[PSES] Goodbye
This is just a short note to let all my friends on the EMC-PSTC list know that I am retiring, effective 3 January 2012. Yes, I finally made my decision, and soon I'll be no more than a puff of smoke on the horizon. It may sound overly sentimental, but the people on the EMC-PSTC list have helped to make my efforts a bit easier on so many occasions, and I will remember so many of you. By the time you read this, my Cubic mail account will likely be closed, so if you would like to reach me, use my edpr...@cox.net address (I also subscribed my home address to the list). I will probably be taking a little vacation from EMC for a while, but I doubt I can ever leave it completely, so I'll still be available for free advice and maybe a project or two. Thanks for a great 15 years of intriguing questions, provocative assertions, good advice, and even a few laughs about our shared conditions! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Quasi-peak
I have never thought of myself as an EMC Crusader, although EMC Evangelist might apply. BTW, have I ever said how much I enjoy deciphering your sigs? Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Friday, December 02, 2011 12:32 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak In message A7C32E638E804E6CA1B9E8454809B594@JohnHP, dated Thu, 1 Dec 2011, John Shinn jmsh...@pacbell.net writes: Actually there are FIVE: In responding to amateur 'EMC crusaders' who dream up curious and impracticable requirements (such as a complete ban on conducted harmonic current emissions), I have had to add a sixth: NO-ONE cares. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Quasi-peak
Tony: I don’t want to appear to be overly picky, but your diagrams don’t show “what happens to the emissions,” but rather show how the QP detector receiver “sees” the emissions. In a dithered, or frequency hopping clock, the clock hops to a frequency, dwells there for a short moment and then hops to a new, relatively far away frequency. If your receiver happens to be sitting right at say, 100 MHz, and the clock hops to 100 MHz, the receiver only has a short time (before the clock hops again) to indicate the amplitude of the signal. A peak detector will quickly charge and show the signal level, but a QP detector has a slower time constant, so it can’t get up to the full signal amplitude before the clock hops away from the receiver’s “view.” The clock’s amplitude doesn’t change or spread or in any way decrease; all the dithered clock does is hop and jump all over a range of frequencies. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty From: Anthony Thomson [mailto:ton...@europe.com] Sent: Thursday, December 01, 2011 2:36 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak Hello Amund, Just to clarify one point, a spread spectrum clock is very different to a spread spectrum transmission scheme. Bluetooth is just one example of a spread spectrum transmission scheme where the modulated carrier ‘hops’ between frequency channels within a defined band. The receiver has to synchronously tune itself to the transmission frequency. Keeping with the Bluetooth example, simplistically there are 79 x 1MHz spaced bands between 2402 and 2480 MHz. During transmission, the carrier hops between these carrier frequencies, it connat stay at any one frequency for more than 400ms. Relevant to your question…. Spread spectrum clocks are used in digital systems to reduce emissions. It’s a little bit of a ‘cheat’ because the energy of the overall emissions is generally the same, but the narrowband levels measured by an averaging and/or integrating detectors (e.g. CISPR) are greatly reduced. Say you have a digital system clocking at 100MHz, you have potential narrowband emissions problems at 100MHz, harmonics thereof and any other frequencies divided down or synthesised up. If you ‘modulate’ your 100MHz clock by e.g. +/- 0.5% (99.5 – 100.5 MHz) you spread your emissions across a proportionate band. This band is generally much greater than the measurement bandwidth of measuring receivers. This is basically what happens to the emissions. | Narrowband Clock | | | |- - - - - / \ - - - - - Limit | / \ | | | | / \ + | Spread Spectrum Clock | | |- - - - - - - - - - - Limit | |~~~| | / \ | | | + - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Quasi-peak
Don: I think that the spread spectrum clock works because of both the receiver bandwidth and the detector function. For instance, imagine a pure CW clock signal, and it is being hopped around in 1 kHz steps, all in the range of 10 kHz. Now imagine that a receiver with a 1 MHz resolution bandwidth is watching that signal. The indicated amplitude will be the same with Peak, QP Average detectors. Because the hopping is always within the receiver bandwidth, the hopping has no effect. As the hopping stays within the receiver BW, each detector has plenty of time to reach the full amplitude of the signal. Now imagine that a hop starts well outside the RBW; the receiver sees nothing. Then the clock hops into the RBW, and each detector starts charging. Fifty microseconds later, the clock hops out of the RBW. You look at the three detectors, and the Peak reads, say 1.0. The QP might read 0.1, and the Average might read 0.0. The difference was all about how long the receiver had to observe the signal; all detectors saw the same amplitude signal, but they could only report what their time constants allowed. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: don_borow...@selinc.com [mailto:don_borow...@selinc.com] Sent: Thursday, December 01, 2011 7:22 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak Spread spectrum clocks work due to the measurement bandwidth of the receiver, so this effect holds for peak, quasi-peak, and average. Donald Borowski Schweitzer Engineering Labs Pullman, Washington, USA - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Quasi-peak
But Albert was a Theoretician, not an Experimentalist. Doing the same thing over over may be boring, but every so often, something truly weird does happen, and these are the moments that illuminate (or incinerate). Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, December 01, 2011 11:15 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak In message 1abb0f6ff6cb7545adad042f566d5f4449101...@sv-mailbox01.ohdc.com, dated Thu, 1 Dec 2011, Sundstrom, Michael michael_sundst...@overheaddoor.com writes: Richard Schultz (of ANSI C63) always told me there were 3 answer to any EMC question asking about 'if' it will affect something? YES NO MAYBE But Albert clearly never did any EMC testing: Albert Einstein once said, The definition of insanity is doing the same thing over and over again and expecting different results. We are all insane. QED! -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc- p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Quasi-peak
