 1.Do they have the same status?

 Peter: Yes, to a certain extent. You must check the scope of their
 acceditations in OSHA's and Standard Council of Canada's websites.


 2.What requirements do the end users/ buyers have, do most of them prefer
 one
 of the approvals?

 Peter: Depends on the categories. But most end-users are not aware that
 other NRTLs are capable of giving the same Listing service.
 You must educate them.

 3.Do we have to go for both of them?

 Peter: One is enough, but as I said above, you must educate end-users to
 accept and also check if the test house is accredited for the particular
 standards.

 Best regards
 Amund Westin, Oslo/Norway



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Re: Susceptibility level of medical devices (incubator) - urgent!

[Ralph Cameron]

Antonio:

I would say many incubators were manufactured when there were no concerns
and the susceptibility was a function of the design and very variable. I
have heard they vary from 0.1V/m to 10V/m but don't think there is any set
standard. The medical gurus prefer to isolate their equipment by physical
barriers and hope that something will not affect them

In Canada Health Canada could answer thequestion . In the U.S. I believe its
the Food and Drug Administration.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale).


- Original Message -
From: Antonio Sarolic antonio.saro...@fer.hr
To: emc-p...@majordomo.ieee.org
Sent: Monday, August 27, 2001 11:59 AM
Subject: Susceptibility level of medical devices (incubator) - urgent!



 Hi

 I need urgent info on susceptibility level of medical electronic devices,
 especially baby incubators. Can anyone confirm if it is 1V/m (according to
 EU standards)? The EMI source is the GSM BS antenna (900MHz).

 Thanks very much.
 Antonio

 Antonio Sarolic, M.S.E.E.
 Faculty of Electrical Engineering and Computing
 Dept. of Radiocommunications and Microwave Engineering
 Unska 3, HR-1 Zagreb, CROATIA
 tel. +385 1 61 29 789, fax. +385 1 61 29 717
 E-mail: antonio.saro...@fer.hr




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Re: board scanning on the cheap (sort of)

[Ralph Cameron]

I think this was known as Kirlian photogrphy - spelling may be wrong.
It can detect the electrostatic charge surrounding living tissue.

Ralph Cameron


- Original Message -
From: geor...@lexmark.com
To: emc-p...@ieee.org
Sent: Thursday, August 09, 2001 4:00 PM
Subject: board scanning on the cheap (sort of)





 Well, this discussion has reached the point where I must add something
 I read about some years ago.  It goes something like this:

 For many years, Russia was known to conduct many experiments involving
 paranormal activity, probably to determine if there were any military
value
 in such phenomena as psychic communications etc., if in fact they existed.

 I was surprised to see an article in a National Geographic years ago that
told
 of one such experiment.  It involved photography of the aura (presumably
 electromagnetic fields) that surround the human body.  The peaks in this
aura,
 or field were found to be consistent with the primary acupuncture points
long
 before identified by the Chinese.

 A faith (hand-on) healing was photographed, revealing that the aura of
 the healer diminished during the process while the aura of the person
being
 healed increased, i.e. a possible transfer of energy.

 The point of all this is if the Russians truly developed a means to
photograph
 the low power EMF surrounding humans, it would seem that the same
technique
 would also photograph the EMF surrounding PCBs etc.

 I have no comment on whether any of the above is true science, but I DID
read
 it in the generally respected National Geographic, albeit not a scientific
 journal.

 George Alspaugh



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Re: ESD - time between successive discharges

[Ralph Cameron]

John:

I thought I had lost your original statement about CE not having a bearing
on Quality. I would agree also. The statement was made, as I recall, in some
article in Compliance Engineering.  Not that UL is a quality mark or RU or
FCC 15 etc.   Quality is highly dependant on how your marketing people
perceive it and refers to appearance, dependability, reputation, need
fulfillment and a host of things thought to benefit the cutomer - from the
manufacturer's view.

On the other hand a CE mark is a rating of performance and how many
consumers even know about it?  I ask every computer salesman I have occasion
to meet the meaning of CE and I have yet to find one who knows. After I
explain it to him, he agrees that some generic immunity is a good thing.

If you look at all the components and larger computer peripherls now bearing
a CE mark, it must be cost effective to include it.

I suppress consumer equipment that suffers from no immunity with a simple
non intrusive method and suggest to the same consumer to be aware and next
time look for a product with the CE mark.   I yet to encounter a problem
with a CE marked product ( modems, video cards, displays, CD players, and
even boom boxes) that could never hack it in today's RF environment.

CE is a consumer benefit because it guarnatees a minimum level of immunity
With all these domestic wireless devices , it makes prudent engineering
sense. Designed in is the only way to go. I don't want to do this forever.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics.
(after sale)

- Original Message -
From: John Woodgate j...@jmwa.demon.co.uk
To: emc-p...@majordomo.ieee.org
Sent: Tuesday, August 07, 2001 4:34 PM
Subject: Re: ESD - time between successive discharges



 95fbd8b0830ed511b7720002a51363f1319...@exw-ks.ks.lsil.com, Ehler, Kyle
 keh...@lsil.com inimitably wrote:
 
 No John, I'm not referring to you. (or anyone else in particular) I
dont
 know you well enough -yet..lol
 I'm just spaking on how we do the job of ensuring that our products
meet the
 standards.

 I only pick up typos when they are amusing (like, 'We then repeated the
 tests for completemess.'), or could create confusion.
 
 We take this work very seriously and I agree with you that the CE
mark is
 not a quality mark,

 Good; my comment was directed to those who might think it is.

 I agree with most of the rest of your comments.
 --
 Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
 This message and its contents are not confidential, privileged or
protected
 by law. Access is only authorised by the intended recipient - this means
YOU!
 The contents may be disclosed to, or used by, anyone and stored or copied
in
 any medium. If you are not the intended recipient, please advise the
sender
 yesterday at the latest.

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Re: TV nostalgia

[Ralph Cameron]

  As I recall, the old pcb material was made from urea and smelled like it. Or 
the exploding selenium rectifiers  were a dead giveaway, just like H2S. 

  - Original Message - 
  From: oover...@lexmark.com 
  To: emc-p...@majordomo.ieee.org 
  Sent: Friday, August 03, 2001 5:55 PM
  Subject: RE: TV nostalgia




  I have noticed several responses related to the smell of the old equipment.
  I had been thinking the very same thing.

  You could trouble-shoot by the type of smell a failed component produced (cap
  vs. resistor, vs choke, etc.)

  Ever notice how connected one's memory and smells are connected?
  Think about the number of things, both good and bad, that particular smells
  recall.

  Fresh cut grass, a certain type of perfume, a new or old car, fresh paint,
  burning leaves, foods, etc.





  rbusche%es@interlock.lexmark.com on 08/03/2001 05:02:21 PM

  Please respond to rbusche%es@interlock.lexmark.com

  To:   emc-pstc%majordomo.ieee@interlock.lexmark.com
  cc:(bcc: Oscar Overton/Lex/Lexmark)
  Subject:  RE: TV nostalgia



  How about the reported X-Ray emissions from the old high voltage regulators
  and the 25-35KV anode voltages? Those old color sets were beasts.

  It is interesting to note that the process of keeping the CRT filaments
  warm, (instant on) was the cause of numerous TV fires.

  But you know, there's something pleasant (or nostalgic) about the smell of a
  tube type radio or TV. Perhaps it's just my age.

  Rick Busche

  -Original Message-
  From: Ehler, Kyle [mailto:keh...@lsil.com]
  Sent: Friday, August 03, 2001 2:38 PM
  To: 'Ralph Cameron'; 'EMC and Safety list'
  Subject: RE: TV nostalgia


  Which reminds me of other oddball video contraptions.
  A few years back I had to dispose of a Heathkit GR-2000 25 TV w/onscreen
  digital clock option.
  Alas, it worked great, but the digital matrix tuner did not like CATV (ch.
  2-13 only).
  Its entire chassis was copper plated steel.  All pcb's were 94V0 and,
  typical of Heath products,
  documented more than thoroughly.  Very well made!
  kyle

  -Original Message-
  From: Ralph Cameron [mailto:ral...@igs.net]
  Sent: Friday, August 03, 2001 2:41 PM
  To: Ehler, Kyle; 'Rich Nute'; 'EMC and Safety list'
  Subject: Re: TV nostalgia


  And lest we forget the Hallicrafters electrostatic deflection systems. You
  could sure get a poke off those.

  Ralph Cameron


  - Original Message -
  From: Ehler, Kyle mailto:keh...@lsil.com
  To: 'Rich Nute' mailto:ri...@sdd.hp.com  ; 'EMC and Safety list'
  mailto:emc-p...@majordomo.ieee.org
  Sent: Friday, August 03, 2001 9:23 AM
  Subject: RE: TV nostalgia


  My experience was with the Packard-Bell transistorized models.
  I think the aversion I have was prejudiced by the fellow
  who mentored me.  I had little reason to doubt, but then
  the sets I worked on, had a callback history that may have
  been created by my mentor.
  -kyle

  -Original Message-
  From: Rich Nute [ mailto:ri...@sdd.hp.com mailto:ri...@sdd.hp.com ]
  Sent: Thursday, August 02, 2001 5:36 PM
  To: emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org
  Subject: TV nostalgia






  Okay... more nostalgia and a bit on safety
  back in those days... so that we don't stray
  too far from the subject matter of this
  forum.

  My first TV was a Motorola 7-inch round in
  a Bakelite cabinet.  The speaker was the
  same size as the CRT.

  My second was the famous RCA 10-inch round
  chassis with 32 tubes.  I could pull out
  15 tubes and still have a usable picture.

  Kyle mentions Packard Bell, which I considered
  a straight-forward, good product.  It used the
  Standard Coil turret tuner.

  The one that won my respect was Muntz TV.
  It was CHEAP!  When you looked inside the
  chassis, there was nothing there compared to
  the other TVs.  They really knew how to take
  the cost out of the TV!  Amazingly enough,
  its picture was among the best, and its
  reliability was indeed the best -- no parts
  to go bad!  The company was owned by Mad
  Man Muntz, the classic Los Angeles used
  car dealer.

  In the mid-fifties, GE came out with a
  transformerless 17-inch TV.  One side of
  the power line was tied to the chassis
  (2-wire plug back in those days).  The
  only protection was the plastic knob on
  the shafts of the various controls.  When
  servicing this TV, you quickly learned
  never to touch the chassis!

  The power supply was a simple full-wave
  rectified power line.  The tube heaters
  were connected in a series-parallel
  arrangement.

  These sets were the initiation of UL's
  investigation into antenna coupling
  capacitors.  These capacitors provided
  the isolation between the TV antenna
  terminals and the mains voltage.

  TV sets of those days consumed between
  400 and 600 watts.  When they were turned
  on, the cold filaments were a very low
  impedance, so the turn-on current was
  very high.  The off-on switch

Re: TV nostalgia

[Ralph Cameron]

RE: TV nostalgiaAnd lest we forget the Hallicrafters electrostatic deflection 
systems. You could sure get a poke off those. 

Ralph Cameron
 
  - Original Message - 
  From: Ehler, Kyle 
  To: 'Rich Nute' ; 'EMC and Safety list' 
  Sent: Friday, August 03, 2001 9:23 AM
  Subject: RE: TV nostalgia


  My experience was with the Packard-Bell transistorized models. 
  I think the aversion I have was prejudiced by the fellow 
  who mentored me.  I had little reason to doubt, but then 
  the sets I worked on, had a callback history that may have 
  been created by my mentor. 
  -kyle 

  -Original Message- 
  From: Rich Nute [mailto:ri...@sdd.hp.com] 
  Sent: Thursday, August 02, 2001 5:36 PM 
  To: emc-p...@majordomo.ieee.org 
  Subject: TV nostalgia 







  Okay... more nostalgia and a bit on safety 
  back in those days... so that we don't stray 
  too far from the subject matter of this 
  forum. 

  My first TV was a Motorola 7-inch round in 
  a Bakelite cabinet.  The speaker was the 
  same size as the CRT. 

  My second was the famous RCA 10-inch round 
  chassis with 32 tubes.  I could pull out 
  15 tubes and still have a usable picture. 

  Kyle mentions Packard Bell, which I considered 
  a straight-forward, good product.  It used the 
  Standard Coil turret tuner. 

  The one that won my respect was Muntz TV. 
  It was CHEAP!  When you looked inside the 
  chassis, there was nothing there compared to 
  the other TVs.  They really knew how to take 
  the cost out of the TV!  Amazingly enough, 
  its picture was among the best, and its 
  reliability was indeed the best -- no parts 
  to go bad!  The company was owned by Mad 
  Man Muntz, the classic Los Angeles used 
  car dealer. 

  In the mid-fifties, GE came out with a 
  transformerless 17-inch TV.  One side of 
  the power line was tied to the chassis 
  (2-wire plug back in those days).  The 
  only protection was the plastic knob on 
  the shafts of the various controls.  When 
  servicing this TV, you quickly learned 
  never to touch the chassis! 

  The power supply was a simple full-wave 
  rectified power line.  The tube heaters 
  were connected in a series-parallel 
  arrangement. 

  These sets were the initiation of UL's 
  investigation into antenna coupling 
  capacitors.  These capacitors provided 
  the isolation between the TV antenna 
  terminals and the mains voltage. 

  TV sets of those days consumed between 
  400 and 600 watts.  When they were turned 
  on, the cold filaments were a very low 
  impedance, so the turn-on current was 
  very high.  The off-on switch was often 
  mounted on the back of the volume control.  
  Eventually, the contact resistance of the 
  switch would grow to the point where the 
  I**2*R power would melt the solder and 
  the power wires would come loose.  It was 
  common to have a customer report that his 
  TV was dead, and it was due to the lack 
  of a good connection to the switch. 

  At one company, we had metal bat-handle 
  toggles blow out of the switch due to the 
  cold filament load. 

  Out of this experience, UL developed the 
  requirements for the TV-rated switch, 
  which had specially-designed contacts 
  that would not overheat when used in a 
  TV or similar application. 



  Best regards, 
  Rich 








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Re: EM-Field Head Protection

[Ralph Cameron]

Too bad they don't give the resonant frequency of such a device. It could
have interesting applications for university lectures. ( in the near
field ).



Ralph Cameron

EMC Consulting and Suppression of Consumer Electronics
(After sale)

- Original Message -
From: Price, Ed ed.pr...@cubic.com
To: emc-p...@ieee.org
Sent: Wednesday, July 18, 2001 10:22 AM
Subject: EM-Field Head Protection



 Finally, there's a site with construction details and usage suggestions,
for
 aluminum foil EM-field head protectors. Design, metallurgy and history of
 the subject are also covered.

 http://zapatopi.net/afdb.html

 Ed

 Ed Price
 ed.pr...@cubic.com
 Electromagnetic Compatibility Lab
 Cubic Defense Systems
 San Diego, CA  USA
 858-505-2780  (Voice)
 858-505-1583  (Fax)
 Military  Avionics EMC Services Is Our Specialty
 Shake-Bake-Shock - Metrology - Reliability Analysis


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Re: Test Equipment ...

[Ralph Cameron]

Bob, thanks for that information. I guess the second question would be is
the device required to bear a part 15 complaince label?

This iinformation is very helpful because most of the answers I get from the
authorities indicate Canada's Digital Emission standard ( identical to FCC
Part15) is for digital products or those containing mnicroprocessors.

Thanks

Ralph Cameron



- Original Message -
From: r...@etlsemko.com
To: ral...@igs.net; taniagr...@msn.com; dmck...@corp.auspex.com;
emc-p...@majordomo.ieee.org
Sent: Wednesday, August 01, 2001 2:43 PM
Subject: RE: Test Equipment ...


 Part 15 does NOT address only digital devices. It does make a lot of
 reference to digital devices, presumably because these are the worst
 offenders. However, it defines incidental radiator as a product that
 generates RF energy while it operates, but is not designed to
intentionally
 generate RF (e.g. clocks). Examples Part 15 gives include dc motors and
 mechanical light switches. Part 2.802 defines a radiofrequency device as
ANY
 device which is capable of emitting RF energy including The incidental,
 unintentional and intentional radiators defined in part 15.

 Part 15 addresses incidental radiators with its 'motherhood and apple pie'
 statement (15.5(b)) - it must not cause interference and must accept it.
It
 also says (15.13) that manufacturers shall employ good engineering
 practices to minimize the risk of harmful interference.

 15.101 covers Class A and B external switching power supplies and says
that
 they are subject to verification.

 For many incidental radiators it may not make sense to do the testing
 because the RF generated is very low. However, it may be wise to test some
 items like lamp dimmers.

 The bottom line is that Ralph's observation, re: noisy analog devices. is
 supported by the FCC. Regardless of being digital or analog, a product is
 required to be verified to the limits/intent of Part 15.

 Bob Martin, P.E., N.C.E.

 Intertek Testing Services NA, Inc.

 ETL SEMKO

 70 Codman Hill Road

 Boxborough, MA 01719

 Tel (978) 263-2662 Fax (978)263-7086

 www.etlsemko.com rmar...@etlsemko.com mailto:rmar...@etlsemko.com




 -Original Message-
 From: Ralph Cameron [mailto:ral...@igs.net]
 Sent: Wednesday, August 01, 2001 10:01 AM
 To: Tania Grant; Doug McKean; EMC-PSTC Discussion Group
 Subject: Re: Test Equipment ...


 Many analog devices such as smps emit (conduct) terrible noise in the
radio
 spectrum yet they are exempt. How come? I can  cite the supplies for low
 level halogen/xenon lighting , exercise treadmills and some computer
 displays. A switch is a switch is a switch and anything that breaks
current
 is capable of generating harmful interference- analog  is no exception.
The
 higher the current - the worse the spectral effluent.  Where's the
rationale
 there?

 Ralph Cameron
 EMC Consulting and Suppression of Consumer Elelctronics
 ( After sale)

 - Original Message -
 From: Tania Grant mailto:taniagr...@msn.com
 To: Doug McKean mailto:dmck...@corp.auspex.com  ; EMC-PSTC Discussion
 Group mailto:emc-p...@majordomo.ieee.org
 Sent: Wednesday, August 01, 2001 12:15 AM
 Subject: Re: Test Equipment ...

 Doug, et al,

 FCC Part 15 addresses digital devices only.   And they continue to use the
 term digital over and over again.   The scope of FCC Part 15 does not
 address analog devices, whether they be industrial, commercial, or medical
 test equipment.  However, the FCC are exempting (and some say temporarily)
 digital devices that are used exclusively as industrial, commercial, or
 medical test equipment.   Therefore, no, a company that makes analog test
 equipment does not have to EMC test such products.   (And someone tell me
 please how exactly they would test them if they wanted to!)

 taniagr...@msn.com mailto:taniagr...@msn.com


 - Original Message -
 From: Doug McKean
 Sent: Tuesday, July 31, 2001 5:46 PM
 To: EMC-PSTC Discussion Group
 Subject: Re: Test Equipment ...


 Price, Ed wrote:
 
  Doug:
 
  The rationale that I recall is that test equipment is expected to be
 used by
  people who understand the nature of electrical measurements and
 safety.
  These people will have the knowledge and resources, beyond those of
 a
  typical consumer, to recognize and ameliorate interference and other
  problems. Further, it is argued that compliance measures might
 hinder
  absolute accuracy and sensitivity of measurement equipment. Also,
 that test
  equipment is not usually manufactured in numbers comparable to
 typical
  consumer equipment, so the impact on a society is less.
 
  IIRC, there is a somewhat shorter and simpler explanation buried
 somewhere
  in Part 15.

 Okay, follow me on this for just a minute.

  47 CFR, 15.103, Exempted devices.
 (c) A digital device used exclusively as industrial, commercial,
  or medical test equipment.

 The important word is digital.  Why just digital?  Does this mean
 if a company makes analog industrial

Re: Test Equipment ...

[Ralph Cameron]

Many analog devices such as smps emit (conduct) terrible noise in the radio 
spectrum yet they are exempt. How come? I can  cite the supplies for low level 
halogen/xenon lighting , exercise treadmills and some computer displays. A 
switch is a switch is a switch and anything that breaks current is capable of 
generating harmful interference- analog  is no exception. The higher the 
current - the worse the spectral effluent.  Where's the rationale there?  

Ralph Cameron
EMC Consulting and Suppression of Consumer Elelctronics 
( After sale) 
  - Original Message - 
  From: Tania Grant 
  To: Doug McKean ; EMC-PSTC Discussion Group 
  Sent: Wednesday, August 01, 2001 12:15 AM
  Subject: Re: Test Equipment ...


  Doug, et al, 

  FCC Part 15 addresses digital devices only.   And they continue to use the 
term digital over and over again.   The scope of FCC Part 15 does not address 
analog devices, whether they be industrial, commercial, or medical test 
equipment.  However, the FCC are exempting (and some say temporarily) digital 
devices that are used exclusively as industrial, commercial, or medical test 
equipment.   Therefore, no, a company that makes analog test equipment does 
not have to EMC test such products.   (And someone tell me please how exactly 
they would test them if they wanted to!)

  taniagr...@msn.com

- Original Message -
From: Doug McKean
Sent: Tuesday, July 31, 2001 5:46 PM
To: EMC-PSTC Discussion Group
Subject: Re: Test Equipment ...


Price, Ed wrote:

 Doug:

 The rationale that I recall is that test equipment is expected to be
used by
 people who understand the nature of electrical measurements and
safety.
 These people will have the knowledge and resources, beyond those of
a
 typical consumer, to recognize and ameliorate interference and other
 problems. Further, it is argued that compliance measures might
hinder
 absolute accuracy and sensitivity of measurement equipment. Also,
that test
 equipment is not usually manufactured in numbers comparable to
typical
 consumer equipment, so the impact on a society is less.

 IIRC, there is a somewhat shorter and simpler explanation buried
somewhere
 in Part 15.

Okay, follow me on this for just a minute.

 47 CFR, 15.103, Exempted devices.
(c) A digital device used exclusively as industrial, commercial,
 or medical test equipment.

The important word is digital.  Why just digital?  Does this mean
if a company makes analog industrial, commercial, or medical test
equipment, that equipment MUST be tested?

Regards, Doug McKean  (slowly becoming more confused ...)



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Re: Examples of EMC problems in the real world

[Ralph Cameron]

When the material of the core and the windings are as specified , the
emission reduction is uniform over the range for which it is designed-
1Mhz-30Mhz. Resonance is avoided by a distributed winding

Ralph Cameron

- Original Message -
From: Wan Juang Foo f...@np.edu.sg
To: Ralph Cameron ral...@igs.net
Cc: emc-p...@majordomo.ieee.org
Sent: Thursday, June 28, 2001 1:45 AM
Subject: Re: Examples of EMC problems in the real world



 The so call reduction in emmission does not happen all the time.   There
is
 still the possibility of resonance, this I have observed in several cases
 over  the past 7 years .

