Any restriction in Europe over the band of 90KHz to 250KHz?

[Robert Macy]

Intentional radiator that is narrow band but rather
energetic.

Is there any frequency I can set this transmitter at in
this low frequency range and not accidentally step on a
restriction.

Vaguely remember some military bands down there that forbid
*any* transmitters down there, but can't find any
documentation supporting that memory.

Robert

-

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Information on operation in the 6.78 MHz ISM Band

[Robert Macy]

Does anyone have experience in this band?
 
Or, have URLs to find limits and required characteristics
to operate in this band?

Robert

-

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Re: Germanium & ITO Window shielding effectiveness

[robert Macy]

Andrew,

My firm has the technology to make optically transparent
magnetic shield.  Optical transparency is better than 65%.

Costs relate to the requirement of how much
  field of view
  reduction of field

Please contact me directly, off the group.

   - Robert -

   Robert A. Macy, PE. . m...@california.com
   408 286 3985. . . . . . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Thu, 16 Sep 2004 08:21:12 +0100
 "Price, Andrew P (UK Basildon)"
 wrote:
> Hello group.
>
> Can anyone help with finding information on shielding
> effectiveness of Germanium and ITO coated windows against
> magnetic fields?
>
> Regards
> Andy
>
> Andrew Price
> Principal Development Engineer (EMC Specialist)
> BAE SYSTEMS Avionics
> A125
> Christopher Martin Road
> Basildon, Essex
> SS14 3EL
>
> tel:   +44 (0) 1268 883308
> email: andrew.p.pr...@baesystems.com
>
>


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Re: Difference between the HP 8566A and the HP 8566B

[robert Macy]

Alas, all my vintage reference books are in storage.  

As I recall, B refers to lower frequency capability and/or
finer BW resolution, like from 30Hz BW down to 10Hz BW

Simply has extended lower ranges.  

  - Robert -

On Tue, 25 Nov 2003 08:38:30 -0800
 "Pettit, Ghery"  wrote:
> 
> Not true.  The 8566 (A or B) goes to 22 GHz.  The 8568 (A
> or B) goes to
> 1.5 GHz.
> 
> Ghery Pettit
> 
> 
> -Original Message-
> From: owner-emc-p...@majordomo.ieee.org
> [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of
> Gaby F. Abboud
> Sent: Tuesday, November 25, 2003 6:37 AM
> To: lfresea...@aol.com; emc-p...@ieee.org
> Subject: Re: Difference between the HP 8566A and the HP
> 8566B
> 
> 
> 8566A can be used up to 1GHz
> 8566B can be used up to 22GHz
> 
> I hope this helped.
> 
> Gaby,
> > 
> > From: lfresea...@aol.com
> > Date: 2003/11/24 Mon PM 11:23:10 EST
> > To: emc-p...@ieee.org
> > Subject: Difference between the HP 8566A and the HP
> 8566B
> > 
> > Hi there,
> > 
> > can anyone tell me the difference between the two
> spectrum analysers?
> > 
> > Thanks,
> > 
> > Derek N. Walton
> > Owner, L F Research EMI Design and Test Facility
> > Poplar Grove,
> > IL 61065
> > 
> > 
> 
> 
> ---
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Re: RFID tags

[robert Macy]

My vote..

Passive means to modify the field, this includes harmonic
content.

Active means use the field to generate new frequencies, as
though a battery were attached.  

  - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Thu, 20 Nov 2003 14:38:05 -0500
 djumbdenst...@tycoint.com wrote:
> 
> I have heard the term "passive" used 2 ways, as indicated
> below or as a
> device that actually transponds an independent code from
> that which it
> received from the interrogator, powered off the
> interrogator's field.  Thus
> in the latter it is a function of with or without a
> battery, with = active,
> without = passive.  What is the consensus of the Forum
> for "passive"
> regarding RFID tags?
> 
> Don Umbdenstock
> Sensormatic 
> 


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Re: Leakage at Enclosure Seams

[robert Macy]

>From vague memory...
there was some work done by Don White (?) that shows tables
of this type of improvement.  Full of practical data and
information.  

 - Robert -

On Mon, 17 Nov 2003 15:21:54 -
 "Jeff Chambers"  wrote:
> 
> I  have been asked to comment on what improvement might
> be expected in
> changing the design of an equipment lid from:
> 
> A flat lid sat on the edges of the box, where the gaps
> between fasteners can
> be modelled as a simple aperture, where the attenuation
> decreases linearly
> with log(f) to zero at a half wavelength.
> 
> To:
> A stepped lid, with the lid sat on the edges, and with
> the projection
> extending below the inner edge of the box.This removes
> the 'line of sight'
> gap into the enclosure. Does this improve the
> attenuation? Intuitively it
> should, but if the leakage occurs because of the
> interruption in shielding
> conductivity and hence current flow at the seam, it
> won't.
> 
> Does anybody have any references to analyses of the
> above, or comments,
> please?
> 
> (No emi gaskets are used btw).
> 
> Thanks, Jeff Chambers
> 
>

> Dr Jeff Chambers
> Westbay Technology Ltd
> Main St
> Baycliff
> Ulverston
> Cumbria LA12 9RN
> England
> Tel: 01229 869 108
> Fax: 01229 869 108
> http://www.westbay.ndirect.co.uk
> 
> 
> 
> ---
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Re: System test PCs - Are we cops?

[robert Macy]

Isn't it fraud to sell an item that does not meet spec?  As
in, the vendor says the product is compliant when it is
not.  

Don't all the customers then have a legal recourse to
return any/all product?  

Doesn't policing the policy of compliance then become a
"non-governmental" function?  

As far as competition, it would not be out of line for the
marketing representative of a compliant company to disuade
potential customers from buying noncompliant products by
pointing out that fraud between the other vendor and this
customer sets a bad tone of a business relationship.  One
could stretch this to the point of mentioning "complicity".
 

   - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112
 





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Re: Effective length of half wave dipole

[robert Macy]

Uh,...

By "effective length" do you mean the comparison of the
length to a standard dipole?  

What I mean is, a 1/4 wave dipole against a ground plane is
(?)0.95 a dipole and a 1/8 wave dipole TUNED to resonate is
(?)0.91 effective length.  

In other words, for receiving signals a short antenna works
as well as a long antenna and has nearly the same effective
length.  

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



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Re: Effective length of half wave dipole

[robert Macy]

>From Dave Cuthbert's comments to me regarding a 1/4
wavelength dipole; he said that the current moves down the
rod as the rod becomes thicker, which implies that the
current distribution absolutely determines the effective
length.  Was that "effective length" or "tuned length"? hmm

However, the whole thing may start with the conductivity of
real life materials...

Interesting to see the others' comments.

 - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Wed, 29 Oct 2003 16:59:20 +0800
 kcc...@hkpc.org wrote:
> 
> 
> Dear all
> 
> I got confused with the effective length of a half wave
> dipole.
> 
> 1) It is due to non-constant current distribution, or
> 
> 2) It is due to the wave velocity in materials different
> from that in
> vacuum.
> 
> 
> What do you think which one is correct?
> 
> Regards
> KC Chan
>
  


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Re: Help finding Company

[robert Macy]

David,

Just did a search in Rich's Northern California Directory
for both "air" and "modem" which showed many companies, but
no results.

Also searched through Reference USA for *any* firm with
"modem" in their name, again many companies, but no
results.  

If a company has been around for a while and is fairly
large, these lists usually have it.  If new, or small, or
privately owned; a company can get missed.  

If serious about search; make certain of the name, check
the registry of corporations in Sacramento.

Are they looking for "Air-Space", an ISM band wireless
modem company made up of the people previously at Metricom
(Ricochet product line)?

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Mon, 13 Oct 2003 19:39:19 -0400
 "David Seabury"  wrote:
> 
> A friend in Europe is trying to obtain contact info on a
> company called
> "Air-Modem Inc".  He thinks they are in Northern
> California.  Does anyone
> know where there might be located?  He has a contact
> name, Ashwin Mody??
> 
> Thanks,
> 
> David Seabury
 


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Re: Corrosion tests - NEBS or Milspec acceleration factors?

[robert Macy]

Gary, 

These were stainless steel wires inside protective polymer
sheathing, extra thick multiple coatings.  

The wires were mounted on a "fence" and then placed under
tension to make their resonance from wind, etc fairly high
frequency - like the e string on a bass guitar.  

Seems the tension put so much internal stress into the
wires and encouraged so much corrosion that the wires would
only last a year, even 2 miles from an ocean.  

 - Robert -

On Fri, 10 Oct 2003 14:56:39 -0700
 "GARY MCINTURFF"  wrote:
> Robert,
> Thanks for the info. Do you mean stress from normal
> nut/bolt torque or from a press-fit application. Here is
> another small tidbit you might consider - a trick I got
> from an aircraft mechanic. Even if the part is stainless
> steel if you are working around it with non-stainless
> tools you can compromise the stainless part with the
> tool. It is the tool material that could be starting the
> corrosion. In the particular instance I was discussing it
> was stainless steel panels that were being sheared, and
> the shear didn't have stainless "shoes" or whatever the
> actually shearing components are. These shoes smeared
> onto the stainless parts and viola corrosion. When they
> put stainless shoes on the shear the problem disappeared.
> This was a Boeing 747 crew chief so he certainly has
> the experience to make him believable. Might want to
> check your manufacturing plant just for grins.
> Gary
>   - Original Message - 
>   From: robert Macy 
>   To: GARY MCINTURFF ; emc-p...@ieee.org 
>   Sent: Friday, October 10, 2003 12:01 PM
>   Subject: Re: Corrosion tests - NEBS or Milspec
> acceleration factors?
> 
> 
> 
>   Gary,
> 
>   From experience with security systems only "close" to
> the
>   seashore (approx 2 miles away) it is best to *NEVER*
> have
>   any of the metal parts under stress/tension, else the
>   corrosion rates are incredibly accelerated.  
> 
>   The particular stainless steel part had been tested
> real
>   time in worse environments with absolutely no
> degradation
>   detectable.  Yet, in the actual application under
> mounting
>   stress the stainless steel part repeatably failed
> within 1
>   year even that far away from the ocean.   
> 
> - Robert -
> 
>  Robert A. Macy, PE .. m...@california.com
>  408 286 3985 . . . .. . . fx 408 297 9121
>  AJM International Electronics Consultants
>  101 E San Fernando, Suite 402
>  San Jose, CA  95112
> 
> 
> 
>   On Fri, 10 Oct 2003 09:47:40 -0700
>"GARY MCINTURFF"  wrote:
>   > Ernie,
>   > I know you received Naftali's  email so I will
> just
>   > clarify a little more. We test and pass the GR-487
>   > outdoor enclosure requirements for the
> telecommunications
>   > industry but I have a client who is non-telecom.
>   > Telecommunciations customers seem to accept the test,
>   > because past experience has shown in meets the
> equipment
>   > and time needs (20 years). Non-Telecommunications
>   > customers not familiar with the tests kind of expect
> some
>   > sort of acceleration factor for the hours under test
> to
>   > demonstrate how long the equipment will work, rather
> than
>   > a more or less pass fail salt fog test. He wants to
> how
>   > long the equipment can withstand the elements at his
>   > coastal location. Is there any sort of acceleration
> model
>   > used in the salt fog test, or the mixed gasses and
>   > hygroscopic tests?  He is a little unhappy with my
>   > current response (understandably) that experience
> shows
>   > the test satisfies the screening requirements or else
>   > they  would have been changed long ago to something
> that
>   > did meet the equipment and time requirements.
>   > Can you give me a little insight?
>   > Thanks
>   > Gary McInturff
> 


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Re: Corrosion tests - NEBS or Milspec acceleration factors?

[robert Macy]

Gary,

>From experience with security systems only "close" to the
seashore (approx 2 miles away) it is best to *NEVER* have
any of the metal parts under stress/tension, else the
corrosion rates are incredibly accelerated.  

The particular stainless steel part had been tested real
time in worse environments with absolutely no degradation
detectable.  Yet, in the actual application under mounting
stress the stainless steel part repeatably failed within 1
year even that far away from the ocean.   

  - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Fri, 10 Oct 2003 09:47:40 -0700
 "GARY MCINTURFF"  wrote:
> Ernie,
> I know you received Naftali's  email so I will just
> clarify a little more. We test and pass the GR-487
> outdoor enclosure requirements for the telecommunications
> industry but I have a client who is non-telecom.
> Telecommunciations customers seem to accept the test,
> because past experience has shown in meets the equipment
> and time needs (20 years). Non-Telecommunications
> customers not familiar with the tests kind of expect some
> sort of acceleration factor for the hours under test to
> demonstrate how long the equipment will work, rather than
> a more or less pass fail salt fog test. He wants to how
> long the equipment can withstand the elements at his
> coastal location. Is there any sort of acceleration model
> used in the salt fog test, or the mixed gasses and
> hygroscopic tests?  He is a little unhappy with my
> current response (understandably) that experience shows
> the test satisfies the screening requirements or else
> they  would have been changed long ago to something that
> did meet the equipment and time requirements.
> Can you give me a little insight?
> Thanks
> Gary McInturff



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PSpice model for 1/4 wavelength antenna

[robert Macy]

Does someone out there have a PSpice model for a 1/4
wavelength antenna? 433.92MHz 

Something that I can change to reflect diameter of the rod,
detuning, etc. 

Or, do you know someone who has such a model? 

Need it fast, please.

  - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


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Re: GFI Question

[robert Macy]

Scott,

How much wire is buried in the wall between the GFI and the
outlet that doesn't cause the problem?  

Does the addition of an extension cord between the present
outlet and the shredder calm it down?  

Do you have metal conduit?  If so, you have a small filter
through your AC mains to the other outlet.  Around 7 to 10
uH common mode choke and some capacitance.  Don't know, but
probably in the order of 50 to 100pF.  Might be just enough
filter components to solve the "touchiness".  

Let us know if a 9-12 foot extension cord solves the
problem.  

 - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



> From: "Scott Douglas" 
> To: "EMC-PSTC List" 
> Sent: Thursday, September 11, 2003 12:09 PM
> Subject: GFI Question
> 
> 
> >
> > Fellow Listees,
> >
> > It's been bugging me for a long time. So now I have to
> ask you all for
> > some wisdom.
> >
> > Here is the setup:  table top shredder, rated 120V, 60
> Hz, 2.0 A. UL/CUL
> > Listed, made in China. It has a 60 inch 3 wire power
> cord with 3 prong
> > plug (presumably 3rd wire is PE).
> >
> > The problem:  The shredder is plugged into the GFI
> outlet in the laundry
> > room (nothing else active on circuit). This GFI is the
> protector for 3
> > outlets in the laundry & 1/2 bath as well as for a 4th
> outlet in the
> > upstairs bath. From time to time the GFI trips while
> shredding envelope
> > addresses. Not always, just sometimes, it may be a
> length of run time
> > related thing but have not been able to verify that as
> yet and it is not
> > consistent. There is another outlet 60 inches away
> (down the counter)
> > protected by this GFI outlet. If I plug this same
> shredder into the
> > distant outlet, the GFI never trips. Never. Note the
> shredder sits
> > immediately in front of the GFI outlet on the counter.
> Even if I leave
> > it in the same place and just stretch the cord to plug
> into the other
> > outlet I get the same results.
> >
> > That makes me wonder. GFI. Is this some kind of leakage
> from the
> > shredder motor? Is this leakage reduced when you
> connect to the distant
> > outlet? Are GFI outlets susceptible to EMI of any kind?
> And most
> > important, is there an easy fix while leaving the
> shredder where it is
> > and plugged into the GFI outlet? I suppose a GFI
> circuit breaker in the
> > panel in the basement would do it, but that could be a
> costly item.
> >
> > Last up, and to the point of this forum, would this
> problem be exhibited
> > in any kind of safety or EMC testing that would be
> required on this type
> > of product?
> >
> > Looking forward to your comments, on- or off-line.
> >
> > Regards,
> > Scott Douglas
> > Email:  sdoug...@ptcnh.net


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Re: Conformal Coatings

[robert Macy]

Michael,

Back when I used to design coin operated games we had a
problem with intentional ESD doing damage to the
electronics.  

Turns out, that ESD would, every now and then, give a free
game.  Being rewarded with free games, they quickly learned
a damaging ritual - the kids would link arms, up to six of
them, scuff their feet around the carpeting and then
discharge to the machine through a quarter to really blast
the machine.  More than likely they killed the machine, but
what did they care?  

First thing I did was make the electronics extremely robust
for ESD, *THEN* I modified the software so the slightest
(interpret that to mean so low level that it wasn't
damaging) ESD event simply reset the game, even erased
accumulated games.  They lost their money.  Never had
problems after that.  The next time we watched a field
installation, you couldn't believe how the kids protected
those machines from even the most accidental of discharges.
 Like yelling at another kid to keep away while he's
playing the game.  

Anyway, it was one way to get the customer to help protect
your electronics.  It's all in the reward/punishment
system.  

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Wed, 3 Sep 2003 10:31:58 -0500 
 "Sosnoski, Michael"  wrote:
> 
> Ladies & Gentlemen,
> 
> I am wondering if you have ever heard or know of any
> printed circuit board
> conformal coatings that are better than others for
> protecting against ESD?
> Are some just better than others for anything?
>  
> Not that we don't use proper grounding, shielding & board
> layout techniques,
> but this industry is concerned with deliberate, and
> intentional
> stimuli to the equipment, and the more robust I can make
> the boards,
> connectors, etc,.. the better.  Also, as in any
> commercial industry--the
> accountants
>  
> Thanks,
> Mike
> 
> 
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
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Re: ESD from wiring

[robert Macy]

Sounds like you just described the triboelectric(sp?)
effect and teflon insulation has one of the highest
"electron work functions" you will find.  

Mechanical motion causes a separation of the insulation
>from and along the conductor.  That mechanical separation
causes a GUARRANTEED charge separation.  Generates a
voltage.  

This effect is the bane of cable makers, that is why the
insulation is so tightly wrapped and stuck to the
conductor.  If not, 1000 feet of cable and the slightest
slippage and you have voltage.  

This principle is used in the security industry to make
buried cables that detect any motion for the cable.  Cables
in walls detect drilling and digging through them.  Cables
buried in the ground detect footsteps of people walking
around above ground.  Yes, it is that sensitive.  

An example of such a cable is a coax made with teflon
insulation, very loosely wrapped around the center
conductor.  So loose that if you grab the center conductor
with pliers and pull, you can pull the whole 20 feet of
center conductor right out of the coax.  

I thought we were talking millivolts when I first heard of
such a cable.  So to check signal level, used a scope on
the cable and with a light tap produced over 8 volts!  The
scope is a high impedance load and the cable is a high
impedance source, but still very energetic.  

It is my understanding that this is one of forms of
deterioration for aging cables.  

Alas, the solution is to not let a cable move.  

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




On Sun, 31 Aug 2003 15:49:43 EDT
 lfresea...@aol.com wrote:
> Hi all,
> 
> well, I have found myself involved with an interesing
> problem. I'm testing an 
> aircraft system, that only has a few wires... 8 or so,
> that interface with 
> the outside world. 28 volt dc power, an programming loop,
> a manually operated 
> switch and an indicator.
> 
> Well, evey time the push button is pressed, I see a 10 to
> 50 nS pulse, very 
> consistant. The problem first was noticed during RE
> testing, and I found it 
> easier to hook my scope to the antenna rather than use
> the SA. I have eliminated 
> the EUT operating, since I have disabled the trigger by
> removing the component 
> that allows it to trigger. I did leave in place the 2
> resistors that 
> terminate the push button wire. I have a predictable set
> up.
> 
> I remove either of the two reminating components, and the
> signal drops, it 
> almost goes away.
> 
> Anyway, after I'd removed the circuit board to make a
> change, I pushed the 
> wire harness and saw a very similar transient! So I
> jiggled the harness and saw 
> many... Cursing a loose connection, I checked, they were
> all sound. Not sure 
> what was going on, I disconnected power, I could still
> got them. So I stripped 
> down to my cotton shorts.. still got them.
> 
> One section of the harness is sleeved with heatshrink
> sleeving, it holds the 
> wires tighly. Jiggling that produced no events.
> 
> So, I can only conclude, that the wire is generating a
> charge during the 
> movement/jiggling, that when it discharges any one of a
> number of places causes my 
> event. The parasitics of the harness set the ringing
> frequency. When I press 
> my push botton, I believe I also kick the wiring with the
> impulse, again it 
> rings very close to the frequency when I jiggle the
> cables.
> 
> My questions are, am I off base with the charging
> supposition? The cable 
> appears to be a teflon type insulation.
> 
> If so, how can I get around it. I can't really blame the
> EUT for it.
> 
> Opinions very welcome
> 
> Thanks,
> 
> Derek Walton



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Re: 94V-0 question

[robert Macy]

Kapton comes to mind.

 - Robert -

On Tue, 12 Aug 2003 11:55:25 -0600
 drcuthb...@micron.com wrote:
> 
> I need a sheet of plastic that goes between a PCB and a
> metal enclosure. This is to make a creepage spec. What
> plastics are good for this? Will polycarbonate be
> suitable and have a 94V-0 rating? Thanks.
> 
>Dave Cuthbert
>Micron Technology
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
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Re: Thanks to EMC-PSTC List!!

[robert Macy]

Muriel,

Congratulations!

Is your thesis in English?  If so, is there a location to
make it available for download?  I'm sure many would be
interested in it.  