Brian: Wow, you want a practical answer!! Well, in my experience of doing susceptibility on a lot of military systems (where the comm links are almost always encrypted digital bit streams), I find that the default 1 kHz 50% duty cycle (square wave) is a good choice for modulation. One of our data links might be running in Ku-band, with a 20 MB stream. We might have frames of data that are a millisecond long, with each frame consisting of words which are in turn composed of bits. The time slot of each bit is used as a place-holder for either a 1 or a ) logic bit. If we have a word that is supposed to be say 100111110, and we drop our test signal onto this bit stream, the link receiver might see 1. This is not what was sent, and would cause an error to be declared for the word. If there is no provision for error correction or redundancy, then this bad data could do most anything, from causing one tiny anomaly to crashing the whole system. All you have to do is drop some energy at the moment that 0's are happening, and the receiver reads them as 1's. When you manage to create interference, the threshold is very sharp. The digital channel doesn't degrade gracefully, but rather collapses precipitously. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: Brian Oconnell [mailto:oconne...@tamuracorp.com] Sent: Thursday, December 01, 2011 9:22 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak Good stuff, this empirical experience. But the question remains - does this spread-spectrum stuff, for a comparative power level, increase or decrease interference with my master-blaster 5000 remote toilet controller? One member said that it only will affect stuff that is very close to the operating freq and that the most digital receivers would not see it. But EMC amateurs such as me need MOAR empirical experience from Don and Ed and et al. For my employer's products, I am more concerned about customer complaints than demonstrated margin from some fantastical limit line in an EMC standard. Brian -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Thursday, December 01, 2011 8:58 AM To: Price, Edward Cc: EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Quasi-peak Ed- Given your scenario, you are right. However, in my experience of measuring radiated emissions of spread spectrum clocks, I have always noticed a decrease in not only the quasi-peak and average measurements, but the peak measurement as well. I think this may be due to the bandwidth of the spreading signal -- if it is wider bandwidth than the receiver bandwidth (120 kHz CISPR in my case), then there will be reduction in the peak as well. With a high bandwidth spreading signal, the RF will not spend enough time within the bandwidth of the receiver for the receiver to respond to the full amplitude of the signal. Donald Borowski EMC Compliance Engineer Schweitzer Engineering Labs Pullman, WA, USA From: Price, Edward ed.pr...@cubic.com To: don_borow...@selinc.com, EMC-PSTC@LISTSERV.IEEE.ORG Date: 12/01/2011 08:06 AM Subject:RE: [PSES] Quasi-peak Don: I think that the ?spread spectrum clock? works because of both the receiver bandwidth and the detector function. For instance, imagine a pure CW clock signal, and it is being hopped around in 1 kHz steps, all in the range of 10 kHz. Now imagine that a receiver with a 1 MHz resolution bandwidth is watching that signal. The indicated amplitude will be the same with Peak, QP Average detectors. Because the hopping is always within the receiver bandwidth, the hopping has no effect. As the hopping stays within the receiver BW, each detector has plenty of time to reach the full amplitude of the signal. Now imagine that a hop starts well outside the RBW; the receiver sees nothing. Then the clock hops into the RBW, and each detector starts charging. Fifty microseconds later, the clock hops out of the RBW. You look at the three detectors, and the Peak reads, say 1.0. The QP might read 0.1, and the Average might read 0.0. The difference was all about how long the receiver had to observe the signal; all detectors ?saw? the same amplitude signal, but they could only report what their time constants allowed. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: don_borow...@selinc.com [mailto:don_borow...@selinc.com
Re: [PSES] Quasi-peak
Maybe Six!! YES NO MAYBE DON'T KNOW DON'T CARE How much money left in the budget? Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: John Shinn [mailto:jmsh...@pacbell.net] Sent: Thursday, December 01, 2011 4:56 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak Actually there are FIVE: YES NO MAYBE DON'T KNOW DON'T CARE John Shinn, Ph.D., PE -Original Message- From: Sundstrom, Michael Sent: Thursday, December 01, 2011 10:55 AM To: John Woodgate ; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Quasi-peak Richard Schultz (of ANSI C63) always told me there were 3 answer to any EMC question asking about 'if' it will affect something? YES NO MAYBE I'd guess Mr. Schultz knew enough to say that! Michael Sundstrom OHD / TREQ Dallas Electronic Lab Analyst, EMC Lead 2170 French Settlement Rd, Suite B Dallas, Texas 75212 (214) 579 6312 (940) 390 3644c KB5UKT Albert Einstein once said, The definition of insanity is doing the same thing over and over again and expecting different results. -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, December 01, 2011 12:22 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Quasi-peak In message 2b83256001484461b5f6adf4c41df...@tamuracorp.com, dated Thu, 1 Dec 2011, Brian Oconnell oconne...@tamuracorp.com writes: But the question remains - does this spread-spectrum stuff, for a comparative power level, increase or decrease interference with my master-blaster 5000 remote toilet controller? As is very common with such EMC questions, the answer is a definite 'maybe'. Closely define the environment, separation and the immunity characteristics of your robot loo and you may get a slightly more definite 'maybe'. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc- p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc
Re: [PSES] Quasi-peak
Amund: Start by looking at Ed Bronaugh's paper: http://www.ieee.org/organizations/pubs/newsletters/emcs/summer01/pp.bron augh.htm I might get an argument on this, but it's my opinion that a spread-spectrum clock does not solve any emission problems, other than providing easier compliance with standards that require a QP detector. If we assume that the purpose of compliance is to increase the probability that you will not cause degradation of a communication channel, then the QP detector method is only useful for something like AM radio protection. If your channel uses something considerably different that AM, perhaps a digital bit stream, then a Peak detector yields a more true indication of potential harm. At a simple level, a QP detector charges as fast as a Peak detector, but discharges much more slowly (but still faster than an Average detector discharges). Most real emissions will register higher on a Peak detector than on a QP detector, and the Average detector will read even lower than the QP detector. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: Amund Westin [mailto:am...@westin-emission.no] Sent: Wednesday, November 30, 2011 11:11 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Quasi-peak I tried to find some information on how the Quasi-Peak detetor works. How long time does it measure at each frequency, why does a spread spectrum clock solve emission problem, etc Anybody who knows where I can find it? B.r Amund - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc- p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: [PSES] LISN Calibration
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Wyatt Sent: Tuesday, February 10, 2009 11:02 AM To: John Woodgate Cc: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] LISN Calibration Hi John Grace, Interesting you should bring this up. I worked for Agilent for over 20 years as their senior EMC engineer before retiring to consult in EMC. I'm currently working on an EMC Measurements seminar under contract with Silent Solutions, an EMC consultancy based in New Hampshire. I'll be covering the details of EMC testing, plus verification testing, oriented for the EMC engineer or technician. They are planning on releasing this new seminar (along with their normal EMC offerings) in Chelmsford, MA, the week of May 4th. For additional information, please contact Lee Hill at www.silent-solutions.com. Regards, Ken -- Ken Wyatt Woodland Park, CO Email: k...@emc-seminars.com Web: www.emc-seminars.com Ken: I would hazard a guess, based on what I have seen and my own experiences, that most EMC engineers are not well acquainted with network analyzers. It took me a long time before I grudgingly came around to understand that a network analyzer could be a lot more elegant solution to certain EMC tasks (calibration of current probes, filter characterizations, resonance studies) than a discrete signal sweeper and a spectrum analyzer. Try to work some elementary NA tasks into your seminar. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Calibration Standards for LISN