 Tim Foo,  E-mail:  f...@np.edu.sg
 ECE, School of Engineering,
 http://www.np.edu.sg/ece/  Tel: + 65 460 6143
 Ngee Ann Polytechnic,  Fax: + 65 467 1730
 535 Clementi Road,
 Singapore 599489



 Ralph Cameron
 ral...@igs.net   To:
rehel...@mmm.com
 Sent by:   cc:
emc-p...@majordomo.ieee.org, (bcc: Wan Juang
 owner-emc-pstc@majordomFoo/ece/staff/npnet)
 o.ieee.org Subject: Re:
Examples of EMC problems in the real world


 06/27/01 09:16 PM

 Please respond to
 Ralph Cameron







 Bob:

 It just occurred to me that list members may not be failimiar with the
 application of these components after manufacture. If needed I would be
 glad
 to elaborate.  Basically, since conducted immunity also decreases
conducted
 emissions its a double benefit.








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Re: Examples of EMC problems in the real world

[Ralph Cameron]

Bob:

It just occurred to me that list members may not be failimiar with the
application of these components after manufacture. If needed I would be glad
to elaborate.  Basically, since conducted immunity also decreases conducted
emissions its a double benefit.

regards

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale)


- Original Message -
From: rehel...@mmm.com
To: Ralph Cameron ral...@igs.net
Cc: emc-p...@majordomo.ieee.org
Sent: Wednesday, June 27, 2001 6:51 AM
Subject: Re: Examples of EMC problems in the real world



 Ralph, what is a toroidal cord? Is it a power cord with toroids?

 Bob Heller
 3M Product Safety, 76-1-01
 St. Paul, MN 55107-1208
 Tel:  651- 778-6336
 Fax:  651-778-6252




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Re: Examples of EMC problems in the real world

[Ralph Cameron]

Bob,

I wish it were then I wouldn't have to wind it. No my eyesight is getting
poor and I mean toroidal ( ring / donut shaped ) core. of powdered iron
material.

Ralph

- Original Message -
From: rehel...@mmm.com
To: Ralph Cameron ral...@igs.net
Cc: emc-p...@majordomo.ieee.org
Sent: Wednesday, June 27, 2001 6:51 AM
Subject: Re: Examples of EMC problems in the real world



 Ralph, what is a toroidal cord? Is it a power cord with toroids?

 Bob Heller
 3M Product Safety, 76-1-01
 St. Paul, MN 55107-1208
 Tel:  651- 778-6336
 Fax:  651-778-6252




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Bluetooth-IEEE802.11 interference potential

[Ralph Cameron]

The website that contains one opinion on this problem has surfaced at 
www.wireless-nets.com/whitepaper_interference.htm

Other links from there are quite productive. 

Ralph Cameron
EMC Consulting and Suppression of Consumer Elecrtonics
(After sale)

Re: Radio controlled cars (toys)

[Ralph Cameron]

In Canada both the 27Mhz and 72-75Mhz bands are available for radio controlled 
models. There are power restritions and the frequency assignements may be 
viewed on p.14 of the pdf file at http://strategis.ic.gc.ca/pics/sf/ric18.pdf 

Ralph Cameron

  - Original Message - 
  From: Lothar Schmidt 
  To: 'EMC-PSTC (E-mail)' 
  Sent: Wednesday, June 20, 2001 3:29 PM
  Subject: Radio controlled cars (toys)


  Hi all

  Thanks a lot for the inputs I got.

  It is great to have a group like this you can just ask questions and you get 
a lot of answers.

  Thanks again.

  Lothar





  Hi Group,

  is there any special frequency range assigned to radio remote control toys?
  Are there different classes like professional devices to control e.g. 
planes or helicopters?
  My customer is looking for a frequency range above 300 MHz.
  Best Regards 

  Lothar Schmidt 
  Technical Manager EMC/Bluetooth, 
  BQB, Competent Body 
  Cetecom Inc. 
  411 Dixon Landing Road 
  Milpitas, CA 95035 
  Phone: +1 (408) 586 6214 
  Fax: +1 (408) 586 6299 

Re: FCC + FCC = FCC? - Outlaw

[Ralph Cameron]

Doug:

I think you hit the crux of the matter with one correction, if I may.  Hams
in the U.S. are operating as amateurs but have a legal obligation to the
country in times of need . In Canada , we operate ( myself included) with
permission and have no legal obligations to the government. Our equipment
could be comandeered but not the operator. This is a disticntion between our
two countries.

I advise any consumer in a known high ambient RF area ( such as near
broadcast /commercial /ham transmitters to look for the CE mark.  9 times
out of 10  the additional components have not been omitted to seel to North
America.

Likewise in Canada, Industry Canada no longer investigates consumer EMC
complaints ( i.e. lack thereof)  as of two years ago.


Ralph Cameron
EMC Consulting and Suppression of Consumer Electronic Equipment
( after sale)

- Original Message -
From: Doug McKean dmck...@gte.net
To: emc-p...@majordomo.ieee.org
Sent: Thursday, June 21, 2001 2:32 AM
Subject: RE: FCC + FCC = FCC? - Outlaw



 Sorry but I respectfully disagree ...

 If the FCC were to say yes to anyone being an
 outlaw for building their own PC and not having
 it tested, then why does the FCC label essentially
 tell everyone suffering from interefernce to take
 care of it themselves?

 The FCC was created to protect the big alphabet
 communication companies from themselves. Me building
 my own PC is peanuts compared to some of the issues
 these guys deal with.  And cable tv is starting to
 make the issue of interfering with commercial
 broadcast a moot point.  Heck, I don't even see
 the pixels blink at all anymore even with the
 microwave being used only 10 feet away.

 I was told, not sure how true it is, that the
 FCC in the early years of Part 15 took to task
 a famous computer company selling computers
 which hooked up to your tv screen.  They were
 famous for intereference.  I know, I had one.
 So the FCC threatened to confiscate the units
 from said company.  Well, the sales were going
 down and the company said, sure big brother,
 to ahead ...  So the FCC took them.  Lots of
 them.  In fact, so many, they had to store them
 all in an area which closed down part of the
 FCC facility.  The company went on to declare
 it all as a loss.  The FCC got stuck with the
 inventory.

 I don't think they want to repeat that again.

 And thus the reason for the wording of the
 label.  Unless you're a real threat to
 commercial communications (such as a ham)
 they really don't want to be bothered.

 Just my 3.1415 cents worth ...

 - Doug McKean


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Re: FCC + FCC = FCC?

[Ralph Cameron]

I  think this raises a parallel issue of testing methodology versus
practical application.

Many devices/ boards/ add ons are tested with minimal connecting attachments
i.e. conductors, other than those to power the devie and those required to
make the measurement.

When separate devices such as those mentioned are placed into actual service
, the systems themselves become attached to conductors with sizeable
electrical lengths.  Here we have a computer with internal modem , external
speakers, keyboard and display- all have connecting cables external to the
deices which have been tested but now the environment contributes external
signals which weren't present when these devices were tested indicidually.

Without reducing CE or taking steps to improve conducted immunity it seems
logical that emissions will be radiated by the connecting attachments and
the devices become more susceptible to external interfering sources such as
high ambient RF signals.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale)
- Original Message -
From: Doug McKean dmck...@corp.auspex.com
To: EMC-PSTC Discussion Group emc-p...@ieee.org
Sent: Wednesday, June 20, 2001 8:32 PM
Subject: Re: FCC + FCC = FCC?



 Building your own machine doesn't constitute you
 being a PC mfr.  I think that's the reading here.

 - Doug

 - Original Message -
 From: Steve Grobe ste...@transition.com
 To: 'IEEE Forum' emc-p...@majordomo.ieee.org
 Sent: Wednesday, June 20, 2001 2:03 PM
 Subject: RE: FCC + FCC = FCC?


 
  If you are so am I.  As are a few dozen people I know.  The only way
 to get
  an OS other than Windows to run well is to build your own machine.
 
  Steve
 
  -Original Message-
  From: Massey, Doug C. [mailto:masse...@ems-t.com]
  Sent: Wednesday, June 20, 2001 2:42 PM
  To: 'IEEE Forum'
  Subject: RE: FCC + FCC = FCC?
 
 
  Just to further confuscate the issue - I once built my own home PC.
 I bought
  a box, motherboard, CPU, memory, variety of ISA cards, etc.
 
  It worked so well, I built a couple or three more for family and
 friends,
  and sold them to those family and friends at a good price.
 
  I didn't check radiated emissions.
 
  Am I an FCC Outlaw ?
 
  Doug Massey
  LXE, Inc.
 
 
 
  snip
 
 
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Re: Radio controlled cars (toys)

[Ralph Cameron]

I believe the I.S.M. bands in Canada but will verify that tomorrow-  

Ralph Cameron

  - Original Message - 
  From: Pettit, Ghery 
  To: 'Bailey, Jeff' ; EMC-PSTC (E-mail) 
  Sent: Wednesday, June 20, 2001 1:40 PM
  Subject: RE: Radio controlled cars (toys)


  Just remember that the frequencies between 50 and 54 MHz require an amateur 
radio license in order to use them.  They are not for unlicensed use.

  Ghery Pettit
  Intel

  -Original Message-
  From: Bailey, Jeff [mailto:jbai...@mysst.com]
  Sent: Wednesday, June 20, 2001 10:18 AM
  To: EMC-PSTC (E-mail)
  Subject: RE: Radio controlled cars (toys)


  Lothar:

  There are also several channels allocated in the 75 MHz, 50 MHz and 27MHz 
region.  

  Jeff

  Jeff Bailey 
  Compliance Engineering 
  SST - A Division of Woodhead Canada 
  Phone: (519) 725 5136 ext. 363 
  Fax: (519) 725 1515 
  Email: mailto:jbai...@mysst.com
  Web: www.sstech.on.ca 

-Original Message-
From: Price, Ed [mailto:ed.pr...@cubic.com]
Sent: Wednesday, June 20, 2001 10:19 AM
To: 'Lothar Schmidt'; EMC-PSTC (E-mail)
Subject: RE: Radio controlled cars (toys)


Lothar:

There are several channels allocated in the 72 MHz region for the USA. I'm 
not current on this area, but I believe there are some channels specifically 
for model aircraft control (possibly only by the modelers' private convention).

Ed


Ed Price 
ed.pr...@cubic.com 
Electromagnetic Compatibility Lab 
Cubic Defense Systems 
San Diego, CA  USA 
858-505-2780  (Voice) 
858-505-1583  (Fax) 
Military  Avionics EMC Services Is Our Specialty 
Shake-Bake-Shock - Metrology - Reliability Analysis 

  -Original Message-
  From: Lothar Schmidt [mailto:lothar.schm...@cetecomusa.com]
  Sent: Tuesday, June 19, 2001 4:59 PM
  To: EMC-PSTC (E-mail)
  Subject: Radio controlled cars (toys)


  Hi Group,

  is there any special frequency range assigned to radio remote control 
toys?
  Are there different classes like professional devices to control e.g. 
planes or helicopters?
  My customer is looking for a frequency range above 300 MHz.
  Best Regards 

  Lothar Schmidt 
  Technical Manager EMC/Bluetooth, 
  BQB, Competent Body 
  Cetecom Inc. 
  411 Dixon Landing Road 
  Milpitas, CA 95035 
  Phone: +1 (408) 586 6214 
  Fax: +1 (408) 586 6299 

Re: Wireless Network Issues

[Ralph Cameron]

Kyle:

Take a look at www.Intellon.com .  They detail a link to some of the
problems associated with proximity of Bluetooth devices to  802.11 LAN
specs. These are claimed to be potential interference problems related to
hop frequency differences in the two spread spectrum systems.

There is also concern with the  power line conducted control systems and the
Continental Automated Building Associated attempted to address some of the
issues related to compatibility during their conference held at the end of
May.  There are some 26 different standards all independantly developed
which I'm sure is enough for a statistical study of the problem.

There have been several papers on lack of EMC in hospitals - some
originating from McGill University in Montreal. The main problem there seems
to be lack of any emc equipment requirements ( although changing due to
liability ) and the solution has been to isolate the areas containing the
radio sensitive equipment.

Tha Radio Advisory Board of Canada's EMC sub committee did address some
concerns toward cable TV radiation and possible effects on some aircraft
frequencies. With those problems largely overcome by regulating the cable
operators , another issue has arisen and that could affect radio aids to
navigation and it may have to do with radiation from home wiring above 2Mhz
.. This is conceivable with ever increasing data rates and unshielded wiring.

When I was chairman of the RABC EMC committee for a couple of years, there
were many instances of life threatening incidences related to lack of EMC.


Ralph Cameron
Electromagnetic Compatibiliy Consulting and Suppression of Consumer
Electronics
( after sale)


- Original Message -
From: kyle_cr...@dell.com
To: emc-p...@majordomo.ieee.org
Sent: Monday, June 11, 2001 5:23 PM
Subject: Wireless Network Issues



 Hi All,
 I am currently researching wireless intereference issues for a
 project and I was wondering if anyone could answer a few of my questions.
 First off, any links to information that deals directly with wireless
 interference on airplanes or in hospitals would be appreciated.  Secondly,
I
 am curious how similar cell phone wireless technology is to wireless
network
 technology(Wi-FI), from an EMI standpoint.  The reason I ask is that I can
 find a lot of information about cell phone intereference, but I have found
 nothing about wireless network interference.  I am still learning a lot
 about this, so any information that you could provide would be
appreciated.

 Thanks,
 Kyle

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Re: Ethernet baluns

[Ralph Cameron]

Paolo:

I wonder if you could suffer a little line loss and match the balun with a
resistive minimum loss pad and use 50 ohm connecotrs?. That way you could
minimiz reflections and possiby improve EMC?

My two sents worth.

Ralph Cameron EMC Culting and Suppression of Consumer Electronics
(After Sale)-


- Original Message -
From: Paolo Roncone paolo...@tin.it
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, May 30, 2001 11:53 AM
Subject: Ethernet baluns



 Hi everyone:

 I'm looking for a passive (no ac/dc power supply needed) balun to convert
 from an Ethernet 10b2 (unbalanced coax 50 ohm) to an Ethernet 10bT
 (balanced, twisted pair, UTP, 100 ohm).
 Anyone knows if this kind of box exists ? So far I came up with a perfect
 match, but for the impedance of the coax connector (75 ohms instead of 50
 ohms).
 We need this in order to improve the EMC behavior of the 10b2 Ethernet
that
 we have to live with (you bet it's a real damn pain in the neck EMC-wise
!!!).

 Thanks
 Paolo


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Re: 120V appliance on 240V supply

[Ralph Cameron]

I would think the clock timing and microprocessor timing would suffer and as
a result it may deliver heat but programming prarameters could be
drastically incorrect.

For short periods of time the heating effects would be minimal but who knows
what a safe time period would be. Better to have deisgned the trasnformers
for 50Hz to begin with .

Ralph Cameron

EMC Consulting and Suppression of Consumer Electronics
(After sale)

- Original Message -
From: Ravinder Ajmani ajm...@us.ibm.com
To: emc-p...@ieee.org
Sent: Monday, May 14, 2001 11:48 AM
Subject: 120V appliance on 240V supply




 Hi,
 I am interested in knowing if a 120V, 60Hz microwave oven can be safely
 used on a 240V, 50Hz mains supply with a step-down transformer.

 Regards, Ravinder

 Email: ajm...@us.ibm.com

***
 Always do right.  This will gratify some people and astonish the rest.
  Mark Twain



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Re: 2. 4 GHz cordless telephone, question of general interest

[Ralph Cameron]

In terms of heating ( cooking ) 900Mhz is more efficient but its a question
then of density of tissue , I understand that between 70-90Mhz the human
body absorbs most energy and that first microwave ovens were designed around
450Mhz  but 2.4 Ghz was an I.S.M. band so permitted limitless power.

The leakage in the average Microwave oven should be so small that you'd
never hear it on a 2.4Ghz cell phone (i.e. 50Mhz off frequency)

many offie type 2.4Ghz cordless phone use 900mw on the base unit and 200mw
on the handset. I would suspect the field intensity that close to the head
could be substantial.

Ralph Cameron

- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: emc-p...@ieee.org
Sent: Friday, April 20, 2001 5:40 PM
Subject: 2. 4 GHz cordless telephone, question of general interest



 Someone on this forum likely knows the answer to this question...

 I was at Wal-Mart the other day and they had 2.4 GHz cordless phones on
 clearance.  My home cordless phones are 900 MHz.  One is multiple
channels,
 the other is some kind of spread spectrum.  2.4 GHz is very close to 2450
 MHz, the microwave oven frequency that resonates with H2O molecules.  Is
2.4
 GHz close enough to 2450 MHz to cause significantly more heating than 900
 MHz (in the human head adjacent to the head/handset antenna)?  I realize
 this is very low power relative to a cell phone, but I wonder if the issue
 was ever addressed.  Another way of asking this question is, what is the
Q
 of H20 resonance?  If it is much better than 50, the problem is not
 important.  If it is 50 or less, then 2.4 GHz would transfer more energy
to
 head tissue than 900 MHz.  One way of measuring this effect would be to
time
 how long it takes to raise the temperature of a beaker of water a set
amount
 at 2450 MHz, and then time how long it takes at 2400 MHz...

 But this all must have been done already...

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Re: RSS139 and RSS210

[Ralph Cameron]

RSS stands for Radio Standards Specification and RSS210 covers Unlicensed
Low power transmitting devices ( All Bands) . I can send you the PDF file if
you wish.

The Industry Canada web site has most of these specs and RSS 139 is one I'm
not familiar with but I will obtain the title for you.

Try their website at
www.strategis.ic.gc.ca/s10372e.html#miscellaneousDocuments




Regards

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After Sale)
- Original Message -
From: Peter Merguerian pmerguer...@itl.co.il
To: EMC-PSTC (E-mail)  emc-p...@majordomo.ieee.org
Sent: Thursday, April 19, 2001 6:52 AM
Subject: RSS139 and RSS210



 Dear All,

 Can anyone identify what RSS139 and RSS210 standards stand for? It looks
 like Canadian requirements for receiving and transmitting equipment. If
so,
 what are the equivalent FCC or other standards?

 Thank you.

 PETER S. MERGUERIAN
 Technical Director
 I.T.L. (Product Testing) Ltd.
 26 Hacharoshet St., POB 211
 Or Yehuda 60251, Israel
 Tel: 972-3-5339022  Fax: 972-3-5339019
 Mobile: 972-54-838175






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Re: Ferrites experience ....... last comment

[Ralph Cameron]

To the Ferrite discussion:

I've refrained from responding to the ferrite question because of being away
but I would confirm what Amand states.  I use powdered iron FT240-43 from
Fair-Rite  as they make them for Amidon  and have the properties desired to
reduce common mode signals appearing on connecting cables to consumer
devices- VCR, TV sets, Hi-Fi speaker cables etc.

I have treated over 300 cases of RF getting into telephones ( via the phone
cable connection) , VCRs via the sheath on the TV cable , modems, speaker
cables etc.  Success in siolating the offending RF ( 500Khz- over 30Mhz )
has been in ecess of 90%.  I say if it works, don't know kit,.

20 years ago I had an EMC engineer characterise the attenutaion over the
above frequency range and Mix 43, with init. perm of 850 was the best
compromise.  As Amand states Mix 77 would work better below 500Khz.   The
minimum attenutaion was 15dB and approached 27dB at 35Mhz . At 30 dB it
provided rejection of RF common mode signals of 25dB.

It is important that between 8-9 tuuns be used and spaced over the surface
of the toroid to flatten the attenuation curve.  Many telephone filters made
by ATT and others I have found to have a very peaked response over the HF
range and will work sometimes and sometimes not.

The nice thing about external devices like this are they don't degrade
performance in any way,  are re-useable, quite economical  and easy to
install.
It is also important to keep the toroids as close as possible to the device
being protected in order to minimize pickup due to re radiation.

This is a simple procedure which many manaufacturers overlook , yet could
save them a bundle in returned product and in some cases litigation. The
components can be used to suppress incoming RF our outgoing.from the
product.


I started out doing this type of suppression free of charge but after using
several hundred toroids ( the 2.4  O.D. ones for power line cables) I
started to recover my costs.

These thinbgs really do work.

Ralph Cameron
EMC Consutling and Suppression of Consumer Electronics
( After sale)


- Original Message -
From: am...@westin.org
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, March 14, 2001 5:22 PM
Subject: Re: Ferrites experience ... last comment



 Hi all,

 Many thanks to all of you who participated in this ferrite discusson. I
have
 leard a lot about ferrites the last 10 days.

 In my special case, I would like to give you some information:

 We had a problem with conducted emisson on the DC supply line to a telecom
 product. The harmonic switching frequency was 160kHz and our problems was
in
 the range 160kHz-5MHz. We used a toroid (DC cable five turns in the
Toroid)and
 we managed to decrease the noise about 10-15dB in the frequency range
1-5MHz.
 The toroid had an outer/inner diameter of 61mm/36mm (a big one). We used a
 toroid with material 43 and its permeability is approximate 850. Material
43
 has its application areas from 30-200MHz, so we should have had a toroid
with
 an other material.
 I think a toroid with a material 77 (permeability 2000) could have helped
us
 with the 160kHz-1MHz band. Next time .

 One last comment, try to avoid snap-on ferrites. Remember the air gap, you
will
 have a large increase in the impedance even if you use strips to tighten
it
 together. Use the solid ones 

 See you later.

 Best regards
 Amund Westin, Oslo/Norway



 On 6 Mar 2001 19:16:37 - am...@westin.org wrote:
 
 Hi all,
 
 During conducted emission test, we have 150kHz power supply switching
 distrubance on the 48VDC-line, and we can not insert capacitors,chokes or
any
 filters on the line.
 
 Do you have any experience using ferrites to suppress noise in the band
 100kHz -
  5MHz ?
 
 We have used ferrites with success on I/O-lines during radiated emission,
but
 no experience on DC-lines (use LISN).
 
 Best regards
 Amund Westin, Oslo / Norway
 
 --
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Re: Battery terminals isolation

[Ralph Cameron]

John:

How about an insulated wrench?

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale)

- Original Message -
From: John Woodgate j...@jmwa.demon.co.uk
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, February 28, 2001 3:47 PM
Subject: Re: Battery terminals isolation



 sa9d1398.077@sao0002n, SERGIO LUIZ DA ROCHA LOURES SERGIO
 sergioro...@siemens.com.br inimitably wrote:
 Can the group tell me if there is any requirement about isolations of
lead acid
 battery terminals?
 We have a 48V equipment powered by lead acid batteries. The negative of
the
 batteries set is connected to the enclosure. When the batteries need to
be
 replaced, short circuit happens if the tool used to detach the connectors
touch
 the enclosure and the positive of the batteries.
 Information to disconnect the negative terminal first before replace the
 batteries is clear in the service manual, but I don't know if only this
is
 sufficient.