   - Robert -

On Mon, 11 Aug 2003 16:19:58 -0300
 "Muriel Bittencourt de Liz"  wrote:
> 
> Hello List-members,
> 
> I'm sending this e-mail this e-mail to thank you. Last
> friday, august, 8,
> I've got my doctor degree in electrical enegineering,
> with a thesis about
> reduction of EMI in switched mode power supplies.
> 
> This thesis would not be the same without the
> contribution of the members
> from this invaluable list. A lot of topics that were not
> clear to me at the
> beggining became clear with your help, through the list
> or private e-mails
> answering my "basic" questions.
> 
> Be sure that your comments were all referred in my
> bibliographic references
> chapter. I'd like to put some names that help me most,
> but I think that I
> could forget someone! ;-) and it would no be just...
> 
> Once again, I'd like to emphasize the importance and
> relevance of this list
> to my work and another works of research world-wide.
> 
> Best Regards,
> 
> Muriel Bittencourt de Liz
> August, 11, 2003
> Florianópolis, Santa Catarina, Brazil
> Electrical Engineering Department
> Federal University at Santa Catarina (UFSC)
> 
> 
> 
> ---
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Re: Clayton Pauls - Intro to EMC - an error or two? for those that have the text

[robert Macy]

Simple eqn to remember

  (2
skin depth = sqrt ( -- )
  ( w * u * sigma 

w is radians per sec; or 2 pi f, with f in Hz
u is permeability . or . u rel * u free space
   u free space is 4 pi 10-7
sigma is conductivity in S/m
all MKS units so 
skin depth in meters

One important point to remember is that this formula
calculates skin depth, like attenuation versus depth, for a
*PLANAR WAVE*  

If the impinging wave has curvature, like from a close by
radiator; that wave really "punches" through and there is
not as much attenuation. 

How much?  Depends on curvature, but for close sources the
effective thickness can be reduced to less than half.

Conclusion:. Use thicker material than you think you need.
 

  - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112
 







On Fri, 8 Aug 2003 13:33:24 EDT
 garymcintu...@aol.com wrote:
> My anal-retentive self is having some trouble
> with an occasional 
> example in the text and I need either a confirmation or a
> slap in the forehead.
>I was just fiddling around with the text and
> reviewing some of the 
> examples and in section 6.4 he presents a table of skin
> depth for copper, but 
> then in question 6.2 he asks for the skin depth of steel
> - and the numbers for 
> the skin depth are the same. My calculations say
> otherwise and makes sense to me 
> since the permeability is different between the
> materials. copper = 1 and 
> steel is 1000, that and the conductivity is different
> between the two. 
>If you have the text and little or nothing else to
> do could you give 
> me the number you come up with? ( in mm's or mils)
>When I'm trying to learn or relearn stuff and I'm
> at odds with the 
> various references it just drives me wild and I don't
> have anyone else to confer 
> with up here. One is torn between the I'm right response
> and the author's 
> obvious authority on the subject.
>Thanks
>Befuddled (Gary)
>



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Re: Carton box dimension and gross weight to EU

[robert Macy]

Paul,

Forgot to mention, one company years ago added their own
maximum width dimension of less than 30 inches so the boxes
could be put on a two wheel truck and easily wheeled
through a standard door!

   - Robert -

On Tue, 29 Jul 2003 15:41:54 +0800
 "Paul Chan"  wrote:
> Dear all,
> 
> I have been asked for the max. dimension and weight of
> the carton box [loaded with product].  Do you know any
> requirements/guidelines?
> Thanks in advance
> Paul Chan
> 



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Re: Carton box dimension and gross weight to EU

[robert Macy]

Paul,

Sample shippers:

  http://www.ups.com
At UPS website could not find any numbers, only
definitions.  

  http://www.fedex.com
At the FedEx website could not find any weight
restrictions, but did find "Maximum length plus girth* per
piece" is 300 inches . where *Girth = 2(Width + Height)

Maximum height per piece 70 inches
Maximum length per piece 119 inches

There was a footnote that said anything different could
still be discussed.  


I remember a maximum from old days as either 60, or 70
pounds, essentially what a man could carry.  But I believe
that maximum restriction has been removed.  

Hope that helps

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Tue, 29 Jul 2003 15:41:54 +0800
 "Paul Chan"  wrote:
> Dear all,
> 
> I have been asked for the max. dimension and weight of
> the carton box [loaded with product].  Do you know any
> requirements/guidelines?
> Thanks in advance
> Paul Chan
> 



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Re: self blinking LEDs as EMI sources WAS: LED lamps

[robert Macy]

Interesting observation.  You said hum gets louder.
 Implying hum is already there.  What kind of phone?  

Is it only that one telephone instrument?  

Only occurs when LEDs are near the instrument, not near the
phone lines with the phone in another location?  

Is the effect more pronounced at less than 3m?

Are the LEDs turned on/off while appear to be on?  In other
words, LEDs are OFF then come ON OFF ON OFF ON OFF at some
high rate, perhaps near the 50Hz frequency?

Do the LED ckts affect an AM/FM radio held close by?  

  - Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




On Sat, 26 Jul 2003 11:36:37 +0800
 "Wan Juang Foo"  wrote:
> 
> Dear All,
> I observe recently that some self blinking (and color
> changing) LEDs 'are'
> what seem to be a substantial emitters of radiated
> emission/interference.
> These LEDs are rigged up by hobbyists as decorative
> illuminators and acts
> more or less like the blinking lights for Christmas
> trees.  I observe that
> each of theses circuits can be made to hung like
> Christmas tree ornaments.
> 
> I came across a situation where the telephone lines were
> 'substantially
> noisier' :-) when several sets of battery operated
> circuits was about 3 m
> away from the telephone.  It is not a very scientific
> method but I did a
> quick check and found by the method of elimination ;-) or
> what some would
> call systematic trials to find the source of the problem.
>  It took me by
> surprise that the LEDs had a substantial role to play in
> the interference.
> LED circuits gets connected (on), hum gets louder. LEDs
> circuits gets
> disconnected, hums gets quieter and so on and so forth...
> 
> These are very simple circuits with a single resistor and
> the LED in
> series.  The 2 AA sized NiCad battery with holder, single
> resistor and LED
> including wire, total length about 5", tip to tip.  These
> circuits were
> found to (well at any rate, seems to) emit interference
> that cause a
> telephone to pick up (50Hz) hum!  It looks like the mains
> hum was pick up
> and modulated by the 'device' and reradiated or
> broadcasted...
> 
> I can see that the blinking action at about 1 Hz have a
> duty cycle and that
> may generate a lot of ringing but what is surprising is
> the interference
> finding its way into the a telephone handset! I find it
> hard to believe
> that how the 'carrier' of the mains hum can eventually
> gets demodulated a
> puzzle.
> 
> One wonders what can be observed if I get the circuits to
> a OATS? There
> again, how do I recreate the 50 Hz environment to couple
> the mains into
> these LED circuit? I had the Helmholtz coil in mind but
> can that be
> 'treated' as part of a test setup?
> 
> Did anyone here have similar observation? One wonders if
> there any 'product
> specific standards' for such battery operated device that
> uses LEDs as
> decorative illuminators.
> 
> :-)
> 
> One wonders what will happen if there are such gadgets
> line up to 'hit' the
> market this Christmas...
> 
> Looks like there will be a lot of testing work coming for
> EMC engineers!
> 
> Tim Foo
> 
> 
> 
> 
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
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Re: MRI-safe test lab

[robert Macy]

In case you have difficulty finding a strong enough field,
there is a company in St. Louis that makes a medical device
that creates 3D fields strong enough to rip a piece of
metal around inside the brain under computer control for
Parkinson surgery.  

Their fields are in excess of 1 to 3 tesla, I believe.
 Anyway the fields are generated using helium cooled
superconducting coils.  

Just in case you have difficulty getting the field strength
you need, you might be able to use their equipment.   

- Robert -

   Robert A. Macy, PE .. m...@california.com
   408 286 3985 . . . .. . . fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Mon, 21 Jul 2003 10:36:58 -0700
 "Knudsen, Patricia J."  wrote:
> 
> I am looking to test to ASTM F 2052, "Standard test
> method for measurement
> of magnetically induced displacement force on medical
> devices in the
> Magnetic Resonance environment".  It involves applying a
> large magnetic
> force to the EUT to see if it will get pulled inside an
> MRI machine during a
> scan.
> 
> Patty
> 
> -Original Message-
> From: Peter L. Tarver
> [mailto:peter.tar...@sanmina-sci.com]
> Sent: Monday, July 21, 2003 10:33 AM
> To: emc-p...@majordomo.ieee.org
> Cc: Knudsen, Patricia J.
> Subject: RE: MRI-safe test lab
> 
> 
> Patricia -
> 
> Can you be more specific as to what standards are
> applicable
> and what aspect of such testing you are looking for (EMC,
> safety, operational, other)
> 
> 
> Regards,
> 
> Peter L. Tarver, PE
> Product Safety Manager
> Sanmina-SCI Homologation Services
> San Jose, CA
> peter.tar...@sanmina-sci.com
> -Original Message-
> From: Knudsen, Patricia J.
> Sent: Monday, July 21, 2003 7:33 AM
> 
> I am looking for a lab that can test medical products for
> use within an MRI room.  Does anyone know of a test house
> that can do this, preferrably in the U.S. on the west
> coast?
> 
> Patty
> Patricia Knudsen
> Sr. Certification Engineer
> Alaris Medical Systems
> Ph:  (858) 458-7280
> Fax: (858) 458-7095
> pknud...@alarismed.com
> 
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
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Re: Instrument Controller Software

[robert Macy]

John,

If you buy a GPIB card for your laptop *and* your analyzer
has the GPIB interface *and* you get your analyzer's
software manual, you can learn and write all the software
you need for your project in less than 2 hours.  

Ok, ok, more like 6 hours, but still

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Tue, 08 Jul 2003 18:29:04 +
 "John Cronin"  wrote:



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Re: Source of noise

[robert Macy]

Derek,

Most of the PS manufacturers I've dealt with use passive
dummy loads or "quiet" active loads.  These very handy
quiet active loads provide programmable loading, BUT IN NO
WAY SIMULATE THE SUPPLY'S ACTUAL USE.  In other words, how
many quiet loads do you power?  Almost every load is a
micro or some digital electronics.  

I've been training my clients to inject heavy noise at
their load outputs [common mode and differential mode] to
make certain that their supplies are not "transparent" to
those variable loads.  Most now test some time during
development with active digital loads to make certain their
supplies don't pass the noise right back through the
supply.  

Above 30MHz does not require a lot of bulk for filtering.
 Most of the bulk is there for the near 150KHz noise.
 You'll find that part selection and layout are more
critical for filtering above 20MHz.  

I always encourage end-users to include "operating" specs
in their PS purchase agreements to put the burden for
proper design back onto the PS manufacturers.  

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Wed, 2 Jul 2003 15:16:22 EDT
 lfresea...@aol.com wrote:
> Hi All,
> 
> 
> Thanks for the great replies!
> 
> looks like the PCI bus is the problem.. But here's the
> quandry..
> 
> Now we are adding the cards back in, they should add
> little to the profile, 
> correct? After all, they all have the CE mark on them,
> and some have the FCC 
> sticker too.
> 
> This is not happening, in fact some emissions are quire
> strong.. I've also 
> noticed that the Power supply is letting the PC noise
> out. I opened the power 
> supply ( bang goes the warrenty ), and there is the
> minimal of filters.. Are the 
> power supplies tested individually to carry the agency
> sticker?, with a real 
> PC? or just load resistors? Are they designed to suppress
> the PC noise?
> 
> Cheers,
> 
> Derek N. Walton
> Owner L F Research EMC Design and Test Facility
> Poplar Grove,
> Illinois,  USA
> www.lfresearch.com



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Re: Crest Factor

[Robert Macy]

I use 3, with 10 as "worst" case.  

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


- Original Message - 
From: 
To: 
Sent: Friday, June 13, 2003 3:57 AM
Subject: Crest Factor


> 
> I'm trying to spec a power supply. Can someone provide me with a typical
> crest factor that a typical power supply should be able to source without
> distortion.?
> 
> Thanks,
> Bob Heller
> 3M EMC Laboratory, 76-1-01
> St. Paul, MN 55107-1208
> Tel:  651- 778-6336
> Fax:  651-778-6252
> ===
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
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Re: Graphing Software

[robert Macy]

Doesn't Excel work for this?  

If not, I use a simple one called Grafdemo.exe which is
best for plots up to 150 data points *and* has curve
fitting SW for smooth displays and approx formulas.  

Or, Computer Calculus 4.0  CC4  which plots 2D and surface
plots

CC4 has good presentation of 2D with maxima *plus* you can
rotate all the axes around for best view.  

Both have a good price - free.  

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112





On Fri, 16 May 2003 12:44:49 EDT
 lfresea...@aol.com wrote:
> Hi All,
> 
> I'm looking at plotting the response of devices on a
> polar plot, either 2D or 
> 3D. In this cases it's the response of a field probe.
> Several plots will be 
> used for different frequencies.
> 
> Does anyone have suggestions of what package to use? I
> know or Origin, but 
> it's very expensive.
> 
> Cheers,
> 
> Derek N. Walton
> Owner L F Research EMC Design and Test Facility
> Poplar Grove,
> Illinois,  USA
> www.lfresearch.com



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Re: ESD gun verification

[robert Macy]

Most spectrum analyzers don't do very well with a "single"
event.  The repetitive waveform needs to be there to be
operated upon.  

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



On Fri, 9 May 2003 08:28:11 -0400
 "Chris Maxwell"  wrote:
> 
> One question that struck me is:  Why isn't a spectrum
> analyzer used to verify the waveform?  Most labs don't
> have a 4Ghz oscilloscope; but they almost all have a
> 10Ghz spectrum analyzer.  It seems that the spectrum of
> the waveform should be just as traceable and repeatable
> as the waveform itself.
> 
> >From my own experience, I use this method to quickly
> verify our EFT generator in our own lab (although I'm
> just a manufacturer, not a third party lab).  We have the
> EFT generator calibrated yearly; and whenever I use it, I
> turn on the spectrum analyzer and read the spectrum just
> to make sure that it's working.
> 
> Chris Maxwell | Design Engineer - Optical Division
> email chris.maxw...@nettest.com | dir +1 315 266 5128 |
> fax +1 315 797 8024
> 
> NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA
> web www.nettest.com | tel +1 315 797 4449 | 
> 
> 
>


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Re: FCC Limits

[robert Macy]

Interference from an adjacent/inband radiating source is
likely to cause the receiver's AGC circuitry to limit the
incoming RF signal to the point where the signal you're
trying to receive gets buried in the system's noise.  Or,
the interfering signal is of sufficient magnitude so as to
simply "confuse" the receiving electronics.  

Ghery, are you Insturment Rated, yet?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Tue, 29 Apr 2003 10:32:20 -0700
 "Pettit, Ghery"  wrote:
> Ken,
> 
>  
> 
> The FCC made the change for several reasons,
> international harmonization
> being foremost.  We do have users of the RF spectrum
> below 450 kHz in the
> US.  The ADF receivers in the airplanes I fly tune in
> non-directional
> beacons below that frequency.  I'd really rather home in
> on one of those as
> opposed to your PC (although there is a rather large
> difference in the
> signals, but...).  The only significant opposition in the
> Rule Making came
> from some interests who wanted even lower limits to lower
> frequencies.  They
> were not successful.  Manufacturers of ITE with
> international markets
> supported the change as they were already testing to the
> CISPR 22 limits and
> this was a non-issue to them.
> 
>  
> 
> Ghery Pettit
> 
> Intel Corporation
> 


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Re: Low signal switching

[robert Macy]

Don,

It is my understanding that physical switch contacts are
"cleaned" with current - and use.  

It is probably ok at the lower signal levels since from
time to time you're running the higher levels through the
switches.  

Is there someway you can switch and then verify contact?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Mon, 21 Apr 2003 13:27:38 -0400
 djumbdenst...@tycoint.com wrote:
> 
> Hello Friends,
> 
> I have an application in which I would like to switch
> system signals on coax
> cables. One system is 80 to 1000 MHz, the other is 1-2
> GHz.  I have found
> coax switches by Narda, DB Products and Dow Key. Dow Key
> indicates that the
> signals should be above -20 dBm to ensure that contact
> resistance doesn't
> cause a problem.  The others do not spec or address low
> signal issues. My
> branches operate at -35 dBm, 0 dBm and 50 dBm.  The 2
> higher values are not
> a problem, just the -35 dBm.  Are there other companies
> that you are aware
> of that make 50 ohm coax switches that are specified to
> operate at low
> signal levels?  Other ideas?
> 
> Best regards,
> 
> Don Umbdenstock
> Sensormatic
> 
>


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Re: Noise Factor

[Robert Macy]

I originally posted this 12/26/01 Dec of 2001





NoiseFigure new
  = sqrt (  ( NF1^2 - 1 )  + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... + 1 )
 where all noise figures are ratios and referenced to a
single location.


A few points:

1  Definition:
Noise Figure is the ratio of increased noise in a system above the expected
level of Johnson noise.  For our 50 ohm system that will give a voltage of
sqrt(4KTRBw)  where K is Boltzmann's constant, T is temperature in absolute
Kelvin, R is the resistance of the system (for our case 25 ohms {50 ohms in
parallel with 50 ohms}), and Bw is the bandwidth of interest in Hertz.  For
a Bw of 1 MHz that yields a noise floor of around 0.641uV, or -3.9dBuV


2  Relate noise figure to some place in your system.
For simplicity (and ease of using specs) relate to the "front end"  Noise
figure specs relate to the front end of a system block.  The noise is
amplified, or attenuated, along with the signal and therefore track
together.  As you go from the output to the input of each system block, gain
subtracts from the NF and attenuation adds to the NF.  Modify the Noise
Figure by each block you must go through to get to the input.  For example,
through cable loss, add the few dB.  For gain, subtract the gain.

3  Make up a list (Use Excell spread sheets)  You will end up with
contributions from every block now referenced to the front end.  then...

4  Remember that uncorrelated noise does not add, but adds as the square
root of the sum of squares.  However! you must only take into consideration
the noise contribution from each "additional" noise source.  You cannot keep
adding in the contribution from the 50 ohm source impedance.  Therefore,
each Noise Figure ratio must be squared and then have 1 subtracted from it.
After combining all the contributions, you will add the 1 back.  Simply take
the square root of that total sum and find the 20log value and you will have
your total system's new NoiseFigure.


For example, let's find the noise figure for a receiving system that
attaches to an antenna consisting of long cable, amp, cable, and spectrum
analyzer (SA).

Passive devices have 0 dB noise figure (they do not add any noise)

Antenna is passive, but converts volts per meter into volts in a 50 ohm
system.  Since it does not add any noise, there is no difference between
minimizing the NF at the antenna port or at the field that it measures.



So let's find out the NF of our system  at 200MHz

long cable 3dB attenuation
amp24dB   6 dB NF
cable   -
SA  32dB

Note:  You could have a perfect receiver that contributes no noise located
after the long cable and you would still have a 3 dB NF   That's why
amplifiers are placed near the signal source.

Check your particular SA.  It can have a Noise Figure from 26dB to 36dB
depending on its design.  That means for a 1 MHz bandwidth you can only see
down to around -80dBm.

So let's move the amplifier out to the antenna and change the order of the
list:

cable   -
amp   gain 24dB with NF = 6 dB
long cable atten  3dB
SA with NF = 32dB

The list would show 6 dB NF at the input  and (32-24+3=11) 11dB from the SA.
That is a ratio of 2 and a ratio of 3.55.


New Noise Figure is sqrt(  (2^2-1) + (3.55^2-1) + 1 ) = 4 or 12dB
See how the SA still dominates?



To rewrite the equation:

NoiseFigure new
 = sqrt (  ( NF1^2 - 1 )  + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... +
1 )
 where all noise figures are ratios and referenced to a
single location.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




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Re: high immunity

[robert Macy]

If GW, wouldn't that voltage be more like 600KV/m, or at
least 30KV/m?

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


On Wed, 26 Mar 2003 17:30:14 -0700
 drcuthbert  wrote:
> 
> With the advent of E-weapons we might need some new
> immunity specs. I read that they can output several GW.
> Testing for equipment survival at over 5000 V/m should be
> fun (and profitable to some).
> 
> Dave Cuthbert
> Micron Technology
> 


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Re: Help wanted with succinct subject description for non-special ists

[robert Macy]

To me, all this regulation can be synopsized:  

Electronics shall not put out stuff - conducted or radiated

Electronics shall not be upset when stuff comes in -
susceptibility to conducted or radiated.  


Difference in attitude between US and elsewhere:

It is my understanding that in the US the FCC thought not
to complicate the manufacturing process by adding
susceptibility tests to product testing, but rather have
the consumer simply modify their behaviour.  If a product
does not work well because it is easily upset by stuff
coming in, the consumer will buy a different product and/or
complain to the manufacturer, thus automatic control
without FCC intervention.  But in the EC and elsewhere,
they thought to add tests ahead of time in order to
establish a minimum quality standard of performance for the
consumer, like prescreen for the consumer.  


Which is better control?  Arguments go both ways.  

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




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Re: Ethernet coax connection

[Robert Macy]

It is my understanding there is a spec relating to both the voltage handling
capability and the impedance between ethernet coax and earth ground.

At low frequency (must be more than a certain level) it is quite high in
order to prevent potentially damaging ground loops from forming.  At high
frequency (must be less than a certain level) to effectively reference the
shield to chassis potential and make certain that the coax doesn't radiate.

There are manufacturers that sell coax panel connectors with the "proper"
built in capacitor.  I recall $10 each price tag.

I further recall that we used to use 0.001uF 2kV caps.  WELL DRESSED AND
MOUNTED EXTREMELY PROPERLY.

Vaguely remember that the impedance was to be more than 1Meg at 60Hz and
less than 50 at 3MHz, but you should check the ethernet spec.