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Spencer, David H Sent: Tuesday, January 27, 2009 9:58 AM To: Ralph McDiarmid; emc-p...@ieee.org Subject: RE: Calibration Standards for LISN Ralph, ANSI C63.4 also has the procedure: Section 4.1.2 and Annex E. In short, it's a verification of the LISN impedance and insertion loss characteristics. Typically this requires a network analyzer to perform the verification. Also, if you use AC line filters on the line side of the LISN those should be part of the LISN impedance characterization (no AC mains connected naturally). Regards, Dave Spencer EMC Engineer Xerox Corp. But isn't it the purpose of the AMN to present an impedance to the EUT which is unaffected by whatever unknown impedance exists at the source of the power? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration Standards for LISN
So I would have to deduce then that ANSI C63.4 is schizophrenic, in that it doesn't trust the specified LISNs to work as they say they should. If the standard wants you to measure the LISN plus your facility filter, then you are characterizing your facility, not just the LISN. Logically, where does it end? Surely the impedance of the local powerlines has a slight effect on the overall impedance, and then what about the generators at the power station? Of course, I'm being absurd here, but why can't they just spec a LISN that provides sufficient isolation under all conditions? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: Spencer, David H [mailto:david.spen...@xerox.com] Sent: Tuesday, January 27, 2009 10:15 AM To: Price, Edward; emc-p...@ieee.org Subject: RE: Calibration Standards for LISN Ed, I agree, and I've verified that with the LISN(s) I use there is no impact; however, ANSI C63.4, E1, b) states that unless it can be shown that the RF filters do not impact the impedance then you must perform the verification with the RF filters in circuit. Really it's a case for either performing the verification in house OR sending the RF filters with the LISN out as part of the calibration (at least once). I know some facility RF line filters are not easily removed! Regards, Dave Spencer EMC Engineer Xerox Corp. -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Price, Edward Sent: Tuesday, January 27, 2009 1:04 PM To: emc-p...@ieee.org Subject: RE: Calibration Standards for LISN But isn't it the purpose of the AMN to present an impedance to the EUT which is unaffected by whatever unknown impedance exists at the source of the power? - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration Standards for LISN
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Tuesday, January 27, 2009 10:37 AM To: emc-p...@ieee.org Subject: Re: Calibration Standards for LISN In message 9d04b979323dcd428297dda95108893e0120c...@bb-corp-ex2.corp.cubic.cub, dated Tue, 27 Jan 2009, Price, Edward ed.pr...@cubic.com writes: But isn't it the purpose of the AMN to present an impedance to the EUT which is unaffected by whatever unknown impedance exists at the source of the power? Yes, but the calibration process has to include a verification of that 'unaffected'. Just want to clarify our terms here. When you calibrate, is this describing a process where you compare something to a standard value, and then adjust the something into as similar a condition as possible? In the case of an LISN, there are no adjustable components available. It seems like when we measure the parameters of an LISN, we simply then declare it good or bad; within the acceptable tolerance or not. I would call this a characterization, not a calibration. Right? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration Standards for LISN
Dave John: Certainly I agree that all of a lab's LISNs should be on periodic calibration. Anything that's in you signal path, or that affects the signal being measured, should be controlled in the lab environment. If there is a concern about how well the LISN creates the artificial impedance that it is supposed to present to the EUT, then there's three ways to verify that. First, you could specify the LISN be characterized with the facility powerline filter. In effect, this is a characterization of your whole facility. Not bad, but certainly cumbersome, especially for those labs that have to send everything to an outside metrology lab! Second, you could characterize the LISN using several extreme impedances placed on its input (short or open). This would satisfy me, but possibly someone might wonder if there might not be some strange interactions at intermediate impedances. So, to satisfy EVERYONE, you might be forced to use a large number of input impedances, or even asked to somehow present a swept impedance. That could be a long science project. Third, you could design an LISN such that the inherent circuit precludes any powerline impedance from affecting the EUT side impedance (to some tolerance). That way, all you would have to do is characterize the EUT side impedance once, and also verify that the circuit components are also unchanged from the original design. I guess I lean toward the third option, since it puts more of the burden on the LISN designer (who ought to be a super expert), and simplifies the workload on the test lab's staff. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty -Original Message- From: Spencer, David H [mailto:david.spen...@xerox.com] Sent: Tuesday, January 27, 2009 10:46 AM To: Price, Edward; emc-p...@ieee.org Subject: RE: Calibration Standards for LISN Ed, I've seen white board presentations at the IEEE Symposia, that suggest that the AC mains impedance does impact the final conducted emissions reading. A quick glance at Lab 34 (or CISPR 16-4-2) show that in terms of uncertainty the LISN impedance variations can account for as-much-as 3.6dB. All that being said, I didn't write the standard. I don't see any variation in my facility when I connect or disconnect the LISNs. BUT, as many lab are accredited these days and it is part of a standard that many use, it's worth at least taking a look at if for no other reason than quantifying the uncertainty rather than using the generic figures (which I'm sure no one does). Regards, Dave Spencer EMC Engineer Xerox Corp. -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Price, Edward Sent: Tuesday, January 27, 2009 1:25 PM To: emc-p...@ieee.org Subject: RE: Calibration Standards for LISN So I would have to deduce then that ANSI C63.4 is schizophrenic, in that it doesn't trust the specified LISNs to work as they say they should. If the standard wants you to measure the LISN plus your facility filter, then you are characterizing your facility, not just the LISN. Logically, where does it end? Surely the impedance of the local powerlines has a slight effect on the overall impedance, and then what about the generators at the power station? Of course, I'm being absurd here, but why can't they just spec a LISN that provides sufficient isolation under all conditions? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Cigarette socket in vehicles