 I don't know of anything explicit in any standard, but the consequences
 of shorting a 48 V battery could be very serious, up to loss-of-life.
 Therefore I would think in terms of the General Safety Directive, which
 says, in effect, 'make it safe, then make it safer'. So:

 - put a warning notice **next to the battery** saying 'Disconnect THIS
 terminal first.' Don't rely on a drunken blind, idiot knowing which is
 the negative one.

 - if possible, fix to the negative connector a plastic shield that
 covers up the positive terminal and connector, so you can't even get at
 the positive terminal without first removing the negative one. If you
 need to be able to measure the battery voltage with a multimeter, put a
 small hole in the shield that will just admit a test-prod.

 You could perhaps put the warning notice on the shield itself.
 --
 Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839
 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Foxhunters suffer from
 tallyhosis. PLEASE do not mail copies of newsgroup posts to me.

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Re: Copper Thieving

[Ralph Cameron]

Doug:

A picture says a 1000 words.
Well Done.

Ralph Cameron

- Original Message -
From: POWELL, DOUG doug.pow...@aei.com
To: rehel...@mmm.com; emc-p...@majordomo.ieee.org
Sent: Monday, January 22, 2001 11:40 AM
Subject: RE: Copper Thieving




I would like to add a little more to this discussion.

Last August we had a serious problem occur when a board house arbitrarily
added thieving dots to one of our PCBs.  This significantly reduced the
spacing requirement in a safe-unsafe area.  As it turned out, we did not
catch the problem immediately because the hipot test did not uncover the
problem.  Eventually the PCB board house started using a different stamping
ink on their inspection stamp that had organic content and it failed hipot.
They were using stamp pad ink from the local office supply and could not
immediately identify its content.  As it turned out the basic board design
had enough spacing (barely) because it was originally designed with 230V
(L-N) systems in mind and is only used on 120V (L-N) products.  We still
insisted that they remove the dots from the Gerber files.

In the process I learned that there are several things to watch for.

1) Thieving dots and thieving bars are used primarily for balancing copper
during etch and plating and for balancing the wave during assembly.  These
dots may be added at the time Gerber files are generated or even edited into
the Gerber files by the PCB house and never show up on a CAD system.

2) Venting of PCBs, I am not entirely clear on this but I understand that
this is a modification to the ground plane and other copper fills, to allow
process gases to escape from between the laminates on inner layers.  Watch
for changes in ground currents and reduced maximum current capability.  This
also has the Gerber files editing problems.

3) Inspection stamps should be epoxy based only, also adhesive labels often
applied by companies to identify PCB's should not be printed with LaserJet
toner!  Toner is very conductive and should not be allowed to bridge
safe/unsafe areas.

Attached is a photo of a PCB with the thieving dots and triangular
inspection stamp that failed hipot.  If you look closely at the stamp you
can see the trench created by the hipot test.


-doug


=
Douglas E. Powell
Regulatory Compliance Engineer
Advanced Energy Industries, Inc.
1625 Sharp Point Dr.
Ft. Collins, Co 80525

mailto:doug.pow...@aei.com
www.advanced-energy.com
=




-Original Message-
From: rehel...@mmm.com [mailto:rehel...@mmm.com]
Sent: Thursday, January 18, 2001 7:15 AM
To: emc-p...@majordomo.ieee.org
Subject: Copper Thieving



Please excuse my lack of knowledge..what is copper
thieving?


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Re: Consumer Electronics Compatibility

[Ralph Cameron]

Sorry, the attachment called EMCAB-1, Elecrtomagnetic Compatibility
Bulletin -1 is 230K of PDF format so it exceeds the server limit.

If any one is interested i will send it to you separately.

Ralph Cameron

- Original Message -
From: Price, Ed ed.pr...@cubic.com
To: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Tuesday, January 16, 2001 10:02 AM
Subject: Consumer Electronics Compatibility



 Ralph:

 Would you provide a little more detail about the 30MHz Consumer
Electronics
 compatibility problems that you have been addressing? Are you finding that
 the path is a direct galvanic connection, or is the problem caused
primarily
 by radiation of energy off of the power lines? What are the most common
 emitting devices, and what types of devices are the most numerous victims?
 And of course, what's usually the best solution?

 Thanks,

 Ed



 -Original Message-
 From: Ralph Cameron [mailto:ral...@igs.net]
 Sent: Monday, January 15, 2001 7:57 PM
 To: Ken Javor; dan kwok
 Cc: EMC-PCST (E-mail)
 Subject: Re: Site Correlation



 No, your message is clear, what I am saying is that the emissions below
 30Mhz cause the majority of the interference problems to consumer
 electronics and that's not being addressed.

 Ralph Cameron

 - Original Message -
 From: Ken Javor ken.ja...@emccompliance.com
 To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com
 Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
 Sent: Monday, January 15, 2001 10:34 PM
 Subject: Re: Site Correlation


  I must have been unclear in my previous message.  The purpose of
 controlling
  cable cm CE is to control the resultant cable-induced RE, which are
  controlled to protect tunable antenna-connected radio receivers, period.
  There was never any other purpose for controlling CE or RE.
 
  Ken Javor

 Ed  Price
 ed.pr...@cubic.com
 Electromagnetic Compatibility Lab
 Cubic Defense Systems
 San Diego, CA.  USA
 858-505-2780 (Voice)
 858-505-1583 (Fax)
 Military  Avionics EMC Services Is Our Specialty
 Shake-Bake-Shock - Metrology - Reliability Analysis

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Re: Site Correlation

[Ralph Cameron]

What it boils down to Chris is the lack of immunity of the consumer
equipment contributes to degradation of the intended function. Once the
undesired energy reaches the consumer device there's no way to get rid of
it. The rememdy is to prevent it from reaching the device and or isolating
it from the source.

At one time injection clamps were used for immunity testing- are they still?

Ralph Cameron


- Original Message -
From: Chris Maxwell chris.maxw...@gnnettest.com
To: 'Ralph Cameron' ral...@igs.net; Ken Javor
ken.ja...@emccompliance.com; dan kwok dk...@intetron.com
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Tuesday, January 16, 2001 8:38 AM
Subject: RE: Site Correlation


 Seems like this thread has gotten into how to correlate common mode cable
 currents with their expected radiated emissions.

 For those interested, Fischer Custom Communications makes coupling and
 measuring clamps which can measure common mode surface currents on cables
 and surfaces.  They used to publish some application notes regarding the
 usage of their clamps to measure surface/cable currents and how to
correlate
 them to expected radiated emissions.

 I read them a couple of years ago.  I never bought the clamps, but it did
 make for some very good technical reading.

 I do know of a table top power supply manufacturer that uses this method
 almost exclusively.  They send one power supply to a calibrated OATS.
They
 get it to pass.  Then, when the sample comes back to the factory, they
take
 clamp measurements of the common mode currents of the AC input and DC
output
 cable.

 They then model the power supply as a dipole antenna with the AC input
cable
 and DC output cable being the two poles.

 For future power supplies, they then use the clamp method in-house to
 measure the cable currents, if the currents pass, they assume the supply
 passes radiated emissions.

 This won't work for every product, but it does fit this application well.
 The power supply company could make more than 10 versions (3.3VDC, 5VDC,
 9VDC, 12VDC ...) of a power supply with the same case and cabling so it
can
 save them a great deal of time and money.  The supplies only have two
 cables, which is easy to model.  The supplies have clock speeds in the
 100-500Khz range, meaning that most of thier harmonics will be dead over
 230Mhz, which is the cutoff for most coupling clamps.

 I thought that this method would be difficult to use for our products
since
 we have higher clock speeds and multiple cables.

 I guess many times the measurement method is somewhat defined by what
you're
 measuring.

 Chris Maxwell
 Design Engineer
 GN Nettest
 6 Rhoads Drive, Building 4
 Utica,NY 13502
 email: chris.maxw...@gnnettest.com
 phone:  315-266-5128
 fax: 315-797-8024




  -Original Message-
  From: Ralph Cameron [SMTP:ral...@igs.net]
  Sent: Monday, January 15, 2001 10:57 PM
  To: Ken Javor; dan kwok
  Cc: EMC-PCST (E-mail)
  Subject: Re: Site Correlation
 
 
  No, your message is clear, what I am saying is that the emissions below
  30Mhz cause the majority of the interference problems to consumer
  electronics and that's not being addressed.
 
  Ralph Cameron
 
  - Original Message -
  From: Ken Javor ken.ja...@emccompliance.com
  To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com
  Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
  Sent: Monday, January 15, 2001 10:34 PM
  Subject: Re: Site Correlation
 
 
   I must have been unclear in my previous message.  The purpose of
  controlling
   cable cm CE is to control the resultant cable-induced RE, which are
   controlled to protect tunable antenna-connected radio receivers,
period.
   There was never any other purpose for controlling CE or RE.
  
   Ken Javor
  
   --
   From: Ralph Cameron ral...@igs.net
   To: Ken Javor ken.ja...@emccompliance.com, Dan Kwok
  dk...@intetron.com
   Cc: EMC-PCST \(E-mail\) emc-p...@majordomo.ieee.org
   Subject: Re: Site Correlation
   Date: Mon, Jan 15, 2001, 8:51 PM
   
  
Perhaps what you state is correct Ken but there has been a
supposition
  that
RE , induced or other wise when converted to conducted current does
  not
effect other devices connected to those same conductors whether they
  be
power, incoming TV or telephone cables etc.  All these conductors
  intercept
RE and their effects have been eliminated in 90% of cases(  I have
personally suppressed ) , by suppresseing the common mode
signals.Over
  300
successes is a significant statistic.
   
Ralph Cameron
   
   
.
- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: Dan Kwok dk...@intetron.com; Ralph Cameron
ral...@igs.net
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Monday, January 15, 2001 5:42 PM
Subject: Re: Site Correlation
   
   
   
Mr. Kwok's theories are logical and no doubt bear on the subject,
but
there
is a historical angle that bears

Re: Site Correlation

[Ralph Cameron]

No, your message is clear, what I am saying is that the emissions below
30Mhz cause the majority of the interference problems to consumer
electronics and that's not being addressed.

Ralph Cameron

- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Monday, January 15, 2001 10:34 PM
Subject: Re: Site Correlation


 I must have been unclear in my previous message.  The purpose of
controlling
 cable cm CE is to control the resultant cable-induced RE, which are
 controlled to protect tunable antenna-connected radio receivers, period.
 There was never any other purpose for controlling CE or RE.

 Ken Javor

 --
 From: Ralph Cameron ral...@igs.net
 To: Ken Javor ken.ja...@emccompliance.com, Dan Kwok
dk...@intetron.com
 Cc: EMC-PCST \(E-mail\) emc-p...@majordomo.ieee.org
 Subject: Re: Site Correlation
 Date: Mon, Jan 15, 2001, 8:51 PM
 

  Perhaps what you state is correct Ken but there has been a supposition
that
  RE , induced or other wise when converted to conducted current does not
  effect other devices connected to those same conductors whether they be
  power, incoming TV or telephone cables etc.  All these conductors
intercept
  RE and their effects have been eliminated in 90% of cases(  I have
  personally suppressed ) , by suppresseing the common mode signals.Over
300
  successes is a significant statistic.
 
  Ralph Cameron
 
 
  .
  - Original Message -
  From: Ken Javor ken.ja...@emccompliance.com
  To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net
  Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
  Sent: Monday, January 15, 2001 5:42 PM
  Subject: Re: Site Correlation
 
 
 
  Mr. Kwok's theories are logical and no doubt bear on the subject, but
  there
  is a historical angle that bears inspection.  About the time FCC limits
  for
  IT equipment were being drawn up (late '70s) PCs were not yet on
  everyone's
  desktop.  Most of the business equipment that would have been
envisioned
  to
  be qualified to USC Title 47, Part 15, Subpart J would have been
  stand-alone
  items such a copier, with the only cable connection being ac power.
The
  report which documents the development of the CE and RE limits/test
  methods
  found in the above mentioned FCC limits specifically states that 30 MHz
  was
  picked as the cutoff between CE and RE for the reason of radiation
  efficiency per Mr. Kwok's surmise, but also because 30 MHz was the
lowest
  frequency at which a 3 m OATS measurement would provide the desired
  accuracy.
 
  Ken Javor
 
  P.S.  Said report also demonstrated that the CE limit below 30 MHz
  sufficed
  to control RE from the power cable to levels sufficient to protect
against
  cable radiation-induced rfi.
 
  --
  From: Dan Kwok dk...@intetron.com
  To: Ralph Cameron ral...@igs.net
  Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
  Subject: Re: Site Correlation
  Date: Mon, Jan 15, 2001, 2:49 PM
  
 
  
   Hello Ralph:
  
   That's a good question. At one time, I pondered the same question
   myself. There are obviously plenty of communication systems operating
   under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does
not
   specify radiated emissions below 30 MHz. I can suggest one
possibility.
   Perhaps others here will come up with more.
  
   For a fixed cable of length L, the ratio of L/lambda gets
progressively
   small for frequencies much less than 30 MHz with most commercial
EUTs.
   If we consider the cable part of dipole antenna, the reduction in
   frequency has a diminishing effect on the antenna's radiation
   resistance. Given a constant current, the radiated power would
decrease
   with decreasing radiation resistance. At 550 KHz (bottom of the AM
   broadcast band in North America), the 1/4 wavelength is 136 meters.
Even
   if the antenna's reactance is ignored, one would need very long
cables
   driven by a significant CM noise voltage at this frequency to radiate
   much energy.
  
   --
 
 
   Daniel Kwok
   Principal EMC Engineer
   Intetron Consulting, Inc.
   Vancouver, Canada
   Phone (604) 432-9874
   Email dk...@intetron.com
   Web http://www.intetron.com;
  
  
   Ralph Cameron wrote:
  
   Ken:
  
   I like the idea of setting a limit to common mode currents on
attaching
   cables but mI wonder why CISPR has chosen to start such measurements
at
   30Mhz when most of the common mode currents are the result of
switching
   products and are generated harmonically from the fundamental  and as
  such
   propagate from the low Khz range up through 30Mhz. is there no
  consideration
   for those who occupy the spectrum below 30Mhz?
  
  
   ---
   This message is from the IEEE EMC Society Product Safety
   Technical Committee emc-pstc discussion list

Re: Site Correlation

[Ralph Cameron]

Perhaps what you state is correct Ken but there has been a supposition that
RE , induced or other wise when converted to conducted current does not
effect other devices connected to those same conductors whether they be
power, incoming TV or telephone cables etc.  All these conductors intercept
RE and their effects have been eliminated in 90% of cases(  I have
personally suppressed ) , by suppresseing the common mode signals.Over 300
successes is a significant statistic.

Ralph Cameron


.
- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Monday, January 15, 2001 5:42 PM
Subject: Re: Site Correlation



 Mr. Kwok's theories are logical and no doubt bear on the subject, but
there
 is a historical angle that bears inspection.  About the time FCC limits
for
 IT equipment were being drawn up (late '70s) PCs were not yet on
everyone's
 desktop.  Most of the business equipment that would have been envisioned
to
 be qualified to USC Title 47, Part 15, Subpart J would have been
stand-alone
 items such a copier, with the only cable connection being ac power.  The
 report which documents the development of the CE and RE limits/test
methods
 found in the above mentioned FCC limits specifically states that 30 MHz
was
 picked as the cutoff between CE and RE for the reason of radiation
 efficiency per Mr. Kwok's surmise, but also because 30 MHz was the lowest
 frequency at which a 3 m OATS measurement would provide the desired
 accuracy.

 Ken Javor

 P.S.  Said report also demonstrated that the CE limit below 30 MHz
sufficed
 to control RE from the power cable to levels sufficient to protect against
 cable radiation-induced rfi.

 --
 From: Dan Kwok dk...@intetron.com
 To: Ralph Cameron ral...@igs.net
 Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
 Subject: Re: Site Correlation
 Date: Mon, Jan 15, 2001, 2:49 PM
 

 
  Hello Ralph:
 
  That's a good question. At one time, I pondered the same question
  myself. There are obviously plenty of communication systems operating
  under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does not
  specify radiated emissions below 30 MHz. I can suggest one possibility.
  Perhaps others here will come up with more.
 
  For a fixed cable of length L, the ratio of L/lambda gets progressively
  small for frequencies much less than 30 MHz with most commercial EUTs.
  If we consider the cable part of dipole antenna, the reduction in
  frequency has a diminishing effect on the antenna's radiation
  resistance. Given a constant current, the radiated power would decrease
  with decreasing radiation resistance. At 550 KHz (bottom of the AM
  broadcast band in North America), the 1/4 wavelength is 136 meters. Even
  if the antenna's reactance is ignored, one would need very long cables
  driven by a significant CM noise voltage at this frequency to radiate
  much energy.
 
  --
  
  Daniel Kwok
  Principal EMC Engineer
  Intetron Consulting, Inc.
  Vancouver, Canada
  Phone (604) 432-9874
  Email dk...@intetron.com
  Web http://www.intetron.com;
 
 
  Ralph Cameron wrote:
 
  Ken:
 
  I like the idea of setting a limit to common mode currents on attaching
  cables but mI wonder why CISPR has chosen to start such measurements at
  30Mhz when most of the common mode currents are the result of switching
  products and are generated harmonically from the fundamental  and as
such
  propagate from the low Khz range up through 30Mhz. is there no
consideration
  for those who occupy the spectrum below 30Mhz?
 
 
  ---
  This message is from the IEEE EMC Society Product Safety
  Technical Committee emc-pstc discussion list.
 
  To cancel your subscription, send mail to:
   majord...@ieee.org
  with the single line:
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  For policy questions, send mail to:
   Richard Nute:   ri...@ieee.org
 
 

 ---
 This message is from the IEEE EMC Society Product Safety
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Re: Site Correlation

[Ralph Cameron]

Hello Dan:

Your explanation makes a lot of sense, as applied to RE.  It appears that
conducted emissions or CE have been largely ignored' nevertheless, cause
many problems when the radiating source is external to the device.  The
average home is a great unintentionl  antenna and when conducted currents
from noisey switching power supplies or RF from local transmitting
facilities, etc   appear on house wiring it causes two problems:  It
radiates ( or re readiates, as the case may be) and disupts or causes
radiosensitive equipment to malfuntion or as they say,  respond in an
unintended manner.   This issue has not been addressed very well, except
equipment bearing the CE mark does have some conducted immunity , so it is a
feature that has a benefit in spite of how some have defined the CE mark.

My reason for asking about the frequency range of the RE measurements was to
determine the background behind the restriction in the frequency range. It
also related to the incidence of equipment malfucntion being almost entirely
due to common mode conducted currents.   Of course, once RE are intercepted
by house wiring they become conducted and that's when the problem begins.

You answerd the original question , thanks.

Ralph Cameron
EMC Consulting and Suppression of Consumer Elecrtonic Equipment
( After sale)

p.s. After sale means that only common mode suppression techniques are used
to suppress line conducted currents. This does not effect warranty or
electrical safety in any way.
- Original Message -
From: Dan Kwok dk...@intetron.com
To: Ralph Cameron ral...@igs.net
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Monday, January 15, 2001 3:49 PM
Subject: Re: Site Correlation


 Hello Ralph:

 That's a good question. At one time, I pondered the same question
 myself. There are obviously plenty of communication systems operating
 under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does not
 specify radiated emissions below 30 MHz. I can suggest one possibility.
 Perhaps others here will come up with more.

 For a fixed cable of length L, the ratio of L/lambda gets progressively
 small for frequencies much less than 30 MHz with most commercial EUTs.
 If we consider the cable part of dipole antenna, the reduction in
 frequency has a diminishing effect on the antenna's radiation
 resistance. Given a constant current, the radiated power would decrease
 with decreasing radiation resistance. At 550 KHz (bottom of the AM
 broadcast band in North America), the 1/4 wavelength is 136 meters. Even
 if the antenna's reactance is ignored, one would need very long cables
 driven by a significant CM noise voltage at this frequency to radiate
 much energy.

 --
 
 Daniel Kwok
 Principal EMC Engineer
 Intetron Consulting, Inc.
 Vancouver, Canada
 Phone (604) 432-9874
 Email dk...@intetron.com
 Web http://www.intetron.com;


 Ralph Cameron wrote:
 
  Ken:
 
  I like the idea of setting a limit to common mode currents on attaching
  cables but mI wonder why CISPR has chosen to start such measurements at
  30Mhz when most of the common mode currents are the result of switching
  products and are generated harmonically from the fundamental  and as
such
  propagate from the low Khz range up through 30Mhz. is there no
consideration
  for those who occupy the spectrum below 30Mhz?
 



---
This message is from the IEEE EMC Society Product Safety
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 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Jim Bacher:  jim_bac...@mail.monarch.com
 Michael Garretson:pstc_ad...@garretson.org

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org

Re: Site Correlation

[Ralph Cameron]

Ken:

I like the idea of setting a limit to common mode currents on attaching
cables but mI wonder why CISPR has chosen to start such measurements at
30Mhz when most of the common mode currents are the result of switching
products and are generated harmonically from the fundamental  and as such
propagate from the low Khz range up through 30Mhz. is there no consideration
for those who occupy the spectrum below 30Mhz?

In my applications of common mode suppression, almost every case, the source
generating the common mode currents , when suppressed with simple external
common mode chokes, satisfactorily reduced all the localized radiation
caused by such effects.

Series common mode chokes not only suppress the outgoing but reduce the
incoming common mode currents that have the same potential for casuing
equipment malfunction.


Ralph Cameron
EMC Consulting and Suppression of Consumer Electronic Equipment
(After Sale).

- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: David Heald dhe...@curtis-straus.com; Tudor, Allen
allen_tu...@adc.com
Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Sent: Saturday, January 13, 2001 3:43 AM
Subject: Re: Site Correlation



 I must say that this thread has been a refreshing alternative to the
 EMC-law/regulations questions that typically occupy this service.  Not
 complaining either, because If I suddenly found myself working commercial
 EMC issues I would likely be flooding this line with those self-same
 questions.

 Almost as an aside, Mr. Heald raises an issue of enduring interest to
myself
 and others.

 Another important factor... is to manipulate the cables during testing
(oh,
 how much easier our job would be without  cables).

 The same issue was raised parenthetically in my answer to the question
about
 GTEM polarization. The issue is control of cable-sourced  radiated
 emissions.  I am now about to allegorically take a baseball bat to a
 hornets' nest...

 Bela Szentkuti pointed out almost twenty years ago that it would be much
 more efficient and accurate to analytically/experimentally determine the
 relationship between cable common mode currents and the resultant radiated
 field based on the maximum possible radiation efficiency of that cable,
and
 use that relationship to derive a common mode current limit for cables
from
 30 MHz to 1 GHz, using the absorbing clamp as a measuring tool.  This
would
 speed up OATS or any other kind of RE testing by deleting the requirement
to
 maximize cable radiation.