You can tell a lot about the cap's mounting (and quality) by looking at the
spectrum of the radiated emissions.  For example, internal clock and the cap
is referenced to a noisy spot.  Or, spectrum related to the ethernet traffic
and a loop exists around the coax terminations and bypass cap.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112



From: "Ken Javor" 
To: 
Sent: Wednesday, March 05, 2003 12:37 PM
Subject: Ethernet coax connection


>
> Question for list members:
>
> Background:  I am troubleshooting a complex integration of military
hardware
> and COTS.  One COTS piece of equipment has an RG-58 coaxial connection,
but
> the coax connector is an isolated feedthrough bnc.  From a radiated
> emissions point-of-view, that is hurting us.  One of the engineers here
said
> that is part of the spec - Ethernet shields are not supposed to be chassis
> grounded.
>
> Question:  Can someone please explain the reason for that, and how this is
> usually handled to minimize radiated emissions?
>
> Thank you.
>
> Ken Javor
> EMC Compliance
> Huntsville, Alabama
> 256/650-5261
>




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Re: HP 6034L Power supply schematics / repair (was Agilent 6842A)

[Robert Macy]

Being a past employee of HP and having met David Packard and Bill Hewlett
(just as the HP-35 calculator was coming out), it was with great sadness I
watched as the management team headed by Carly F effectively dismantled
everything they had built and stood for despite and in front of Bill's son.


For manual's, I've seen them for printing fee available on the news group:
sci.electronics.repair

If you can find the threads there, you'll find at least two sources I
remember seeing offering them.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




From: Kurt M. Marden
To: emc-p...@majordomo.ieee.org
Cc: Michael Taylor ; 'emcp...@aol.com'
Sent: Wednesday, February 05, 2003 8:40 AM
Subject: HP 6034L Power supply schematics / repair (was Agilent 6842A)


On that note of (lack of) support, Agilent has no or will not release
documentation on the
old 6034L power supply.  I recently acquired one which powers up but has no
output
and the front panel display shows 0 volts / amps. Agilent will be happy to
charge me $140
just to "look at it". "Best effort" is all they can guarantee on a repair
(which would be over
and above the $140). Sheesh! Anybody have a owners manual or repair guide /
schematics
 for this model?

Thanks,

Kurt

Michael Taylor wrote:

If you think Carley and the rest of HP / Agilent upper management are really
more concerned about your thoughts - over short term profits,  there are
several of us that would like to interest you in some swamp land in Florida
and a bridge in New Jersey.

Seriously,  I have had several instances lately with Agilent that convince
me that the old HP is gone and the NEW - "lean-mean Agilent machine"  no
longer values customer loyalty the way the old HP did.  In my case,  the way
I was treated on several issues would have never occurred under the old HP.
The net result is I now consider purchasing test equipment from others -
something I would have never done in the past.

Welcome to the brave new world of "bean counting" business.

Michael Taylor
(loyal HP test equipment fan)
Frozen in Colorado

From: emcp...@aol.com [mailto:emcp...@aol.com]
Sent: Tuesday, February 04, 2003 11:00 AM
To: emc-p...@majordomo.ieee.org
Subject: Agilent 6842A


I think all of the people that own the Agilent 6842A Harmonic and Flicker
Test System should get together and request Agilent to update their software
for the new standards.  As a loyal HP/Agilent customer, I would expect them
to take care of this issue.  This is why we buy certain brands of test
equipment, and not others.  I feel that we "got ripped" on this deal since
the 6842A is not a cheap piece of test equipment.

Tim Pierce


--
Kurt M. Marden
Environmental Simulation Manager

Curtis-Straus LLC   kmar...@curtis-straus.com
Laboratory for EMC,Safety   Environmental Simulation Lab
NEBS,SEMI-S2 and Telecom168 Ayer Rd.
527 Great Road  Littleton,  MA   01460
Littleton, MA 01460 voice (978) 486-8880
http://www.curtis-straus.comfax   (978) 486-0806



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Re: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS

[Robert Macy]

Ian,

Contact me off line and I will share with you the SW tools (free on the
internet) that I use to do these calculations.

The first is an antiquated tool that runs on DOS called Computer Calculus
4.0, or CC4  I like it because it's powerful but easy to learn and retain.

The second is a 2D finite element analysis program called femm that is
located at
http://femm.berlios.de/

When you use the SW in asymmetric analysis you get true 3D values, so it's
very powerful.

You can use the program for plotting the B field over whatever effective
area of interest you're after.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112




From: "Gordon,Ian" 
To: "'IEEE EMC-PSTC GROUP'" 
Sent: Thursday, January 23, 2003 7:15 AM
Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS


>
> All
> I would like to construct a Helmholtz coil to perform magnetic field
> immunity testing at DC frequencies and thus simulate the effect of a
> permanent magnet. There are some details on construction in EN61000-4-8
> which details power frequency magnetic field immunity testing within the
> scope of the EMC directive. However the fields referred to are measured in
> A/m, whereas I need a field of, for example, 5mTesla.
> Can anybody advise me as to how to construct such a coil with a test
volume
> of 0.5 x 0.5 x 0.5m and a field of 5mTesla?
> Thanks
> Ian Gordon
>
>




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Meaning of ACRONYMs

[Robert Macy]

Ran across these two.  What do they mean?

IRAD development and management

ESM, including RF parameter measurements, pulse sorting techniques

   - Robert -




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Re: Measuring AC Line Impedance

[Robert Macy]

Do you have the liberty to share your report - or details and results with
the group?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   101 E San Fernando, Suite 402
   San Jose, CA  95112


- Original Message -
From: "Spencer, David H" 
To: 
Sent: Wednesday, October 30, 2002 8:57 AM
Subject: RE: Measuring AC Line Impedance


>
> Follow up
>
> Having just completed an ton of work on this using input I got around here
> (thanks to Don Borowski, Patrick Lawler, Joe Randolph and  John Woodgate).
> I believe we have characterized the AC mains of our facility.
>
> As a sanity check/ technical check can any one comment on process.
>
> Part one
> 1)Open circuit voltage measured.
> 2)Resistive load placed in circuit.
> 3) Voltage drop and current measured.
> 4) Voltage drop divided by current provides  resistance component of AC
> mains.
>
> Part 2
> 1) Open circuit voltage measured.
> 2)Reactive load placed in circuit (approximately 120uF!)
> 3) Voltage change (increase really) and current measured (phase angle was
> recorded to back check math vectorialy).
> 4) Voltage change divided by current provides reactive component of AC
> mains.
>
>
> As a side note, I also connected an isolation transformer as the reactive
> load,  the reactive numbers were very very close.
>
> The resistive number + reactive number then make up the AC line impedance
> for this site:  Ztest if you will.
>
>
>
> My two remaining questions:
>
> Is this method of characterizing the AC line impedance valid (is there
> something I'm missing)?
>
> Based on my knowledge of these values, and their ratio to the reference
> impedance(s) specified in EN61000-3-3 and EN61000-3-11, I should be able
to
> calculate and correlate the measured Dmax, Pst, et. al...to the limits
> specified in those standards.
> (REFERENCE section 6.1.3 of EN61000-3-11), using our existing AC mains.
>
>
> Any comments or input would be welcome.
> Thanks
>
> Regards
> David Spencer
> Xerox Corp.
>
>
> -Original Message-
> From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
> Sent: Thursday, September 19, 2002 11:56 AM
> To: emc-p...@majordomo.ieee.org
> Subject: Re: Measuring AC Line Impedance
>
>
>
> I read in !emc-pstc that Spencer, David H 
> wrote (in <052106A55179D611B34300096BB02E3F8B1D@USAMCMS4>) about
> 'Measuring AC Line Impedance' on Thu, 19 Sep 2002:
>
> >Is anyone familiar with a method to measure and calculate those values.
> The
> >generic values I have for short circuit condition (which include 4 wires
in
> >a magnetic conduit) come out higher than my measured values, and those do
> >not include the motor generator source.
>
> Put a large capacitor (mains voltage rated) across the mains and measure
> the voltage change; it may actually increase. You need about 50 uF to
> get a decent change on 120 V 60 Hz mains. With that result and the one
> with the resistive load, you can calculate the source impedance as an R
> and L in series.
>
> I'd be interested to learn the result.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
>
> Interested in professional sound reinforcement and distribution? Then go
to
> http://www.isce.org.uk
> PLEASE do NOT copy news posts to me by E-MAIL!
>
> ---
> This message is from the IEEE EMC Society Product Safety
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Need services of Professional (PE) Mechanical Engineer registered in California

[Robert Macy]

Dear group,

A fabricator of shell and tube heat exchangers located in Stafford, Texas
has a requirement for a California PE to perform a structural design check
on supports on two vessels that will be erected at the Shell Oil Plant in
Martinez, California.

Could you recommend a California PE?

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112






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Re: Need Drivers & Programming Guide for HP8592B

[Robert Macy]

Andy,

About 4 years ago I bought a book called something like "Programming Guide
for the ..." from HP which cost around $20.  Not sure if it was for this
model or not, but watch out.  Their system had the wrong part number and I
got some unrelated book and it took another 10 days to get the right one.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


- Original Message -
From: 
To: 
Sent: Tuesday, August 13, 2002 4:33 AM
Subject: Need Drivers & Programming Guide for HP8592B


>
> Is there anyone who can help?
>
> I require information on HP8592B Commands and Programming for GPIB
> interface.
>
> Regards
> Andy
>
> Andrew Price
> Principal Development Engineer (EMC Specialist)
> BAE SYSTEMS Avionics
> A125
> Christopher Martin Road
> Basildon, Essex
> SS14 3EL
>
> tel:   +44 (0) 1268 883308
> email: andrew.p.pr...@baesystems.com
>
>
>
> 
> This email and any attachments are confidential to the intended
> recipient and may also be privileged. If you are not the intended
> recipient please delete it from your system and notify the sender.
> You should not copy it or use it for any purpose nor disclose or
> distribute its contents to any other person.
> 



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Re: Need copies of specs addressing ISM bands in Europe

[Robert Macy]

Bill, Rich,

Just couldn't find out all of what I wanted there.  Did find individual
country's allocation for ISM bands and that was encouraging.  What am I
doing wrong?


At this site I at least found some numbers:

http://europa.eu.int/comm/enterprise/newapproach/standardization/harmstds/re
flist/radiotte.html

  ETSI EN 300 328-2 V1.1.1 (07-2000) Electromagnetic compatibility and Radio
Spectrum Matters (ERM); Wideband Transmission systems; Data transmission
equipment operating in the 2,4 GHz ISM band and using spread spectrum
modulation techniques; Part 2: Harmonized EN covering essential requirements
under article 3.2 of the R&TTE Directive.  ETS 300 328/A1:1997 Date expired
(30.04.2001) Art.3.2
  ETSI EN 300 328-2 V1.2.1 (11-2001) Electromagnetic compatibility and Radio
Spectrum Matters (ERM); Wideband Transmission systems; Data transmission
equipment operating in the 2,4 GHz ISM band and using spread spectrum
modulation techniques; Part 2: Harmonized EN covering essential requirements
under article 3.2 of the R&TTE Directive  EN 300

But no documents.


My question is still, "What is the equivalent European requirement that
matches FCC Part 15.247 regarding ISM bands?"

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



- Original Message -
From: "Bill Morse" 
To: "'Robert Macy'" ; 
Sent: Monday, August 12, 2002 12:52 PM
Subject: RE: Need copies of specs addressing ISM bands in Europe


>
> Try the following URL.
>
> http://www.ero.dk/
>
> Technical Staff
> Senior EMC Engineer
> William Morse NCE
> Phone 916.630.2540
> FAX916.630.2501
> EMAILbill...@verifone.com
>
>  -Original Message-
> From: Robert Macy [mailto:m...@california.com]
> Sent: Monday, August 12, 2002 10:07 AM
> To: emc-p...@ieee.org
> Subject: Need copies of specs addressing ISM bands in Europe
>
>
> Apologize if duplication of question here.
>
> Is there a website to get a copy of the European Community's rules
regarding
> ISM bands similar to FCC Part 15.245-9?
>
> - Robert -
>
>Robert A. Macy, PEm...@california.com
>408 286 3985  fx 408 297 9121
>AJM International Electronics Consultants
>619 North First St,   San Jose, CA  95112
>
>



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Need copies of specs addressing ISM bands in Europe

[Robert Macy]

Apologize if duplication of question here.

Is there a website to get a copy of the European Community's rules regarding
ISM bands similar to FCC Part 15.245-9?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112




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Re: NEBS compliance for 100baseT / 1000base T

[Robert Macy]

The people who supply these inbedded filter connectors, Regal Electronics,
can answer this and more.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Muhammad Sagarwala 
To: emc-p...@majordomo.ieee.org 
Date: Monday, July 22, 2002 3:32 PM
Subject: NEBS compliance for 100baseT / 1000base T


Hello Gurus,

I am new to this list so pardon me if my questions sound naive.

The question I had was, for nebs compliance we need to pass power cross
and lightening tests.  For boards with copper ports (100baseT and 100base
T), is it possible to use rj45 connectors with integrated magnetics and
still get pass these tests. Has anybody done that - if yes, is it possible
to share the method.  I believe there are components (e.g. sedactors) one
can use, but

those are capacitve and might impact the signal integrity.  Also, mostly
that kind of stuff is used on the line side of the transformer.  I am just a
little bit hesistant to put in on the secondary side...

Any input would be highly appreciated...

Thanks

Muhammad



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Re: case of units

[Robert Macy]

Still use KHz

For me it's a logical carrier over from
small letter = small value
capital letter = large value

   mOhm   means milli Ohm  NOT   mega Ohm
   mHz   is milliHertz
   KHz is kilo Hertz   (note magnifier is larger than one)
   MHz  is megaHertz
  and so on

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Price, Ed 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, June 24, 2002 8:24 AM
Subject: RE: case of units


>
>
>
>>-Original Message-
>>From: Brent DeWitt [mailto:bdew...@ix.netcom.com]
>>Sent: Sunday, June 23, 2002 7:04 PM
>>To: emc-p...@majordomo.ieee.org
>>Subject: case of units
>>
>>
>>
>>I've always found it interesting that the small "k" is the
>>only lower case
>>letter used for multipliers greater than unity.  I presume it
>>is because the
>>temperature folks got there first with Lord Kelvin's initial.  Too bad
>>really since "kilo" has a linguistic meaning for numbers and
>>Kelvin is just
>>a name.  Also rather interesting that we have no trouble using
>>"G" for both
>>Giga and Gauss.
>>
>>Just Sunday evening thoughts.
>>
>>Brent DeWitt
>
>
>Brent:
>
>For years, I had always written kiloHertz as KHz. Then, as a hirling, I
>bumped up against the Information Technology Group at General Dynamics
>Electronics Division. I noticed that all my text came back using "kHz."
>After a few cycles of this, I decided to follow up on the cause. I found
>that they worked to a bureaucratic "style manual", which dictated the style
>for abbreviations and technical terms. I had the temerity to ask who wrote
>the style manual, and why KHz was rendered as kHz. They finally produced a
>Mil-Std, which had a list of acronyms and special terms. And, there on the
>list, was "kHz"! No explanation, just "kHz". So I asked them if maybe the
>Mil-Std was just a typo error, and that shouldn't we allow logic to
prevail?
>No, because if they did that, someone might think the abbreviation actually
>meant "degrees Kelvin Hertz". They won.
>
>Lately, after many more years of continuing to personally use KHz (and
>having re-educated my MS Word about my preference), I find that I am
>wearying of the explanations, and have started to use kHz. Yup, they won.
>
>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
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
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>
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>
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Re: Lightning Protection for PA System

[Robert Macy]

Scott,

Not knowing how your system is "exactly" built makes it difficult to second
guess the lightning.

However, here is one way to protect your amplifiers:  Move the protection
interface out to the edge of your building.  Use rod located there with all
referenced to ground.  At this same location use a 10A AC mains line filter
between the amplifier and the speakers (cheap filtering which should be able
to pass the audio) with AC line towards amp and load towards speakers.
Between filter and speakers place fusing in series (won't do much for truly
high voltage which will jump, but will take care of a lot of nuisance
discharges) place gas discharge tubes there.  [ If you can get a surplus
telephone entry block, the type with the carbon "shorts", they work great
here, too. ]  Back side of filter place tranzorbs, then back at amp place
more tranzorbs.

You prevent lightning damage by designing a filtering system which limits
the maximum amplitude that can get into your electronics.  And the most
effective rejection filter is always high impedance in series, low impedance
to ground, high impedance in series and low impedance to ground, ad nauseum.
Just make multiple paths that do this and you can even sustain a direct hit.
Speakers and wires will probably fry though.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Scott Lacey 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Saturday, June 15, 2002 9:19 AM
Subject: Lightning Protection for PA System



To the group,

I am seeking advice as to the best methods of protecting a Public Address
system
against recurring lightning damage. The system uses several commercial PA
amplifiers, each driving several speakers at indoor and outdoor locations.
There are
also several locations where microphones can be plugged in. The longest
speaker
wires may be up to 250 yards long. It is believed that the charge is being
coupled to
the speaker wires where it then returns to ground at the amplifier location
within the
building, destroying the solid state devices within the amplifier. A
technician has
added fuses to all external microphone inputs and speaker outputs. While
these
have blown several times during storms without obvious damage to the
amplifiers it
is my belief that fuses are generally too slow to protect semiconductor
devices. I am
seeking advice as to surge suppression devices.
System particulars are as follows:

1) The PA amplifiers have 70 volt outputs. All speakers are transformer
coupled.

2) All microphones use standard XLR connectors. They plug into metallic
conduit
mounted jacks at locations inside and outside the building. The outside
microphones
are unplugged during storms.

3) The amplifiers are located on the second floor of the building. Each
amplifier is
dedicated to a set of speakers at one location. The amplifier driving the
longest wires
is the one which most often has to be replaced.

4) The building is in a location known to be susceptible to lightning
activity. Electrical
appliances have been destroyed on at least two occasions.

5) All protective grounding efforts to date have been made to the conduit. I
am
recommending that this be supplemented by driven rods.

It is pretty easy to buy commercial surge suppression devices for the ac
lines. I feel I
need advice as to the best methods to protect the audio inputs and outputs.

For the 70 volt outputs I am thinking of using gas tubes to earth where the
wires
enter the building supplemented by MOV, Tranzorb, or other devices near the
amplifier location. I welcome suggestions as to device types.

For the microphone inputs I am thinking of using semiconductor transient
voltage
suppressors near the amplifier. Again, any suggestions are welcome.

Thanks in advance for any advice and guidance.

Scott Lacey
sco...@world.std.com




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Re: Side Issue: Proximity Cards in Wallets ...

[Robert Macy]

No

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Doug McKean 
To: EMC-PSTC Discussion Group 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, June 13, 2002 11:07 AM
Subject: Side Issue: Proximity Cards in Wallets ... 


>
>A proximity card reading security system is used in 
>a company, possibly based on the Wiegand Effect. 
>Some of the employees put their security cards in 
>their wallets to have them all the time.  When needing 
>access to an area that requires a card, users simply 
>pull out their wallets, swipe the wallet in front of the 
>reader and thus gain access.  For those people with 
>cards in their wallets, they do not pull the security card 
>out of the wallet and then swipe the reader. They all 
>swipe the reader with the wallet. 
>
>A question was posed to me that involved the swamping 
>of the card with a magnetic field to identify the card.  The 
>electronics in the card generates a series of pulses from 
>the pulsed magnetic field that when received by the card 
>reader validate or invalidate the card. 
>
>Is this field strong enough to wipe any magnetic strips on 
>any credit or bank or any of the other types of cards using 
>magnetic strips that may also be in the wallet? 
>
>Regards, Doug McKean 
>



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Re: ferrite transient voltage/current response

[Robert Macy]

Then why would a 10 A surge change their characteristics?

Unless it cracks it?

- Robert -

-Original Message-
From: Robert Wilson 
To: Robert Macy ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, June 06, 2002 8:51 AM
Subject: RE: ferrite transient voltage/current response


Soft Ferrites cannot be permanently magnetized. This is precisely why
they are used as beads and cores.

Bob Wilson
TIR Systems Ltd.
Vancouver.