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of rk...@chrysler.com Sent: Monday, January 19, 2009 6:37 AM To: Scott Xe Cc: emc-p...@ieee.org Subject: Re: Cigarette socket in vehicles Hello Scott, In the case of 12V accessories to plug in normally they have a regulator installed to prevent the overvoltage. Thank you. Rob Kado EMC Engineer - Module Laboratory Operations Chrysler Initial assumptions can be deceiving. I recently bought a Magellan GPS. It operates on 5 VDC, and came equipped with an external cigarette socket adapter. I assumed the cheapest, that there was a little resistor inside the adapter, or just possibly a cheap linear regulator. On taking the adapter apart (yes, I tend to do things like that), I was quite surprised to find a little 2 custom IC switching converter, with input inductors, filter capacitors and a hefty input overvoltage clamp. The input voltage range was not specified, but it seems likely to be capable of 24 VDC operation. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Electrical product recall request
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Pickard, Ron Sent: Tuesday, January 13, 2009 6:56 AM To: Scott Xe Cc: emc-p...@ieee.org Subject: RE: Electrical product recall request Scott et al, Compliance engineering is a term to describe the engineering activities to ensure that products conform to these regulations. In that aspect, compliance engineering does mimic the legal profession. Ron Pickard Ron: In companies where there is a specifically designated Compliance Engineer, what do you see as the trend in the depth of knowledge of such an engineer? Does this person hold technical responsibility for issues of safety, EMC, ROHS, etc, as you would expect of an engineer? Or is the scope so broad that the person acts more like a manager or coordinator of other specialists (designers and possibly outside vendors), more toward the lawyer end of the scale? Regards, Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Anechoic Chamber: Pass-through vs. Bulkhead
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of cmander...@micron.com Sent: Tuesday, January 13, 2009 1:50 PM To: emc-p...@ieee.org Subject: Anechoic Chamber: Pass-through vs. Bulkhead EMC Gurus, We have a Space Saver chamber that we bought used and installed ourselves. When we installed it, we ran our antenna (signal) cabling through a pass-through along with our fiber optics. Today, someone mentioned that we ought to have at least our antenna cable connected through a bulkhead so that the cable shielding was terminated on the chamber. When we went to disassemble the chamber when we bought it, there were no bulkheads for anything. Are the bulkheads necessary? Does anyone else use a pass-through for the antenna cable? It doesn't seem to have had an effect on measurements, but I still have a lot to learn so hopefully someone can share some wisdom. Thanks, Chris Anderson The traditional technique with a shielded enclosure was to have a specially designated penetration port. This was usually a thick plate of aluminum or tin-plated steel, about 16 x 16 x 1/4, mounted to the side of the chamber like a picture on a wall. The plate covered a 12 x 12 hole cut into the chamber wall and was bolted around its perimeter to chamber wall. There's nothing magical about those dimensions, they are simply convenient. This provided an access panel that could be customized for the special needs of an EUT. Did the EUT need cooling water, visual observation, optical stimulus, compressed air, a waveguide port, big multiconductor I/O cabling; you could machine and equip a panel as needed without ripping into the chamber itself. You could keep several special port covers for recurring unique jobs. The penetration port was a way of organizing your use of the chamber. Thus, there is no real need to use one. You are free to run every penetration as you want, but the many possible problems with this (control of grounds, preservation of shielding effectiveness, crosstalk, safety) will probably make you wish you had used designated penetration ports. (I have 3 penetration ports on my chamber, one primarily for emission testing, another primarily for immunity testing, and the third as an I/O port to a second smaller shielded chamber typically used to contain the EUT support equipment. I once built a penetration port for the transfer of jet turbine gas out of a chamber.) More to your specific question, John Woodgate has pointed out the issue of safety (RF can travel along the ungrounded shield, possibly toasting you or your equipment or radiating into the environment, although this is more of an issue in military testing than in commercial testing). The ungrounded coax cable could just as well allow external RF (radio stations or noise from your own test and support equipment) to get into the chamber and be taken for emissions from the EUT. Ken Javor talked about my favorite technique of grounding the coax without breaking the continuity by use of a packing gland or stuffing tube, but he didn't say why you might want to go to this trouble. Let me add a few words here. The easiest way to ground your coax as it penetrates the chamber wall (hopefully at a penetration port) is to use a female-female bulkhead feedthrough fitting. These are cheap and easily replaced when worn or damaged. The down side is that they are always a slight impedance discontinuity, and will create loss at extremely high frequencies and with high power, present a small concern of voltage breakdown or localized heating. If you use the packing gland method, you do not break the coax structure, and eliminate a pair of male-female connections. I use this on an ultra low-loss coax that I use for emission testing up to 18 GHz. The same techniques would also be a good choice for conveying high-power RF into the chamber (but those of you who are pushing 3 kW into your chamber have probably already heard of this technique). Bottom line is; ground that coax, no matter how you do it (well, don't use a pigtail strap with alligator clips). It's simply good engineering practice. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send
RE: iNARTE PS or IEEE
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ted Eckert Sent: Saturday, January 10, 2009 2:57 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: iNARTE PS or IEEE I am both an IEEE member and an iNARTE certified Product Safety Engineer. For both, I have found the value to be commensurate with the effort I have put into my membership. I have been an IEEE member for about 20 years. For much of that time, it was nothing more than a very expensive magazine subscription for me. Many see IEEE as an academically oriented organization and that is what it has become in recent years. I remember seeing an IEEE Spectrum article from a number of years ago showing that 35 years ago, the majority of papers submitted for IEEE publication came from people in industry. Now, the vast majority come from academia. Ted Eckert Compliance Engineer One Microsoft Way Redmond WA, 98052 (425) 707-9205 ted.eck...@microsoft.com Ted touches on a raw subject about the IEEE. Almost 35 years ago, there was a strong challenge to the existing IEEE structure addressing that exact question. Academia and management won, the working engineer lost. Certainly the reasons were more complex than the arguments, but one key aspect to understand is that working engineers were usually too busy with their own careers to put much personal time and effort into volunteering for the IEEE, especially at a time when the IEEE was growing beyond the USA. My subjective observation was that the greater the presence in the IEEE, the further a person was from the working engineer category. Another important reason for the shift of the IEEE focus is that academic types need to publish, establishing that printed record of their work. The IEEE Transactions and Spectrum were ideal venues, hungry for papers that could establish their professional status among publications and a great conduit for those wishing to get published. Again, my subjective view is that the Transactions became useless to me, a quarterly shipment of smoke in a green binder. Spectrum was also remarkably stuffy, although it has been vastly improved in the past year or so. Obviously, these are personal opinions. However, for those looking for metrics, try counting up the ads in Spectrum. How many ads are looking for radar engineers (pick you category of working engineer) and how many are looking for academic positions. These ads are placed by people who spend their money expecting results, and they professionally understand who Spectrum reaches. You might begin to wonder if the IEEE shouldn't change its name to reflect truth in advertising. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: EMC Eduction and Training