 So this question is a poll.  How do the subscribers to this service feel
 about cable common mode current control in lieu of direct measurement of
 cable-sourced RE measurement?  The idea being that first you would measure
 and bring cable cm CE into compliance with a cable-type limit and only
then
 would you make the RE measurement.  The cables would only be support
 equipment which did not contribute to the RE profile, hence any measured
 emissions at or near the limit would be guaranteed EUT enclosure-related.

 Polite responses only, please!!!

 Ken Javor



 --
 From: David Heald dhe...@curtis-straus.com
 To: Tudor, Allen allen_tu...@adc.com
 Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
 Subject: Re: Site Correlation
 Date: Fri, Jan 12, 2001, 9:36 AM
 

 
  Greetings again.
 I received some questions about this off list and there has been more
  discussion in this direction, so I thought I would throw my other two
  cents in.
 For small fully anechoic chambers with little room for antenna height
  adjustment, you should be able to have uncertainty of about 6dB or so
  (10dB is much safer realistically) when you apply correction factors for
  a 10m site.  The reason for this is, as John Barnes pointed out, the
  absence of reflected waves being received in addition to the direct
  waves.  The key importance to a fully lined chamber (including the
  floor) is that destructive waves are not present.  With a reflective
  floor, destructive waves can lower your readings by more than 30dB.  Add
  this to the 6 dB or so of uncertainty for additive waves and your total
  error could be enormous.  With an absorber lined floor, the influence of
  the destructive waves is eliminated or reduced, so a correlation of 6dB
  (again 10dB is safer) should be achievable (this simply accounts for the
  absence of constructive interference).
 Another important factor to ensure you don't have any surprises when
  moving from precompliance to a compliance run is to manipulate the
  cables during testing (oh, how much easier our job would be without
  cables).  Large signal strength changes can be achieved just by moving
  cables a few inches.
 I also have to agree with Gert's and Ken's comments on far field
  measurements.  I mentioned this in my original message, but didn't
  elaborate at all.  These are very important considerations that can
  greatly affect any expected correlation to a 10m OATS.
 
  --
  David Heald

Re: Zo

[Ralph Cameron]

The old style B insulated wire used for telephone drops and similar lamp
cord when twisted always made good balanced feedline for antennas with an
impedance somewhere around 70 ohms. This assumes conductors in the range
16-18ga. a.w.g. with rubber insulation.


Ralph Cameron
EMC Consulting and Suppression of Consumer Electronic Equipment
(After sale)

- Original Message -
From: William D'Orazio dora...@cae.ca
To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org
Sent: Thursday, January 11, 2001 9:49 AM
Subject: Zo



 Does anybody know the characteristic impedance of a twisted pair?
 Thanks in advance,

  ...OLE_Obj...

 William D'Orazio
 CAE Electronics Ltd.
 Electrical System Designer

 Phone: (514) 341-2000 (X4555)
 Fax: (514)340-5552
 Email: dora...@cae.ca


 ---
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Re: CE Marking Passive devices

[Ralph Cameron]

Thanks to all who helpfully directed me to the web site with the details.

Ralph Cameron

- Original Message -
From: Brian Jones e...@brianjones.co.uk
To: Ralph Cameron ral...@igs.net; Courtland Thomas
ctho...@patton.com; emcpost emc-p...@majordomo.ieee.org
Sent: Tuesday, December 12, 2000 2:39 PM
Subject: Re: CE Marking Passive devices



 Ralph

 Toy Safety Directive, 88/378/EEC.

 For more information, have a look at
 www.europa.eu.int/scadplus/leg/en/lvb/121005.htm

 Best wishes

 Brian Jones
 EMC Consultant and Competent Body Signatory

 - Original Message -
 From: Ralph Cameron ral...@igs.net
 To: Courtland Thomas ctho...@patton.com; emcpost
 emc-p...@majordomo.ieee.org
 Sent: Tuesday, December 12, 2000 5:16 PM
 Subject: Re: CE Marking Passive devices


 
  Many passive plastic and paper toys coming from China carry the CE
label.
 Is
  there a reason for it ?
 
 
  Ralph Cameron
  EMC Consultiant and Suppression of Consumer Electronics
  (After sale)
 
  - Original Message -
  From: Courtland Thomas ctho...@patton.com
  To: emcpost emc-p...@majordomo.ieee.org
  Sent: Tuesday, December 12, 2000 12:36 PM
  Subject: CE Marking Passive devices
 
 
  
   Hello group,
  
   I would like to know if there are any requirements for CE Marking a
 cable
  or
   any passive device, such as a basic surge protector.
  
  
   Thanks,
  
   Courtland Thomas
   Patton Electronics
  
  
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Re: CE Marking Passive devices

[Ralph Cameron]

Many passive plastic and paper toys coming from China carry the CE label. Is
there a reason for it ?


Ralph Cameron
EMC Consultiant and Suppression of Consumer Electronics
(After sale)

- Original Message -
From: Courtland Thomas ctho...@patton.com
To: emcpost emc-p...@majordomo.ieee.org
Sent: Tuesday, December 12, 2000 12:36 PM
Subject: CE Marking Passive devices



 Hello group,

 I would like to know if there are any requirements for CE Marking a cable
or
 any passive device, such as a basic surge protector.


 Thanks,

 Courtland Thomas
 Patton Electronics


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Re: IEC 61000-3-2 -3-3

[Ralph Cameron]

My comments re Woodgate   was confsuing. What I meant to say was the
transformerless SMPS s appear to generate considerable nosie as opposed to
the passive transformer. Is anyone concerned about this noise?

Ralph Cameron

- Original Message -
From: Ralph Cameron ral...@igs.net
To: Dick Grobner dick.grob...@medgraph.com; IEEE EMC-PSTC E-Mail Forum
(E-mail) emc-p...@majordomo.ieee.org
Sent: Tuesday, November 28, 2000 11:14 PM
Subject: Re: IEC 61000-3-2  -3-3



 J.M.Woodgate's comments are very appropriate to identify where all the
 conducted noise is coming from in consumer residences but does nothing to
 mitigate the problem. The unfiltered SMPS used for replacement of the old
 reliable non noise generating physical transformer contributes little or
no
 noise.

 As soon as some of these high efficiency noise (e.g. Halogen /Xenon
 lighting supplies) generators start  truning the Samrt House  concept
into
 a Haunted House, watch the brickbats fly.

 Ralph Cameron
 EMC Consulting and Suppression of Consumer Electronics
 (After sale)

 p.s. That goes for the  trasnformerless supplies in treadmills too.

 - Original Message -
 From: Dick Grobner dick.grob...@medgraph.com
 To: IEEE EMC-PSTC E-Mail Forum (E-mail) emc-p...@majordomo.ieee.org
 Sent: Tuesday, November 28, 2000 3:50 PM
 Subject: IEC 61000-3-2  -3-3


 
 
 
  At the web address below you will find an article written by J.M.
Woodgate
  dealing with 61000-3-2  -3. This may be of interest to some on this
forum
  as I know the issue seems to surface about every other week.
  Happy Reading!
 
 
  http://www.conformity-update.com/iec-61000-000908.htm
 
  Dick Grobner
  Compliance Engineering
  Medical Graphics Corporation
  350 Oak Grove Parkway
  St Paul, MN 55127
  651-766-3395
  651-766-3389 (fax)
  dick.grob...@medgraph.com
 
 
 
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Re: IEC 61000-3-2 -3-3

[Ralph Cameron]

J.M.Woodgate's comments are very appropriate to identify where all the
conducted noise is coming from in consumer residences but does nothing to
mitigate the problem. The unfiltered SMPS used for replacement of the old
reliable non noise generating physical transformer contributes little or no
noise.

As soon as some of these high efficiency noise (e.g. Halogen /Xenon
lighting supplies) generators start  truning the Samrt House  concept into
a Haunted House, watch the brickbats fly.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale)

p.s. That goes for the  trasnformerless supplies in treadmills too.

- Original Message -
From: Dick Grobner dick.grob...@medgraph.com
To: IEEE EMC-PSTC E-Mail Forum (E-mail) emc-p...@majordomo.ieee.org
Sent: Tuesday, November 28, 2000 3:50 PM
Subject: IEC 61000-3-2  -3-3





 At the web address below you will find an article written by J.M. Woodgate
 dealing with 61000-3-2  -3. This may be of interest to some on this forum
 as I know the issue seems to surface about every other week.
 Happy Reading!


 http://www.conformity-update.com/iec-61000-000908.htm

 Dick Grobner
 Compliance Engineering
 Medical Graphics Corporation
 350 Oak Grove Parkway
 St Paul, MN 55127
 651-766-3395
 651-766-3389 (fax)
 dick.grob...@medgraph.com



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Re: Speed Measuring Devices

[Ralph Cameron]

Peter:

I acted as a professional witness in a similar claim that clocked a
neighbour doing 110 in an 80 Km zone. The neibour lost.

I attempted to prove there was the possibility of EMI from a local 50Kw
broadcast transmitter which was less than 1/4 mile away. Since the reading
taken is a gated reading  the gun is only listening for a very few
miliseconds to acquire the signal that pretty well ruled out EMI as a souce.

Re the calibration. The officier was cross examined by the defendant's
lawyer as to his training and qualifications that would ensure he/she knew
that the rinstrument was calibrated. They simply use a tuning fork with the
gun pointed at it ( one method) and it can be self calibrated.

One can request at what time was the gun calibrated and what is the maximum
length of time between calibrations as these things do drift over time .
This particular gun operated in the 10Ghz band  and was relatively new.
Older units that did not take a gated reading were susceptible to errors.

Another point to make is the angle at which the reading was taken. It was
overlooked in the case in which I participated  but there was a sharp bend
in the road and there was no way my neiighbour could have been travelling at
the speed claimed from the angle where the reading was taken.   It cost him
$1000 and some demerit points.

Many judges will side with the officer when push comes to shove but at least
ask the right questions and you may find yourslef believed.

Ralph Cameron,   EMC Consulting and Suppression of Consumer Electronics
 After sale)



- Original Message -
From: Peter Merguerian pmerguer...@itl.co.il
To: emc-p...@majordomo.ieee.org
Sent: Thursday, November 16, 2000 9:28 AM
Subject: Speed Measuring Devices



 Dear All,

 Yes, I did get a speeding ticket today! I am not sure if I was speeding or
 not - I do not have my eyes on the speedometer all the time! I asked the
 policewoman to show me the calibration certificate on her speed measuring
 gun. She did not know what I was talking about! I inspected the gun and
did
 not see any stickers on it.

 I plan to go to court and attempt to convince the judge that the speeding
 gun was not calibrated and/or the gun's measurement data may have been
 affected by emissions from another device.

 Can anyone in the calibration business send me professional opinions on
the
 methods and reasons for calibrating speeding guns?

 What is the best way to present this case in court?
 Peter Merguerian
 Managing Director
 Product Testing Division
 I.T.L. (Product Testing) Ltd.
 Hacharoshet 26, POB 211
 Or Yehuda 60251, Israel

 Tel: 972-3-5339022 Fax: 972-3-5339019
 e-mail: pmerguer...@itl.co.il
 website: http://www.itl.co.il

 TO LEARN ABOUT AUSTRALIAN AND NEW ZEALAND REQUIREMENTS, CONTACT ME AT THE
 EARLIEST STAGES OF YOUR DESIGN; REQUIREMENTS CAN BE TRICKY!






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ESD

[Ralph Cameron]

I referred the ESD question to a good friend of mine who studied lightning and 
its mode of operation for many years and  share this reply. 

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronics (After Sale)

Re: Electron Flow

[Ralph Cameron]

Ross:

I'm with you. The earth represents the reference plane so the charge
actually moves from the earth to the cloud to neutralize it.

Ralph Cameron

- Original Message -
From: Hunt, Richard rh...@canoga.com
To: 'Lichtenstein, Ross' ross.lichtenst...@owenscorning.com; 'Barry
Ma' barry...@altavista.com; emc-p...@majordomo.ieee.org
Sent: Thursday, October 05, 2000 12:23 PM
Subject: RE: Electron Flow



 Here we go...this ought to be good.
 
 Richard Hunt
 Engineering Services Manager   Direct:  (818) 678-3860
 Canoga Perkins Corp.   Main:(818) 718-6300
 20600 Prairie Street   FAX: (818) 678-3760
 Chatsworth  CA  91311-6008 e-mail:  rh...@canoga.com
 rh...@canoga.com
 


 -Original Message-
 From: Lichtenstein, Ross [mailto:ross.lichtenst...@owenscorning.com]
 Sent: Thursday, October 05, 2000 7:54 AM
 To: 'Barry Ma'; emc-p...@majordomo.ieee.org
 Subject: RE: Electron Flow


 Barry,

 I could be wrong, and if so I would stand corrected, but from my basic
 electronics training,
 I recall that electron flow is from negative to positive.

 I also recall being taught that lightning actually travels from earth
(neg.
 charge) upward
 to the positive charge of the clouds.  Then there is also the case of
 lightning between clouds
 of opposite charge, and again the electron flow direction is from neg. to
 pos.

 Ross

 -Original Message-
 From: Barry Ma [mailto:barry...@altavista.com]
 Sent: Wednesday, October 04, 2000 5:58 PM
 To: emc-p...@majordomo.ieee.org
 Subject: Re: ESD Opportunities



 Please allow me to ask a relevant question only for curiosity.

 We have no idea of what charge (positive or negative) would go to the DUT
in
 ordinary ESD.
 That's why we have to test two polarities in ESD immunity test.

 Lightning is a kind of ESD happened between a charged cloud and objects on
 earth surface. Some figures imply that an electron current flows from the
 charged cloud to the earth. Is it possible to have an opposite direction -
 electron flows from earth to cloud?

 Thanks.
 Barry Ma

 ___

 Free Unlimited Internet Access! Try it now!
 http://www.zdnet.com/downloads/altavista/index.html

 ___


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Re: Power Line Voltages

[Ralph Cameron]

Reference Data for Engineers has this information. A local library would
have it.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronic Equipment
(After Sale)

- Original Message -
From: Flinders, Randall randall.flind...@emulex.com
To: emc-pstc emc-p...@majordomo.ieee.org
Sent: Wednesday, October 04, 2000 8:00 PM
Subject: Power Line Voltages


 Greetings group!

 I am looking for a resource, preferrably but not neccessarily on the
 web, were I can get all of the power line voltages and frequencies for
 every country.  This includes Europe, The Pac Rim, Autralia, Africa,
 Middle East, etc

 Can anyone direct me to this information?  Any help would be greatly
 appreciated!

 Regards,


 Randy Flinders
 EMC Engineer
 Emulex Corp.
 r.flind...@ieee.org



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Re: Leakage Current Measurements

[Ralph Cameron]

Ken:

Analog meters are inherently good low pass filters and will mask any high
frequency components. The same is truefor most DMMs unless they have been
specified for higher frequencies.  Typically, don't expect much accuracy
beyond 100Khz for soem of the best DMMs.

You can always use a scope with adequate bandwidth if you susepct high
frequency conducted components. That way, you can not only identify whether
noise is present but its waveshape. Any changes to make to reduce the noise
are readily visible.

RF power meterssuffer from the same deficiency unless specifically rated and
designed for pulsed waveform measurments. I recall an evaluation done my our
Dept of National Defence that found many gross errors in instruments not
designed or compensated for narrow pulses.

As mentioned on this forum, check for a true rms voltmeter function and
assure yourself what kind of accuracy you're getting at the highest
frequencies of interest. If you can live with 5-10% error - go for it.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
( After sale)

- Original Message -
From: Matsuda, Ken matsu...@curtisinst.com
To: emc-p...@majordomo.ieee.org
Sent: Tuesday, October 03, 2000 3:44 PM
Subject: Leakage Current Measurements



 I found something interesting today.  While measuring leakage current with
a
 digital multimeter, I noticed a high amount of leakage.  The unit
 incorporates a switching power supply, with some EMI/EMC circuitry.
Anyhow,
 I read somewhere that DMMs are some times inaccurate with high frequency
 line conducted emissions.  Took a old Simpson analog meter (took forever
to
 figure it out, since I've never touched a analog meter  hehehe) and found
 measurements that were rather low.  The questions is, I'm wondering if UL
or
 for that matter, any other testing agency actually know about this fact,
or
 merely fail their clients with incorrect data.


 Any input on this subject would be appreciated.



 Ken

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Re: ESD Opportunities

[Ralph Cameron]

Try an internet search on electrostatic dischareg and you will finf there
are hundreds of papers on the subject. Merely rubbing your hand across wool
or cloth or a waxed desk and garbbing an electronic device will cause ESD .
Hold a pocket calculator in your hand while you rub your hand against your
pant leg and /or shuffle your shoes across a rug and lay your hand on the
LCD display. If there's no ESD protection - the LCD display will blank. -
caused by charge dispersal.

Most modern electronic test equipment manufactured in North America is
protected to 10Kv ESD disharge  anywhere on the outdide of the intrument for
the same reason.

In the case of a cell phone it used to be possible to blow the front end by
holding on to the antenna after charging up some part of the body through
friction. In wintertime the problem is very bad in contacting computing
equipment.  When you find the CE mark on computer equipment  you may be
assured that it will at least have some immunity to both ESD and radiated
and conducted currents.

Obviously, the time to incorporate either ESD immunity or EMC is at the
design stage.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
(After Sale)


- Original Message -
From: appengr...@aol.com
To: litlkim2...@hotmail.com; emc-p...@majordomo.ieee.org
Sent: Wednesday, October 04, 2000 12:02 AM
Subject: Re: ESD Opportunities



 ESD is a term used for an electrical discharge that occurs from one
charged
 surface to another un-charged surface usually generated by frictional or
 triboelectric effects.  I have never heard of ESD issues within cell
phones
 or LCD displays.  It may be possible that a person with a large charge
build
 up on their bodies could discharge into the phone when they touch the
phone,
 or possibly the phone could have a charge that could discharge into your
 hand, but in either case it seems very unlikely that an electrical
discharge
 would happen or if it did that it would have much effect on the cell phone
or
 display.  Have you ever heard of ESD being an issue?  Outside of good
EMC/EMI
 practices I am not sure where or what could be done to prevent ESD.  Maybe
 others on the list may have some insight into this issue.

  I am doing a graduate research project on the ESD opportunities that
exist
  in the telecom market, specifically cell phones and laptops that have
LCD's
  which are affected by ESD. Is this a market to look into, and what are
the
  requirements and trends that you see going on? What materials or
solutions
  are currently being used to address ESD problems in these systems, and
are
  they they working?  Lastly, is ESD a factor that is considered when
  designing EMI shielding solutions?

  I would appreciate any insight you may have. Thanks!
  kl 

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Re: Probing power plane with analyser.

[Ralph Cameron]

Cameron:

That's fairly easy to do as long as you:

1.  Take all measurments from the same reference points before and after the
changes  and

2. Use a DC block on the input to the analyzer ;other wise you may have an
expensive input to replace. Most analyzers inputs are not protected for DC.
Most companies sell the DC isolator as an accessory.

Ralph Cameron

EMC Consultant and Suppression of  Consumer Electronic Equipment.


- Original Message -
From: Cameron O'phee O'p...@ali.com.au
To: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org
Cc: Roman Seifert seif...@ali.com.au
Sent: Wednesday, September 27, 2000 8:59 PM
Subject: Probing power plane with analyser.



 Hello All,

 I have been asked by one of our design engineers if I can measure the RF
 signature on the 3v plane on one of our PCB designs.  The purpose of this
is
 to compare it to proposed changes for cost reduction, ie removal of bypass
 caps.  I would assume I need some sort of CDN but I have no designs for
this
 application.  Does anyone have any ideas on how I can safely probe a 3v DC
 power rail with an EMC analyser (HP8591E)?


 Regards,

 Cameron O'Phee.
 EMC  Safety Precompliance.
 Aristocrat Technologies Australia.

 Telephone : +61 2 9697 4420
 Facsimile  : +61 2 9663 1412
 Mobile  :   0418 464 016

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Re: Re[3]: Battery Safety

[Ralph Cameron]

Barry:

This is the same principal used to charge the batteries for the artificial
heart- an inductive loop.

Ralph Cameron

- Original Message -
From: Barry Ma barry...@altavista.com
To: eric.petitpie...@pulse.com
Cc: emc-p...@ieee.org
Sent: Tuesday, September 26, 2000 8:26 PM
Subject: Re: Re[3]: Battery Safety



 Eric,
 Thanks for the nice answer.
 Barry Ma
 -
 On Tue, 26 September 2000, Eric Petitpierre wrote:

 
   Barry,
 
   There is likely an excitation coil in the base.  I sends out a
   magnetic field.  The recever, (toothbrush) has a receive coil that
   charges the battery.
 
   In other words, the primary of the transformer is in the base.
The
   secondary of the transformer is in the toothbrush.  When the
   toothbrush is in the base, the proximity is close enough to charge
the
   battery.
 
   Eric Petitpierre
 ___


 ___

 Free Unlimited Internet Access! Try it now!
 http://www.zdnet.com/downloads/altavista/index.html

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Re: Battery Safety

[Ralph Cameron]

Chris:

Is the battery a rechargeable?   Have you tried disconnecting the 91K
reisstor and measuring the resulting voltage increase?  Doesn't make sense
to me.

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(After sale)

- Original Message -
From: Maxwell, Chris chr...@gnlp.com
To: 'EMC-PSTC Internet Forum' emc-p...@majordomo.ieee.org
Sent: Monday, September 25, 2000 11:30 AM
Subject: Battery Safety



 All,

 We have inherited a design from a company which we purchased.  The product
 is a handheld and can be operated from a pair of Alkaline batteries.
Inside
 the unit, there is a 91 KOhm resistor across the + and - terminals of the
 batteries.  Since the people who designed the instrument are long gone,
some
 of my collegues have asked me if this resistor could be a safety  feature.

 I can't think of any way this resistor would help the safety of the
 instrument.  I did read through the safety test report; and I found no
 reference to this resistor being required.   All it does is provide a
 constant drain on the battery (reducing battery life).  It has been
 suggested to me that some designers put resistors across batteries to
reduce
 the electrical noise in a product.  To me a capacitor would be better for
 this because it wouldn't drain the battery while it was filtering.  Even
so,
 isn't a battery the ultimate capacitor?  I'm just drawing a blank why
anyone
 would do this.  I'd love to recommend that we pull this resistor out
because
 it's a pain to solder and it affects battery life.  However, I don't want
to
 sacrifice the safety of the product.

 Anybody want to take a guess at this one?

 Thanks.

 Chris Maxwell, Design Engineer
 GN Nettest Optical Division
 6 Rhoads Drive, Building 4
 Utica, NY 13502
 PH:  315-797-4449
 FAX:  315-797-8024
 EMAIL:  chr...@gnlp.com



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Re: Component Qualification

[Ralph Cameron]

Tony:

I have sold these systems and also used them and they are good for graphing
a profile of a scanned board and giving the field intensity vs postion over
the board area. You can quickly find trouble spots using the computer
interface.