-Original Message-
From: Robert Macy [mailto:m...@california.com]
Sent: June 5, 2002 11:20 PM
To: don_borow...@selinc.com; emc-p...@majordomo.ieee.org
Cc: shbe...@rockwellcollins.com
Subject: Re: ferrite transient voltage/current response


He may have magnetized it.  Degaussing with one of those Radio Shack
thingies would probably brought it back.  Can he try it again?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



-Original Message-
From: don_borow...@selinc.com 
To: emc-p...@majordomo.ieee.org 
Cc: shbe...@rockwellcollins.com 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, June 05, 2002 2:52 PM
Subject: RE: ferrite transient voltage/current response


>
>
>
>While I was at Agilent in Spokane, one of the engineers or technicians
claimed
>that he had changed the RF characteristics of a 6-hole ferrite bead
(wound
with
>2 1/2 turns) used on a power supply trace to a noisy assembly. The
normal
>current was about 1 amp, but he accidently shorted the power supply
voltage
>after the inductor. This caused a current spike as the power supply
filter
>capacitor discharged (and then the supply current limited at about 10
amps).
>After this, there was a problem with RF leakage from the assembly.
Replacing the
>inductor fixed the problem. Apparently the effect was repeatable.
>
>I didn't observe this personally, so I can't guarantee it.
>
>Don Borowski
>Schweitzer Engineering Labs
>
>
>Sorry that I wasn't clear; I typically try to keep my questions general
so
>  not to get too detailed about the specific application. And
thanks to
Bob,
>  Chris and Mike who have responded ... putting it into Chris's
words
... I
>  was just trying to find out if ferrites had ratings to prevent
them
from
>  "j
>  ust plain blowing the ferrite to smithereens".  Also, I was
looking
for a
>  shortcut if someone else had faced this question rather than
reading
>  through all of the vendor web sites.
>
> I understand and have used ferrites quite often for typical EMI
>suppression; the ferrites typically being rated for the application
>currents, voltages, etc.  In this case, the program is trying to
protect a
>power supply input from the DO-160 waveform 5B pin injected lightning
pulse
>of 300 volts open circuit & 300A short circuit.  If the Gas Discharge
Tube
>is located past (closer to the supply which was done for packaging
>limitations) than the "T" EMI filter, a question was raised as to
whether
>the ferrite properties would be altered by the lightning pulse.  Most
of
>the standard literature on the use of ferrites does not address these
types
>of transients.
>
>
>Susan Beard
>
>
>
>
>
>
>
>"Robert Wilson" @majordomo.ieee.org on
06/04/2002
>02:16:48 PM
>
>Please respond to "Robert Wilson" 
>
>Sent by:owner-emc-p...@majordomo.ieee.org
>
>
>To:, 
>cc:
>
>Subject:RE: ferrite transient voltage/current response
>
>
>
>Your question is not all that clear. It appears to imply that
transients
>have an affect on the ferrite beads, but it is the other way around
>(maybe that is what you meant). But in general, small ferrite beads
have
>little effect, except at very high frequencies (hundreds of MHz),
unless
>they are no longer "beads" (i.e. they are very large).
>
>Have a look at the various magnetics vendors data sheets and app notes.
>
>Magnetics Inc: www.mag-inc.com
>Fair-Rite Inc: www.fair-rite.com (whoever came up with THAT name should
>be shot!
>Steward Inc: www.steward.com
>Ferroxcube: www.ferroxcube.com
>Epcos (was Siemens): www.epcos.com
>
>
>Bob Wilson
>TIR Systems Ltd.
>Vancouver.
>
>-Original Message-
>From: shbe...@rockwellcollins.com [mailto:shbe...@rockwellcollins.com]
>Sent: June 4, 2002 8:57 AM
>To: emc-p...@ieee.org
>Subject: ferrite transient voltage/current response
>
>
>Could someone point me to some good App Note information on the
response
>of
>and affect on ferrite beads to transient voltage & current waveforms?
>The
>waveforms are based

Re: ferrite transient voltage/current response

[Robert Macy]

He may have magnetized it.  Degaussing with one of those Radio Shack
thingies would probably brought it back.  Can he try it again?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



-Original Message-
From: don_borow...@selinc.com 
To: emc-p...@majordomo.ieee.org 
Cc: shbe...@rockwellcollins.com 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, June 05, 2002 2:52 PM
Subject: RE: ferrite transient voltage/current response


>
>
>
>While I was at Agilent in Spokane, one of the engineers or technicians
claimed
>that he had changed the RF characteristics of a 6-hole ferrite bead (wound
with
>2 1/2 turns) used on a power supply trace to a noisy assembly. The normal
>current was about 1 amp, but he accidently shorted the power supply voltage
>after the inductor. This caused a current spike as the power supply filter
>capacitor discharged (and then the supply current limited at about 10
amps).
>After this, there was a problem with RF leakage from the assembly.
Replacing the
>inductor fixed the problem. Apparently the effect was repeatable.
>
>I didn't observe this personally, so I can't guarantee it.
>
>Don Borowski
>Schweitzer Engineering Labs
>
>
>Sorry that I wasn't clear; I typically try to keep my questions general so
>  not to get too detailed about the specific application. And thanks to
Bob,
>  Chris and Mike who have responded ... putting it into Chris's words
... I
>  was just trying to find out if ferrites had ratings to prevent them
from
>  "j
>  ust plain blowing the ferrite to smithereens".  Also, I was looking
for a
>  shortcut if someone else had faced this question rather than reading
>  through all of the vendor web sites.
>
> I understand and have used ferrites quite often for typical EMI
>suppression; the ferrites typically being rated for the application
>currents, voltages, etc.  In this case, the program is trying to protect a
>power supply input from the DO-160 waveform 5B pin injected lightning pulse
>of 300 volts open circuit & 300A short circuit.  If the Gas Discharge Tube
>is located past (closer to the supply which was done for packaging
>limitations) than the "T" EMI filter, a question was raised as to whether
>the ferrite properties would be altered by the lightning pulse.  Most of
>the standard literature on the use of ferrites does not address these types
>of transients.
>
>
>Susan Beard
>
>
>
>
>
>
>
>"Robert Wilson" @majordomo.ieee.org on 06/04/2002
>02:16:48 PM
>
>Please respond to "Robert Wilson" 
>
>Sent by:owner-emc-p...@majordomo.ieee.org
>
>
>To:, 
>cc:
>
>Subject:RE: ferrite transient voltage/current response
>
>
>
>Your question is not all that clear. It appears to imply that transients
>have an affect on the ferrite beads, but it is the other way around
>(maybe that is what you meant). But in general, small ferrite beads have
>little effect, except at very high frequencies (hundreds of MHz), unless
>they are no longer "beads" (i.e. they are very large).
>
>Have a look at the various magnetics vendors data sheets and app notes.
>
>Magnetics Inc: www.mag-inc.com
>Fair-Rite Inc: www.fair-rite.com (whoever came up with THAT name should
>be shot!
>Steward Inc: www.steward.com
>Ferroxcube: www.ferroxcube.com
>Epcos (was Siemens): www.epcos.com
>
>
>Bob Wilson
>TIR Systems Ltd.
>Vancouver.
>
>-Original Message-
>From: shbe...@rockwellcollins.com [mailto:shbe...@rockwellcollins.com]
>Sent: June 4, 2002 8:57 AM
>To: emc-p...@ieee.org
>Subject: ferrite transient voltage/current response
>
>
>Could someone point me to some good App Note information on the response
>of
>and affect on ferrite beads to transient voltage & current waveforms?
>The
>waveforms are based on the indirect lightning pulses specified in
>Section
>22 of DO-160.
>
>Thanks in advance,
>Susan Beard
>
>
>This e-mail may contain SEL confidential information.  The opinions
expressed
>are not necessarily those of SEL.  Any unauthorized disclosure,
distribution or
>other use is prohibited.  If you received this e-mail in error, please
notify
>the sender, permanently delete it, and destroy any printout.  Thank you.
>
>



---
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Re: Constant for Change of Resistance formula.

[Robert Macy]

Bill,

Big oops.

Measuring the resistance to determine the temperature is not productive
*unless* the resistance dominates the resistance measurement.

Picture three equal valued resistances in a row.  The middle one gets very
hot (more than 100C rise) and increases over 40%, the two on the edges are
heat sinked and barely increase in temperature.  The resulting change in
resistance is 13% which implies the temperature in there has only gone up
around 33C.

Measuring the resistance doesn't tell you much.  At least with transformers
the dominant resistance is pretty much the bulk resistance.

- Robert -


-Original Message-
From: Bill Ellingford 
To: 'Robert Macy' ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Monday, May 13, 2002 1:56 PM
Subject: RE: Constant for Change of Resistance formula.


>
>Hi Robert / group
>OK, Not the best choice of website to demo the answer.  The differing
>figures are because the formula has been transposed to give Temp from
change
>of R from the original formula which gives R from change of T.  To do this,
>another constant (The 234.5 constant) is required.  This is the implied
>point of zero resistance for copper on the Celsius scale.  The formula we
>use is:
>
>  Rfinal - Rorig
>  x (234.5 + Tamb start) -(Tamb finsh - Tamb start)
>  Rorig
>
>The Tamb start and finish are the changes (if any) in Room ambient.  If the
>room remains at 20c then 234.5 + 20 is the multiplier.
>
>-Original Message-
>From: Robert Macy [mailto:m...@california.com]
>Sent: 13 May 2002 14:54
>To: Bill Ellingford; emc-p...@majordomo.ieee.org
>Subject: Re: Constant for Change of Resistance formula.
>
>
>Bill,
>
>Thanks for the site.
>
>Went there and found the same formula and constant I use.
>
>For copper, Temp Coeff = 3.9 x 10-3
>
>Then I clicked on table of coeff and there was a very long list of
>materials, but the temp coeff of copper there was 6.8 x 10-3  ???!!!
>
>Any ideas for this disparity?
>
>- Robert -
>
>   Robert A. Macy, PEm...@california.com
>   408 286 3985  fx 408 297 9121
>   AJM International Electronics Consultants
>   619 North First St,   San Jose, CA  95112
>
>
>-Original Message-
>From: Bill Ellingford 
>To: 'Colgan, Chris' ;
>emc-p...@majordomo.ieee.org 
>Date: Monday, May 13, 2002 5:38 AM
>Subject: RE: Constant for Change of Resistance formula.
>
>
>
>Hi Folks
>Further to the answer given, here is a little more data.
>The constant used is for the change of resistance with temperature.  metals
>and alloys (conductors) all exhibit a different constant.  This can be used
>for calculating temperature rise or resistance change.  i.e. find the temp
>rise from a start and finish test measurement on a winding (for example) at
>the begining and end of a on load heat run or, find R for a given temp:
>using a table or the formula, resistance at various temperatures can be
>pre-determined from a measurement made at one particular temperature.
>
>A website with the formulae can be found at
>http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html
>
>Where you have a transition from one metal type to another, you must
measure
>each metal part individually.  If you have only two metals in contact, you
>may be able to apply a combination of the temp coefficient methods and
>transposition of the measurement of change of junction voltage formulae
i.e.
>Thermocouple laws.
>
>Hope this adds some value:  Bill Ellingford
>
>-Original Message-
>From: Colgan, Chris [mailto:chris.col...@tagmclaren.com]
>Sent: 13 May 2002 10:28
>To: emc-p...@majordomo.ieee.org
>Subject: RE: Constant for Change of Resistance formula.
>
>
>
>Ned is referring to the constant used in the "temperature rise calculated
by
>change in resistance formula" ie
>
><<...>>
>
>Where dt is the temperature rise, R1 is start resistance, R2 is end
>resistance, T1 is start ambient and T2 is end ambient.  234.5 is the
formula
>constant for copper.
>
>This formula is used extensively when heat testing transformers and coils.
>
>I'm afraid I don't know the constant for brass but I believe the figure may
>be related to the "inferred absolute zero" of a material.  Try asking a
>metallurgist?
>
>Regards
>
>Chris Colgan
>Compliance Engineer
>TAG McLaren Audio Ltd
>The Summit, Latham Road
>Huntingdon, Cambs, PE29 6ZU
>*Tel: +44 (0)1480 415 627
>*Fax: +44 (0)1480 52159
>* Mailto:chris.col...@tagmclaren.com
>* http://www.tagmclaren.com
>
>
>
>
>> -Original Message

Re: Constant for Change of Resistance formula.

[Robert Macy]

Bill/group

Let's check all these numbers.

Room temp of 20C?  68F (br).  More like 25C, 77F.

Most people assume room temp is 297K (or is that 298?) which is more like
23.82C, ~75F (seems more reasonable), putting that into the linear equation
gives

  234.5 + 23.82 = 0.00387
error less than 0.7% compared to
0.0039

However the formula is very clear that this is a short range linearity

When you extrapolate to 100C, or 75C rise above ambient, the linear formula
predicts 1.295 times the room temp resistance, but the actual value climbs
more like:

(1+0.0039)^75  = 1.339   (for 1 degree steps)
  error is now more than 3%

My conclusion is to just measure it.

Run current through the contacts, measure the resistance, then stick the
whole thing in a temp chamber and increase temp 'til you read the same
resistance.

Or, lower the temp from ambient, until you read the SAME resistance.  Then
that temperature difference is your rise above ambient.

I know, I know.  The first method does not take into account thermal
gradients that cool parts of the conductors and would suggest less rise than
actually occurs - which could be a large error, say measure 25C rise, but
actually have 35C rise in the hotspots.

The second method is moving into the nonlinear range, but for a temp change
of 25C is only 0.4% error.  Therefore, to more closely approximate the
actual conditions, I'd recommend you cool the connector and reproduce the
resistance measurement made at room temp.


Any idea why their chart (at that website) showed temp coefficient of 0.0068
for copper?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



-Original Message-
From: Bill Ellingford 
To: 'Robert Macy' ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Monday, May 13, 2002 8:15 AM
Subject: RE: Constant for Change of Resistance formula.


>Hi Robert / group
>OK, Not the best choice of website to demo the answer.  The differing
>figures are because the formula has been transposed to give Temp from
change
>of R from the original formula which gives R from change of T.  To do this,
>another constant (The 234.5 constant) is required.  This is the implied
>point of zero resistance for copper on the Celsius scale.  The formula we
>use is:
>
>  Rfinal - Rorig
>  x (234.5 + Tamb start) -(Tamb finsh - Tamb start)
>  Rorig
>
>The Tamb start and finish are the changes (if any) in Room ambient.  If the
>room remains at 20c then 234.5 + 20 is the multiplier.
>
>-Original Message-
>From: Robert Macy [mailto:m...@california.com]
>Sent: 13 May 2002 14:54
>To: Bill Ellingford; emc-p...@majordomo.ieee.org
>Subject: Re: Constant for Change of Resistance formula.
>
>
>Bill,
>
>Thanks for the site.
>
>Went there and found the same formula and constant I use.
>
>For copper, Temp Coeff = 3.9 x 10-3
>
>Then I clicked on table of coeff and there was a very long list of
>materials, but the temp coeff of copper there was 6.8 x 10-3  ???!!!
>
>Any ideas for this disparity?
>
>- Robert -
>
>   Robert A. Macy, PEm...@california.com
>   408 286 3985  fx 408 297 9121
>   AJM International Electronics Consultants
>   619 North First St,   San Jose, CA  95112
>
>
>-Original Message-
>From: Bill Ellingford 
>To: 'Colgan, Chris' ;
>emc-p...@majordomo.ieee.org 
>Date: Monday, May 13, 2002 5:38 AM
>Subject: RE: Constant for Change of Resistance formula.
>
>
>
>Hi Folks
>Further to the answer given, here is a little more data.
>The constant used is for the change of resistance with temperature.  metals
>and alloys (conductors) all exhibit a different constant.  This can be used
>for calculating temperature rise or resistance change.  i.e. find the temp
>rise from a start and finish test measurement on a winding (for example) at
>the begining and end of a on load heat run or, find R for a given temp:
>using a table or the formula, resistance at various temperatures can be
>pre-determined from a measurement made at one particular temperature.
>
>A website with the formulae can be found at
>http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html
>
>Where you have a transition from one metal type to another, you must
measure
>each metal part individually.  If you have only two metals in contact, you
>may be able to apply a combination of the temp coefficient methods and
>transposition of 

Re: Constant for Change of Resistance formula.

[Robert Macy]

Bill,

Thanks for the site.

Went there and found the same formula and constant I use.

For copper, Temp Coeff = 3.9 x 10-3

Then I clicked on table of coeff and there was a very long list of
materials, but the temp coeff of copper there was 6.8 x 10-3  ???!!!

Any ideas for this disparity?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Bill Ellingford 
To: 'Colgan, Chris' ;
emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, May 13, 2002 5:38 AM
Subject: RE: Constant for Change of Resistance formula.



Hi Folks
Further to the answer given, here is a little more data.
The constant used is for the change of resistance with temperature.  metals
and alloys (conductors) all exhibit a different constant.  This can be used
for calculating temperature rise or resistance change.  i.e. find the temp
rise from a start and finish test measurement on a winding (for example) at
the begining and end of a on load heat run or, find R for a given temp:
using a table or the formula, resistance at various temperatures can be
pre-determined from a measurement made at one particular temperature.

A website with the formulae can be found at
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html

Where you have a transition from one metal type to another, you must measure
each metal part individually.  If you have only two metals in contact, you
may be able to apply a combination of the temp coefficient methods and
transposition of the measurement of change of junction voltage formulae i.e.
Thermocouple laws.

Hope this adds some value:  Bill Ellingford

-Original Message-
From: Colgan, Chris [mailto:chris.col...@tagmclaren.com]
Sent: 13 May 2002 10:28
To: emc-p...@majordomo.ieee.org
Subject: RE: Constant for Change of Resistance formula.



Ned is referring to the constant used in the "temperature rise calculated by
change in resistance formula" ie

<<...>>

Where dt is the temperature rise, R1 is start resistance, R2 is end
resistance, T1 is start ambient and T2 is end ambient.  234.5 is the formula
constant for copper.

This formula is used extensively when heat testing transformers and coils.

I'm afraid I don't know the constant for brass but I believe the figure may
be related to the "inferred absolute zero" of a material.  Try asking a
metallurgist?

Regards

Chris Colgan
Compliance Engineer
TAG McLaren Audio Ltd
The Summit, Latham Road
Huntingdon, Cambs, PE29 6ZU
*Tel: +44 (0)1480 415 627
*Fax: +44 (0)1480 52159
* Mailto:chris.col...@tagmclaren.com
* http://www.tagmclaren.com




> -Original Message-
> From: Robert Wilson [SMTP:robert_wil...@tirsys.com]
> Sent: Friday, May 10, 2002 7:00 PM
> To: emc-p...@majordomo.ieee.org; Ned Devine
> Subject: RE: Constant for Change of Resistance formula.
>
> What are the units? 234.5 ...what?? Looking at what the units are, will
> basically tell you exactly what the property is related to.
>
>
>
> Nonetheless, you cannot possibly directly determine what the temperature
> change of something as physically and geometrically complex as a
> connector, merely by factoring in what its resistance change is. Among
> other things, the solution is extremely non-linear and iterative. Changing
> resistance will generate more heat, which will increase temperature, which
> will generate even more heat and on and on! Add this to the fact the
> resistance coefficient with temperature is itself non-linear, and you can
> see how this complicates things further. The final temperature that the
> "system" stabilizes at, is reached when the logarithmically increasing
> (i.e. also very non-linear) heat transfer to the environment caused by
> increasing temperature, balances increased heat being generated.
>
>
>
> To reach a solution, you need to iterate your calculations, where the
> results of one calculation are plugged as variables into the next
> iteration. Typically a thermal analysis program will require several
> hundred iteration before a converged solution results.
>
>
>
> Bob Wilson
> TIR Systems Ltd.
> Vancouver.
>
> -Original Message-
> From: Ned Devine [mailto:ndev...@entela.com]
> Sent: May 10, 2002 8:29 AM
> To: emc-p...@majordomo.ieee.org
> Subject: Constant for Change of Resistance formula.
>
>
>
> Hi,
>
>
>
> Does any one know how the constant for CoR formula was determined? I know
> the K is 234.5 for copper and 226 for aluminum, but what property is this
> related to?
>
>
>
> I am trying to determine the change in temperature of a connector, based
> on the change of resistance. The connector contacts are made of brass.
>
>
>
> Thanks
>
>
>
> Ned
>
>
>
>
>
> Ned Devine
> Program Manager
> Entela, Inc.
> 3033 Madison Ave. SE
> Grand Rapids, MI 49548
> 1 616 248 9671 Phone
> 1 616 574 9752 Fax
> nd

Re: Constant for Change of Resistance formula.

[Robert Macy]

Ned,

Not familiar with this K term.  For straight resitance changes in
transformers, we always used 0.0039 per C.  Does K somehow include contact
resistance, not just bulk resistance?

This is definitely the time to measure it.

Environmental chamber at -50, 0, 50, 100, and 150.  Make your own curves.



- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Ned Devine 
To: emc-p...@majordomo.ieee.org 
Date: Friday, May 10, 2002 8:45 AM
Subject: Constant for Change of Resistance formula.


Hi,

Does any one know how the constant for CoR formula was determined?  I
know the K is 234.5 for copper and 226 for aluminum, but what property is
this related to?

I am trying to determine the change in temperature of a connector, based
on the change of resistance.  The connector contacts are made of brass.

Thanks

Ned


Ned Devine
Program Manager
Entela, Inc.
3033 Madison Ave. SE
Grand Rapids, MI  49548
1 616 248 9671 Phone
1 616 574 9752 Fax
ndev...@entela.com e-mail

Entela, Inc. A Certified Woman Owned Business
www.entela.com











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Re: ESD

[Robert Macy]

Slight adjustments

Part I   http://www.pcdmag.com/mag/archives/OEG20010928S0122.html
Part II  http://www.pcdmag.com/online/redux_0701_esd.html

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: John Barnes 
To: Richard Jones ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, April 23, 2002 7:10 AM
Subject: Re: ESD


>
>Richard,
>I invite you to read my article "Designing Electronic Equipment for ESD
>Immunity".  Part I was published in the July 2001 Printed Circuit Design
>magazine (vol. 18 no. 7, pp. 18-26).  Part II was published on the
>magazine's web site in November 2001.  You can download the entire
>article from the Internet:
>*  Part I-- http://www.pcdmag.com/story/OEG20010928S0122
>*  Part II-- http://www.pcdmag.com/redux/0701_esd.html
>
>I also have a (partially-) annotated bibliography for the article at
>   http://www.r-e-d-inc.com/esd-anno.htm
>which covers close to 1400 source documents on the subject.
>
>Enjoy!
> John Barnes
> Consultant, Robust Electronic Design, Inc.
> President, dBi Corporation
>



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Re: Marking - Made in XXX

[Robert Macy]

Amund,

I believe it's a law in the US that all products be labeled with their
country of origin.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: am...@westin-emission.no 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Saturday, April 20, 2002 3:08 PM
Subject: Marking - Made in XXX


>
>Is it necessary to describe where a product is manufactured, as in "Made in
>XXX". I have see this statement/label on many products, but is it only
>voluntary ?
>
>Best regards
>Amund Westin, Oslo/Norway
>
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
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>
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>
>All emc-pstc postings are archived and searchable on the web at:
>http://ieeepstc.mindcruiser.com/
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Re: Decoupling - capacitor values

[Robert Macy]

Years ago in ultrasonic echocardiography instrumentation (the ultrasonics
analog is a wide band receiver listening in the 1-10MHz region down to less
than 10uV, so the digital had better be quiet!) which used a bit slice
architecture system containing Schottky logic with a clock of 20MHz for
controlling and manipulating images in real time.  We're talking 4 PCBs
using 10 amps each board, so you can see the opportunity for generating
horrific noise that would be injected into the analog section.  We found
that power distributed using a "tree" type of distribution where traces were
thick then thinner out at the extremities *and* +5 was over top of GND made
for the quietest distribution.