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Cortland Richmond Sent: Tuesday, December 16, 2008 3:11 AM To: emc-p...@ieee.org Subject: Re: EMC Eduction and Training That is the argument I used at Wang. How much do you make us every year? Nothing. But you'd pay out $8 million more a year if we weren't here. NOT what they wanted to hear. It never is. FWIW... I have EMC as a *quality* function. No one else does everything. Cheers! Cortland KA5S Perhaps you can take some comfort from Kipling's words of 125 years ago, when he addressed the peculiar way that society only appreciates you when they really, really need you: For it's Tommy this, an' Tommy that, an' Chuck him out, the brute! But it's Saviour of 'is country when the guns begin to shoot; An' it's Tommy this, an' Tommy that, an' anything you please; An' Tommy ain't a bloomin' fool -- you bet that Tommy sees! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: EMC Eduction and Training
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Kunde, Brian Sent: Tuesday, December 16, 2008 6:52 AM To: EMC-PSTC Subject: RE: EMC Eduction and Training Hey, lets think about this for a minute. Do we really want this “black magic” stuff we do for a living to be better taught in universities? Lets face it, we have a good thing going here and we don’t need some greenhorn engineer thinking he knows more about it than we do. As mentioned earlier, this job is more experience and technique than science. The best EMC engineers and technicians I know where not taught in school, but had been mentored by an older experienced EMC engineer. Like a magician passing on his secretes to his apprentice. This is how it has been done and the way it has to be done. The Other Brian The Other Brian touches on an interesting and salient feature of the happy EMC Engineer. EMC demands a more hands on approach than most of the other disciplines. Those students who are not already building their own circuits and frying their own power supplies will not do well in EMC, or at minimum, will try to stay toward the academic / computational edge of EMC. To the rigidly academic, it must be terrifying to discover that EMC problems have so many unknowns and (usually) more than one solution. I'm not so sure that a mentoring / apprentice system HAS to be the only way to assure continuity, but, from my observation, it has been an effective and efficient method. Certainly, we could get into an endless discussion of whether our educational system rationally assigns talent to appropriate needs (after all, they told me I could be anything I wanted; what they didn't tell me was that what I wanted also had to be needed). Remember Pachinko and Pinball machines? There's something fascinating about watching the life-arc of a ball, despite us knowing with 6-sigma certainty the origin and destination of every ball. Uhhh, what was the question? Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Cables On The Floor
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Wednesday, December 10, 2008 12:21 AM To: emc-p...@ieee.org Subject: Re: Cables On The Floor In message 9d04b979323dcd428297dda95108893e0120c...@bb-corp-ex2.corp.cubic.cub, dated Tue, 9 Dec 2008, Price, Edward ed.pr...@cubic.com writes: You would think that the odds of stepping on the cable would be 285 to 1. You might, initially, but think about this. To make the math easier, assume a square room and 289 footprints (17^2). So there are 24 footprints along a diagonal. Lay a cable along that diagonal, and all 24 footprints cover it, to a greater or lesser extent. Then there are 23 new footprints along the other diagonal, then 15 new ones along each side... So with 6 cables we have 107 footprints on them, out of 289. Admittedly, this includes 'spherical cow' type approximations, but it shows a trend. -- John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I'll defer to your logic, as I was sick the day they explained combinations and permutations to us. BTW, I'm almost afraid to ask, but what's a spherical cow? I think that might great to be able to authoritatively cite that in my next lab status report! Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Mobile Phones in EMC Labs
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Haynes, Tim (SELEX GALILEO, UK) Sent: Wednesday, December 10, 2008 5:10 AM To: Luke Turnbull; emc-p...@ieee.org Subject: RE: Mobile Phones in EMC Labs Luke, Yes, because: The phone radiation might interfere during emission tests by entering the chamber via a penetration interfering with external support equipment create spurious emissions by creating secondary mixing products immunity tests by being amplified (in the amplifier) along with the wanted immunity signal causing failures in the support equipment that are laid against the item under test No, because business is more reliant than ever on mobile communications and a ban will cut your customers off from their business if your emc test lab is bothered by any of the items under yes your customers might suspect your EMC skills are not up to the mark you might not want your personal calls going through the company switchboard Otherwise - it is your call... Regards Tim I have had some success in controlling the test support environment by posting a couple of signs declaring that All personal electronics will likely be vaporized! Seriously, I provide several wired telephones in my lab area, a wired Ethernet link, and cell-phone operation is so bad inside our plant building that it doesn't take much persuasion to shift customers to land-line use. I also have a single 49 MHz portable phone (remember, they called them cordless phones?). The 49 MHz signal is much less likely to find a leakage path or an efficient radiator. I also find it amazing how many younger customers look at this cordless phone in wonder, muttering about how big it is, and how they never saw anything like that. And the darn thing doesn't even have a camera! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Cables On The Floor