Ralph Cameron

- Original Message -
From: Tony J. O'Hara tonyoh...@compuserve.com
To: Koh Nai Ghee koh...@cyberway.com.sg
Cc: EMC-PSTC emc-p...@majordomo.ieee.org
Sent: Wednesday, September 20, 2000 4:42 PM
Subject: Re: Component Qualification



 You may want to look at using a PCB Electromagnetic Scanning System!  One
 of the advertised uses for these test devices is for quickly comparing EMC
 performance when component changes are made etc.! I believe there are 4
 different manufacturers who make these devices. The one that I'm just
 starting to learn about is made by EMSCAN in Canada. Their web is
 www.emscan.com
 Maybe someone who has  uses one of these scanners can provide an
 experienced viewpoint?
 Regards
 Tony
 Colorado

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Re: Component Qualification

[Ralph Cameron]

Chris,

Don't get me wrong. I didn't read the full text of the application and
merely supported the utility of the EMSCAN system.

If you know of sources where you cn get ferrites, specifically ferrite
toroids for a dime a dump truck, I'd be interested. In the past two years my
costs for them have more than tripled as the mfr now uses dealers who have
minu\imum quantities which are out of sight for the small vendor. With the
heavier weights , shipping costs skyrocket.

I like your methods of determining ferrite application and how to look for
hpt spots.

 My opinions are my own since I work for me.

regards

Ralph Cameron
EMC Consultant and Suppression of Consumer Elecronics
(after sale).
- Original Message -
From: Maxwell, Chris chr...@gnlp.com
To: 'Ralph Cameron' ral...@igs.net; Tony J. O'Hara
tonyoh...@compuserve.com; Koh Nai Ghee koh...@cyberway.com.sg
Cc: EMC-PSTC emc-p...@majordomo.ieee.org
Sent: Thursday, September 21, 2000 7:58 AM
Subject: RE: Component Qualification


 Wait a minute!

 Buying a board scanning system to evaluate different vendors for ferrites
 and oscillators?  My company doesn't have that kind of money to throw
 around.  These systems can cost 10's of thousands of dollars.   Ferrite
 beads cost about a dime for a dump truck load.  If it costs $10,000 to
 evaluate a second source for ferrites, I 'll stick with the ferrites I
have.
 I'd like to offer a lower cost alternative.

 Koh Nai asked about what specifications were important for qualifying
 alternate sources for ferrites and oscillators.

 When it comes to ferrites, I look at three things:  I look at the PCB
 footprint (it won't work if it won't fit).  I look at the impedance curve
 and the current capacity.  If all three of these specifications are equal
or
 better than what I need, I accept them.  I don't even consider re-testing
 for emissions if I have checked these three specifications.  Alternate
 sources for ferrites can be qualified for the cost of reading a spec
sheet.

 Oscillators are a different story.  When one of my digital design
colleagues
 wants to change oscillators.  They consider its PCB footprint, the output
 frequency, its ambient stability, its temperature stability and its load
 driving capability.  If it meets their needs; then I take a circuitboard
 with the existing oscillator and run a near field probe over it near the
 oscillator until if find a location of maximum near field emissions.  (If
 you really are strapped for cash, you can make your own near field probe.)
 I write down the exact position and orientation of the near field probe
and
 I either print out or write down the spectrum analyzer readings.  I then
put
 the new oscillator on the exact same board and repeat the experiment.  If
 the measurements are close (within a dB or two) I don't worry.  If the
 measurements are more than  4 dB higher, then I look further. Then I
 consider:  testing the whole unit with the new oscillator with my antenna
 set up 1 meter away  in-house, or re-testing the unit for emissions at an
 OATS, or not using the new oscillator.

 ONE WARNING:  if the new oscillator is at a different frequency, then the
 method above WILL NOT yield any useful results.

 One thing that we have done with new designs is to put a 1206 surface
mount
 PCB footprint in line with the oscillator output.  We start our testing
with
 a 0 ohm resistor.  If we run into problems, we can put either a ferrite
bead
 or higher value resistor in this position to cool off the oscillator.
 This has worked well with oscillators under 100MHz. I don't know if it
will
 work for faster oscillator.

 I know that there are problems with using near field probes to make such
 correlations, however using a board scanning device would cost much more
 than a near field probe and still only be measuring near fields.  Even so,
 if I had the budget, I'd love to try one out.

 To me, the real method of doing this starts with the initial testing of
your
 product.  I try to get more than a 5dB margin during the initial testing.
 With these margins, I don't need to worry so much about component
 differences.  I know that this is sometimes not possible.  I have
sacrificed
 margins in order to get a product's testing done and released (I don't get
 paid if we don't ship.)  The problem is, without margins, I need to worry
 more about component differences.

 Another point to remember is that EN 55022 and other emissions standards
go
 by the 80 % rule.  A product passes if  we are  confident that 80% of
 the units that we ship meet the emissions requirements.  Anybody who wants
 to dispute whether your units pass or not is REQUIRED to test up to 7
 samples in order to get enough data to use statistical methods to compute
 the confidence factor.  One failing unit does not equal a guilty verdict.
 (Of course, if one unit is failing by 20dB, that's a problem.)  The people
 at CISPR put this slack into the limits to allow for slight component
 differences

Re: Supplies of HV Rectifiers

[Ralph Cameron]

Brian:

You can obtain the HV rectifiers from K2AW's Silicon Alley
175 Friends Lane
Westbury NY. 11590

Tel/Fax 516-334-7024

e-mail :  silicona...@aol.com

He stocks rectifiers to 14KV PIV with Max Fwd Avg Current to 1000 ma. and
Max Fwd Peak Surge Current of 250A

Prices run about $14 each U.S.

He carries lower voltages also at correspondingly less money.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronics
(After Sale)

- Original Message -
From: Brian Harlowe brian.harl...@vgscientific.com
To: emc-p...@ieee.org
Sent: Tuesday, September 19, 2000 10:04 AM
Subject: Supplies of HV Rectifiers






  I apologise that this question is outside the remit of this group but I
am
  in a desperate situation and with the wealth of experience there is out
  there I hope some one can help me.
 
  We have manufactured in the past an X. Ray power supply that gets its
EHT
  from a rectified three phase supply. Because all you whizzy electronic
  engineers are now using multipliers to make high voltage. Rectifiers
that
  can handle 7-8kV at up to 20mA are getting like Rocking Horse manure to
  obtain in the UK.
 
  My question is can anyone point me in the direction of a supplier in the
  US
  or Far East of such beasts
 
  Many thanks in advance
 
  Brian Harlowe
 
 
  Brian Harlowe
  V.G. Scientific
  Tel +44 (0)1342 327211
  Fax +44 (0)1342 315074
 
  Received: from ruebert.ieee.org ([199.172.136.3]) by mail.monarch.com
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schematic

[Ralph Cameron]

Low level halogen and Xenon lighting make use of electronic transformers. 
Does anyone have a typical circuit of one of these transformers?

I attempt to do suppression of devices such as these that generate considerable 
broad band noise at broadcast as well as short wave frequencies and need to 
know what is causing the conducted distortion to feed back to the powerline. 

I am told by producers of these noise generators that most producers use the 
the same or a similar circuit. I believe SCRs or unstabilized switch mode 
supplies are the culprits. 

Any help would be appreciated. 

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
( after sale)

Re: R: Conducted Emissions on Telecom Ports

[Ralph Cameron]

Steve:

Please tell me more about the immunity standards- they are non existent in
Canada

Ralph Cameron
EMC Consulting and Suppression of Consumer Electronic Equipment
(After sale)
p.s  Ever listen to the radio near some home treadmills?

- Original Message -
From: Steve Grobe ste...@transition.com
To: ieee pstc list emc-p...@ieee.org
Sent: Thursday, September 07, 2000 1:35 PM
Subject: RE: R: Conducted Emissions on Telecom Ports



 Has anyone seen problems with ethernet and conducted emissions?  I have a
 home office with 4 PCs networked with ethernet running over UTP and I
 haven't seen much of a problem.
 Granted, the longest cable run I have is to a file server in the basement
 (about 10 meters) but both my AM radio and my shortwave set seem to work
 just fine.  The only thing I remember picking up is 20MHz on the shortwave
 set. (Most 10Mbit ethernet devices use a 20MHz clock.)  At work we have
both
 10 and 100Mbit ethernet (150-200 nodes) and the AM reception is really bad
 but I attribute that to the building (big steel and brick box) more than
 noise as reception improves as you get closer to a window.  I haven't
tried
 the shortwave at work being that shortwave reception is usually bad during
 the day anyway.

 As far as telephone lines are concerned my ears don't pick up much noise
 above 19kHz.  I would think anything else would be covered by immunity
 standards.

 Steve

 -Original Message-
 From: Cortland Richmond [mailto:72146@compuserve.com]
 Sent: Thursday, September 07, 2000 11:01 AM
 To: Paolo Roncone; ieee pstc list
 Subject: Re: R: Conducted Emissions on Telecom Ports



 Paolo Roncone wrote:

 The scope of emissions standard should be
 to protect the outside (i.e. public)
 environment from interference. So only
 ports that connect to public telecom
 networks should be covered by the standard.

 I disagree.

 The purpose of emissions standards is to prevent interference.  Some are
to
 similar functions, some are to other media.  There is no interface for
 interference at which point the manufacturer may say: Interference when
 you use this isn't our problem. We may say: Use shielded cable, or Put
 a ferrite on your cable, but we can't evade the physical fact that it is
 our own equipment which is the source of interference, and the cable is
its
 antenna.

 It does not matter that we do not own the cable; if you plug it in and
 there is  interference, it is up to the people who made the equipment to
 see the interference reduced.  There is no transfer of ownership for radio
 waves.

 Granted, to call a LAN cable telecommunications is a clumsy construction
of
 the regulation. But those who grasp at that straw to save a few currency
 units will  find themselves later regretting that they have done so. If
you
 are beaten and robbed for a display of wealth, it is no use protesting
that
 the money was counterfeit.

 Cortland Richmond
 (I speak for myself alone and not for my employer)


 == Original Message Follows 

   Date:  07-Sep-00 07:48:16  MsgID: 1072-46656  ToID: 72146,373
 From:  Paolo Roncone INTERNET:paolo.ronc...@compuprint.it
 Subj:  R: Conducted Emissions on Telecom Ports
 Chrg:  $0.00   Imp: Norm   Sens: StdReceipt: NoParts: 1

 From: Paolo Roncone paolo.ronc...@compuprint.it
 Subject: R: Conducted Emissions on Telecom Ports
 Date: Thu, 7 Sep 2000 16:45:03 +0200
 Reply-To: Paolo Roncone paolo.ronc...@compuprint.it



 Hi Eric,

 I 100% agree with you. The scope of emissions standard should be to
protect
 the outside (i.e. public) environment from interference. So only ports
 that connect to public telecom networks should be covered by the standard.
 The problem is (as pointed out in one of the previous notes) that the new
 CISPR22 / EN55022 standard clearly includes LAN ports in the definition of
 telecommunications ports (section 3.6) no matter if they connect to the
 outside world or not.

 Regards,

 Paolo Roncone
 Compuprint s.p.a.
 Italy

 -Messaggio originale-
 Da: eric.lif...@ni.com [SMTP:eric.lif...@ni.com]
 Inviato:mercoledì 6 settembre 2000 17.55
 A:  emc-p...@ieee.org
 Oggetto:Re: Conducted Emissions on Telecom Ports


 All,

 As a not-quite-outside-observer (strictly EN 55011 here) of this thread,
 it's
 not fun seeing LAN ports classified as telecom; IMO that's overkill for
the
 folks using EN 55022.

 Up till now, I considered a port to be telecom only if it connects a
client
 facility to a carrier's network (DSL, ISDN, T1 and so on).

 With repeaters every 5 meters, USB and 1394 can support a bus long enough
 to
 connect between adjacent buildings.  So, I wonder if some fanatic will
soon
 be
 promoting USB/1394 ports as telecom?

 If Chris is right, and the EN 55022 version of the old telecom port
 conducted
 emission standard was intended to protect other telecom signals in a
 bundle,
 then I would think that this test is clearly redundant to the immunity

Re: RF Immunity levels

[Ralph Cameron]

DB

What physical volumes are needed for containing the EUT ?

Ralph Cameron

- Original Message -
From: Brumbaugh, David david.brumba...@pss.boeing.com
To: 'emc-pstc' emc-p...@ieee.org
Sent: Tuesday, August 01, 2000 7:37 PM
Subject: RF Immunity levels



 Hi, group

 Here's a question for you test lab folks out there, or anyone familiar
with current test lab capabities -

 What are the maximum E field levels achievable between 2 GHz and 40 GHz?
I'm looking for a maximum at each frequency (narrowband nulls excluded).
Even if peak levels at discrete frequencies are all that can be achieved,
I'd like to know that, too. I'd appreciate a test house contact in the US if
anyone has an answer.

 Thanks,

 DB

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Re: Electrical safety of firearms

[Ralph Cameron]

I think if ther is an electronic circuit that activates the triggering
device and that circuit lacks EMC , it has the potential to malfunction. If
the electronic ciruit is the one to commence the action of firing without
any electrical interface then it had better perform its intended funtion in
the presence of strong radiated fiields.  I didn't read EED into what Phil
mentioned and I would certainly agree that ESD needs consideration. I would
expect too that the intended use may have a bearing on what safety measures
are imperative.


Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After sale)

- Original Message -
From: Ken Javor ken.ja...@emccompliance.com
To: Ralph Cameron ral...@igs.net; pgodf...@icomply.com;
emc-p...@majordomo.ieee.org
Sent: Thursday, July 27, 2000 12:31 AM
Subject: Re: Electrical safety of firearms


 I think both Mr. Firth and Mr. Cameron are confusing ordnance activated by
 an electro-explosive device (EED) with ordinary bullets.  In the case of
an
 EED, it is very important to not only provide safe and arm capability, but
 also to ensure that field-to-wire coupling does not inadvertently inject
 enough electrical energy to set off the EED.  This concern is addressed in
 such documents as MIL-STD-1385, MIL-STD-1512, MIL-E-6051D and MIL-STD-464.
 Together, these standards define no-fire and all-fire levels, and EMC
safety
 margins X dB below the no-fire level.

 But none of this would apply to a trigger, hammer and powder-loaded
 cartridge based system.  There is no electrical interface to the
cartridge,
 hence no need for safety margins, etc.  I assume that the only difference
 between the electronic trigger and a conventional trigger is that there is
 no mechanical linkage between trigger and hammer - the trigger applies
 electrical potential to a solenoid, which ejects a hammer substitute into
 the cartridge base.

 I would want a solenoid that operated at a high enough potential and drew
 enough current that the field-to-wire pickup from even the strongest
 possible nearby field would be insufficient to energize the solenoid.  And
 the solenoid would require several milliseconds of applied power, so that
a
 short duration pulse (ESD, EFT) could not trip the hammer.  Any additional
 safety interlock would be a mechanical switch.  If you get fancy and start
 putting 3 or 5 Volt logic in this thing, then you open yourself up to ESD
 and any number of other problems.

 In today's atmosphere where even ordinary firearms are viewed as defective
 products, imagine the ruckus some lawyer could cause with a twenty five
year
 old handgun in which an old battery corroded and caused enough degradation
 that the gun malfunctioned and fired without a pull of the trigger.  It
 would matter not that the gun had been sold and resold or stolen and
resold.
 In fact, they could make the case that the nth owner is less likely to
 understand the thing than the original buyer.

 It's not paranoia if they really are following you...


 --
 From: Ralph Cameron ral...@igs.net
 To: pgodf...@icomply.com, emc-p...@majordomo.ieee.org
 Subject: Re: Electrical safety of firearms
 Date: Wed, Jul 26, 2000, 8:40 PM
 

 
  Phil:
 
  I would hope that the electronic trigger cisrcuit has been designed with
EMC
  in mind.  Not like the Toronado aircraft that had its munitions explode
  whennflying too close to a local European trasnmitter.
 
  Ralph Cameron
  EMC Consultant for Suppression of Consumer Electronics
  ( After Sale).
 
  - Original Message -
  From: pgodf...@icomply.com
  To: emc-p...@majordomo.ieee.org
  Sent: Wednesday, July 26, 2000 3:50 PM
  Subject: Electrical safety of firearms
 
 
 
  Here's one that you feel should have something, just because of the
nature
  of the equipment, but your not quite sure what!!
 
  Does anyone have the least inkling of any safety requirements specific
to
  a
  firearm with an electronic trigger. I am not particularly interested in
  firearms laws/regulations etc but any requirements that the electronics
  may
  fall under. This device will be powered by a 9-volt battery.
 
  Thanks in advance of any responses.
 
  Phil Godfrey
 
  ps. Domestic, EU, Aus and a few more. Thanks
 
  Phillip Godfrey - Manager, Product Safety
  KTL Dallas, Inc.
  802, N.Kealy,
  Lewisville,
  Texas 75057-3136
 
  Tel : (972) 436-9600
  Fax: (972) 436-2667
  http://www.ktl.com/
 
  email : pgodf...@icomply.com
 
 
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  This message is from the IEEE EMC Society Product Safety
  Technical Committee emc-pstc discussion list.
 
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Re: 8591EM monitor output

[Ralph Cameron]

Jeff:

Radio Shack sells an RF modulator that will do the job. If you feed it to a
VCR you can also record the results as well as view it on a TV set.  As
mentioned, it produces NTSC compatible video on CH3 or 4.  Price should be
around $25. U.S.


Ralph Cameron
EMC Consulting and Suppression of Consumer Electronics
(after sale).

- Original Message -
From: Scott Lacey sco...@world.std.com
To: Jim Bacher jim_bac...@mail.monarch.com
Cc: emc-p...@ieee.org
Sent: Monday, July 24, 2000 6:29 PM
Subject: RE: 8591EM monitor output



 Jeff,
 I think the piece of hardware you need is an RF Modulator. These output
your
 video on Channel 3 (sometimes switchable to channel 4). Should be
available
 for $25-$50 dollars. Try MCM Electronics (800 543-4330)if you can't find
one
 locally. The one I have is their P/N 33-1480 Audio/Video Modulator. It is
 about 3 x 5 x 1, with an attached (120V) line cord, and a switch to
 select CH3/CH4.

 Scott Lacey

 -Original Message-
 From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf
 Of Jim Bacher
 Sent: Monday, July 24, 2000 3:42 PM
 To: Bailey; Jeff; 'emc-pstc'
 Subject: Fwd:8591EM monitor output



 forwarding for Jeff.

 Reply Separator
 Subject:8591EM monitor output
 Author: Bailey; Jeff jbai...@mysst.com
 Date:   7/24/00 12:06 PM

 Hello all,

 Have any of you successfully hooked up a television to an HP8590 series
EMC
 analyzer?  The monitor output does provide NTSC format, I am now assuming
 that I need to provide a carrier for the monitor output to ride on in
order
 for the TV to see the NTSC signal and know what to do with it.  Is there
an
 easier way to do this than to build my own modulator?

 Thanks,

 Jeff Bailey
 Compliance Engineering
 SST - A Division of Woodhead Canada
 Phone: (519) 725 5136 ext. 363
 Fax: (519) 725 1515
 Email: jbai...@sstech.on.ca
 Web: www.sstech.on.ca

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Re: Adjacent Channel Power Measuring Equipment

[Ralph Cameron]

Paul:

Tektronix has a good application note covering measurement of adjacent
channel power.   I am not sure but I don't think the 8566B can be triggered
to perform such measurements, I've been away from the field a little too
long . Tek markets the Rhode and Schwartz products and most modern spectrum
analyzers have that capability.  A call to the local office should get you
some help.

Ralph Cameron
EMC Consultant forSuppression of Consumer Electronics
(After sale)

- Original Message -
From: Paul Slavens paul_slav...@hotmail.com
To: emc-p...@ieee.org
Sent: Wednesday, June 28, 2000 5:28 PM
Subject: Adjacent Channel Power Measuring Equipment



 Hello Group,

 I am having a little trouble with section 8.5 (adjacent channel power) of
 ETSI EN 300 220-1.  Specifically, I am having difficulty understanding the
 requirements for the power-measuring receiver defined in Annex B.  My
 questions are:

 1. Is the HP EMI rack, consisting of an 8566B spectrum analyzer, an 85685A
 RF pre-selector, and an 85650A quasi-peak adapter a suitable instrument
for
 making adjacent channel power measurements?

 2. If the HP EMI rack will not properly measure adjacent channel power per
 ETSI EN 300 220-1, what instrument or instruments will?

 If anyone could help shed a little light on the above question, I would be
 most thankful.

 Regards,

 Paul Slavens

 
 Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com


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Re: MITI/Dentori-T

[Ralph Cameron]

George:

I read some Japanese but do not know the meaning of dentori unless it is a
compound of two other nouns.  I would say, dentori because there is no Y
in the Japanese syllabry.

Japanese are quite flexible in their phonetic liberties particularly when
appealing to an English speaker.

Ralph Cameron
EMC Consultant for the Suppresion of Consumer Electronics
(After Sale)

- Original Message -
From: geor...@lexmark.com
To: emc-p...@majordomo.ieee.org
Sent: Tuesday, June 20, 2000 11:13 AM
Subject: MITI/Dentori-T



 Dumb question:

 I've used the term Dentori-T mark when referring to the Japan
 mark authorized by MITI.  Lately I have seen this spelled as
 Dentory, even on foils presented by Japanese companies.

 I am confused.  Which is the correct spelling:

 Dentori or Dentory

 George Alspaugh



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Re: Measuring noise, spectrum analyzer

[Ralph Cameron]

Ron

Tektronix has some application notes for using spectrum analyzers in
measuring CDMA signals which would apply to OATS sites. You may want to
contact their local office as the notes are free.  They may even be
available on their web site


Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After sale)

- Original Message -
From: ron_cher...@densolabs.com
To: emc-p...@ieee.org
Cc: rcher...@home.com
Sent: Monday, June 19, 2000 3:41 PM
Subject: Measuring noise, spectrum analyzer



 I am looking for information or articles written on measuring a CDMA or
 noise-like signal with a
 spectrum analyzer. I will be doing EIRP measurements on an OATS.
 Thanks in advance,
Ron Chernus, DENSO



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Re: Looking For Video Pattern Generator

[Ralph Cameron]

Eric,

Give Teltronix a call. They used to have such an instrument.



Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After Sale)   (and retired Tek emploee)

- Original Message -
From: eric.lif...@ni.com
To: emc-p...@ieee.org
Sent: Thursday, June 08, 2000 2:08 PM
Subject: Looking For Video Pattern Generator



 Hello Listers,

 We're looking for a stand-alone video pattern generator (both PAL and NTSC
 formats) to test video capture boards for the EMC Directive; and,
hopefully the
 generator itself would pass too.  We need one that would include a display
of
 time so we can detect a lack of trigger or frozen acquire.