The tree technique worked much quieter than the "recommended" grid structure
where +5 distribution on bottom layer goes one direction with GND
distribution on the top going the other.  This structure made little tiny
loop antennas that radiated energy all around inside the box and was awful!
But easier for the layout people.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: am...@westin-emission.no 
To: ieee pstc list 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, April 18, 2002 12:49 AM
Subject: SV: Decoupling - capacitor values


>
>Correct, the picture is complex. The PCB is 2-layer with signal, 5V-power
>and 0V-ref lines routed on both sides. There is no ground layer/plane.
There
>must be a large number of RF current loops because the 0V-lines are routed
>up and down and around.
>Beside trying to achieve a good decoupling I assume that reducing loop area
>is the most important.
>
>Amund
>
>
>
>-Opprinnelig melding-
>Fra: Cortland Richmond [mailto:72146@compuserve.com]
>Sendt: 18. april 2002 00:54
>Til: am...@westin-emission.no; ieee pstc list
>Emne: Re: Decoupling - capacitor values
>
>
>Yes, it makes sense. But the goal here is preventing or reducing Vcc drop
>during the time the microprocessor is switching. You need not only low
>reactance, but *also* enough capacitance to supply the current needed
>_while it is switching_. You have not given enough information here to tell
>if 820pF is sufficient.
>
>Regards,
>
>Cortland Richmond
>
>Amund Westin wrote:
>
>>> Insert a SMD ceramic capacitor of value 820pF in parallel with the
>existing
>100nF. The reason for the low value 820pF is because the capacitor
>self-resonance frequency is approximate 180MHz, and I believe it is
>important to choose a Cap value with a resonance frequency higher than the
>frequency we would like to decouple.
>
>Does it make sense?
>
><<
>
>



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Re: Faying

[Robert Macy]

Ed,

Thank you.  Especially the part blaming Woodgate.

My grandfather's name was Fay (son of Irish immigrant) and I always wondered
at the origin of that name.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Price, Ed 
To: 'EMC-PSTC List' 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, April 01, 2002 7:13 AM
Subject: Faying


>
>A couple of weeks ago, there was a thread discussing bonding techniques for
>ground studs. I suggested that MIL-B-5087 had some nice drawings showing
>typical accepted military practices. Of course, MIL-B-5087 has been
>superseded by MIL-STD-464, but you can still find electronic copies of
>MIL-B-5087.
>
>Jacob Shanker read through all of the 464 sections on Bonding, and then
>asked me if I knew what the term "faying" meant. It seems that MIL-STD-464
>uses that term without any definition, as if it's a very common American
>English word. IMHO, I consider myself to possess a rather decent
vocabulary.
>But "faying" left me puzzled, even after closely reading the context of the
>several citings in MIL-STD-464. It's certainly not in any common usage in
my
>part of the world. I certainly wouldn't want to call something "faying" at
>any typical US military base. So, off to the dictionary web sites.
>
>1. Britannica says: "not found".
>2. Merriam Webster says: Main Entry: fay // Pronunciation: 'fA // Function:
>verb
>   Etymology: Middle English feien, from Old English fEgan; akin to Old
High
>German fuogen to fit, Latin pangere to fasten
>   Date: before 12th century : to fit or join closely or tightly
>3. Harcourt's Metallurgy Engineering Dictionary says: faying surface //
>Metallurgy: the interface between two metallic parts that are to be joined.
>4. Finally, turning to Google in desperation for a simple explanation, I
>find pictures at:
>http://www.offroaders.com/info/tech-corner/reading/bolt-tension/bolt_tensio
n
>.htm
>
>So after all this searching, I find that MIL-STD-464 "faying" is just a
12th
>Century Old English way to say "facing" or "mating" surfaces. I'm not sure
>how he did it, but I suspect John Woodgate is to blame for this.
>
>Regards,
>
>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: Relative merits of various logic families in not generating RFI

[Robert Macy]

Thank you for the prompt reply.

Yes, faster rise time would lend the "signal" and its generation to create
energetic RFI, but just in case there were some internal states that blew
power out, or high impedance return paths through the substrate that caused
all the outputs to dance in common mode horror would be examples of the
"gotchas" I was looking for.

   - Robert -

-Original Message-
From: peter.pou...@invensys.com 
To: Robert Macy 
List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, March 19, 2002 8:23 PM
Subject: Re: Relative merits of various logic families in not generating RFI


>
>Robert,
>
>I suggest you have a look at the logic selection guides and application
>notes from the major semiconductor logic manufacturers.
>
>As a starting point, check out page 13 to 15 of
>http://www.fairchildsemi.com/ms/MS/MS-520.pdf for a rule-of-thumb guide on
>how to assess EMI generation from the manufacturer's specs for the logic.
>
>Generally the slower the rise & fall time, the lower the emissions.
>
>
>
>
>
>
>"Robert Macy"
>  To:

>Sent by:   cc:
>owner-emc-pstc@majordomFax to:
>o.ieee.org Subject: Relative
merits of various logic families in not
>   generating RFI
>

>20/03/02 08:49
>Please respond to
>"Robert Macy"
>
>
>
>
>
>
>
>Group,
>
>What are the relative merits of the various logic families HCT, HC, AC, ACT
>with regard to generating RFI?
>
>I remember one time we replaced an HCT which made more noise than Schottky
>TTL due to an internal overlap in the switching causing a power rail
>"shorting" spike.
>
>I'm sure by now that most IC vendors have addressed the EMC problems
>associated with poorly designed chips, but what's the status on these now?
>
>What's the order of preference?  Which one's best?
>
>   - Robert -
>
>   Robert A. Macy, PEm...@california.com
>   408 286 3985  fx 408 297 9121
>   AJM International Electronics Consultants
>   619 North First St,   San Jose, CA  95112
>
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
>Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>
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>
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>
>
>
>


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Relative merits of various logic families in not generating RFI

[Robert Macy]

Group,

What are the relative merits of the various logic families HCT, HC, AC, ACT
with regard to generating RFI?

I remember one time we replaced an HCT which made more noise than Schottky
TTL due to an internal overlap in the switching causing a power rail
"shorting" spike.

I'm sure by now that most IC vendors have addressed the EMC problems
associated with poorly designed chips, but what's the status on these now?

What's the order of preference?  Which one's best?

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



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Re: creepage v breakdown voltage

[Robert Macy]

Doing high voltage power supplies we found we always got in trouble using
20,000 V/in and things worked well when we kept below 10,000 V/in.

Metric that's 790 V/mm and 390 V/mm

This was free air and not some kind of "pointy" structure.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Roman, Dan 
To: 'MCA Compliance' ; Emc-Pstc Post

List-Post: emc-pstc@listserv.ieee.org
Date: Friday, March 15, 2002 6:49 AM
Subject: RE: creepage v breakdown voltage


>
>I was looking into this a few weeks ago also and found similar results
>experimentally as other posters have mentioned.  The only voltage per inch
>spec I was able to come up with was in the IPC specs but they were way out
>of whack!  0.12 mils per volt or more meaning that 2121 Vdc distance that
>the safety standards say should be 2.5 mm the IPC spec is saying you need 5
>mm
>
>While the safety standards may be conservative to allow for temperature,
>grease, dirt, etc. over time the IPC specs are ultra-conservative.  The
>dielectric tables for hermetically sealed material group III is probably
>closer to the actual breakdown but I never did find a spec I could use to
>predict the ACTUAL breakdown voltage of a gap between traces.  If anyone
>finds a rule of thumb or equation I'd like to have it also.
>
>Dan
>
>-Original Message-
>From: MCA Compliance [mailto:bally...@iolfree.ie]
>Sent: Friday, March 15, 2002 4:54 AM
>To: Emc-Pstc Post
>Subject: creepage v breakdown voltage
>
>
>
>does data exist which correlates creepage distance on a pcb with
>hi-potential test voltage it should withstand ?
>
>for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute
>and a creepage of 2.5mm (material group III) for basic insulation.
>
>How did they arrive at 2.5 mm ???
>
>Brian
>email: i...@mcac.ie
>



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Re: Don'r Get Caught Running a Red Traffic Light!

[Robert Macy]

Did you take a look at the people who make traffic light controllers?  , and
the magnetic sensor people?

If you can't find something, I'll see what's in archives around here.  Know
nothing related to your needs, just some of the players' names.

Also, you'd be amazed the information you can get from the city engineers
regarding this stuff - well at least here in San Jose.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Peter Merguerian 
To: "EMC-PSTC (E-mail)" < 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, March 06, 2002 9:18 AM
Subject: Don'r Get Caught Running a Red Traffic Light!


>
>Dear All,
>
>For an outdoor pole-mounted computerized camera taking pictures of your car
>and its license plates when you run over a red light, does anyone have an
>objection to the following safety standards for ITE? Is it ok to assume
that
>the mains transient voltage for outddor equipment is limited to 2500V?
>
>UL60950:2000]
>EN60950:2000
>IEC60950:2000
>
>This e-mail message may contain privileged or confidential information. If
>you are not the intended recipient, you may not disclose, use, disseminate,
>distribute, copy or rely upon this message or attachment in any way. If you
>received this e-mail message in error, please return by forwarding the
>message and its attachments to the sender.
>
>
>PETER S. MERGUERIAN
>Technical Director
>I.T.L. (Product Testing) Ltd.
>26 Hacharoshet St., POB 211
>Or Yehuda 60251, Israel
>Tel: + 972-(0)3-5339022  Fax: + 972-(0)3-5339019
>Mobile: + 972-(0)54-838175
>http://www.itl.co.il
>http://www.i-spec.com
>
>
>
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
>Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
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Re: CCFL light output

[Robert Macy]

Recommend you get a copy of Westinghouse Lighting Handbook

In one table they show lumens output for various fluorescent lamps with
current and volts input required.

for the Preheated
des.len curr. vol. *pwr lumens *lumens/watt
4W   6  0.132 32   4.32  115   26.6
6W   9  0.147 47   6.91  250   36.2
8W  12  0.170 56   9.56  420   43.9
20W 24  0.380 56   21.321220   57.2
30W 36  0.355 98   34.8 2100   60.3
84W 60  1.530 63   96.4 6250   64.8

for the High Output
len*pwr   lumens   *lumens/watt
24 32.8160048.8
48 60  400053.5
72 90.4645071.3
961328 900068.2

for the Super-Hi, Outdoor, and Low temp-jacketed
len*pwr   lumens   *lumens/watt
48 129 6900   53.5
72 19211100   62.5
96 25815500   60.1

*calculated values


Appears to be a nonlinear relationship.

Also, Slimline which come in smaller/different diameters have different
lumens per watt for the same length.


There is another curve rating efficiency (lumens per watt) which ranges from
52 lumens per watt for a natural color lamp to 80 lumens per watt for warm
white lamps.  But it doesn't say which basic tube is used as a reference.
Probably 72inch


Is this enough for you to do your modeling?

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Wani, Vijay (V) 
To: 'emc-p...@majordomo.ieee.org' 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, February 27, 2002 8:27 AM
Subject: CCFL light output


>
>Group:
> I am trying to build a thermal model a cold cathode fluorescent lamp
(CCFL)
>for cooling analysis.  CCFL manufacturer showing a chart of light output in
>Lumens as a function of lamp length and diameter.  I need to convert lumens
>to watts for input into Icepak. I would appreciate any help you can
provide.
>
>thank you in advance.
>
>Vijay Wani
>



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Re: Use of PCB Traces as Fuse and Voltage suppressor

[Robert Macy]

Jim,

You touch on an important issue concerning a fuse - just how does it "blow"?

Years ago I discovered by accident that fuses were designed with some
remarkable properties, when we had to make our own transient generator to
verify some telcom equipment's compliance to a BABT power supply transient
spec.

The BABT spec required that you simulate some very husky power transients.
It was like a short occurs in adjacent electronics followed by the inductive
kick.  The -48 voltage would clamp to around 10 volts then "pop" up to over
300 volts capable of supplying 500A for something like more than 50mS.  If
you didn't design your protection properly you would have a lot of
unintentional PCB trace fuses.  [  Actually heard that the spec originated
because a workman had dropped his wrench across the 1 inch diameter rods
which supply the -48 to the telco building from the battery building.  After
the wrench evaporated, they found the whole room of equipment was blown,
thus the spec.  Somebody verify that?  ]

The simulator used 4 deep discharge current vehicle batteries supplying the
telcom equipment through 50uH of inductance (that was  cable on a
spool).  Parallel to that you used a starter solenoid to short out a fuse
with a dead short.  Amazingly the larger fuses never produced much kick
back.  They were designed to blow gently away.  Tried all kinds.  Most of
the 8AG didn't do much, other types, nothing, even the 100 amp cartridge
types, nothing,  The absolute best was a 1A 8AG type.  When that went, you'd
get a flash of light, 300 volts trying to drive 500 amps into everything,
and even the coil would "jump" up off the floor.

Talk about PCB traces acting like fuses.

Anyway, I learned a respect for people who design fuses to make them go away
so gently when there is an incredible potential for some extremely high
voltage transients.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



-Original Message-
From: Jim Bacher 
To: 'Cortland Richmond' <72146@compuserve.com>; Chris Maxwell
; ieee pstc list 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, February 25, 2002 3:04 PM
Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor


>
>Long time ago we found that the traces worked well as fuses when the
>batteries were fully charged. However, when the batteries were mostly
>discharged, the PC Board traces did not work well as fuses. At lower
battery
>charge levels, the traces became very hot and ignited the PC Board rather
>than opening the traces up.  I therefore would recommend against using PC
>Board traces as fuses.
>
>
>Jim
>
>Jim Bacher,  Senior Engineer
>Paxar Corp.
>e-mail: jim.bac...@paxar.com  or  j.bac...@ieee.org
>voice: 1-937-865-2020
>fax: 1-937-865-2048
>
>-Original Message-
>From: Cortland Richmond [mailto:72146@compuserve.com]
>Sent: Thursday, February 21, 2002 12:53 AM
>To: Chris Maxwell; ieee pstc list
>Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor
>
>
>
>When do you need a fuse? Level II is the only time you are allowed to lose
>functionality, and the requirement for THAT is, it can't catch fire or
>explode. I've seen "trace fuses" tried. The problem comes after the trace
>blows.  You are at the mercy of your board shop, and if you use a number of
>them, results might not be all that repeatable.  AS i said earlier, I've
>had a board catch fire in my hand (though not as a result  of stress, but a
>solder splash). It is instructive.
>
>Cortland
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
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Re: Need Help on Inner PCB plane for RF shielding in isolated circuit

[Robert Macy]

Chris,

Using a PCB layer as an RF shield.  Don't forget you probably have that PCB
layer cut into swiss cheese with vias, unless you used blind vias.


Background:

A microstrip trace will radiate off the board a certain amount - makes sense
since part of its field is out in free space.

A stripline should not radiate anything because it is between two ground
layers, right?  Wrong.  A stripline in a practical PCB layout will only drop
the emission around 14dB, due to all the swiss cheese that got cut into the
PCB.


My point is, knowing the above practical information are you sure that an
"RF shield" made by a swiss cheese PCB layer will give you that much
shielding?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Chris Wells 
To: EMC-PSTC Discussion Group 
Date: Thursday, February 21, 2002 5:45 AM
Subject: Need Help on Inner PCB plane for RF shielding in isolated
circuit


Hi - I'm looking for some practical advise on using an inner Printed
Circuit Board "PCB"  plane tied at the corner mounting holes of the chassis
as a shield from RF exposure coming in on an isolated field circuit relative
to another digital logic board.

Questions:
a.. Must my shield layer be the bottom most inner plane to be
effective? Note that the 2 board solder sides face each other.  Layout wise
it is very difficult to do without going to a 6 layer board - I am trying to
stay with 4 if possible.
b.. Would I get some capacitive bypass protection if the grounded
shield plane where the top inner layer of the field circuit and the isolated
field circuit common was the bottom inner plane exposed to the adjacent
board?  I know the field would not be blocked but the capacitive bypass to
the chassis should reduce the RF intensity.
c.. Would the placing of the grounded plane between the top PCB
components and the Isolated common plane disturb the performance of the
field circuitry?  What would this do to the field circuit return path loop
area?
d.. Would a ground pour on the solder side of the adjacent PCB hurt
or help?  It would increase the capacitance between the two boards but it
would reduce the loop area of the traces on the solder side of the adjacent
board too.
e.. PCB clearance issues within a PCB - What are the
clearance/voltage rating issues within a PCB?  What voltages can I support
from:
a.. Surface trace to inner grounded plane - Can 240VAC be
supported.
b.. Electrically hot via passing through the grounded plane -
What inner pad clearance would one use on a 240VAC circuit?
f.. What do the safety standards say? - I see that UL3111 version of
IEC 61010-1 can treat the PCB as a molded void free material and so the
clearance issues are not addressed.  I understand that IPC has a spec on
voltage ratings versus construction - I am looking for it now.

Details:
The circuit worked fine at 10V/M but I am now being asked to take this
to 35V/M and that is somewhat of a challenge.
Testing to ANSI C37.90.2 1995 25-1000 MHz.
My problem area is 400-500 Mhz.
I am trying to keep RF energy on field circuit from coupling over to an
adjacent board and corrupting the bus of some microprocessor based logic.
The two boards are only .200" apart.
I have experimented with an insulated grounded shield plane placed
in-between the two boards and it works great.
I can withstand 50V/M WITH 80% modulation!!!
Unfortunately the shield is very difficult to make for production and
the cost is an issue.

I am trying to put the shield into the 4 layer PCB in the area around
the field circuit.
The solder sides of the two boards face each other.
The field circuitry has lots of through hole PCB type components and so
there are leads and trace pads that are exposed on the bottom of the field
PCB.
I have trimmed the leads and this helps some.
Even with a 6 layer board and the bottom inner layer as a grounded
shield I would have the leads sticking through the shield like holes in
cheese.
The field circuit construction is:
a.. top +5V pour plus a couple traces
b.. top inner layer presently free - this is where I would like to
put the grounded shield plane.
c.. second inner layer (solder side) is the isolated field circuit
common,
d.. Bottom solder side are a number of field circuit traces.
Unfortunately the free plane is not the bottom inner plane but the
second from the top component side.
The two boards have DC:DC and opto signal isolation on the field board
relative to the adjacent logic board.
The two boards and are connected at one edge of the board with a pin
header.
The field circuitry in questi

Re: Use of PCB Traces as Fuse and Voltage suppressor

[Robert Macy]

Our experience with gas discharge tubes was that they worked according to
spec in the lab.  fired perfectly around 400V like they're supposed to, but
down inside of the PVC oil tank holding the 150KV isolation transformer they
liked to fire at 600V+

Guess they needed photon energy to make the gas trigger or something.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



-Original Message-
From: Chris Maxwell 
To: bogda...@pacbell.net 
Cc: EMC-PSTC Internet Forum 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, February 20, 2002 2:15 PM
Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor


>
>Hi Bogdan,
>
>I'm sorry if you thought that my previous message was an endorsement for
>using necked down PCB traces as a fuse.  I understand and share the
>sentiment that it is an unpredictable and probably not even cost
>effective solution.
>
>I was wondering why anyone would shape a PCB trace in such a way (two
>triangles pointing at each other with a thin trace between the points).
>A "fuse" is probably not the likely intention.  A reasonable explanation
>may be a "cut jumper".  The triangles make the trace visible; while the
>thin trace provides an easy spot for the trace to be cut with an exacto
>knife which permanently removes the "jumper".Another reason
>(suggested by a colleage) are alignment marks used by the PCB fab house
>to help align layers.
>
>Just to be sure... I'm not suggesting the above as design ideas.  I'm
>just trying to figure out why anyone would do such a thing.
>
>One solution to the original problem that I haven't seen suggested is
>the good old "air discharge tube", "gas-discharge tube", "gas tube"
>...whatever you want to call them.  Of course, they aren't free (about
>$1 each).  They are more predictable than open air terminals, they are
>UL/CSA recognized and they can handle some massive breakdown currents.
>They are available from Bourns and Sankosha USA... probably some other
>manufacturers as well.
>
>Chris
>
>
>
>> -Original Message-
>> From: bogdan matoga [SMTP:bogda...@pacbell.net]
>> Sent: Wednesday, February 20, 2002 4:19 PM
>> To: gab...@simex.ca; Chris Maxwell; emc-p...@mahordomo.ieee.org
>> Subject: Use of PCB Traces as Fuse and Voltage suppressor
>>
>> Gabi:
>> I believe that there is a basic rule which is not published anywhere:
>> when you design something, then do it right.
>> When transient suppressors are needed, then use the correct component,
>> which will not depend on Paschen's Law and give predictable
>> performance.
>>
>> Same for "necked down" fuses.
>> When you want performance, then do it right. The above original
>> suggestions are perfect for Mickey-Mouse-engineering.
>> Bogdan.
>>
>



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Re: CM Choke simulation

[Robert Macy]

Derek,

Yes, do it all the time.   As long as you don't get into saturating any
cores, you can pretty much use lumped models and none of the nonlinearities
associated with core material.

Don't forget to include your AC mains cable.  It's a trifilar wound
transformer.  A Belden AC cord looks like a 3 winding transformer with 7uH
core.

You can also model the LISN and the parasitic capacitance in your test
setup.  Very educational.

Why do you ask?

   - Robert -




-Original Message-
From: lfresea...@aol.com 
To: emc-p...@majordomo.ieee.org 
Date: Friday, February 15, 2002 1:42 PM
Subject: CM Choke simulation


Hi all,

I'm trying to model a common mode choke in Micro-sim. Has anyone tried
this? Failing that, any suggestion on how to model one in Spice, possibly
using magnetic models?

Thanks in advance.

Derek.


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Re: Clean class B test bed

[Robert Macy]

Tony,

When we had to test a 100MHz video "two board" system, weaknesses in grounding 
structures of the PC's became extremely evident.  Two stood out as the best 
(best internal motherboard grounding) Gateway (best) and Dell (very close 2nd 
best).  No other PC's yielded a compliant system.  [ Even had to "fuss" with 
the grounding plates on the back.]

Sorry, don't know model numbers, but they were large with the proportions of 
the old rack mount types.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Tony 
To: emc-p...@ieee.org 
Date: Friday, February 08, 2002 11:42 AM
Subject: Clean class B test bed


Hello,

I am looking to find a clean Class B test bed (PC) for radiated emission 
testing. If anyone knows of such a thing please post the manufacturer, model 
number, any other information I would need to acquire one for use here.