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Gert Gremmen Sent: Tuesday, December 09, 2008 12:23 PM To: Pettit, Ghery; Luke Turnbull; emc-p...@ieee.org Subject: RE: Mobile Phones in EMC Labs Of course once your gold-plated coaxial connectors wear out, and your cables became flat from standing on it, you will see all kind of spurious outdoor signals in your result. Gert Gremmen Although I am naturally pessimistic, I am not superstitious. However, how else to explain the near magical capabilities of a cable laying on the floor to attract human feet? If I lay a BNC or SMA cable (assuming 1/4 cross section by 10 foot exposure length) onto the working area (about 16' by 12'), the cable occupies only 30/27,468, or only about 0.11% of the floor area. The typical human feet cover 4 by 12 by 2, or 96 square inches. So there are 27,468/48, or 286, places where you can step in the room. You would think that the odds of stepping on the cable would be 285 to 1. But from experience, as you talk with a visitor in the chamber, how many times have you looked down to see one of their feet planted squarely across a cable? Indeed, it's not all that remarkable for a visitor to managed coverage with both feet. Or to amble along the cable as if it were some kind of guidance wire! Some programs attract a disproportionate amount of official (management) visitors, and it was during one of those that I implemented my experiment with sacrificial cables. After walking each visitor into my chamber, while repeating the mantra of please be careful not to step on a cable and pointing at a cable so that they understand what a cable looks like, I began to notice the mathematical anomaly of non-random foot placement. I decided to test my suspicions, so, as we moved into conducted susceptibility testing, I laid four BNC cables around the chamber working area. (These were cables accumulated during the radiated emission test; cables which had endured numerous verified foot stomps.) Then I began watching the visitor pattern. I wish I had kept accurate data, for I'm sure that I could have produced a very important and controversial paper (that could have given me a decent vacation for its presentation). However, I am left with only the subjective memory of those trials. I concluded that cables have some kind of unexplained power to strongly direct the human mind to place a foot over a cable whenever the physical opportunity is available. Although I never conducted further trials, I have speculated as to the attractive mechanism that causes this. I wonder if it may somehow be related to the technique by which cows are kept off of a roadway (cows will not cross a couple of parallel painted stripes on the ground). True, this would be an inverse relationship, as cables attract the foot, but I think I'm really onto something important here. BTW, the test cables were all later found to be in acceptable condition, and were returned to service. I must assume that either I am being too alarmist about the dangers of stepping on a cable, or, my management just leaves no lasting impression on physical reality. More studies are needed! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: High frequency Antennas for EM surveys
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Price, Andrew (SELEX GALILEO, UK) Sent: Wednesday, December 03, 2008 11:56 PM To: emc-p...@ieee.org Subject: High frequency Antennas for EM surveys Hi everyone I am looking for an Antenna 1GHz to 18GHz that can be used for em survey work. This antenna is required for measureing EM fields inside vehicles as well as outside. The standard double ridge horn has too much directivity. I have already identified an antenna to cover the frequency range 30MHz to 1GHz this is an active dipole by Credence Technologies. Can anybody advise??? Regards Andy Andrew P. Price Principle Hardware Engineer, EMC Specialist Andy: Fields inside a vehicle are going to be influenced considerably by reflections from the many nearby surfaces. You might want to consider measuring power density and converting to a field strength. If you still want to use an antenna, then the very old Polarad CA-B comes to mind. This antenna was a vertically polarized discone, so it was omni in the horizontal axis. Antenna factor was about 40 dB from 1 GHz to 10 GHz, so I don't know if it degraded gracefully up to 18 GHz or what. Still, the design is valid, if you want to build your own discone. Essentially, a coax penetration of a 12 diameter ground plane, with the center conductor blended into a cone that extends maybe 6 to a 6 diameter. Build it solid and get a traceable calibration, and you're ready to go. It might be advisable to think about using a couple of stirrers to maximize you detection probabilities within the vehicle. Regards, Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Radiated emission - time at each frequency
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Amund Westin Sent: Thursday, December 04, 2008 2:56 AM To: emc-p...@ieee.org Subject: Radiated emission - time at each frequency When doing Radiated emission 30-1000 MHz according to EN55022, for hold long time do you measure at each frequency (band)? Best regards Amund Amund: I'm not a commercial measurements expert, but I'll toss out my opinion. The simplistic answer is that you should dwell at a frequency long enough for the detector to respond to any emission that occurs. Since the charge time constant of the CISPR detector is 1 millisecond, then 1 millisecond is the minimum dwell time. However, you should also dwell long enough for any event that might occur in the EUT. For instance, if the EUT cycles through an internal function every 35 milliseconds, then you should be dwelling for at least that long. (Who knows, the EUT may turn on something very noisy only between 21 and 28 milliseconds into its cycle!) You are probably using a 120 kHz resolution bandwidth, so each discrete measurement point is including the spectrum 60 kHz below and above the indicated frequency. Since the BW edges are defined as the 3 dB down points, you should hop to your next measurement frequency of something like Fo + 80 kHz to allow for some overlap. Then you can start another dwell period. There might also be some additional constraint with the decay time of the detector. IIRC, the decay time constant of the CISPR detector is 550 milliseconds. Unless your measurement system has some kind of rapid drain of the detector when you initiate a frequency hop, then you may have to wait at least 550 milliseconds once you hop, but before you read your detector. Regards, Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Radiated emission - time at each frequency
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Thursday, December 04, 2008 7:08 AM To: emc-p...@ieee.org Subject: Re: Radiated emission - time at each frequency In message 9d04b979323dcd428297dda95108893e0120c...@bb-corp-ex2.corp.cubic.cub, dated Thu, 4 Dec 2008, Price, Edward ed.pr...@cubic.com writes: The simplistic answer is that you should dwell at a frequency long enough for the detector to respond to any emission that occurs. It's a base rumour that some regulatory test houses dwell until they get a 'FAIL'. (;-) Seriously, it's a very difficult question to answer. If the product has some sort of cyclic behaviour within a short time, waiting some tens of milliseconds may be acceptable, but what about a washing machine with a 150 minute cycle? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I think the conservative way to approach that would be to see if you could eliminate the time delays in a cycle without affecting the events of the cycle. For instance, you could rig the wash cycle to turn on, then off again in a second or two, eliminating 5 minutes of boring motor running. You could rig a water level detector to trip without the tub actually filling, etc. You might also do an analysis to show that certain functions are redundant or duplicative, for instance, the spin cycle may consist of a motor start/stop operation identical to a spin cycle, so you could eliminate one of the whole cycles. Some of my test setups have used multiple strings or cords so that I can yank a cord to fake some mechanical sensor in an EUT into thinking it is ready to move on to the next function. Regards, Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: possible power line cause of recent San Diego fires