 Any suggestions?

 Regards,
 Eric Lifsey
 National Instruments



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Smoke Alarms

[Ralph Cameron]

Not sure if this is apprpriate for this group. 

Can anyone tell me what the audible requirements are for standard approved 
smoke alarms?  

Is there a spec for them ?

Mny seniors have difficulty hearing a high pitched tone and I am attempting to 
determine alternatives. 

Thanks 

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After sale)
 

Re: interference to Comm devices due to overhead catenaries

[Ralph Cameron]

Susan:

Are the catenaries enrgized?  In any event you can expect some signal
degradation and perhaps complete cancellation as the locomotive moves
becuase the catenaries will screen the GPS signals.  As you may be aware,
GPS relies on a minimum of two visible satellite signals and sometimes is
able to see six or more which makes accuracy more achievable.

Any metallic medium interspersed between the GPS antenna and the direct
satellite signal will cause a certain attenuation to the signal.

Can you provide more specifics?

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After Sale)

- Original Message -
From: Beard, Susan sbe...@ge-harris.com
To: emc-p...@ieee.org
Sent: Tuesday, May 23, 2000 3:56 PM
Subject: interference to Comm devices due to overhead catenaries



 Could anyone provide any information relative to overhead catenary noise
and
 its affects on locomotive roof top comm systems (e.g., GPS)?

 Susan Beard

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Re: Charge moving from decoupling capacitors

[Ralph Cameron]

Barry

Thanks for correcting me. Practical solutions have changed from the time I
made many measurements on PCBs with discrete components. I'll be interested
to read the article you mentioned since I wasn't aware a single SMA cap
could do a better job.

Regards,

Ralph Cameron

- Original Message -
From: Barry Ma barry...@altavista.com
To: ral...@igs.net
Cc: emc-p...@ieee.org
Sent: Friday, May 19, 2000 11:33 AM
Subject: Re: Charge moving from decoupling capacitors


 Ralph,

 Please be cautious about what you said below: the reason why most power
buses on PCBs use several values of decoupling is to ensure that a wide
range of frequencies are covered.

 Several V curves shown in the figure of impedance vs. frequency, which we
are all familiar with, would easily convince us the above statement. But
those V curves only show the absolute value of impedance around
self-resonance frequency of various capacitors. If considering related phase
relations, the total impedance of several values of decaps would become not
as simple as we expected - having low impedance over wider frequecy range.
You may refer to an article by Paul, C. R.:

 Effectiveness of multiple decoupling capacitors, IEEE EMC Vol. 34, p.
130, May 1992.

 In my practice of using SMA caps, only the largest value of capacitance
available for given SMA size is selected, if I have a PCB with 10 mil or
less plane spacing.

 Regards,
 Barry Ma
 b...@anritsu.com

 
 On Thu, 18 May 2000, Ralph Cameron wrote:

  As I read in an article related to bypassing for good decoupling ( in
1971)
  one can select from a number of EIA values and by cutting the lead
lengths
  correctly ( e.g. from 1/2- less than 1/4  ) the series reonant
frequency
  will drop by a considerable amount so - yes, the reason why most power
buses
  on PCBs use several values of decoupling is to ensure that a wide range
of
  requencies are covered.  Perhaps, with surface mount caps, that is
easier to
  predict because they are essentially leadless.
 
  I once cured a very severe case of an FM receiver responding to the 7th
  harmonic of a 14Mhz transmitter because an untuned mixer was used.
Placing
  a 100pf cap with 1/4 leads right across the mixer IC completely cured
the
  problem without degrading mixer sensitivity.
 
  Ralph Cameron
  EMC Consultant for Suppression of Consumer Electronics
  (After Sale)


 ___

 Why pay when you don't have to? Get AltaVista Free Internet Access now!
 http://jump.altavista.com/freeaccess4.go

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Re: Re:RE: Charge moving from decoupling capacitors

[Ralph Cameron]

As I read in an article related to bypassing for good decoupling ( in 1971)
one can select from a number of EIA values and by cutting the lead lengths
correctly ( e.g. from 1/2- less than 1/4  ) the series reonant frequency
will drop by a considerable amount so - yes, the reason why most power buses
on PCBs use several values of decoupling is to ensure that a wide range of
requencies are covered.  Perhaps, with surface mount caps, that is easier to
predict because they are essentially leadless.

I once cured a very severe case of an FM receiver responding to the 7th
harmonic of a 14Mhz transmitter because an untuned mixer was used.  Placing
a 100pf cap with 1/4 leads right across the mixer IC completely cured the
problem without degrading mixer sensitivity.

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(After Sale)


- Original Message -
From: Jim Bacher jim_bac...@mail.monarch.com
To: george_t...@dell.com
Cc: emc-p...@ieee.org
Sent: Thursday, May 18, 2000 4:24 PM
Subject: Re:RE: Charge moving from decoupling capacitors



 Forwarded for George.

 Reply Separator
 Subject:RE: Charge moving from decoupling capacitors
 Author: george_t...@dell.com
 Date:   5/18/00 2:30 PM

 Barry,

 Thanks for the comments.  Here are my comments:

 Ok, you put caps at a certain distance away from the IC because you only
 want them to work at 100 MHz.  But that distance turns out to be the 1/4
 wave distance at 400 MHz, and you placed enough caps at the 1/4 wave
 distance to cause board resonance.  Now what?  Do you tell the caps not to
 work at 400 MHz because it's not their frequency?


 For your 2nd comment:

 I used the words loosely define for that reason.  If you are interested
in
 high frequency decoupling and instantaneous current, you really want to
have
 all your charges moving in phase.  At 1/4 wavelength, the charges are 90
 degrees out of phase, so they will not do much for your instantaneous
 current.  1/8 wavelength is what I consider to be acceptable.  You can
 certainly pick a different number.

 Regards,

 George Tang
 george_t...@dell.com


 -Original Message-
 From: Barry Ma [mailto:barry...@altavista.com]
 Sent: Thursday, May 18, 2000 10:50 AM
 To: george_t...@exchange.dell.com
 Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org
 Subject: RE: Charge moving from decoupling capacitors


 George,

 Thanks for your long input. I'd like to make some comments below.
 -
 On Wed, 17 May 2000, george_t...@dell.com wrote:

  Large parallel plates behave as transmission lines.  A quarter
wavelength
  transmission line with a short at the end has infinite impedance, so
  capacitors placed 1/4 wavelength away are bad.

 That's why decaps work on low frequency portion. Let's set 100 MHz and
below
 for decaps to cover. The wavelength at 100 MHz is 3 meters. A quarter of
it
 is 75 cm. It's long enough to ordinary PCB size. (The cap is directly
 connected to pwr/gnd planes.)


  This means that we can loosely define the largest usable board area
 capacitance as 1/8
  wavelength radius of copper surrounding the IC power pin.  Charges
stored
 on the planes
  further than 1/8 wavelength away are not very usable due to the time
 delay.
  At 500MHz in FR4, 1/8 wavelength is 1.5 inches.  Is such a board
capacitor
  good enough for your IC?

 George, I beg for differentials. How did you jump from capacitors placed
 1/4 wavelength away are bad to the largest usable board area capacitance
 as 1/8 wavelength radius?

 Can I use the same token to infer from caps placed one wavelength away
are
 good to the largest usable board area capacitance is within 1/2
wavelength
 radius? And so, and so on.

 Regards,
 Barry Ma
 b...@anritsu.com



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Re: Need a substitute part

[Ralph Cameron]

Try a search in www.partminer.com   that's a hope.

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronic Equipment
(After sale)



- Original Message -
From: Allan, James james_al...@milgo.com
To: 'emc-pstc' emc-p...@majordomo.ieee.org
Sent: Tuesday, May 16, 2000 1:19 PM
Subject: Need a substitute part



 HELP!  I am looking for an equivalent to a connector from Spectrum Control
 part number 93538-1. This is a shielded 8 position modular phone jack with
a
 capacitive filter of 110 pf at 710VDC on each pin. It was formerly Amp
part
 number 93538-1 before Spectrum Control bought the rights. Any one out
there
 have an idea of who might make an equivalent? (Yeah - Right)
 Link to Spectrum catalog page here

 http://www.spectrumcontrol.com/sigconpdfs/jackconn.pdf

 Jim Allan
 Senior Compliance Engineer
 Milgo Solutions Inc.
 E-mail james_al...@milgo.com


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Re: Re[2]: [SI-LIST] : Charge moving from decoupling capacitors

[Ralph Cameron]

Equally important is that respect has to be paid to impedance matching ;
other wise, energy is reflected from the load and this will degrade the
risetime as well as cause some energy to be radiated. The dielectric
material must be low loss so that you ensure the signal is conducted with
minimum attenuation.and keeping the path length to the chip to a minimum
keeps the undesired switching products very low.

Ralph Cameron
EMC Consultant for Suppression of Consumer Electronics
(after Sale).

- Original Message -
From: Jim Bacher jim_bac...@mail.monarch.com
To: Larry Miller ldmil...@nortelnetworks.com; EMC-PSTC
emc-p...@ieee.org
Sent: Friday, May 12, 2000 11:24 AM
Subject: Re[2]: [SI-LIST] : Charge moving from decoupling capacitors



 Forwarded for Larry.

 Reply Separator
 Subject:Re: [SI-LIST] : Charge moving from decoupling capacitors
 Author: Larry Miller ldmil...@nortelnetworks.com
 Date:   5/12/00 7:37 AM

 Hi, Barry,

 Responses below:
 At 03:49 PM 5/11/00 -0700, Barry Ma wrote:
 Hi,
 
 As the speed of digital signals gets faster and faster, people begin
being
 concerned with the distance for electric charge to move on power and
ground
 planes of multilayer PCB during the signal rise time from a decoupling
 capacitor (cap) to a chip it serves. I would like to raise two questions.
 
 (1) The charge is moving in a metalic plane, not inside the dielectric
 between pwr and gnd planes. Please let me know why you have to use the
 propagation velocity in the dielectric, instead of that in the metal.

 Due to skin effect at anything above a few tens of kHz, the current flows
 mainly on the surface of the trace, so it has to interact with the
 dielectric in accordance with Maxwell's equations for electromagnetic
waves.

 (2) The second question is regarding distance between the cap and the
 chip. Do we really have to limit the distance letting the charge have
 enough time to move from the cap to the chip during the rise time
interval?
 I doubt it.
 
 No, you have to let the wave propagate (see below).

 Take the running water system for example. When we open, then close the
 water faucet within one second, does the water we've got in basin come
from
 water tower (or water station, or reservoir)? No, it is the water that
 resides in the pipe. As a matter of fact, we have a very large pipe -
 pwr/gnd planes. Well, of cause you know, I did not mean we don't need
water
 tower - the cap. ..

 The running water analogy breaks down here (at AC). Another analogy would
 be that the current is comprised of many successive collisions between
 billiard balls, not the motion of one single ball. Yet another analogy
 would be to look at the current as a game of Chinese checkers, where an
 individual electron can only move into a hole in the board vacated by
 another electron (if you overcome this you get superconduction!). As I
 recollect, the actual speed of an identifiable electron, assuming you
could
 actually identify it, is on the order of a few meters/sec, though the
 electromagnetic wave caused by the transfer of energy between electrons
 travels at the speed of light in the medium.

 Larry Miller



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Re: Ground potential differences....

[Ralph Cameron]

Doug:

Just to enhance your observation, at RF ( i.e. broadcast frequencies
520-1800 Khz)  there is a pseudo resonant effect that places RF ground at
different places in a building , home etc. The RF ground is dependant on the
intereception of direct radiation and is related to how much wiring is
exposed and the angle of exposure.   It would make an interesting problem to
model.

In one case, a CD system on a second floor was completely disabled by RF
 common mode) and the only way to re establish a ground reference was tying
the ground lead from the CD player to the bedprings.  It may sound far
fetched, but it worked.

Sometimes plugging into a different AC outlet in the same room , cleared the
problem.

Ground potential difference can also occur when transformer insulation
becomes leaky , mainly due to age.

Cheers.

Ralph Cameron
EMC Consultant for Suppression of Consuemr Electronic Equipment
(After Sale)

- Original Message -
From: Doug dmck...@gte.net
To: emc-p...@majordomo.ieee.org
Sent: Saturday, May 06, 2000 1:18 PM
Subject: Re: Ground potential differences



 I'm going to stick my neck out here and say from two
 experiences with this topic, there's a couple of things
 to consider ...

 First, ideally, any potential difference between GROUNDS
 should be zero.  If you had asked about NEUTRALS, I'd have
 to say - unknown.  The physical connection is a function
 of the connection to the transformer by the electricians
 and imperfections in the transformer.

 Second, it's a function of what's sourcing the difference.
 I worked at a place where the outlets in one half of the
 lab were supplied by a different substation than the outlets
 at the other end of the lab.

 Without knowing the issue, we connected two different machines
 with a coax.  Each machine eventually connected to different
 substations by way of differently sourced outlets.  And we
 watched with amazement as the rubber jacket of the coax melted.
 All with a 15V difference.  The electricians were notified
 and the problem was solved but a potential difference of
 some sort was still there.  I don't think you'll ever get
 away from it.

 So, I guess what I'm saying is that you should not only
 consider the voltage difference, but the power involved.
 And that would be have to tested some other way.

  - Doug McKean

 Kelly Tsudama wrote:
 
  Hi gang!
 
  I have been asked to look into ground potential differences by one of
the teams that I support.  Can any of you provide any insight on how I can
determine the maximum potential difference between different ground circuits
within a building???  I've heard numbers ranging from 2V to 50V!!!  Even
with all the bonding requirements in the NEC, there must be some voltage
differential between grounding points???
 
  Thanks for any help you can provide.
 
  Kelly

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Re: E-Field Probe Question

[Ralph Cameron]

That's a bit of a puzzler Robert.
As I recall, Tektronix used to state ristetime in terms of that observed
when passing through amplifiers with gaussian rolloff and it was Rt(ns)=
Bandwidth(Mhz) / 350

Ralph Cameron

- Original Message -
From: Robert Macy m...@california.com
To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net;
EMC-PSTC Group emc-p...@majordomo.ieee.org
Sent: Monday, January 24, 2000 8:54 PM
Subject: Re: E-Field Probe Question



 At first that looked like what is asked for is the ability to pass signals
 with a bandwidth of 10Hz.  Given what they're looking for, stating
frequency
 would make it easier to understand.

 But isn't the risetime 1/2pi F??

 Or, are they just saying that the readings pop out at least 10 times per
 second, with the ability to respond in one reading?

   - Robert -


 Ralph Cameron wrote:
 
  Tr usually ment risetime when referred to pulsed signals. In this case
I
  think it refers to response time less than 10Hz. In other words  you'll
 get
  a reading in less than the period of ten hertz at the frequency of
  measurement.
 
 
 Hi Ralph,
 
 Would that be more appropriately stated as 0.10 sec? Just curious.
 
 Regards,
 Dan Kwok
 --
 =
 Daniel Kwok Vancouver, BC, Canada
 Intetron Consulting, Inc.  Telephone 604.432.9874
 
 Email dk...@intetron.com
 FREE EMC Tips @ our website http://www.intetron.com;
 =



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Re: E-Field Probe Question

[Ralph Cameron]

Yes, Dan, you're correct.

Ralph Cameron

- Original Message -
From: Dan Kwok dk...@intetron.com
To: Ralph Cameron ral...@igs.net; EMC-PSTC Group
emc-p...@majordomo.ieee.org
Sent: Monday, January 24, 2000 6:50 PM
Subject: Re: E-Field Probe Question


 Ralph Cameron wrote:
 
  Tr usually ment risetime when referred to pulsed signals. In this case I
  think it refers to response time less than 10Hz. In other words  you'll
get
  a reading in less than the period of ten hertz at the frequency of
  measurement.
 

 Hi Ralph,

 Would that be more appropriately stated as 0.10 sec? Just curious.

 Regards,
 Dan Kwok
 --
 =
 Daniel Kwok Vancouver, BC, Canada
 Intetron Consulting, Inc.  Telephone 604.432.9874

 Email dk...@intetron.com
 FREE EMC Tips @ our website http://www.intetron.com;
 =



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Re: E-Field Probe Question

[Ralph Cameron]

Tr usually ment risetime when referred to pulsed signals. In this case I
think it refers to response time less than 10Hz. In other words  you'll get
a reading in less than the period of ten hertz at the frequency of
measurement.

Ralph Cameron

EMC Consultant and Suppression of Consuemr Electronic Equipment
(After Sale)

- Original Message -
From: Martin Rowe (TMW) m.r...@ieee.org
To: emc-p...@ieee.org
Sent: Monday, January 24, 2000 12:17 PM
Subject: E-Field Probe Question




 I need clarification on a spec for an e-field probe. The spec is
 Tr less than 10 Hz.

 What is Tr?

 The probe is specified in SAE J1113/27 Electromagnetic
 Compatibility Measurements Procedure for Vehicle Components:
 Part 27:Immunity to Radiated Electromagnetic
 Fields-Reverberation Method.

 Thanks,

 /\
 | Martin Rowe  |   /  \
 | Senior Technical Editor  |  /\  /\
 | Test  Measurement World | /  \/  \/\  
 | voice 617-558-4426   |/\  /\  /  \/
 | fax 617-928-4426 |  \/  \/
 | e-mail m.r...@ieee.org   |   \  /
 | http://www.tmworld.com   |\/
 


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Re: Surge Test Performance Criterion

[Ralph Cameron]

It wasn't done derek because there is no requirement that is mandatory. My
humble opinion says voluntary standards don't work as well as they should..
Sometimes it requires a resistor to limit the current going to the switch as
it obviously rectifies some of the RF. In some cases a bypass capacitor is
required also.
on the hot lead to ground.


Ralph

- Original Message -
From: Derek Walton l...@rols1.net
To: Ralph Cameron ral...@igs.net
Cc: carlos.perk...@eu.effem.com; Jim Hulbert hulbe...@pb.com;
emc-p...@ieee.org
Sent: Thursday, January 13, 2000 3:12 PM
Subject: Re: Surge Test Performance Criterion


 Ralph,

 if all it takes is a resistor, I wonder why it wasn't done 99% of the
 population are stuck with a crap product The idea with CE was that
this
 shouldn't happen!

 Derek.

 Ralph Cameron wrote:

  Derek:
 
  You want to locate one of those lights next to a transmitter that is
used
  intermittently - the light sequences through LO-Medium-high then turns
off
  only to come back on again when the transmitter is keyed.
 
  The AC switching device lacks immunity to RF but it may be easily cured
with
  the addition of a single resistor.
 
  Ralph Cameron
 
  EMC Consultant and Suppression of Consumer Electronic Equipment.
  (After sale)
 
  - Original Message -
  From: Derek Walton l...@rols1.net
  To: carlos.perk...@eu.effem.com
  Cc: Jim Hulbert hulbe...@pb.com; emc-p...@ieee.org
  Sent: Thursday, January 13, 2000 8:57 AM
  Subject: Re: Surge Test Performance Criterion
 
  
   Sorry Carlos,
  
   I can't go along with this one. If I'm using my PC here in the USA
midwest
  and a
   storm comes along I don't want my PC shutting itself off every few
  minutes Only
   been hit directly with two lightning strikes this last 2 years, but
during
  a storm
   you can continuously heat squeaking as the modem is hit, I know the
power
  is seeing
   voltage surges too. I'll have to put a Dranitz on the power just to
see
  what kinds
   of voltage surges arrive The same applies to surges generated by
  motors etc. If
   every time a motor switches on and my equipment does something, well
that
  would have
   to go back to the store.
  
   By the way, I don't expect to find in the small print all sorts of get
out
  clauses
   once I buy something
  
   A controlled shut down is there to prevent loss of life, destruction
of
  the device,
   or something as equally bad.
  
   By the way, I was back home ( Manchester, England ) last October and
  bought my Mum a
   light that turns on when you touch any metal part of it, it was CE
marked.
  I have a
   similar light here in the USA, mine's not CE marked. BOTH turn on/off
when
  there are
   voltage transients on the power line. Now you can wrangle all you
want,
  but being
   woken up in the middle of the night because the light turned on when
the
  dishwasher
   began it's Saver Seven ( low cost overnight electricity ) cycle, is
not
  acceptable
   performance! If then manufacturer calls this acceptable performance,
then
  perhaps I
   should call him/her in the middle of the night each time to confirm
that
   opinion...;-)
  
   What products do you make again;-)))
  
   Derek.
  
  
   During surge
  
   carlos.perk...@eu.effem.com wrote:
  
Jim,
   
I agree with you, on the basis that in this case, a complete
shut-down
  is a
designed-in function of the product, and the standard says No
  degradation of
performance or loss of function is allowed below a performance level
  specified
by the manfucturer.  You, as the manufacturer, are specifying this
  'loss of
function'.
   
In my mind, all you have to do is make the end user aware that a
  shut-down will
occur when a surge is detected, and you should be OK.
   
Cheers,
   
Carlos.
   
Please respond to Jim Hulbert hulbe...@pb.com
   
To: emc-p...@ieee.org
cc:  (bcc: Carlos A. Perkins/WIN/Effem)
From:   Jim Hulbert hulbe...@pb.com on 12/01/2000 20:08
   
Subject:  Surge Test Performance Criterion
   
A product has a switched mode power supply with a current sensing
  circuit that
causes the supply to shut down when a surge pulse is applied to the
AC
  mains in
accordance with EN61000-4-5/IEC1000-4-5.  After about 10 minutes,
the
  supply can
be turned back on and normal operation of the product can be resumed
by
  the
operator.   Does this product conform to criterion B of the EN
50082-1
  or EN
55024 standards?  I believe it does because the sensing circuit is
  specifically
designed to protect the product against this kind of voltage/current
  surge and
the product operation is fully recoverable by the operator
afterward.
  However,
I would like to hear how others who do this testing would interpret
  this.
   
Jim Hulbert
Senior Engineer - EMC
Pitney Bowes
   
-
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To cancel your

Re: LVD Essential Requirement for Radiation Protection

[Ralph Cameron]

Patrick:

I think you might find this definitive paragraph from the Canadian
Broadcaster's Manual on Non Ionizing Radiation pertintent to your query and
which complements other comments received:

  Radiation, Ionizing and Non Ionizing

... the energy in an electromagnetic wave increases with frequency.
Around the ultraviolet range ( about 2 million Mhz) the energy is sufficient
to dislodge captive electrons, resulting in charged particles (ions) dashing
about with energies sufficient to break down or change atoms or molecular
structures. At this point the energy wave is classed as ionizing
radiation.

Humans endure continuos natural low level ionizing radiation and regulations
control occupational exposure to some 2.5 millirems per hour for x-rays; the
American and Canadian standards for ultraviolet are based on a maximum
exposure of one milliwatt per square centimeter .  Visible light and
infrared are controlled as well, at ten milliwatts per sq. cm.  Excessive
radiation at any frequency can be injurious to health.