 

Thanks for the help.

Tony Rayman

 

Re: Teslars???

[Robert Macy]

That's Tesla, which is a weber per sq meter.  It is a measure of the B
field, flux per area.  If you're English, 1 tesla is 10,000 gauss.

I don't believe those numbers.  We have light rail train go by here which is
powered by 600Vac (I believe it's 600 Vac)  I haven't seen the fields from
the motors, only the fields from the disturbance to the earth's field
(approx 50uT) as it is being deflected by the large metal vehicles.  Much
more an effect than from the power source.

If those specs you quoted go down to 50 Hz or 60Hz, than they relate,
otherwise doubt if you'lll easily relate them.  It would be "susceptibility
to AC mains magnetic fields."

Might also look at the Swedish MPR II, or is that III now?  The limit for a
monitor radiating is 200nT in this bandwidth.

Underneath high tension wires I've seen fields around 100mG,  which
translates to 10uT!  and those fields are considered big.

Again, I question those specs.  Maybe they meant 0.6 to 1.7 microtesla.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: marti...@appliedbiosystems.com 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, February 07, 2002 3:15 PM
Subject: Teslars???


>
>We have a customer that is concerned about how our product, laboratory
>equipment, will respond to electromagnetic disturbances from a high speed
>train that runs close to their lab.  The customer states that the
>disturbance will be around 0.7-1.2 m Teslar.
>
>Can someone please explain what the unit Teslar is and how that unit
>relates, or if it relates, to the immunity tests of EN 61000-4-3 Radiated
>immunity, or any other immunity test.
>
>Has anyone ever had a similar concern from a customer dealing with this
>type of disturbance?
>
>Your responses are appreciated.
>
>Regards
>
>Joe Martin
>EMC/Product Safety Engineer
>Applied Biosystems
>marti...@appliedbiosystems.com
>
>



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Re: Safety Link Offers Classifed Ads to EMC-PSTC members (no-charge)

[Robert Macy]

Agree, worthwhile.

All the newspaper articles in the Career section of the newspapers say that
after being laid off to take off a few weeks, gain bearings, then look for
your new position.  I totally disagree.  I say take 20 minutes, shake your
head, and go for new places as agressively and thoroughly as if looking for
a position were the new job.

Usually, there are severance packages that allow for the following gap in
income.  Any reduction in that gap is "free" money.  Also, you maintain the
mental advantage of not needing the new position so you'll just have a
different attitude while you're looking, one of more power.

Years ago when I was hiring people, I always was more impressed with the
person who "hits the pavement" the next day, even better, the same day.
That makes them look like a self starter, agressive, *and* someone who
actually likes to work, wants to be back at work.

Just my two cents here.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Cortland Richmond <72146@compuserve.com>
To: Art Michael ; ieee pstc list 
List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, February 05, 2002 10:52 AM
Subject: Re: Safety Link Offers Classifed Ads to EMC-PSTC members
(no-charge)


>
>Art,
>
>What a nice thing to do! I am just getting ready to pick up my stuff from
>the office, and then ... Why wait for the outplacement firm? Forward
>momentum!
>
>Cortland
>
>(I cannot speak for Alcatel
>They cannot speak for me;
>OF all that we might choose to say,
>The other now is free!)



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Re: Harmonics measurement instrumentation

[Robert Macy]

Hmmm...measured with a current meter, then measured with a wattmeter and got
different answersHarmonics out of phase? contain no power?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: gunter_j_ma...@embraco.com.br 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, January 22, 2002 11:56 AM
Subject: Harmonics measurement instrumentation



List

I would like your precious opinion about a situation regarding harmonic
current measurement (61000-3-2).

First case:
Using a sinusoidal AC power source, with a controlled output voltage
(almost perfect sine, voltage THD lower than the needed, even with load), I
measured the current harmonics using the internal instrument of the power
source.
The 13th and 15th harmonics were right above the limits (Class A limits).

Second case:
I add a digital wattimeter to measure the harmonics.
The harmonic content became 30% lower than the first case (good enough to
pass). And I got this results with the two instruments (the one inside the
power source, and  the wattimeter).

My first thought was the increased impedance due to the wattimeter (Zm).
But I got 50mV of drop voltage in this instrument (peak voltage), that is
lower than the specified in 61000-3-2, Annex B (0,15Vpeak maximum).
And the impedance of its current shunt is only 0,008 ohms (data from its
manual).
This put my first guess down ! Theoretically, the wattimeter couldn't
attenuate so much the harmonics !

Any idea of what could be happening  ?

Thank you again.

Günter J. Maass
Researcher - Power Electronics Development
EMBRACO S.A.



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Re: radar

[Robert Macy]

I'm going to say British pass on the left because the jousting pole is
usually held by right handers.

Sailors pass on the right, yet don't know the origin of that.  Maybe the
sailing tradition started a propensity to pass on the right for colonists.

Automobiles in the US are made so the driver can easily use his right hand
to operate a stick shift, which was mounted down the center of the
automobile on the transmission system.

 - Robert -



-Original Message-
From: Andrew Wood 
To: 'douglas_beckw...@mitel.com' 
Cc: 'emc-pstc' 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, January 11, 2002 1:38 AM
Subject: RE: radar


>
>I don't know whether it is true or not, but I recall hearing this some time
ago
>The convention of passing to the left on a road dates back to the days of
riding horse back and was related to the normal position for wearing a sword
or pistol.
>The first motor carriages had the driver sat centrally but kept to the same
convention.
> What I don't recall is the final piece of the story ie why most of the non
British Commonwealth nations decided to go the other way.
>
>Andy.
>
>
>
>
>> From:  Douglas Beckwith@MITEL on 01/10/2002 11:17 AM
>> Aha, a man after my own heart. Now you are talking about real cars. As an
ex
>> South African living in Canada, I still can't get used to the idea of
driving on
>> the the wrong side of the road.
>>
>> Doug Beckwith
>>
>>
>>
>>
>>
>> "Veit, Andy"  on 01/10/2002 08:29:14 AM
>>
>> Please respond to "Veit, Andy" 
>>
>> To:   emc-p...@majordomo.ieee.org
>> cc:(bcc: Douglas Beckwith/Kan/Mitel)
>>
>> Subject:  RE: radar
>>
>>
>>
>>
>> >Why would someone want to take a car out of UK with the
>> >steering wheel on the wrong side?
>>
>> I can think of at least one good reason to take a RHD car out of the UK -
>> its called the Lotus Super 7.
>> There, its out in the open now.  I am a British car nut. :)
>>
>> Rerards,
>> Andrew Veit
>> Systems Design Engineer
>> MTS Systems Corp
>> 1001 Sheldon Drive
>> Cary, NC 27513
>>
>>
>> -Original Message-
>> From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
>> Sent: Wednesday, January 09, 2002 3:35 PM
>> To: emc-p...@majordomo.ieee.org
>> Subject: Re: radar
>>
>>
>> I read in !emc-pstc that John Shinn  wrote (in
>> <001f01c1992f$09f5c960$0b3d1...@hadco.comsanmina.com>) about 'radar', on
>> Wed, 9 Jan 2002:
>> >Why would someone want to take a car out of UK with the
>> >steering wheel on the wrong side?
>>
>> There are actually more *countries* where you drive on the left. Not
>> more RHD cars, though. (No, I don't have the list of RHD countries, but
>> it's on the web somewhere - everything is!)
>>
>> Besides, it is *undeniable* that a British car has the steering wheel on
>> the right side.
>> --
>> Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
>>
>> After swimming across the Hellespont, I felt like a Hero.
>>
>> ---
>> This message is from the IEEE EMC Society Product Safety
>> Technical Committee emc-pstc discussion list.
>>
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>This e-mail and its contents may be confidential, privileged and protected
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Re: radar

[Robert Macy]

But on the up side,
if you're stopped in England you don't have to produce a driver's license --
considered an invasion of your rights, or such.

  - Robert -
-Original Message-
From: Pettit, Ghery 
To: 'Nick Rouse' ; emc 
Date: Tuesday, January 08, 2002 1:09 PM
Subject: RE: radar


Does the photo show who was driving the car?  Can't say that I would be
too happy to be summoned to court when one of my kids (or wife) was
speeding.

Ghery Pettit

-Original Message-
From: Nick Rouse [mailto:nickjro...@cs.com]
Sent: Tuesday, January 08, 2002 12:03 PM
To: emc
Subject: Re: radar


I don't know if the technique is used in America but the speed cameras
in the UK are triggered by radar but produce evidence by taking two pictures
illuminated by two strobe pulses timed about 150ms apart. Stripes are
painted across the road spaced so that between flashes a vehicle will
traverse one stripe pitch for every 10mph.If the pictures show you have
traversed more than 7 stripe pitches (on motorways)you will receive copies
of these photos together with a summons to appear in court.
Nick Rouse

 >Jim Freeman wrote:
>Hi All,
>   I apologize for being off subject but I was driving to work and
>noticed aCalifornia Highway Patrol officer on the opposite of the
>freeway an about 500 yards away. What brought him to my attention
was
>what appeared to be a strobe light that was flashing. I have been
>thinking about and I was wondering if the new radar has some ways
of
>taking pictures or if the strobe light really is the radar source.
Any
>help would be appreciated.
>Thanks
>Jim Freeman

Hi All,
I apologize for being off subject but I was driving to
work and
noticed aCalifornia Highway Patrol officer on the opposite
of the
freeway an about 500 yards away. What brought him to my
attention was
what appeared to be a strobe light that was flashing. I have
been
thinking about and I was wondering if the new radar has some
ways of
taking pictures or if the strobe light really is the radar
source. Any
help would be appreciated.
Thanks
Jim Freeman



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Re: Magnetic measurement per CISPR 15

[Robert Macy]

It is my understanding that the "conversion factor" converts the voltage
reading on a 50 ohm receiver to the amperage reading directly.  In other
words, 1dbuV *is* 1dBuA and already takes into account the 50 ohm input
impedance.

Sadly, all this was written before advancements in electronics occured.  For
example, I designed and built a small portable magnetic preamp I use for
measuring magnetic fields.  It has a 4 inch diameter air core coil, produces
1 V per microTesla over the frequency range of 5 Hz to 1 MHz with a noise
floor of around 5 nT (the noise coefficient is dropping as a function of
frequency and integrates over the bandwidth) so most of the noise energy is
around the 5 to 100 Hz range.  It was originally designed to address the
Swedish MPRII rules.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: KC CHAN [PDD] 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, January 04, 2002 8:57 PM
Subject: Magnetic measurement per CISPR 15


>
>Hi all
>
>I got a question about the magnetic measurement per CISPR 15, it says that
the sensitivity of the current probe is 1V/A.
>
>My interpretation is that  X dBuV measurement you got from the EMI
receiver, corresponding to XdBuA, which is then compared to the limit, say
88dBuA at 50 kHz for 2-m 3-loop system.  The manual I have says the same
thing.  Is it correct?
>
>My question is
>1) Do we need to covert the voltage to current taking consideration of the
50 Ohm impedance of the receiver?  If that is the case, we need to minus 34
dB from my voltage measurement  to get the current measurement .
>
>2) In what ways the whole system has considered the impedance variation of
the current probe impedance.  I have checked the impedance of the current
probe, the impedance is ranging from 40+ Ohm at 10kHz to 150+ Ohm  at around
150K and decreases to around 75 Ohm at 1 MHZ.
>
>Thank you
>KC Chan
>
>



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Re: EMC-related safety issues

[Robert Macy]

Perhaps, it merely interfered with the "sensor" electronics, not the true
magnetic field that was being sensed.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Pettit, Ghery 
To: 'James Collum' ;
emc-p...@majordomo.ieee.org 
Date: Thursday, January 03, 2002 11:46 AM
Subject: RE: EMC-related safety issues


I still have a hard time believing it was a compass that was affected by
a laptop computer.  ADF indication, could be.  VOR, maybe.  Magnetic
compass?  I wouldn't want a magnetic source that strong in my lap!  My belt
buckle would be stuck to it.  There is quite a distance between a magnetic
compass in the cockpit of an airliner and anything a passenger is carrying.
Not so in a Cessna 172, but in a DC-10?

Ghery Pettit

-Original Message-
From: James Collum [mailto:james.col...@usa.alcatel.com]
Sent: Thursday, January 03, 2002 10:47 AM
To: emc-p...@majordomo.ieee.org
Subject: Re: EMC-related safety issues




*
A routine flight over Dallas-Fort Worth was disrupted when one of
the compasses suddenly shifted 10 degrees to the right.  The pilot asked if
any passenger was operating an electronic device,  and finding that a laptop
computer had just been turned on requested that it be turned off,  whereupon
the compass returned to normal. Following RTCA guidelines the pilot
requested that the laptop be turned on again 10 minutes later,  when the
compass error returned.
Ref: Compliance Engineering (European edition)  Nov/Dec 1996 p12
*

I am fascinated by this amazing story (which must surely be an urban
myth) and went in search of more info on the internet.
I had never heard of the RTCA ( a private corporation)  before, but
noticed via their web site that you have to be a member company (i.e. pay)
to receive the wisdom that it contains.  Aviation is merely a hobby of mine
but I'm interested in reading a copy of the RTCA's DO-233/214 and 196
documents without shelling out hundreds for the privilege, can anyone
advise? Also does anyone know what recommendations have they made to
modifying FAR 91.21 (as per their web site).
In reading this again, I'm curious as to how the pilot would have known
about a private companies convoluted guideline for fault finding on errant
radio direction equipment involving locating industrious passengers and
commandeering their computers at 10 minute intervals.
Surely he would have done what any professional engineer would do, beat
or kick the 10 degree error out of the RDF equipment?
Or maybe just wonder to him/herself about how strange things happen in
the Dallas Fort Worth area?

Tounge in cheek, my comments and not those of my employer etc.

Jim



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 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

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Re: EMC-related safety issues

[Robert Macy]

Great, Now we have to start adding information on the sales brochure, like "As 
the purchaser of this product places this product into service said purchase is 
forming a licensed arrangement with the vendor to not hold said vendor culpable 
for all uses and potential misuses of this product" You get the drift, 
just copy the MS licensing language on all software.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Gary McInturff 
To: Ken Javor ; cherryclo...@aol.com 
; emc-p...@majordomo.ieee.org 

Date: Wednesday, January 02, 2002 2:38 PM
Subject: RE: EMC-related safety issues


Did the camera have "proximal cause" to the event that befell the 
child, well not unless it fell of of the ceiling or the tripod fell over and 
hit the infant, or the camera overheated and started a fire. Other than that 
the Lawyers need to dig their heads out - juries as well. They are just trying 
to chase the money. Cameras don't cause disease likes SIDS. They don't cause 
buildings to collapse, or burglaries or whatever else might befall the baby 
They are just a convenience. If they an additional input path to the parents 
may stop, but the actual monitoring (or the failure of monitoring) neither 
helped or hindered the health of the child. The camera manufacturer, even if 
this is sold as a baby monitor, I can't see how holding the camera manufacturer 
responsible can even be considered, except that it gives the lawyers somebody 
to sue with some money. I suppose it might give the parents a misplaced sense 
of (and I hate this word) closure because they can blame some body, rather than 
just life, fate, or whatever.
I don't doubt your statement that somebody is trying to hold the 
manufacturer responsible, I just point out that it is asinine and in my opinion 
inexcusable to do so. Recorded history doesn't show a huge plethora of infant 
deaths because parents weren't able to have a video camera in the room. 
Gary 
-Original Message-
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Wednesday, January 02, 2002 11:22 AM
To: cherryclo...@aol.com; emc-p...@majordomo.ieee.org
Subject: Re: EMC-related safety issues


I have read a part of the IEE guide mentioned below.  What I have read 
on a paragraph by paragraph basis is fine, but I find the overall philosophy 
deeply troubling.   The tone of the document is that the manufacturer is 
responsible for all uses or misuse of the equipment he sells in concert with 
every other type of equipment made or that might be made at some time in the 
future.  This document is a trial lawyer's dream.  It takes us from a society 
in which a sale was deemed a transaction of mutual benefit between equals to a 
society in which an Omniscient Producer must cater to the needs of an ignorant, 
childlike Consumer, and in direct corollary, any misuse of any product by any 
consumer is deemed proof that the Omniscient Producer was profiting by taking 
advantage of a helpless victim.   I realize this document merely reflects this 
prevalent view, but the idea that an Industry group would provide such a 
smoking gun for some trial lawyer to use in defense of some poor misled 
swindled consumer is, to say the least, troubling.  To say that Industry 
standards don't go far enough, that it is the responsibility of the Producer to 
be able to determine all possible environments and failure modes that might 
ever occur is placing an impossible burden and any rationale entity, upon 
reading this document will immediately cease production of anything that could 
conceivably ever malfunction in anyway whatsoever.

Case in point:  A friend of mine bought one of these 2.4 GHz remote 
miniature video cameras with integral IREDs and is able to monitor his infant 
twins from his own bedroom, even in the middle of the night with no lights on 
in the twins' bedroom.  Suppose that 2.4 GHz link is disturbed in some way and 
he misses something important happening in that bedroom.  Is the  manufacturer 
of that video system responsible for any ill that then befalls my friend's 
twins?  I think not.  But this safety guide says yes, and places the 
manufacturer at risk.

--
From: cherryclo...@aol.com
To: emc-p...@majordomo.ieee.org
Subject: Re: EMC-related safety issues
Date: Wed, Jan 2, 2002, 9:49 AM



Once again, John, you seem to be trying to give a negative 
impression about the IEE's guide on EMC and Functional Safety (which you now 
admit you haven't read) instead of simply saying what it is that you think is 
wrong with it. 

Of cours

Fw: question on emc and networks

[Robert Macy]

I offered to forward this to the emc group for help.

Please answer directly.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Dieguito 
List-Post: emc-pstc@listserv.ieee.org
Date: Saturday, December 29, 2001 8:04 AM
Subject: question on emc and networks


>Hi there,
>
>I've got this assignment to make for school and I realy don't know where to
>begin:
>
>I have to find what standards a network has to be compliant with,
concerning
>emc levels.
>
>So is there anyone who knows what stardards I need and where I can find
>them, because on iso.org, they ask a lot of money (if just for a silly
>assignment).
>
>And is there someone who knows where to find emc specs on networkcables,
>hubs, etc.? All concerning emc of course.
>
>Or does someone knows a better newsgroup to ask for this? (please let me
>also know the server, I'm now on pandora (belgium)).
>
>Thanks a lot and a happy newyear to all.
>
>Dieguito
>
>


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Re: Field Strength - Substitution Method

[Robert Macy]

Hear, hear.

It may have been "hand waving" but I always assumed that test sites never
correlated very well (although their calibration curves do) because the
actual radiators one is measuring are "strange" and not well controlled
impedances like an antenna.  The sources can be "low" or "high" impedance
and each act completely differently than one expects.

With that in mind, I don't see how it is possible to substitute a controlled
antenna, measure the power going to it, and predict anything to the
original - within plus or minus 12 dB.

Just opinion here and experience fighting battles at test sites.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Cortland Richmond <72146@compuserve.com>
To: Sam Wismer ; ieee pstc list 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, December 27, 2001 10:12 AM
Subject: Re: Field Strength - Substitution Method


>
>Sam,
>
>I think you did it right with one AF and one gain. There's a problem with
>that method.  You need more information needed to make the  _results_
>right.
>
>Given a certain power at the antenna terminal, and a known gain and
>efficiency, you can calculate the free-space field strength at some
>distance due to RF applied to that antenna. Then you add loss or gain due
>to reflection from the ground plane.
>
>This gets you down to some fairly reliable way to estimate what field
>strength will be created over a ground plane at some distance from an
>antenna.
>
>What you don't have -- and what, I think, is most difficult -- is a model
>that reliably correlates a substitution antenna as a source with the
>equipment under test. A rack seven feet tall and two feet on a side -- with
>wires overhead and off to its sides -- will NOT radiate the same as a
>dipole. And it will differ more from an antenna as its dimensions become
>larger than the antenna. I would expect differences to become more
>pronounced, in other words, at higher frequencies. This is what you saw.
>
>Cortland
>(my own opinion and not that of my employers)
>



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Re: Non-compliant product put into EU marked

[Robert Macy]

Wow!  I've been telling clients that even a Beta test is allowed, as long as
absolutely no revenue is derived from it.  Can't sell it.  Can't rent it.
With no revenue, it is an exhibition, a test.

Is this wrong?