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Wednesday, December 03, 2008 12:47 PM To: 'Emc-Pstc' Subject: RE: possible power line cause of recent San Diego fires Update I have removed the systems and have moved from this property, so this (incomplete) test has been terminated. I do not consider the data conclusive. True, your period of observation was not over the normal peak Santa Ana wind days, but did you arrive at any preliminary conclusions about powerlines and wildfire causation? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: EMI Receiver
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Jim Eichner Sent: Tuesday, December 02, 2008 12:03 AM To: emc-p...@ieee.org Subject: RE: EMI Receiver Indeed, however while I too may be losing the will to live, I still have the will to search out a new spectrum analyzer (note I learn from my experiences and have dropped the term-that-shall-remain-unspoken from this posting). So dare I repeat my question and that of Tim's original posting: does anyone care to sing the praises of any particular make/model for pre-compliance radiated and conducted emissions testing? Jim Eichner, P.Eng. It's difficult to resist an invitation to sing. However, since I have been using an HP-8562A Spectrum Analyzer (1987 vintage), an Anritsu MS2601 Spectrum Analyzer (1993 vintage), an HP-4195A Spectrum Analyzer Spectrum Analyzer (really old) and an HP-8572A Receiver System (1994 vintage), I may not have a modern tune. I recently used an Agilent E4440 Spectrum Analyzer, and it was a superb improvement over everything I have. I was especially impressed with it's 26 GHz capability, with a built-in low-noise pre-amp and no need for a harmonic converter. Noise floor was excellent. OTOH, this gadget will cost you north of $100k, which may be too steep to justify for pre-compliance testing. If you have to do it very cheap, you might consider what I use for back-up sanity tests. I have a set of Stoddart/AILTech/Singer/Eaton Series 7 receivers (the NM-17A for 10 kHz to 30 MHz and the NM-37A for 30 MHz to 1 GHz). I bought them both on eBay ($95 $125); one worked right away, the other needed a fix to the tuning voltage power supply. These give you Peak Average values, and you can also look for a CCA-7 QP Adapter (think I got that for about $125 too) to give you true QP capability. Can't beat $350 plus a little labor for a pre-compliance setup. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: EMI Receivers
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of michael.na...@emerson.com Sent: Monday, December 01, 2008 1:05 AM To: emc-p...@ieee.org Subject: RE: EMI Receivers An instrument, IMHO, should not primarily named by its application. In this case, I would call it a test receiver, not an EMI receiver (not good) or EMC receiver (even worse). The same test receiver can be used to measure EMI, but also to measure properties of an RF transmitter. The German term 'Meßempfänger', which means literally measuring receiver coins this quite nicely. Best regards, Michael Nagel But Mike, when receiving, you may be simply monitoring without testing. g BTW, I agree with you in general, but the use of German technical terms has it's own problems, most notably the limitation of the number of characters on a line of text. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: EMI Receivers - Now Terminology
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Friday, November 28, 2008 8:08 AM To: Untitled Subject: Re: EMI Receivers With this sloppy terminology, rife in the commercial world, we are raising a generation of EMC engineers who have no clue why they do what they do, other than they have to meet some legal requirement before marketing a product. It is bad enough that I have seen in this forum otherwise well-regarded engineers claiming that radiated emission requirements are there to protect all electronics from interference, as opposed to radio receivers, which are the sole victim protected by radiated emission limits. Non-antenna-connected electronics don’t require that level of protection. Happy Holidays! Ken Javor While Ken raises valid points, I think he is still defining interference too restrictively. While many official limitations on radiated emissions have been set to provide protection for receiving systems, this has only been the historical precedent. There is no reason why a radiated emission limit cannot also be used to protect non-receivers. Actually, non-receivers is a bad term, because everything is a receiver. I have seen many examples of non-receivers (things like A to D converters or servo systems) which, either by poor design or construction, make fairly good receivers. It can certainly be argued that undesired responses to external energy should be controlled by immunity requirements. Most of the time, that's true. But COMPATIBILITY is a balance between control of emissions and ensurance of immunity. You may go to extremes in both directions, or you can seek a balance (typically defined by cost, weight, size, politics). And that's why radiated emission limits can protect things other than intentional receivers. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: EMI Receivers - Now Terminology
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Friday, November 28, 2008 8:08 AM To: Untitled Subject: Re: EMI Receivers Second, please folks, there is no such thing as an EMC receiver. It may seem like semantics, but you can’t receive electromagnetic compatibility. May be you can ask Santa for it, but I doubt he will deliver. True; it's the Easter Bunny that delivers! What you receive is EMI – electromagnetic interference, and the entire purpose of the receiver is to quantify the amount of EMI, and compare it to a limit. The limit is there to control the amount of EMI generated so that we can expect some level of electromagnetic compatibility. Ken Javor Again, I have to disagree just a bit. What you receive on your spectrum analyzer (or EMI Receiver or whatever) is not EMI; it's just some energy at some point in the spectrum. That energy can only be considered interference if the undesired response of some equipment is considered. Otherwise, that energy is not hostile EMI, it's just there. Your signal is my noise, and my signal is your noise. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
FW: EMI Receiver
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Price, Andrew (SELEX GALILEO, UK) Sent: Monday, December 01, 2008 7:00 AM To: emc-p...@ieee.org Subject: EMI Receiver Hi All What was wrong with the old Stoddart/Ailtech Identity? EMI/Field Intensity Meter Regards Andy Andrew P. Price Principle Hardware Engineer, EMC Specialist While citing Stoddart as a source is pretty definitive, you do have to remember that they were building on government contracts, so logic may not apply. Besides, as I previously said, the energy can't really be called interference by itself. Also, Field Intensity Meter is a bit incorrect, since the meter really measures only the 50-Ohm voltage applied to its front panel. If you connect an antenna, you can measure field strength. But, you could as easily connect a different transducer, perhaps a current probe, and you would then be measuring circuit currents. Other transducers are also possible; an accelerometer for mechanical vibration, a microphone for acoustic energy, a piezo transducer for ultrasonic. Does anyone measure any physical phenomena that I left out? Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: EMI Receiver