Limits do vary from country to country and Canada's Safety Code 6 is a
guidline recently revised where exposure to EM radiation can occur. It
applies to the general population as well as workers in the field. Copies
are availabel in pdf format if needed.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
( After Sale)
.


- Original Message -
From: Patrick Lawler plaw...@west.net
To: emc-p...@majordomo.ieee.org
Sent: Thursday, January 13, 2000 11:49 AM
Subject: Re: LVD Essential Requirement for Radiation Protection



 What does 'non-ioniozing emissions' cover?

 Is it in the category of personnel safety and low-frequency EMF, or
 does it encompass simple product emissions like those specified in
 CISPR 11?

 On Wed, 12 Jan 2000 11:33:02 -0500, wo...@sensormatic.com wrote:
 An interesting thing has happened to the LVD. Until now, the radiation
 essential requirement of the LVD has been interpreted as referring to
 ionizing radiation and there are harmonized standards addressing that
 requirement, for example, EN 60950. That interpretation has now changed.
 
 In a draft mandate to CENELEC, CEN and ETSI, the Commission is now
 interpreting the radiation essential requirement of the LVD to include
 non-ionizing emissions and that the limits for the general public are to
be
 per the Council's EMF Recommendation. The standards bodies are mandated
to
 produce basic and product standards that would apply to the LV and RTTE
 Directives.
 
 There are no worker limits promulgated at the EU level.
 
 Which leads me to my question. When would this new interpretation of the
 essential requirement take effect - now or the DOW of the associated
 standard?

 --
 Patrick Lawler
 plaw...@west.net

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Re: Surge Test Performance Criterion

[Ralph Cameron]

Derek:

You want to locate one of those lights next to a transmitter that is used
intermittently - the light sequences through LO-Medium-high then turns off
only to come back on again when the transmitter is keyed.

The AC switching device lacks immunity to RF but it may be easily cured with
the addition of a single resistor.

Ralph Cameron

EMC Consultant and Suppression of Consumer Electronic Equipment.
(After sale)

- Original Message -
From: Derek Walton l...@rols1.net
To: carlos.perk...@eu.effem.com
Cc: Jim Hulbert hulbe...@pb.com; emc-p...@ieee.org
Sent: Thursday, January 13, 2000 8:57 AM
Subject: Re: Surge Test Performance Criterion



 Sorry Carlos,

 I can't go along with this one. If I'm using my PC here in the USA midwest
and a
 storm comes along I don't want my PC shutting itself off every few
minutes Only
 been hit directly with two lightning strikes this last 2 years, but during
a storm
 you can continuously heat squeaking as the modem is hit, I know the power
is seeing
 voltage surges too. I'll have to put a Dranitz on the power just to see
what kinds
 of voltage surges arrive The same applies to surges generated by
motors etc. If
 every time a motor switches on and my equipment does something, well that
would have
 to go back to the store.

 By the way, I don't expect to find in the small print all sorts of get out
clauses
 once I buy something

 A controlled shut down is there to prevent loss of life, destruction of
the device,
 or something as equally bad.

 By the way, I was back home ( Manchester, England ) last October and
bought my Mum a
 light that turns on when you touch any metal part of it, it was CE marked.
I have a
 similar light here in the USA, mine's not CE marked. BOTH turn on/off when
there are
 voltage transients on the power line. Now you can wrangle all you want,
but being
 woken up in the middle of the night because the light turned on when the
dishwasher
 began it's Saver Seven ( low cost overnight electricity ) cycle, is not
acceptable
 performance! If then manufacturer calls this acceptable performance, then
perhaps I
 should call him/her in the middle of the night each time to confirm that
 opinion...;-)

 What products do you make again;-)))

 Derek.


 During surge

 carlos.perk...@eu.effem.com wrote:

  Jim,
 
  I agree with you, on the basis that in this case, a complete shut-down
is a
  designed-in function of the product, and the standard says No
degradation of
  performance or loss of function is allowed below a performance level
specified
  by the manfucturer.  You, as the manufacturer, are specifying this
'loss of
  function'.
 
  In my mind, all you have to do is make the end user aware that a
shut-down will
  occur when a surge is detected, and you should be OK.
 
  Cheers,
 
  Carlos.
 
  Please respond to Jim Hulbert hulbe...@pb.com
 
  To: emc-p...@ieee.org
  cc:  (bcc: Carlos A. Perkins/WIN/Effem)
  From:   Jim Hulbert hulbe...@pb.com on 12/01/2000 20:08
 
  Subject:  Surge Test Performance Criterion
 
  A product has a switched mode power supply with a current sensing
circuit that
  causes the supply to shut down when a surge pulse is applied to the AC
mains in
  accordance with EN61000-4-5/IEC1000-4-5.  After about 10 minutes, the
supply can
  be turned back on and normal operation of the product can be resumed by
the
  operator.   Does this product conform to criterion B of the EN 50082-1
or EN
  55024 standards?  I believe it does because the sensing circuit is
specifically
  designed to protect the product against this kind of voltage/current
surge and
  the product operation is fully recoverable by the operator afterward.
However,
  I would like to hear how others who do this testing would interpret
this.
 
  Jim Hulbert
  Senior Engineer - EMC
  Pitney Bowes
 
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Re: Radiation levels.

[Ralph Cameron]

David:

I would be very cautious about personal cell phones  field intensity
measurements . The proximity of the antenna is so close to the body (head)
that some field intensity values I've heard about approach 200-500 V/.m.
The power from such devices is very low but  close proximity puts it in the
near field and the jury still seems to be out debating what the actual
values are. I know a company in this area  is modeling the human head with
the intention of re shaping the radiation pattern to offer more protection
to the exposed body.

Another area of concern is high powered airport surveillance radar. The
fields generated derive from many megawatts of effective radiated power
(erp). i.e. power multiplied by antenna gain.

Industry Canada produced a paper called the Electromagnetic Compatibility
Bulletin known as , EMCAB -1, and it ran into three issues. It was a survey
conducted in 1983 and covered the subject of electromagnetic compatibility
urging manufactureres to design immunity into their products because of the
EM interaction due to proximity effects. It was well conceived and well
researched and has a table of all the expected fields to be expected from
users of the EM spectrum.   It gave quite a bit of detail as to why EMC was
desireable and those needs haven't changed much except there are more
devices now and more EMC related problems . This is someowhat off the topic
of this discussion group but EMC is  embedded in any design where safety is
of concern.
The fields applied to each service are useful design criteria.  The point
made in the paper was that it is easier to design EMC into a product than
try to fix it afterwards.


If interested, I can either scan or copy EMCAB-2 for anyone's use.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment.
(After sale)
- Original Message -
From: David Monreal dmonr...@advancedshielding.com
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, January 12, 2000 7:41 AM
Subject: RE: Radiation levels.


 Dear answerers,

 thanks for your kind help.

 The real cases have been VERY useful. If you have more of them, please
send
 the values to me.

 Thanks again.



 David






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Re: Y3K

[Ralph Cameron]

Roger,

Most of this problem occurs from the Latin M= 1000
and the Greek K=1000   What came later just confused the issue- is this an
example of a decision
by committee(s) ?

Ralph Cameron


- Original Message -
From: roger.vi...@wwgsolutions.com
To: emc-p...@majordomo.ieee.org
Sent: Tuesday, January 11, 2000 5:38 AM
Subject: RE: Y3K




 Thanks to all who made their comments following my complaint about the
misuse of
 K for 1000. Maybe a final word about this problem!

 The IEC (even more pedantic!) are attempting to fix this by creating a new
set
 of units for binary multiples (Amendment 2 to IEC International Standard
IEC
 60027-2: Letter symbols to be used in electrical technology - Part 2:
 Telecommunications and electronics.):

 Ki (kibi) = 2E10 (1024)

 Mi (mebi)= 2E20 (1 048 576)

 Gi (gibi) = 2E30 (1 073 741 824)  etc.

 For details (and to check this is not some early April 1 joke) see the SI
prefix
 description on the US National Institute of Standards and Technology
website at:
 http://physics.nist.gov/cuu/Units/prefixes.html (confirms that x1000 is
small
 k!) and then the binary prefix description at:

 http://physics.nist.gov/cuu/Units/binary.html


 I don?t see the whole IT industry changing its usage to this new set of
prefixes
 !


 Roger




 Gary McInturff gmcintu...@telect.com on 06/01/2000 22:49:38

 Please respond to Gary McInturff gmcintu...@telect.com

 To:   'Egon H. Varju' e...@varju.bc.ca, EMC-PSTC emc-p...@ieee.org
 cc:(bcc: Roger Viles/PLY/Global)

 Subject:  RE: Y3K











 Oh my last birthday my children wanted to know if I was really, really sad
 when the Dinosaur's all died - heavy sigh!
 Anyway - M is for Mega or 1,000,000 and K for Kilo or 1,000
 But I'm sorta betting you're getting tired of hearing that.
 Gary
   -Original Message-
   From: Egon H. Varju [mailto:e...@varju.bc.ca]
   Sent: Thursday, January 06, 2000 9:17 AM
   To:  EMC-PSTC
   Subject:  Re: Y3K



   Roger, way back in the days of the caveman, 1M ohms = 1000
 ohms.  Guess
   going metric changed everything.

   Strange ...  During my dinosaur hunting days, 1M ohm used to
 be = 1 000 000
   ohms.  Maybe we grew up in parallel universes ...

   Egon :-)

   __

   Egon H. Varju, PEng
   E.H. Varju  Associates Ltd.
   North Vancouver, Canada

   Tel:   1 604 985 5710 HAVE MODEM
   Fax:  1 604 273 5815 WILL TRAVEL

   E-mail:  e...@varju.bc.ca
   eva...@compuserve.com
   egon.va...@csa-international.org
   __

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Re: Radiation levels.

[Ralph Cameron]

David:

The field strength at any given point remote from the antenna system can be 
quite variable and depends on power output, antenna pattern, height of antenna 
above ground (TV)   and whether you're in the near or far field.  I've seen 
levels of 200V/m   200 ft from a 50Kw broadcast array and the Canadian 
Association of Broadcasters has a software program written in basic to estimate 
the field from a TV/FM antenna. Canadian Safety Code 6 from Health Canada 
provides formulae for such estimates. 


Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
(After sale)

  - Original Message - 
  From: David Monreal 
  To: emc-p...@majordomo.ieee.org 
  Sent: Tuesday, January 11, 2000 5:14 AM
  Subject: Radiation levels.


  Hi all!

  Could anyone tell me the radiation levels (V/m) generated by broadcast 
antennae? (Radio and TV). I also need the radiation levels for any other 
emmitig devices, machinery, GSM antennae, etc. The more information the better.

  Thanks a lot :-)


  David - The V/m guy

Re: Y3K

[Ralph Cameron]

Hans and Dan:

You're overlooking the fact that by definition in modern computers a byte =
8 bits so when they say 100Mb drive they mean exactly that,  100 megabytes =
800 megabits capacity. ( if you ignore the parity bit which is seldom
transmitted  or recorded.). .

A 56K modem downloads files at 5Kbytes/sec = approx. 40kbps with the usual
line loading.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
(After Sale)

- Original Message -
From: Dan Kwok dk...@intetron.com
To: EMC-PSTC Group emc-p...@majordomo.ieee.org
Sent: Friday, January 07, 2000 6:01 PM
Subject: Y3K



 Hello everyone;

 Of the more recent units that have been a major source of confusion for
 many Internet users, myself included, were the units for download
 speeds:   K/sec versus kbps.

 It made a lot of users wonder why their 56K modem only downloaded files
 at 5K/sec instead of say- 40 kbps. It turns out the 5K/sec as indicated
 on the browser, is actually based on an 8-bit word length so 5K/sec
 actually represented 5x8 or 40 kilo-bits-per-second. That is a lot
 closer to 56 kbps even though typical connection speed is limited to the
 range of 40-50 kbps for most ISPs.


 --
 ===
 Dan Kwok Vancouver, BC, Canada
 Intetron Consulting, Inc.Telephone 604.432.9874

  Email dk...@intetron.com
  *FREE* EMC Tips @ our website http://www.intetron.com
 ===

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Re: Y3K

[Ralph Cameron]

Not so strange these circuits from 1926- figs 34 and 34 are examples.
Parallel , Yes.

Ralph

- Original Message -
From: Egon H. Varju e...@varju.bc.ca
To: EMC-PSTC emc-p...@ieee.org
Sent: Thursday, January 06, 2000 12:17 PM
Subject: Re: Y3K




 Roger, way back in the days of the caveman, 1M ohms = 1000 ohms.  Guess
 going metric changed everything.

 Strange ...  During my dinosaur hunting days, 1M ohm used to be = 1 000
000
 ohms.  Maybe we grew up in parallel universes ...

 Egon :-)

 __

 Egon H. Varju, PEng
 E.H. Varju  Associates Ltd.
 North Vancouver, Canada

 Tel:   1 604 985 5710 HAVE MODEM
 Fax:  1 604 273 5815 WILL TRAVEL

 E-mail:  e...@varju.bc.ca
eva...@compuserve.com
egon.va...@csa-international.org
 __

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attachment: audio.jpg

Re: Y3K

[Ralph Cameron]

Roger, way back in the days of the caveman, 1M ohms = 1000 ohms.  Guess
going metric changed everything.

Ralph Cameron

- Original Message -
From: roger.vi...@wwgsolutions.com
To: Jon Griver jgri...@i-spec.com
Cc: emc-p...@majordomo.ieee.org
Sent: Wednesday, January 05, 2000 12:09 PM
Subject: RE: Y3K





 Personally I'm still waiting for another 48 years until the Y2K bug bites!

 Aside from its real meaning as degrees Kelvin, capital K was first used by
the
 computer guys as a de-facto agreed unit for binary thousand (1024) as in
Kbytes.
 Sloppiness by the financial community led to its use there for thousands
of
 dollars, etc. and ignorance by the media has resulted in its general use.
 Together with the shorthand loved by Americans this has led to Y2K!

 However of course the official unit for 1000 has always been lower case k,
as in
 km, kHz, etc.

 Happy Y2k ! (I won't see Y2K!)

 Roger



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Re: Common Mode or Differential Mode

[Ralph Cameron]

Bob,  if you are just trying to identify the type you could connect a
boradband scope with hig impedance input from each line to ground, assuming
the conductors are carrying AC. The voltages from each side to ground should
be nearly identical if the common mode currents are close to the same value,
i.e. equal volatges. If there is much difference, you can be sure DM
currents are flowing.

regards,

Ralph Cameron
Consultant in EMC and Suppression of consumer electronic equipment
(After sale)

- Original Message -
From: rehel...@mmm.com
To: emc-p...@majordomo.ieee.org
Sent: Tuesday, January 04, 2000 5:20 AM
Subject: Common Mode or Differential Mode





 Are there rules of thumb or a quick and dirty means of determining
 whether conducted emission noise (or radiated) is common mode or
 differential mode?

 Thanks and have a great new year.

 Bob Heller
 3M Company



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Re: CE Marking On Shipping Cartons

[Ralph Cameron]

I will only buy computer products that show the CE label. Often this is
marked on the shipping container so it makes it easier to identify .
Proudcts made to CE specs are superior from a radiated  emissions standpoint
and much less susceptible to conducted emissions. In my opinion, it is a
marketing feature yet to be exploited.

Ralph Cameron
Consultant in EMC and Suppresion of Consumer electronic equipment
(After Sale)

- Original Message -
From: roger.vi...@wwgsolutions.com
To: Jacowleff, Bill bjacowl...@vdo.com
Cc: Emc-Pstc (E-mail) emc-p...@ieee.org
Sent: Tuesday, January 04, 2000 4:55 AM
Subject: Re: CE Marking On Shipping Cartons





 The general rule requires that CE marking must be affixed to the product
or its
 data plate. However where this is not possible or not warranted on account
of
 the nature of the product, it must be afixed to the packaging, if any, and
to
 the accompanying documents, where the directive concerned provides for
such
 documents.

 However note that the recent RTTE Directive does appear to mandate
marking the
 packaging:  CE marking must be affixed to the product or its data plate.
 Additionally it must be afixed to the packaging, if any, and to the
accompanying
 documents.

 I guess this is intended to ensure that any mark indicating restrictions
on
 (countries of) use is visible from the outside.

 Roger



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Re: Servicing and repairs

[Ralph Cameron]

Brian:

As a comment I would say that the liability to meet EU approval ends when
the product is sold and ownership is transferred. That's the way it happens
with consumer goods in Canada, in spite of the fact there is CSA approval
required on the original product.

Compliments of the Season

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
(After Sale).

- Original Message -
From: Brian Harlowe bharl...@vgscientific.com
To: emc-p...@ieee.org
Sent: Tuesday, December 21, 1999 9:04 AM
Subject: Servicing and repairs



 Traditionally my company has encouraged it's users to carry out a
 limited amount of servicing and repair on our Electronic units.

 Under the EU Safety legislation I know this is now a No No.

 I am a little bit of a lone voice crying in the wilderness as far as
 our management is concerned.

 Can any one out there quote me any instances or cases that I can use
 to drive home the point with our management

 A happy Christmas to you fellow compliance people and if we survive
 the Y2K business.  Good luck in the new century and may this
 newsgroup continue to prosper

 Best Regards

 Brian Harlowe
 * opinions expressed here are personal and in no way reflect the position
of VG Scientific

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Re: Magnetic field monitors

[Ralph Cameron]

Health Canada, under Safety Code 6 specifies magnetic field strength in A/m
.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronic Equipment
(After Sale)

- Original Message -
From: Mike Hopkins mhopk...@keytek.com
To: 'Rich Nute' ri...@sdd.hp.com
Cc: 'IEEE' emc-p...@ieee.org
Sent: Friday, December 17, 1999 6:42 AM
Subject: RE: Magnetic field monitors



 IEC 1000-4-8 require testing products in a square loop with magentic field
 strengths expressed in Amps/meter; hence, customers want
 measurement/monitoring equipment that reads in Amps/meter.

 Page 17 of 1000-4-8 states The magnetic field strength is expressed in
A/m;
 1 A/m corresponds to a free space induction of 1.26uT.

 Mike Hopkins
 mhopk...@keytek.com

  -Original Message-
  From: Rich Nute [SMTP:ri...@sdd.hp.com]
  Sent: Thursday, December 16, 1999 6:02 PM
  To: mhopk...@keytek.com
  Cc: emc-p...@ieee.org
  Subject: Re: Magnetic field monitors
 
 
 
  Hmmm.  Let's see:
 
  Magnetic field strength is measured in:
 
  amperes/meter
  oerstads
 
  Magnetic flux density is measured in:
 
  tesla
  gauss
 
  As near as I can tell, there is no conversion from
  one to the other.  This would imply they are
  separate phenomenon.
 
  I'm not in the EMC field, but I'm curious as
  to regulatory requirements and what interferences
  such emissions would cause.  (I'm presuming both
  are regulated.)
 
 
  Best regards,
  Rich
 
 

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Re: Piezo lighters

[Ralph Cameron]

You can measure that with a 40KV probe and a digital storage scope set for
single shot event. i.e the scope triggers from the event.  Probe loading
should be as low as possible ( hi Z probe).

Ralph Cameron

- Original Message -
From: carlos.perk...@eu.effem.com
To: emc-p...@ieee.org
Sent: Wednesday, December 15, 1999 11:24 PM
Subject: Piezo lighters



 Dear All,

 Does anyone out there know what the peak voltage of a handheld piezo gas
 lighter is?  Or how to measure it?

 Any tips would be very welcome.

 Many thanks,

 Carlos.



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Re: RTTE Directive EMF Limits

[Ralph Cameron]

Richard:

The Canadian version of your FCC limts is called Safety Code 6 and has
recetnly been revised by  Health Canada. it doesn't permit computer
simulations but of course in the lab you can do anything.

Ralph Cameron
Consultant in EMC and Suppression of Consumer Electronic Euipment
(After sale)

- Original Message -
From: wo...@sensormatic.com
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, December 15, 1999 5:46 AM
Subject: RTTE Directive EMF Limits



 The RTTE Directive includes an essential requirement for health and
 safety which is interpreted by the Commission as human exposure to EMF.
I
 would like to hear from anyone that has equipment operating at less than
100
 kHz and plans on demonstrating compliance to the basic limits. This is
what
 my company plans to do using computer simulation.

 Richard Woods

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Re: Open Frame EMI Filters

[Ralph Cameron]

Doug:

It would seem logical that the shield will guarantee a high degree of
immunity to local radiated fields.  If the filter is a commerical one its
specs are probably dependent on the shield being in situ.  Even though it
may meet the EMC  test requirement, there is an added degree of safety
 i.e. equipment malfunction) with the filter in place. If there is line
voltage appearing on any of the components and they are in areas used by
service people then the question of electrical safety is addressed by having
a shield.   This is only my opinion.

Ralph Cameron
EMC Consultant and Suppression of Consumer Electronics
(After Sale)

- Original Message -
From: POWELL, DOUG doug.pow...@aei.com
To: emc-p...@majordomo.ieee.org; Treg Listserv (E-mail)
t...@world.std.com
Sent: Wednesday, December 08, 1999 2:19 PM
Subject: RE: Open Frame EMI Filters



 Hello once again,

 I have already received a number of replies to my query indicating that
the
 metallic enclosure is required for low inductance coupling to the
components
 or to prevent radiation between circuits within the product.  This is not
my
 question.

 Please remember that one of the criteria that I described for the open
frame
 is the passing all applicable EMC tests.  This means that the open-frame
 design that I propose meets both radiated and conducted emissions levels,
 without the metallic box.  My questions deals more with why is the
enclosure
 required if product passes the tests without it.  In the past I have
 designed a few products with a simple PCB for emissions control.  I
 compensated for the internal re-radiation problem.

 Recently I heard of a commercial EMI Filter company that says the
enclosure
 is required and that the encapsulant is a requirement.  I disagree.

 -doug

 ===
 Douglas E. Powell
 Regulatory Compliance Engineer
 Advanced Energy Industries, Inc.
 1625 Sharp Point Dr.
 Fort Collins, Colorado 80525 USA
 m/s: 2018
 ---
 970-407-6410 (phone)
 970-407-5410 (e-fax)
 800-446-9167 (toll-free)
 mailto:doug.pow...@aei.com
 http://www.advanced-energy.com
 ===



  
   Hello group,
  
   For years I have used off-the-shelf and custom EMI filters
  with a fully
   enclosed metal canister.  Why is this enclosure required?  Are there
   specific provisions in the standards?  My idea is to build
  up the filter
   circuit on a printed circuit board and  make it an integral
  part of the
   power supply.
  
   I am currently looking at EN133200 which has certain seal
  tests but after
   reviewing these, they all appear to be related to climatic or
  environmental
   conditions.  If the product passes these tests without the
  enclosure it
   would seem that the product has passed, period.
  