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Massey, Doug C. 
To: IEEE - PSTC FORUM (E-mail) 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, December 27, 2001 6:20 AM
Subject: RE: Non-compliant product put into EU marked


>
>Article 8.2 of the RTTED (1999/5/EC) allows exemptions for ".. trade fairs,
>exhibitions, demonstrations, etc.". It also requires that a "visible sign
>clearly indicates that such apparatus may not be marketed or put into
>service until it has been made to comply."
>
>Beta testing at a customer site does not fall under the Art. 8.2
exemptions.
>A sales team demonstrating the product to a customer could be exempt for
the
>period of their demonstration. However, you can't call a large scale Beta
>test a demonstration - the Beta test is 'putting into service'.
>
>IMHO, it's in clear violation of the RTTED.
>
>Doug Massey
>Lead Regulatory Engineer
>LXE, Inc.
>
>-Original Message-
>From: am...@westin-emission.no [mailto:am...@westin-emission.no]
>Sent: Monday, December 17, 2001 5:05 PM
>To: emc-p...@majordomo.ieee.org
>Subject: SV: Non-compliant product put into EU marked
>
>
>
>As far as I know the product shall be produced in a large scale. The reason
>for putting it on the marked for a time limiting period is (again as far as
>I know) to run the product ( beta version) in a test installation and
>thereafter will it go through the entire test program (EMC, LVD, etc). It
>seems that they did not manage to do the testing before the 1 month test
>period on the field.
>
>Again, I feel they are not doing things in the consecutive order and I also
>think they are no allowed to put in on the marked, even the short period.
>
>Amund
>
>-Opprinnelig melding-
>Fra: Tania Grant [mailto:taniagr...@msn.com]
>Sendt: 17. desember 2001 19:33
>Til: am...@westin-emission.no; emc-p...@majordomo.ieee.org
>Emne: Re: Non-compliant product put into EU marked
>
>
>Is the manufacturer serious, or completely ignorant?
>
>If serious, I would disassociate from them as much as possible.  If merely
>ignorant, and you have some sort of association with them, I would
recommend
>that you educate them fully.
>
>Another thought, -- is this product slated for mass distribution, even for
>only a month, or is it going to another location or a particular customer
>for some special in-house use or application?   What does this customer
>think?   Are they aware, and do they agree to this?   The Directives do
have
>special provisions for certain special applications where non-compliant (or
>is it merely "untested" !)  product can be shipped to Europe, but I believe
>that under those circumstances, the name of the manufacturer and product
>model name or designation has to be "published" broadly in the EU.   I
don't
>remember the details.   If anyone can shed more light, that would be very
>nice.
>
>taniagr...@msn.com
>
>- Original Message -
>From: 
>To: 
>Sent: Sunday, December 16, 2001 2:06 PM
>Subject: Non-compliant product put into EU marked
>
>
>>
>> Hi all,
>>
>> You place a radio product into the EU marked with the following status:
>>
>> - Not been EMC, radio or safety tested (the previous model was tested and
>> compliant, major modifications have later been implemented)
>> - The product will only be in the marked for a time limiting period ( 1
>> month)
>> - During the time limiting period it will be operating as in a normal
>> condition
>> - No CE mark on the product and no DoC
>>
>> I mean that you can't do this. You have to confirm that you fulfil the
>EMC,
>> radio and safety requirements, DoC in place, even that the product just
>will
>> be in the marked for 1 month and thereafter withdrawal.
>>
>> Any other comments from the list members ?
>>
>> Best regards
>> Amund Westin, Oslo/Norway
>>
>>



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Re: noise figure

[Robert Macy]

NoiseFigure new
  = sqrt (  ( NF1^2 - 1 )  + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... + 1 )
 where all noise figures are ratios and referenced to a
single location.


A few points:

1  Definition:
Noise Figure is the ratio of increased noise in a system above the expected
level of Johnson noise.  For our 50 ohm system that will give a voltage of
sqrt(4KTRBw)  where K is Boltzmann's constant, T is temperature in absolute
Kelvin, R is the resistance of the system (for our case 25 ohms {50 ohms in
parallel with 50 ohms}), and Bw is the bandwidth of interest in Hertz.  For
a Bw of 1 MHz that yields a noise floor of around 0.641uV, or -3.9dBuV


2  Relate noise figure to some place in your system.
For simplicity (and ease of using specs) relate to the "front end"  Noise
figure specs relate to the front end of a system block.  The noise is
amplified, or attenuated, along with the signal and therefore track
together.  As you go from the output to the input of each system block, gain
subtracts from the NF and attenuation adds to the NF.  Modify the Noise
Figure by each block you must go through to get to the input.  For example,
through cable loss, add the few dB.  For gain, subtract the gain.

3  Make up a list (Use Excell spread sheets)  You will end up with
contributions from every block now referenced to the front end.  then...

4  Remember that uncorrelated noise does not add, but adds as the square
root of the sum of squares.  However! you must only take into consideration
the noise contribution from each "additional" noise source.  You cannot keep
adding in the contribution from the 50 ohm source impedance.  Therefore,
each Noise Figure ratio must be squared and then have 1 subtracted from it.
After combining all the contributions, you will add the 1 back.  Simply take
the square root of that total sum and find the 20log value and you will have
your total system's new NoiseFigure.


For example, let's find the noise figure for a receiving system that
attaches to an antenna consisting of long cable, amp, cable, and spectrum
analyzer (SA).

Passive devices have 0 dB noise figure (they do not add any noise)

Antenna is passive, but converts volts per meter into volts in a 50 ohm
system.  Since it does not add any noise, there is no difference between
minimizing the NF at the antenna port or at the field that it measures.



So let's find out the NF of our system  at 200MHz

long cable 3dB attenuation
amp24dB   6 dB NF
cable   -
SA  32dB

Note:  You could have a perfect receiver that contributes no noise located
after the long cable and you would still have a 3 dB NF   That's why
amplifiers are placed near the signal source.

Check your particular SA.  It can have a Noise Figure from 26dB to 36dB
depending on its design.  That means for a 1 MHz bandwidth you can only see
down to around -80dBm.

So let's move the amplifier out to the antenna and change the order of the
list:

cable   -
amp   gain 24dB with NF = 6 dB
long cable atten  3dB
SA with NF = 32dB

The list would show 6 dB NF at the input  and (32-24+3=11) 11dB from the SA.
That is a ratio of 2 and a ratio of 3.55.


New Noise Figure is sqrt(  (2^2-1) + (3.55^2-1) + 1 ) = 4 or 12dB
See how the SA still dominates?



To rewrite the equation:

NoiseFigure new
 = sqrt (  ( NF1^2 - 1 )  + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... +
1 )
 where all noise figures are ratios and referenced to a
single location.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: KC CHAN [PDD] 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 21, 2001 5:46 PM
Subject: noise figure


>
>Hi all
>
>It may not be purely EMC question, actually it is RF related, but I am sure
the experts here can answer my questions.
>
>We all know that we need to have a pre-amp. that is as lower noise figure
as possible, but how low it is enough or how it is related to the noise
floor viewed by a receiver or spectrum analyzer.
>
>Thank you
>KC Chan
>



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Re: High Frequency Pre-amp

[Robert Macy]

Just a reminderalways make certain that no signal gets in to "saturate",
or even start to overdrive, your amplifier at frequencies you're not looking
at.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Ken Javor 
To: rehel...@mmm.com ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 21, 2001 11:42 AM
Subject: Re: High Frequency Pre-amp


>
>MITEQ and Mini-Circuits come to mind for octave and multi-octave  band
amps.
>HP (Agilent) makes the the 8348A covering 1 - 26.5 GHz around $14 K.  The
HP
>model has a 10 dB noise figure and 25 dB gain below 20 GHz.  With MITEQ you
>can pick your noise figure and gain from a large variety of models.
>Mini-Circuits is the low price leader, I saw amps up to 8 GHz but you would
>need several models and the price will still likely be less than with the
>others.  If you are using an HP8566 or similar model which uses harmonic
>mixing above 2 GHz then you need enough gain to push the signal above the
>degraded noise floor.
>
>--
>>From: rehel...@mmm.com
>>To: emc-p...@majordomo.ieee.org
>>Subject: High Frequency Pre-amp
>>Date: Fri, Dec 21, 2001, 10:16 AM
>>
>
>>
>> This question may have recently posted but I'm not able to search the
>> archives so I'll
>> ask again.
>>
>> We have an immediate need for a pre-amp above 1000 MHz. Would you be so
>> kind
>> as to let me know what brands/models and frequency range you are using.
Any
>> pro/con
>> insights would be welcome as well. Please contact me on or off-line.
>>
>> Thanks,
>> Bob Heller
>> 3M Product Safety, 76-1-01
>> St. Paul, MN 55107-1208
>> Tel:  651- 778-6336
>> Fax:  651-778-6252
>>
>>
>> ---
>> This message is from the IEEE EMC Society Product Safety
>> Technical Committee emc-pstc discussion list.
>>
>> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>>
>> To cancel your subscription, send mail to:
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>>
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>> messages are imported into the new server.
>>
>



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Re: power supply to GOST 30429-96

[Robert Macy]

Low frequency conducted noise is usually generated by the periodic demand on
the energy storage cap (greatly, greatly affected by esr).  This noise is
"differential" and no y-cap (unless it's so large it becomes a killer size,
and then not really) will stomp on it.

Your first problem (conducted emissions) is trying to get rid of the
fundamental of the power supply which can be a bit challenging.

You see, the y-caps are low impedance *AND* your noise source is low
impedance, so adding y-caps is not going to "short" out that noise source.

The best way to solve your problem is is to use minimum esr caps and, of
course, very judicious layout inside the supply.

There are external things you can do, but they can get bulky.

How much power does this supply take?  Do you have control over the
manufacturing process at all?

Once you've tackled the conducted emissions, we can move on to the radiated
emissions.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Lou Guerin 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 21, 2001 10:49 AM
Subject: power supply to GOST 30429-96


>
>Dear Fellow EMC workers,
>I am trying to get a SMPS to pass this GOST standard and am having a devil
>of a time getting it done. After 3 days of mitigation testing at our local
>lab we are still out at the low frequency range 10-60kHz and at 15-50MHz.
>We pass the Class A limits for CISPR 22 but these GOST limits are far more
>stringent. The power supply is convection cooled in a IP66 box that is
>powering a repeater. We have been able to determine that the noise is being
>generated by the power supply and thus far we are not able to suppress all
>the low frequency and high frequency conducted noise.  I have copied the
>limit requirements below for your review.
>Has anyone run into this standard before?  Is there something we may be
>overlooking?  We are not using a custom supply, this is an off the shelf
>supply that we are packaging into a IP66 box. The usual "fixes" didn't seem
>to work, X and/or Y caps, ferrite beads, inductor. These were applied
>liberally during the past 3 days.
>The requirements for EMC of radio equipment in Russia (as well as in
several
>other CIS countries) are set by the standard GOST 30429-96 (Electromagnetic
>Compatibility of technical equipment. Man-made noise from equipment and
>apparatus used t6ogether with service receiver systems of civil
application.
>Limits and test methods), according to this standard the following
>measurement must be done.
>1. Conducted Emissions
>Frequency range Limits, dB(uV)
>0.009 MHz - 0.15 MHz  U = 90 - 28.9lg(f/0,01) (Quasi-peak)
>0.15 MHz - 0.5 MHz  U = 66 - 22.7lg(f/0,15) (Quasi-peak)
>0.5 MHz - 6 MHz   U = 54 - 12.97lg(f/0,5) (Quasi-peak)
>6 MHz - 30 MHzU = 40 (Quasi-peak)
>30 MHz - 100 MHzU = 48 (Quasi-peak) 40 (Average)
>
>This test is done looking at the emissions from the 220 V power cables,
>using a LISN
>2. Radiated Emissions
>Frequency range Limits, dB(uV/m)
>0.01 MHz - 0.15 MHzE = 60 - 20.4lg(f/0.01)
>0.15 MHz - 30 MHz   E = 37 - 7.39lg(f/0.15)
>30 MHz - 100 MHzE = 36 - 21.0lg(f/0.30)
>100 MHz - 1000 MHzE = 25 + 20.0lg(f/100)
>
>According to GOST 30429-96 this test is done at 3 meters in frequency range
>0.01MHz - 30 MHz and at 1 meter in frequency range 30 MHz - 1000 MHz in the
>screen room.
>
>Any help will be eagerly accepted.
>Best regards and happy holidays,
>Lou Guerin
>Agency Approvals Manager
>Littlefeet, Inc.
>lgue...@littlefeet-inc.com 
>



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Re: RE:RJ45 filtered connector

[Robert Macy]

Did you see Regal Electronics?  They make filtered RJ45 connectors

If not, try

Regal Electronics 408 988 2288
4251 Burton Dr
Santa Clara, CA  95054

might have a website around www.regalusa.com

A technical contact is Bill Kunz

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Reginald Henry 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, December 20, 2001 11:25 AM
Subject: RE:RJ45 filtered connector


>
>To All,
>
>Can anyone out there tell me where I would be able to purchase a fully
>shielded and filter
>RJ45 connector that is Bulkhead mountable.
>
>The RJ45 must be able to handle data rates from 10Base T to 100Base T
>
>I will be performing CE testing in the chamber so it must be bulkhead
>mountable !
>
>
>Thanks and Happy Holidays to YOU ALL !
>
>Reg



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Re: Power station equipment

[Robert Macy]

Nick,

Contact this man, he has a lot of experience in the technical aspects of the
power distribution business.

Don Kelly
d...@home.com

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Nick Williams 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, December 19, 2001 5:12 AM
Subject: Power station equipment


>
>Can anyone tell me what the likely certification requirements for
>equipment intended for use in the power generation/distribution
>industry in Califiornia will be?
>
>I think I'm reasonably up to speed with what the NEC and OSHA have to
>say, but some practical guidance based on experience would be rather
>welcome.
>
>I'm not at liberty to divulge much detail about the product in an
>open forum, but the equipment I am concerned with is heavy current
>generation equipment, not instrumentation.
>
>Regards
>
>Nick.
>



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Re: Sometimes product safety just isn't enough

[Robert Macy]

AR!!

I went there, read down through much, before it soaked in.

   - Robert -

-Original Message-
From: Pettit, Ghery 
To: 'Robert Macy' ; James Collum
; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 14, 2001 4:15 PM
Subject: RE: Sometimes product safety just isn't enough


Now, you do need to worry about some of these obscure chemicals.  There is
an entire web page devoted to the hazards of DHMO, di-Hydrogen Monoxide.
www.dhmo.org  Check this out.  It could save someone you love.

Ghery Pettit
Intel


-Original Message-----
From: Robert Macy [mailto:m...@california.com]
Sent: Friday, December 14, 2001 1:39 PM
To: James Collum; emc-p...@majordomo.ieee.org
Subject: Re: Sometimes product safety just isn't enough



In deference to the warning label on the peanuts bag.  Some people have life
threatening allergies to peanuts and take warnings such as that and warnings
on cookies, etc very seriously.  But then again, you'd think with the main
label "Peanuts" would be sufficient.  Perhaps, someone is making peanuts out
of soy beans already.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: James Collum 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 14, 2001 1:57 PM
Subject: Re: Sometimes product safety just isn't enough


Following a recent airline flight, I was given a bag of peanuts, marked
"Peanuts" which contained a health warning "contains peanuts".
I was thinking that in a similar style that maybe electrical products
could have an added warning "may contain electricity".
The "may" would elude to the connection of a mains cable for mains
powered equipment, or even batteries in battery powered equipment.  I think
the IEC should be prompt to act in this vital area.
Following this illogical train of thought, the swimming pool should have
a warning "contains water" and the ladder could have a warning "may alter
altitude".
But on a slightly more serious note (but not much) If I am ever present
when someone is about to do something interesting with electricity I always
advise that the person about to do the deed make sure to note who present
will provide the "kiss of life" when it all goes pear shaped. It tends to
work (although I don't know why, as I think I'm very kissable).


Jim


-Original Message-
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Robert Johnson
Sent: woensdag 12 december 2001 19:28
To: emc-p...@majordomo.ieee.org
Subject: Sometimes product safety just isn't enough

I couldnââ'¬â"¢t help passing on this reference to a
bit of unforeseeable misuse.

http://electrical-contractor.net/ubb/Forum4/HTML/48.html
Bob Johnson


.


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Re: Sometimes product safety just isn't enough

[Robert Macy]

In deference to the warning label on the peanuts bag.  Some people have life
threatening allergies to peanuts and take warnings such as that and warnings
on cookies, etc very seriously.  But then again, you'd think with the main
label "Peanuts" would be sufficient.  Perhaps, someone is making peanuts out
of soy beans already.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: James Collum 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 14, 2001 1:57 PM
Subject: Re: Sometimes product safety just isn't enough


Following a recent airline flight, I was given a bag of peanuts, marked
"Peanuts" which contained a health warning "contains peanuts".
I was thinking that in a similar style that maybe electrical products
could have an added warning "may contain electricity".
The "may" would elude to the connection of a mains cable for mains
powered equipment, or even batteries in battery powered equipment.  I think
the IEC should be prompt to act in this vital area.
Following this illogical train of thought, the swimming pool should have
a warning "contains water" and the ladder could have a warning "may alter
altitude".
But on a slightly more serious note (but not much) If I am ever present
when someone is about to do something interesting with electricity I always
advise that the person about to do the deed make sure to note who present
will provide the "kiss of life" when it all goes pear shaped. It tends to
work (although I don't know why, as I think I'm very kissable).


Jim


-Original Message-
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Robert Johnson
Sent: woensdag 12 december 2001 19:28
To: emc-p...@majordomo.ieee.org
Subject: Sometimes product safety just isn't enough

I couldn’t help passing on this reference to a
bit of unforeseeable misuse.

http://electrical-contractor.net/ubb/Forum4/HTML/48.html
Bob Johnson


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Re: IATA

[Robert Macy]

It is also interesting that 2mG limit closely approximates the "emotional"
one established through epidemiological studies.

Here in the Bay Area the field is around 50uT( 500mG )

It is my understanding that the magnetic field has been steadily declining.
>From the time of Christ until now it has dropped in half.   And is evidently
on a decline towards zero (reversing poles) The significance?  I was
told that every ice age was accompanied by a pole reversal (but not every
pole reversal is accompanied by an ice age)

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Andrew Carson 
To: WELLMAN,RON (A-PaloAlto,ex1) 
Cc: 'richwo...@tycoint.com' ;
emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Tuesday, December 04, 2001 1:39 AM
Subject: Re: IATA


>
>You want Packing Instruction 902, within the section on Dangerous Goods.
>
>To summaries the limits are,
>
><2mG at measurement distance of 2.1m - Non Magnetic Material
>>2mG at a measurement distance of 2.1m - Hazardous Magnetic Material, must
be marked accordingly
>>5.25mG at a measurement distance of 4.6m - Can not be transported by
aircraft.
>
>Not much when you think the Earths magnetic field is 450 to 550mG
>



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Re: physics behind EMI powerline filter

[Robert Macy]

Muriel,

Good thinking.

The answer is, depends..Keep in mind that at 30MHz the 1/4 wavelength is
still over 8 feet, so we're not really talking much about waveguides and
volumetric resonators.

Two areas to consider:

First, at the low frequencies most of the energy is simply not used *and*
from the lesser energy source which is simply shorted out only slightly
increases the energy consumed.

The bulk of the energy is in a sense "reflected" back, but a better concept
may be just not used.

There are two main sources for only switching power supply noise, one is
from the high voltage that the FET switches which is transferred around
using parasitic capacitance (high impedance) and is usually a common mode
signal, the other comes from the curent demands placed upon the storage
capacitor across its own esr and appears as differential noise (low
impedance)

These two sources merely present themselves to the AC mains and are allowed
to supply energy down the wires.  However the EMI filter stops this from
happening.  It shorts out the high impedance source using the y-caps so the
noise doesn't go down the AC wires and then blocks the residual signal with
the large valued common mode choke.  The low impedance source is first
converted to a higher impedance as it tries to go through the little
differential inductors, then the signal is shorted with the huge line to
line cap.For the high impedance source it is shorted to ground thus
increasing the losses, while for the low impedance noise source it is
blocked with a high impedance and just left as an "open".

Second, at higher frequency where almost all the noise has become common
mode (and caused more by the load), the filter still acts like an "open" due
to those two differential coils.  So one could say the energy is simply
blocked from escaping.

Now what happens with the combination?  Depends.  One could argue that the
energy stayed inside, but then again one could argue that that energy would
never have been created in the first place had it not been allowed an
egress.

It's a small percentage of power floating around in the box anyway.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Muriel Bittencourt de Liz 
To: EMC-PSTC List 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, December 03, 2001 12:35 PM
Subject: physics behind EMI powerline filter




Hello Group,

I have a "long-time" question, concerning the energy issues in a EMI
powerline filter.

I'll put a case, and ask the question after.

This is the case:

- When trying to minimize the conducted emissions from a electrical
equipment / circuit, one of the things to do is to put a EMI filter at the
power entrance. This filter can be from a manufacturer (ready filter) or you
can make one (with common mode inductors, capacitors, inductors).

This are the questions (they arearelated, i.e., complete each other):

- What, physically speaking, happens to the EMI energy that leaves the
equipment when I add a filter??? When there is no filter, I understand that
the energy goes to the mains?? Does the filter reflect the EMI energy,
keeping it "arrested" inside the equipment?

- Thinking under the light of the principle of energy conservation, what
happens to the EMI energy when I add a filter?? It cannot be lost...

- ... And, supposing that the energy keeps arrested inside the equipment,
isn't it worse for radiated emissions?? i.e., it can increase the level of
radiated emissions??

Thanks in advance for your attention.

Regards,

Muriel Bittencourt de Liz
Ph.D. Student
Interest Areas: EMC for power electronics, RF measures, EM interference
Federal University at Santa Catarina State
Florianópolis, Santa Catarina, Brazil



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Re: [Fwd: User Warning Signal Words]

[Robert Macy]

Perhaps, it's time to utilize "Alert" instead of "Warning" for Class A
compliance information.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: douglas_beckw...@mitel.com 
To: David Heald 
Cc: emc-p...@majordomo.ieee.org ;
ni...@tsd.serco.com 
List-Post: emc-pstc@listserv.ieee.org
Date: Wednesday, November 07, 2001 5:43 PM
Subject: Re: [Fwd: User Warning Signal Words]


>
>
>
>From:  Douglas Beckwith@MITEL on 11/07/2001 04:27 PM
>Hi All,
>If I may submit my two Canadian pesos worth. There is a US miltary handbook
on
>technical writing that discusses the defintion of these words and how they
>should be used. Can't remember what it is off hand, but I will look it up
and
>post it. These are the definitions that we use in our documentation. Here
is a
>brief summary.
>
>CAUTION - Potential damage to the equipment, e.g. ESD or static
>WARNING - Potential minor injury or harm to the the user/maintainer. e.g
sharp
>edges, corners etc
>DANGER - Potential major injury or death of the user/maintainer, e.g.
exposed
>High voltage terminals.
>
>That being said, I have seen so many misuses and applications of these
terms
>that deviate from the definitions, for example in the UK you are required
to put
>an EMC Class A "warning" note in the documentation. In that case, I don't
think
>that Class A emissions from an unintentional radiator are harmful, but that
is
>another debate.
>
>Regards
>
>Doug Beckwith
>Mitel Networks
>
>



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Re: EMC test table construction plans

[Robert Macy]

John,

Your point is well taken with regard to testing a unit while closely
matching the testing environment to the environment it will be used in.
However, we don't sell a lot of equipment to people who have 40 meters of
ground plane, either.