   Alternatively I have considered removing the nomenclature
  EMI filter and
   simply call it an input module, then evaluate it as a part
  of the overall
   system.  If it passes the EMC and Product Safety
  requirements, can I call
   the job complete?
  
   Any thoughts?
  
   ===
   Douglas E. Powell
   Regulatory Compliance Engineer
   Advanced Energy Industries, Inc.
   1625 Sharp Point Dr.
   Fort Collins, Colorado 80525 USA
   m/s: 2018
   ---
   970-407-6410 (phone)
   970-407-5410 (e-fax)
   800-446-9167 (toll-free)
   mailto:doug.pow...@aei.com mailto:doug.pow...@aei.com
   http://www.advanced-energy.com http://www.advanced-energy.com
   ===
  
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Re: warning label overkill?

[Ralph Cameron]

Hi Ron:

In the interest of safety, why place the onus on the consumer when he/she
had nothing to do with the design?

Ralph Cameron


- Original Message -
From: ron_du...@agilent.com
To: emc-p...@majordomo.ieee.org; sobe...@fdanews.com
Sent: Friday, December 03, 1999 6:40 AM
Subject: RE: warning label overkill?



 I agree. I question the warning on champagne bottles. I mean anybody that
 reaches legal drinking age knows a champagne cork can become a projectile.

 This is a prime example of shifting the responsibility from the
responsible
 person to the manufacturer.

 Ron Duffy
 Product Safety Engineer
 Aiglent Technologies

 -Original Message-
 From: sobe...@fdanews.com [mailto:sobe...@fdanews.com]
 Sent: Thursday, 02 December, 1999 14:14
 To: emc-p...@majordomo.ieee.org
 Subject: FW: warning label overkill?



 Serious question even though this involves a non-electrical product: at
 what point do warning labels undermine themselves?

 I was surprised to find this warning label on a 20 oz bottle of Dr.
 Pepper. It seems to be unique to that brand -- Coke, Pepsi and whatnot
 don't seem to carry it.

 ! WARNING (exclamation point is inside a triangle)
 CONTENTS UNDER PRESSURE. CAP MAY BLOW OFF CAUSING EYE OR OTHER SERIOUS
 INJURY. POINT AWAY FROM FACE AND PEOPLE, ESPECIALLY WHILE OPENING.

 It didn't seem to be any more carbonated than the Cokes I usually buy. I
 can see the point of such labels on Champaign with the corks that often
 become projectiles. But the physics of a screw-off soda bottle cap just
 doesn't seem to have the same ballistic potential. (I know, I know, the
 GC made them do it. But still.)

 --
 Sean Oberle
 Vice President of New Products
 Washington Business Information, Inc.
 1117 N 19th St, Ste 200, Arlington, VA 22209
 Voice: 703/247-3429; Fax: 703/247-3421



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Re: Ferrites can increase emissions?

[Ralph Cameron]

The purpose of a common mode choke whether it be of ferrite or powdered iron
is to isolate the connecting conductors from the rest of the mainboard or
chassis.   If the toridal core is correctly placed as close to the source of
the emissions i.e. the PCB, the conductors which carry the emitted noise are
effectively isolated from high frequency noise currents to flow in common
mode.  The attenutaion will vary acording to the efficiency of the material
selected and a permeability of a nominal 850 is useful over the range 3-40
Mhz.

Some of the telphone companies use common mode chokes to attempt to suppress
induced RF energy on phone lines and sometimes it works.  They alsmot always
specify placement of the in line encapsulated choke (ATT Z1000) at the wall
socket.  The amount of connecting cable from the phone to the wall socket is
a good antenna too so picks up RF and bypasses any effect of the common mode
choke. Although the problem is removing the condcuted current before it
becomes a problem , the same principle applies to emitted noise.

In some cases of suppressing consumer equipment there is a dramatic increase
in sensitvity to conducted currents at different frequencies( usually
higher) and this requires that the ground loop provided by the power cord be
isolated from the device.   Inevitably this has cured the problem.  Be aware
that any cabling connected to a device can radiate as well as conduct
undesireable energy into the device. Ferrites provide a simple, non
intrusive, inexpensive solution to such problems.  You will see them on all
the better quality computer monitors and laptops.

Ralph Cameron

Independant EMC Consultant and suppresion of consumer electronics
(After sale)

- Original Message -
From: Douglas C. Smith d...@dsmith.org
To: emc-pstc emc-p...@majordomo.ieee.org
Sent: Wednesday, December 01, 1999 9:46 PM
Subject: Ferrites can increase emissions?



 Hi All,

 I have noticed (like I expect many of you) that sometimes adding a
 ferrite on a cable to suppress common mode current caused emissions
 actually increases emissions at some frequencies. After thinking about
 this and trying an experiment to confirm one mechanism, I wrote up an
 article describing that mechanism. I have posted the article on my
 website (emcesd.com or www.dsmith.org) as the Technical Tidbit
 article for December.

 For the case shown there, a ferrite added at the OPPOSITE end of the
 cable from EUT2 would actually reduce emissions from EUT2 at frequency
 F2. Whereas if added at EUT2, emissions from EUT2 go down but go up
 from EUT1. Sort of an unusual case. Granted this is a special case,
 but the result is interesting and suggests lots of other possible
 configurations with strange results.

 Doug

 --
 ---
 ___  _   Doug Smith
  \  / )  P.O. Box 1457
   =  Los Gatos, CA 95031-1457
_ / \ / \ _   TEL/FAX: 408-356-4186/358-3799
  /  /\  \ ] /  /\  \ Mobile:  408-858-4528
 |  q-( )  |  o  |Email:   d...@dsmith.org
  \ _ /]\ _ / Website: http://www.dsmith.org
 ---

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Re: Ferrites can increase emissions?

[Ralph Cameron]

Hi Doug:

The term ground loop is misleading I agree. I meant to say coupling and by
placing the ferrite remotely from the source of the emissions only serves to
end load the conductors which will change the resonant length.

In the case of placing the toroidal device on the power cord, right at the
point of entry to the PCB, chassis, cabinet etc. the coupling loop as
opposed to ground loop is generally broken and the harmful effects( device
malfunction) disappear.

I guess the point I'm trying to make is why defeat the purpose of a
suppression device by placing it on conductors remotely from the source of
the emissions?

Ralph

- Original Message -
From: Douglas C. Smith d...@dsmith.org
To: Ralph Cameron ral...@igs.net
Cc: emc-pstc emc-p...@majordomo.ieee.org
Sent: Thursday, December 02, 1999 8:43 AM
Subject: Re: Ferrites can increase emissions?


 Hi Ralph and all,

 Please define ground loop in your reply below. Normally, the term
 ground loop only has meaning at low frequencies (60 Hz and DC). At
 high frequencies an infinite number of loops exist and they do not
 require a conductor to complete them. You need to define exactly the
 effect for the particular case below.

 The special case in my article goes a level deeper than your
 discussion to show that ferrites at one end of a cable can either
 increase or decrease emissions from equipment at the opposite end by
 either causing an impedance match or mismatch. No ground loops
 needed to explain this phenomenon.

 Doug


 Ralph Cameron wrote:
 
  The purpose of a common mode choke whether it be of ferrite or powdered
iron
  is to isolate the connecting conductors from the rest of the mainboard
or
  chassis.   If the toridal core is correctly placed as close to the
source of
  the emissions i.e. the PCB, the conductors which carry the emitted noise
are
  effectively isolated from high frequency noise currents to flow in
common
  mode.  The attenutaion will vary acording to the efficiency of the
material
  selected and a permeability of a nominal 850 is useful over the range
3-40
  Mhz.
 
  Some of the telphone companies use common mode chokes to attempt to
suppress
  induced RF energy on phone lines and sometimes it works.  They alsmot
always
  specify placement of the in line encapsulated choke (ATT Z1000) at the
wall
  socket.  The amount of connecting cable from the phone to the wall
socket is
  a good antenna too so picks up RF and bypasses any effect of the common
mode
  choke. Although the problem is removing the condcuted current before it
  becomes a problem , the same principle applies to emitted noise.
 
  In some cases of suppressing consumer equipment there is a dramatic
increase
  in sensitvity to conducted currents at different frequencies( usually
  higher) and this requires that the ground loop provided by the power
cord be
  isolated from the device.   Inevitably this has cured the problem.  Be
aware
  that any cabling connected to a device can radiate as well as conduct
  undesireable energy into the device. Ferrites provide a simple, non
  intrusive, inexpensive solution to such problems.  You will see them on
all
  the better quality computer monitors and laptops.
 
  Ralph Cameron
 
  Independant EMC Consultant and suppresion of consumer electronics
  (After sale)
 
  - Original Message -
  From: Douglas C. Smith d...@dsmith.org
  To: emc-pstc emc-p...@majordomo.ieee.org
  Sent: Wednesday, December 01, 1999 9:46 PM
  Subject: Ferrites can increase emissions?
 
  
   Hi All,
  
   I have noticed (like I expect many of you) that sometimes adding a
   ferrite on a cable to suppress common mode current caused emissions
   actually increases emissions at some frequencies. After thinking about
   this and trying an experiment to confirm one mechanism, I wrote up an
   article describing that mechanism. I have posted the article on my
   website (emcesd.com or www.dsmith.org) as the Technical Tidbit
   article for December.
  
   For the case shown there, a ferrite added at the OPPOSITE end of the
   cable from EUT2 would actually reduce emissions from EUT2 at frequency
   F2. Whereas if added at EUT2, emissions from EUT2 go down but go up
   from EUT1. Sort of an unusual case. Granted this is a special case,
   but the result is interesting and suggests lots of other possible
   configurations with strange results.
  
   Doug
  
   --
   ---
   ___  _   Doug Smith
\  / )  P.O. Box 1457
 =  Los Gatos, CA 95031-1457
  _ / \ / \ _   TEL/FAX: 408-356-4186/358-3799
/  /\  \ ] /  /\  \ Mobile:  408-858-4528
   |  q-( )  |  o  |Email:   d...@dsmith.org
\ _ /]\ _ / Website: http://www.dsmith.org
   ---
  
   -
   This message is coming from the emc-pstc discussion list

Re: Ferrites can increase emissions?

[Ralph Cameron]

Hi Doug:

I would agree with you technically and your intent.

Ralph

- Original Message -
From: Doug Smith dsm...@corp.auspex.com
To: Ralph Cameron ral...@igs.net; d...@dsmith.org
Cc: emc-pstc emc-p...@majordomo.ieee.org
Sent: Thursday, December 02, 1999 2:35 PM
Subject: Re: Ferrites can increase emissions?


 Hi Ralph,

 I don't advocate placing the ferrite on the far end of cords. My example
is
 meant to be instructive of the kind of mechanisms at work here and take
 some of the magic out of using ferrites.

 I would be interested in hearing from others in this group of unusual
 experiences with ferrites or details of other examples that yield
 unexpected results. This kind of discussion between fire fighting episodes
 on the job is the best part of EMC to me.

 Doug

 At 12:09 PM 12/2/99 -0800, Ralph Cameron wrote:
 
 Hi Doug:
 
 The term ground loop is misleading I agree. I meant to say coupling and
by
 placing the ferrite remotely from the source of the emissions only serves
to
 end load the conductors which will change the resonant length.
 
 In the case of placing the toroidal device on the power cord, right at
the
 point of entry to the PCB, chassis, cabinet etc. the coupling loop as
 opposed to ground loop is generally broken and the harmful
ffects( device
 malfunction) disappear.
 
 I guess the point I'm trying to make is why defeat the purpose of a
 suppression device by placing it on conductors remotely from the source
of
 the emissions?
 
 Ralph
 
 - Original Message -
 From: Douglas C. Smith d...@dsmith.org
 To: Ralph Cameron ral...@igs.net
 Cc: emc-pstc emc-p...@majordomo.ieee.org
 Sent: Thursday, December 02, 1999 8:43 AM
 Subject: Re: Ferrites can increase emissions?
 
 
  Hi Ralph and all,
 
  Please define ground loop in your reply below. Normally, the term
  ground loop only has meaning at low frequencies (60 Hz and DC). At
  high frequencies an infinite number of loops exist and they do not
  require a conductor to complete them. You need to define exactly the
  effect for the particular case below.
 
  The special case in my article goes a level deeper than your
  discussion to show that ferrites at one end of a cable can either
  increase or decrease emissions from equipment at the opposite end by
  either causing an impedance match or mismatch. No ground loops
  needed to explain this phenomenon.
 
  Doug
 
 
  Ralph Cameron wrote:
  
   The purpose of a common mode choke whether it be of ferrite or
powdered
 iron
   is to isolate the connecting conductors from the rest of the
mainboard
 or
   chassis.   If the toridal core is correctly placed as close to the
 source of
   the emissions i.e. the PCB, the conductors which carry the emitted
noise
 are
   effectively isolated from high frequency noise currents to flow in
 common
   mode.  The attenutaion will vary acording to the efficiency of the
 material
   selected and a permeability of a nominal 850 is useful over the range
 3-40
   Mhz.
  
   Some of the telphone companies use common mode chokes to attempt to
 suppress
   induced RF energy on phone lines and sometimes it works.  They alsmot
 always
   specify placement of the in line encapsulated choke (ATT Z1000) at
the
 wall
   socket.  The amount of connecting cable from the phone to the wall
 socket is
   a good antenna too so picks up RF and bypasses any effect of the
common
 mode
   choke. Although the problem is removing the condcuted current before
it
   becomes a problem , the same principle applies to emitted noise.
  
   In some cases of suppressing consumer equipment there is a dramatic
 increase
   in sensitvity to conducted currents at different frequencies( usually
   higher) and this requires that the ground loop provided by the power
 cord be
   isolated from the device.   Inevitably this has cured the problem.
Be
 aware
   that any cabling connected to a device can radiate as well as conduct
   undesireable energy into the device. Ferrites provide a simple, non
   intrusive, inexpensive solution to such problems.  You will see them
on
 all
   the better quality computer monitors and laptops.
  
   Ralph Cameron
  
   Independant EMC Consultant and suppresion of consumer electronics
   (After sale)
  
   - Original Message -
   From: Douglas C. Smith d...@dsmith.org
   To: emc-pstc emc-p...@majordomo.ieee.org
   Sent: Wednesday, December 01, 1999 9:46 PM
   Subject: Ferrites can increase emissions?
  
   
Hi All,
   
I have noticed (like I expect many of you) that sometimes adding a
ferrite on a cable to suppress common mode current caused emissions
actually increases emissions at some frequencies. After thinking
about
this and trying an experiment to confirm one mechanism, I wrote up
an
article describing that mechanism. I have posted the article on my
website (emcesd.com or www.dsmith.org) as the Technical Tidbit
article for December.
   
For the case shown there, a ferrite added at the OPPOSITE end

Re: Copy of: D of C - Who Signs?

[Ralph Cameron]

Marin:

Barring non compliant products from entry soon makes its point rather than
trying to untangle the legal liability in such rare cases.

Ralph Cameron
Independant Consulting and EMC suppression in consumer electronics
(after sale)


- Original Message -
From: Martin Green martin.gr...@iti.co.uk
To: 'Allan G. Carr' al...@acarr.demon.co.uk
Cc: 'Price, Ed' ed.pr...@cubic.com; emc-p...@ieee.org
Sent: Thursday, November 25, 1999 6:05 AM
Subject: RE: Copy of: D of C - Who Signs?



 Alan,

 As far as the quotation is concerned, I would refer you to the words in
Reg.
 40(2)(c), Erg 57(2)(c), Erg 70(2)(c) for clauses detailing who signs the
 DoC.  Under the UK regulations it will, as I said in my email, be signed
by
 or on behalf of the manufacturer or his authorised representative and
 identify that signatory

 As far as going to court is concerned, I too thought that action would be
 taken against the responsible person, but when I discussed this with both
 the DTI and some lawyers they said that as the offence would be placing
on
 the market a product that did not meet the protection requirements  - or
 similar words, and it would be a charge raised in a UK court, then it is
the
 person selling it that is charged.  Apparently, there is no cross border
 joint jurisdiction in the EU for CE marking offences.  I understand that
the
 UK authorities would inform the EU commission and they in turn would
inform
 the authorities in Belgium.  The Belgium authorities may then choose to
 investigate the offence to see if an offence had been committed in
Belgium,
 under Belgium law.  However, there is no doubt that the UK courts could
not
 take action against a citizen in Belgium for this type of offence.

 Whether the Belgium authorities would be able to charge a Belgium citizen
 with an offence committed in the UK is open the question.  It is like
being
 charged for speeding in Germany and having a UK court hear the case. It
does
 not work.  As many will know to their cost (including me!), if you commit
a
 motoring offence in Germany then you can pay a fine either on the spot or
in
 court.  Usually it on the spot - even if you are British!  The UK courts
do
 not hear motoring offences committed in Germany.

 Regards

 Martin
  -Original Message-
  From: Allan G. Carr [SMTP:e...@acarr.demon.co.uk]
  Sent: 25 November 1999 13:43
  To: Martin Green
  Cc: 'Price, Ed'; 'emc-p...@ieee.org'
  Subject: Re: Copy of: D of C - Who Signs?
 
  Martin
 
  Thanks for the comprehensive reply to my post.
 
  I have the following comments:-
 
  The UK EMC regulations do not say
  the DoC is signed by the responsible person.  They say the DoC must be
  signed by or on behalf of the manufacturer or his authorised
  representative
  and identify that signatory.
 
  Sorry to be pedantic but the UK Statutory Instrument 1992 No.2372 does
  not contain the above quote.   This quote is from EC EMC Guidelines
  which therefore clarify the issue.
 
 
  The question always arises as to who ends up in court.  As an example,
if
  the DoC is signed in the USA, for a product made in Mexico, being sold
by
  distributors in 10 of the member states in the EU, with the authorised
  rep
  in Belgium acting as the responsible person and there is a court case
for
  infringement of the UK EMC regulations, who ends up in court?  The
action
  is
  taken in UK by the Trading Standards Officers against the person
placing
  the
  product on the market in the UK.  The answer is the distributor.  The
UK
  has
  no jurisdiction over the authorised rep in Belgium or the manufacturer
  outside the EU.
 
  UK Trading Standards tell me that in the above example the prosecution
  would be handed over to the EC country of residence of the responsible
  person who keeps the documentation - in this case Belgium.
 
  However the UK distributor could be in the firing line if UK Trading
  Standards were not happy with the result.
 
 
 
  Thanks again for your excellent response
  Allan
  
 
  In message E17783957970D21193D40080AD1CA3E20526C5@SERVER, Martin Green
  martin.gr...@iti.co.uk writes
  It is always interesting to read the legal interpretation of these
  documents.  I now understand why lawyers make so much money.
  
  If you have the staying power you might find this or interest/value,
  otherwise hit the delete button!
  
  The interpretation below is incorrect.  The UK EMC regulations do not
say
  the DoC is signed by the responsible person.  They say the DoC must be
  signed by or on behalf of the manufacturer or his authorised
  representative
  and identify that signatory.
  
  They also say the that DoC must give the name and address of the
  responsible
  person and where that person is not the manufacturer, of the
  manufacturer.
  
  For those who read this stuff and are not used to the arcane legal
words
  inside UK Statutory Instruments this is often difficult to understand.
  The
  problem

Re: Article to UL

[Ralph Cameron]

I woudn't take the Washington Post articel seriously but unfortunately in
the struggle for the media to retain readership they act as interpreters of
things they don't fully understand and in the course of publishing spread
technical inaccuracies.  The article is only an opinion, albeit one sided.
I would agree with Peter that not juch is to be gained by negative bashing.

Manufacturers should voluntarily ascribe to saftey as an ethical and moral
obligation and promote the profession of responsible engineering.  The same
should apply to EMC immunity in products.  I'd like to see the Washington
Post write about that.  I could help them.

Keep up the objective comments, they lead to progress.

Ralph Cameron

Independant EMC Consulting for suppression of consumer products lacking EMC.
(After sale).


- Original Message -
From: peterh...@aol.com
To: emc-p...@majordomo.ieee.org
Sent: Wednesday, November 24, 1999 8:08 PM
Subject: Article to UL



 Hello group,

 It seems to me that the article in Washington Post, was written by someone
 who really had not done their homework. It sounded as the article was
 criticizing UL for not doing proper testing or not being able to write
their
 standards adequately. Like most of the people in the group, I am certainly
 not a fan of UL for various reasons that are outside the scope of this
 particular subject, but one has to remember that almost majority of the
 standards are written with manufacturers directly involved during the
 generation of the standard. Obviously those of us who are being
represented
 in various standard committee we who are responsible for writing the
 standard, try to influence the standard as much as we can in our industry
 favor and test houses such as UL, CSA , BSI, more or less go along with
it.
 As for testing is concerned, all UL engineers as well as their
counterparts
 in other test houses only test the product to the clauses of the standard
and
 they are not allowed to go any further. On top of that, the way that any
of
 these standard are written it is widely open to interpretation so we as
test
 engineers always try to argue with the test house engineer to try to avoid
 any failure. Another point to bear in mind is that the test house
engineers
 are only human like the rest of us and can make mistake or even overlook
at
 some points. Last but not least, most of us have seen a certified product
 been slightly modified/altered by someone in our company for an unknown
 reason and still bears the safety mark without even informing any of the
test
 houses concerned . So I believe we should look at the root casue of the
 problem and try to improve the situation by
 (a) be honest with the test houses during testing.
 (b) by trying to encourage our designers to make the product almost fool
 proof.
 © do addition in-house testing that exceeds the requirements of the
standard
 (d) by being a truly responsible manufacturer.

 Thanks
 Peter

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Re: Conducted Emissions for PS output

[Ralph Cameron]

Derek

The most common method I've found effective - even after sale- is the use of
a toroidal ferrite core , large enough to take 8-9 turns of the power cord,
mounted as close to the supply as possible. There is 15-20 dB decoupling to
common mode noise provided by this method and I've used it hundreds of
times. It also prevents ingress of RF.

Ralph Cameron
Independent EMC Consultant

- Original Message -
From: Derek Walton l...@rols1.net
To: EMC Discussion Group emc-p...@ieee.org
Sent: Tuesday, November 16, 1999 6:33 PM
Subject: Conducted Emissions for PS output



 HI,

 would anyone like to suggest a specification for controlling conducted
 emissions from the output of a power supply or battery charger. The
 market place is either the USA or Europe.

 Thanks,

 Derek.

 --
 Derek Walton
 Owner
 L. F. Research EMC Design and Test Facility
 12790 Route 76,
 Poplar Grove,
 IL 61065.
 www.lfresearch.com



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magnetic shielding

[Ralph Cameron]

Mu metal with a very high permeability has always been used for shielding CRTs 
from the effects of stray magnetic shields, essentially creating a very low 
reluctance path. it is still used as far as I know. 

Ralph Cameron