It is my understanding a reasonable "false" environment is an attempt to
control the testing environment and obtain repeatable results.   Controlling
the table material so it does not appreciably affect the outcome of the test
seems to be consistent with that goal.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: John Woodgate 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, November 02, 2001 2:30 AM
Subject: Re: EMC test table construction plans


>
>I read in !emc-pstc that Pommerenke, David  wrote
>(in <9da8d24b915bd1118911006094516eaf0ba31...@umr-mail02.cc.umr.edu>)
>about 'EMC test table construction plans', on Thu, 1 Nov 2001:
>>For emissions and immunity you should not use any wood in the table. It
will
>>significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB
for
>>immunity up to 1 GHz) change the test result. My experience has shown that
>>Styrofoam is basicly the best material.
>
>You mean that it gives the worst-case results?
>
>>There are a couple of published
>>papers on this issue. As surface material the following worked out fine:
>>
>>  - Foamed PVC (rather stiff, low dielectric constant due to the foamed
>>nature), maybe 4 mm thick.
>>
>>  - PE sheet, maybe 2 mm thick.
>
>Should the test conditions not reflect the actual environment in use of
>the product, rather than employ these unusual materials?
>--
>Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
>



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Re: Request for Input - Third Party Request

[Robert Macy]

Don't know if anybody responded, or not.

But first I would change your interface to include analog signals (I firmly
believe in never blinding the computer to what's really going on)

Second, the only IF temp meters I remember were made by Raychem, or such
back in the 70's.  But they at least have to have an analog output to
interface to your computer.

Third, write the testing program in the highest level language possible.
(else support will be pure hell)

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: me...@aol.com 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, October 26, 2001 1:20 PM
Subject: Request for Input - Third Party Request


>
>We are testing 2 coil windings (at a same time) for resistance using 4
wires Kelvin connection. Acceptable (Pass) Value ranges for the parts are:
Part  A 2.3 - 2.7 Ohm Part B 5.4 - 5.8 Ohms. We want to know if the part is
within (good) these ranges or out (bad) of these ranges. We should be able
to connect your output to our digital PLC I/O Card, or simply to trigger a
>relay. (NO RS-232)
>
>In the station prior to the testing station, terminals of the coil winding
are being dipped into soldering pot resulting on the temperature increase,
which then effects our resistance readings.
>
>We want (ideally) to measure the temperature of the part using infrared
sensor, inputting that into the tester and compensating for the temperature.
This would require a tester that would be able to do some computation.
>
>Ed
>
>



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Re: 120V Ground Faults

[Robert Macy]

Michael,

The arcing was between hot and neutral.  GFCI outlets would have made no
difference.

- Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: michael.garret...@radisys.com 
To: emc-p...@majordomo.ieee.org 
Cc: Robert Macy 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 5:52 PM
Subject: 120V Ground Faults


>
>Robert,
>
>>From my experience,  I think you will find that arcing ground faults are
>inherently high-resistance in nature and, while dramatic, do not
>necessarily pull significant amounts of current.  Most 15 amp breakers will
>likely require several seconds/minutes to blow at 60/30 amps, which is what
>you'd get with a 2/4 ohm arc.  In reality, I wouldn't be surprised to see
>something more like a 10-20 ohm figure being used for this type of
>phenomenon, which would allow a 15 amp breaker to arc virtually
>continuously (i.e. the home arc-welder).  The fact that arcs are drawn -
>and sustained - at 120 volts is, I believe, relatively rare.
>
>Higher voltage systems (and GFCI outlets) have ground fault systems that
>rely on the detection of zero sequence (neutral leakage) currents.  My
>understanding is that the decision to require this type of protection on
>480 volt systems over 1200 amps was largely due to the increased likelihood
>they'd be able to draw and sustain an arc, as well as the damage that can
>be caused at these higher power levels (balanced with the concerns of
>cost-effectiveness of installing them more broadly).  I feel they drew the
>line in an appropriate place.
>
>In my experience, while problems, such as this, do arise, the frequency and
>relative damage caused by them is relatively small.  I think you would have
>seen a change (like the addition of GFCI about 25 years ago) if the case
>were otherwise.  You should be able to add zero sequence current sensing to
>your household panel, should you care to do so, for ~$500, but where
>out-of-the-box systems exist for 480 volt systems, this would need to be a
>custom design amploying the combination of a sensor relay and a shunt-trip
>breaker.  Of course any nuisance trips you may experience similar to your
>GFCI would take down your main You can buy a LOT of GFCI breakers for
>these dollars.  Caveat Emptor/Engineer.
>
>Regards,
>
>Michael Garretson
>Compliance Engineering Manager
>RadiSys Corporation
>+1 503 615-1227
>
>
>
>"Robert Macy"
> To: "Dan Kwok"
, 
>Sent by:  cc:
>owner-emc-pstc@majordom   Subject: Re: skinny
power cords.
>o.ieee.org
>
>
>10/25/01 02:36 PM
>Please respond to
>"Robert Macy"
>
>
>
>
>
>
>
>It definitely was not supplied by the heater company.  It was a high
>quality
>UL approved cord.  It's just that this cord carbonized and burst into flame
>as the arc was existing.  The flames did immediately extinguish when the
>arc
>was stopped by unplugging the cord which is good.
>
>But again, it was disturbing that the 15A breaker provided no protection.
>
>Anyway, it was a good lesson for this "sleeping" guy.  Now I take
>electrical
>distribution inside my home much more seriously.
>
>       - Robert -
>
>   Robert A. Macy, PEm...@california.com
>   408 286 3985  fx 408 297 9121
>   AJM International Electronics Consultants
>   619 North First St,   San Jose, CA  95112
>
>-Original Message-
>From: Dan Kwok 
>To: Robert Macy ; emc-p...@majordomo.ieee.org
>
>Date: Thursday, October 25, 2001 1:42 PM
>Subject: Re: skinny power cords.
>
>
>>
>>Hi Robert,
>>
>>Recently, I bought several similar heaters for my home. I recall reading
>in
>>the operation instructions, explicit safety warnings against using
>extension
>>cords with the heater. Was the extension cord supplied with the heater?
>>
>>
>>-
>>Dan Kwok,  P.Eng.
>>Principal Engineer
>>Electromagnetic Compatibility
>>Intetron Consulting,  Inc.
>>Ph  (604) 432-9874
>>E-mail dk...@intetron.com
>>Internet  http://www.intetron.com
>>
>>- Original Message -
>>From: "Robert Macy" 
>>To: "Roman, Dan" ; 
>>Sent: Thursday, Octobe

Re: skinny power cords.

[Robert Macy]

It definitely was not supplied by the heater company.  It was a high quality
UL approved cord.  It's just that this cord carbonized and burst into flame
as the arc was existing.  The flames did immediately extinguish when the arc
was stopped by unplugging the cord which is good.

But again, it was disturbing that the 15A breaker provided no protection.

Anyway, it was a good lesson for this "sleeping" guy.  Now I take electrical
distribution inside my home much more seriously.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Dan Kwok 
To: Robert Macy ; emc-p...@majordomo.ieee.org

List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 1:42 PM
Subject: Re: skinny power cords.


>
>Hi Robert,
>
>Recently, I bought several similar heaters for my home. I recall reading in
>the operation instructions, explicit safety warnings against using
extension
>cords with the heater. Was the extension cord supplied with the heater?
>
>
>-
>Dan Kwok,  P.Eng.
>Principal Engineer
>Electromagnetic Compatibility
>Intetron Consulting,  Inc.
>Ph  (604) 432-9874
>E-mail dk...@intetron.com
>Internet  http://www.intetron.com
>
>- Original Message -
>From: "Robert Macy" 
>To: "Roman, Dan" ; 
>Sent: Thursday, October 25, 2001 8:49 AM
>Subject: Re: skinny power cords.
>
>
>>
>> Just have to jump in here with personal experience:
>>
>> In our bedroom we have a deLonghi radiator heater which uses an extension
>> cord (high cost UL approved) heavy guage #12 wire to power it - when it's
>> used.  This extension cord plugs into a "multi outlet" adapter, also
heavy
>> duty UL approved.  At the time of the incident there was no power being
>used
>> from this outlet.
>>
>> I was in another room, my wife was sitting on the edge of the bed
watching
>a
>> news blurb on TV when she heard a funny sound, a scritch, scritch.   She
>> called to me to come listen.  Scritch, scritch, scritch got louder.  As I
>> arrived, flames started lapping up the wall from the outlet while still
>> making arcing sounds.  The flames were less than 6 inches from curtains.
I
>> reached into all this and unplugged the extension cord which luckily
>stopped
>> the fireworks display.  Imagine, if we had not been there.
>>
>> Upon examination, it appeared that an arc had formed between the blades
of
>> the extension cord (remember no power at the time).  That arc was not
>> sufficient to drop the 15A breaker to the outlet, yet was sufficient to
>> carbonize the UL approved material which further sustained the arc.
>>
>> I posted this to the newsgroup alt.home.repair where a fireman jumped in
>> describing how this exact mechanism is what starts most home fires!
Isn't
>> that an encouraging thought!
>>
>> Anyway, a little damn fuse in the plug would not have helped in this
>> circumstance, complete waste of time, much like the main breaker was.
>>
>>  - Robert -
>>
>>Robert A. Macy, PEm...@california.com
>>408 286 3985  fx 408 297 9121
>>AJM International Electronics Consultants
>>619 North First St,   San Jose, CA  95112
>>
>> -Original Message-
>> From: Roman, Dan 
>> To: emc-p...@majordomo.ieee.org 
>> Date: Thursday, October 25, 2001 7:41 AM
>> Subject: RE: skinny power cords.
>>
>>
>> >
>> >I agreed completely with Scott.  A 6 to 9 foot 18AWG cord will handle
well
>> >in excess of 20A for a short period of time without starting to smoke
>> (heck,
>> >it'll handle close to in excess of 60A for a very very short time
without
>> >bursting into flames--not that it was a good experience finding this
out).
>> >Point is, the cordage will handle a fault either indefinitely or long
>> enough
>> >for the branch circuit breaker to trip provided you are connected to a
15A
>> >or 20A branch circuit.
>> >
>> >Another data point, you routinely pass more current through the cord
when
>> >doing the earthing test and that uses more current than the cord is
rated.
>> >Leave the tester on for awhile and the cord does not really heat up
>either.
>> >
>> >What this list needs is a power cord manufacturer or agency safety
>engineer
>> >that d

Re: skinny power cords.

[Robert Macy]

Yes, I believe it was contamination.

There is a tissue box on the night stand above the outlet.  Tissue lint is
insidious.  The extension cord had been plugged in (AND LEFT UNDISTURBED)
for a long period of time.  Exactly, how the buildup made its way to an
inside surface I don't know.

But remember, an experienced fireman related that this is how most
electrical fires start in his experience - an outlet shorts between blades
(or in that area), the breaker does not trip while the arc is sustained,
flames develop, and great damage occurs.

I was upset that the 15A breaker could care less about the arc sizzling at
the outlet.

The reason I mention the extension cord is to point out that the plug
plugged into the outlet was high quality and not a "cheap" lamp cord of
suspect origin.  Yet, this plug still carbonized AND FLAMED! making things
much worse.

Now, I do maintenance around our home using compressed air can to blow the
outlet box clear of everything and unplug everything and wipe all surfaces
clean.  This has worked, but may not always, since sprays etc used in the
area tend to produce a gummy, waxlike deposit on the outlet and there still
may be stuff down inside.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Jim Eichner 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 12:07 PM
Subject: RE: skinny power cords.


>
>I'm curious:  given that North American plug blades are >1/2" apart, there
>must have been substantial contamination to aid in 120Vac jumping that far
>(arcing).  Did you identify any sort of contamination or moisture?
>
>Jim Eichner, P.Eng.
>Manager, Engineering Services
>Xantrex Technology Inc.
>Mobile Power
>phone:  (604) 422-2546
>fax:  (604) 420-1591
>e-mail:  jim.eich...@xantrex.com
>web: www.xantrex.com
>
>
>-Original Message-
>From: Robert Macy [mailto:m...@california.com]
>Sent: Thursday, October 25, 2001 8:50 AM
>To: Roman, Dan; emc-p...@majordomo.ieee.org
>Subject: Re: skinny power cords.
>
>
>
>Just have to jump in here with personal experience:
>
>In our bedroom we have a deLonghi radiator heater which uses an extension
>cord (high cost UL approved) heavy guage #12 wire to power it - when it's
>used.  This extension cord plugs into a "multi outlet" adapter, also heavy
>duty UL approved.  At the time of the incident there was no power being
used
>from this outlet.
>
>I was in another room, my wife was sitting on the edge of the bed watching
a
>news blurb on TV when she heard a funny sound, a scritch, scritch.   She
>called to me to come listen.  Scritch, scritch, scritch got louder.  As I
>arrived, flames started lapping up the wall from the outlet while still
>making arcing sounds.  The flames were less than 6 inches from curtains.  I
>reached into all this and unplugged the extension cord which luckily
stopped
>the fireworks display.  Imagine, if we had not been there.
>
>Upon examination, it appeared that an arc had formed between the blades of
>the extension cord (remember no power at the time).  That arc was not
>sufficient to drop the 15A breaker to the outlet, yet was sufficient to
>carbonize the UL approved material which further sustained the arc.
>
>I posted this to the newsgroup alt.home.repair where a fireman jumped in
>describing how this exact mechanism is what starts most home fires!  Isn't
>that an encouraging thought!
>
>Anyway, a little damn fuse in the plug would not have helped in this
>circumstance, complete waste of time, much like the main breaker was.
>
> - Robert -
>
>   Robert A. Macy, PEm...@california.com
>   408 286 3985  fx 408 297 9121
>   AJM International Electronics Consultants
>   619 North First St,   San Jose, CA  95112
>
>-Original Message-
>From: Roman, Dan 
>To: emc-p...@majordomo.ieee.org 
>Date: Thursday, October 25, 2001 7:41 AM
>Subject: RE: skinny power cords.
>
>
>>
>>I agreed completely with Scott.  A 6 to 9 foot 18AWG cord will handle well
>>in excess of 20A for a short period of time without starting to smoke
>(heck,
>>it'll handle close to in excess of 60A for a very very short time without
>>bursting into flames--not that it was a good experience finding this out).
>>Point is, the cordage will handle a fault either indefinitely or long
>enough
>>for the branch circuit breaker to trip provided you are connected to a 15A
>>or 20A branch circu

Re: skinny power cords.

[Robert Macy]

No soldered connections.  The arc was external to the plug between the
blades.  Carbonizing and then cutting more carbon in the burn track.
Remember the arc was *between* the blades, there was no power going through
the cord itself.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Ron Pickard 
To: m...@california.com 
Cc: emc-p...@ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 11:01 AM
Subject: Re: skinny power cords.


>
>Hi Robert,
>
>In your examination, did you find evidence of compression connections with
soldered(tinned) leads?
>Or, did the compression connections appeared to be loose?. As you might
already know, the solder in
>such a connection cold flows under the pressure of the connection and after
a while this connection
>loosens. In my experience, this "loose connection" is the source where the
arcing occurs.
>
>Comments anyone?
>
>Best regards,
>
>Ron Pickard
>rpick...@hypercom.com
>
>
>
>



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Re: skinny power cords.

[Robert Macy]

Just have to jump in here with personal experience:

In our bedroom we have a deLonghi radiator heater which uses an extension
cord (high cost UL approved) heavy guage #12 wire to power it - when it's
used.  This extension cord plugs into a "multi outlet" adapter, also heavy
duty UL approved.  At the time of the incident there was no power being used
from this outlet.

I was in another room, my wife was sitting on the edge of the bed watching a
news blurb on TV when she heard a funny sound, a scritch, scritch.   She
called to me to come listen.  Scritch, scritch, scritch got louder.  As I
arrived, flames started lapping up the wall from the outlet while still
making arcing sounds.  The flames were less than 6 inches from curtains.  I
reached into all this and unplugged the extension cord which luckily stopped
the fireworks display.  Imagine, if we had not been there.

Upon examination, it appeared that an arc had formed between the blades of
the extension cord (remember no power at the time).  That arc was not
sufficient to drop the 15A breaker to the outlet, yet was sufficient to
carbonize the UL approved material which further sustained the arc.

I posted this to the newsgroup alt.home.repair where a fireman jumped in
describing how this exact mechanism is what starts most home fires!  Isn't
that an encouraging thought!

Anyway, a little damn fuse in the plug would not have helped in this
circumstance, complete waste of time, much like the main breaker was.

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Roman, Dan 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 25, 2001 7:41 AM
Subject: RE: skinny power cords.


>
>I agreed completely with Scott.  A 6 to 9 foot 18AWG cord will handle well
>in excess of 20A for a short period of time without starting to smoke
(heck,
>it'll handle close to in excess of 60A for a very very short time without
>bursting into flames--not that it was a good experience finding this out).
>Point is, the cordage will handle a fault either indefinitely or long
enough
>for the branch circuit breaker to trip provided you are connected to a 15A
>or 20A branch circuit.
>
>Another data point, you routinely pass more current through the cord when
>doing the earthing test and that uses more current than the cord is rated.
>Leave the tester on for awhile and the cord does not really heat up either.
>
>What this list needs is a power cord manufacturer or agency safety engineer
>that does power cords to settle this once and for all!
>
>Dan
>
>-Original Message-
>From: Scott Lacey [mailto:sco...@world.std.com]
>Sent: Wednesday, October 24, 2001 7:43 PM
>To: Gary McInturff
>Cc: emc-p...@majordomo.ieee.org
>Subject: RE: skinny power cords.
>
>
>
>Gary,
>I believe the answer is that the power cord rating of 6 or 10 amps is the
>operating current, at which it will have minimum temperature rise. Under
>fault conditions it will experience a rather dramatic temperature rise that
>is still well below the melting temperature of the insulation. The breaker
>or fuse should clear well before the cord is "cooked" to the point of
>failure.
>
>Scott Lacey
>



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Re: EFT Failures..Help!

[Robert Macy]

Hope you're using more than one sample.  I've been bit by having the one I
brought to the lab not being in compliance.  Anyway, make certain.

   - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112

-Original Message-
From: Alex McNeil 
To: emc-p...@majordomo.ieee.org 
List-Post: emc-pstc@listserv.ieee.org
Date: Monday, October 22, 2001 4:06 AM
Subject: EFT Failures..Help!


>
>Hi Guys,
>
>I am at an EMC test centre today and tomorrow. Unfortunately, my product
>failed EFT testing on the AC power port at 1KV. This is for various
>combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE)
>
>My product is Class II, no Earth. It is supplied by an external power
>supply. This supplies SELV to my product. The power supply manufacturer has
>stated that his power supply meets EN61000-4-4 for 2KV and has emailed me
>this report to verify this.
>
>Has anyone got a quick solution to my problem so that I can implement here
>at the EMC test house?
>
>Kind Regards
>Alex McNeil
>Principal Engineer
>Tel: +44 (0)131 479 8375
>Fax: +44 (0)131 479 8321
>email: alex.mcn...@ingenicofortronic.com
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
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Re: duty cycle correction factors

[Robert Macy]

20log(d)

time is linear, like voltage
not the square, like power, thus the 20log

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112


-Original Message-
From: Stuart Lopata 
To: emc 
List-Post: emc-pstc@listserv.ieee.org
Date: Thursday, October 18, 2001 9:45 AM
Subject: duty cycle correction factors


>
>Part 15.231 devices use a duty cycle correction factor to adjust peak
>readings.  The duty cycle represents the fractional on-time over a given
>period of time (that must be under some limit).  Anyways, given this
>fractional time, d, how do you make the conversion to dB?
>
>10log(d) or 20log(d)?
>
>There have been some misinterpretations, since the readings are made at a
>span of zero hertz (voltage readings).  Normally, a reduction in voltage
>would use the 20log scale.  However, since the duty cycle does not
represent
>a scale down (it represents the off-time versus on-time), the 10log scale
>seems more appropriate.
>
>I have seen conflicting documents, so would like your professional
opinions!
>
>Thanks,
>
>Stuart Lopata
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
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Printable calendar for 2002 sent by request

[Robert Macy]

Ok, ok.

For all those whose virus scanners spit up when seeing files with my
mnemonic names - upon request I'll send to you an unzipped version (about
60K total) with every file renamed with the extension *.txt.  For example,
PRINT_02.BAT will be PRINT_02.BAT.TXT  etc   Then you can do with it what
you want.

  - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



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Re: Printable calendar for 2002

[Robert Macy]

I got two NAV (Norton Antivirus) msgs back from the ieee.org that said my
attachment had a virus in it.

If so, please let me know, because there is nothing but text files (that I
know of) and a simple batch program in that attachment.



Very important that *IF* I have a virus, need to know !!!

   - Robert -


PS   It's just that Norton Antivirus had showed my system clean, but I had
to remove it manually piece by piece because of the way it kept screwing up
all my software.  This is not one happy camper.


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messages are imported into the new server.

Printable calendar for 2002

[Robert Macy]

Apologize for being off topic, but I've attached a printable calendar for
2002.

It prints out on 8 1/2 by 11 (for all the metric people) in landscape mode.

Very little clutter and has big squares to write in.  If you have a DeskJet
500, you can print directly to it.

If not, use the text file  2002_46L.LAN  Each month is 46 lines with no
pagination.

- Robert -


<>

Fluid flow rate

[Robert Macy]

Sorry about this being so far off topic, but I don't know where else to find
the largest group of technology professionals who can answer this question:

How much water will flow out of a 3/4 inch pipe which is under 60 psi?
There is a restriction and the actual inside ID is around 7/16 inch.

My guess is more than 5 gal/min.  For example, when I get gasoline the tank
will fill (20 gal) in less than 2 minutes.  So it's got to be somewhere in
this range, right?

 - Robert -

   Robert A. Macy, PEm...@california.com
   408 286 3985  fx 408 297 9121
   AJM International Electronics Consultants
   619 North First St,   San Jose, CA  95112



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