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Monday, December 01, 2008 8:47 AM To: Untitled Subject: Re: EMI Receiver This may be one of those usage differences that occur on opposite sides of the Pond. After all, what we in the USA call a billion, you call a milliard, and what you mean by a billion is what we call one trillion. Ken Javor So USA 2 billion is a UK billiard? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
DC Coupled Amplifier
I would like to get a modest capability to do some of the ramped power quality tests defined in MIL-STD-704. Typically, I would want to be able to apply various DC voltage inputs to a test specimen, and then slew those voltages following the typical dV/dT requirements. Typical exposures might be 28 VDC for 30 seconds, then ramping to 50 VDC in 10 milliseconds, holding 50 VDC for 5 seconds, then ramping to 12 VDC in 40 milliseconds, etc. The problem I have is that all of my power supplies are too slow to track the ramps, and even when they get close, I am seeing capacitor charge/discharge curves rather than straight ramps. So I have been thinking that maybe what I want is a DC coupled amplifier. Perhaps one possibility is the automotive aftermarket, where those rude idiots buy those thousand watt boom boxes that they use to rattle my house when they drive past. I think they now use Class D switchers for those amplifiers. Does anyone have any suggestions about where I might look? Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: GIFS on the EMC-PSTC list
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Jim Bacher Sent: Friday, November 14, 2008 7:44 AM To: emc-p...@ieee.org Subject: Re: GIFS on the EMC-PSTC list Gif's, large files, etc. can be posted on: http://www.ieeecommunities.org/emc-pstc Jim Jim: The last time anyone posted a document there was June of 2007. Either our group must be almost totally ignorant of the site's location and existence, or there is some other impediment to its widespread use. I hesitate to suggest an explanation and direct link in the information footer that accompanies each post, since that footer is pretty big already, and some of our users might begin to object to the size of this repetitive message. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Test setup for equipment operated intermittently
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of pat.law...@slpower.com Sent: Thursday, November 13, 2008 9:43 AM To: emc-p...@ieee.org Subject: Test setup for equipment operated intermittently Hi, I need to run EMC tests on a piece of high-power medical equipment that is used on an intermittent basis. The run time is about 15 seconds to 2 minutes on-time, followed by about 10 minutes off-time. This is comparable to typical system usage. This causes problems with EMC testing, since you normally need a longer observation period. 1) The equipment could be operated continuously, but extra cooling would have to added to the test setup, which is not part of a typical system. In the spirit of regulatory intent would this be considered overtesting? 2) Could testing be done at the highest power level that allows continuous operation? What load conditions/test setup are appropriate for an application like this? Pat Lawler EMC Engineer SL Power Electronics Corp. Pat: I think you can do most anything that doesn't significantly affect the radiation pattern of the EUT, from a big fan over in the corner of the test chamber to more exotic things. I frequently have to test military systems that have similar duty cycle restrictions. One trick I use is to route shop compressed air, through plastic lines, onto critical components. If I need even more cooling, I have used CO2 in place of air. Once, maybe as more of an experiment than anything else, I used compressed air to drive a vortex tube (a passive gadget that splits the compressed air in a pair of air flows, one hot and one cold), yielding a modest flow of about -40C cooling air. You should also consider if the medical device is always used at a single output setting, or does it allow for a range of exposures? Sometimes, the predominant noise is a function of power supply loading, and it doesn't always follow that maximum device output equals maximum noise output. If I encounter a range of operation, I usually do a quick test at 10% / 50% / 90% output power to see if noise predominates toward one extreme or another. Regards, Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: unloaded motors - EMC testing
Curtis: For the testing of Military systems, I always look for the worst possible, yet normal mode of operation. Sometimes a power supply will be noisier at little load than at high load, so we usually test it at 10%, 50% and 100% loading. Electromechanical devices are operated as close to normal as possible, so that means that actuators driving flight control surfaces are loaded (with weights and/or elastomeric springs) to simulate flight loads. If I had a motor which drove a pump or blower or whatever, I would operate it at its normal speed and torque loading. If the loading was unpredictable, I would do a quick analysis of emissions to determine the worst-case operating point, and then do the rest of my emission testing in that condition. Predicting the worst-case operating condition for susceptibility (immunity) testing is a lot more difficult. If I didn't have a good engineering analysis of the EUT to help me, I would probably use the same operating condition that I used for the emission tests. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Bender, Curtis Sent: Thursday, October 30, 2008 8:56 AM To: emc-p...@ieee.org Subject: unloaded motors - EMC testing Greetings IEEE EMC-PSTC forum members and experts. I am looking to answer some questions concerning the EMC testing of portable commercial and industrial equipment; specifically the testing of motors at “no load”. I have my own “opinions” and experience concerning these questions but I would like to get some factual data (standard reference) and documented EMC standard design philosophy if at all possible. I was hoping the IEC guide 107 would have noted this design philosophy but unless I missed it I did not see it. 1. Can someone explain how and why “no load” frequently occurs in EMC test standards? See CISPR 14-1 section 7.3 for example. 2. Why is “no load” used and why isn’t a loaded or partially loaded motor used? (other than “testing for all possible working conditions is not practical for technical and economic reasons”). Is this representative of “real world” conditions? If not how is it correlated to the “real world?” 3. Typically do the limits included in EMC standards correspond (or are reduced) to the actual application? How is this correlated to “real world” applications? Or is this covered in statements such as: “the limits given in this standard take into account uncertainties” (from CISPR 12)? As always, I look forward to your comments. Regards, Curt __ Curtis Bender | T: 616.994.4221| F: 616.994.4127 Global Technical Approvals/Lead Project Engineer Tennant Company | Creating a cleaner, safer world for 135 years. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
HP Hardware Update
This isn't an ad, just info about a test hardware resource. All the usual disclaimers. I'm sending this as an FYI to owners of old HP spectrum or network analyzers. I have an HP-8562A spectrum analyzer that is a very valued resource, but the display CRT is nearing the end of its life (it's dim and the focus is pretty bad). Unfortunately, HP doesn't stock the tubes for these old analyzers (or for other 85xx, 86xx, 4195, etc analyzers too). Now there's a great opportunity to prolong the service of those old analyzers (and maybe bring some back from the dead). A company called National Test Equipment (in Oceanside): http://www.ntecusa.com/sales/dsp_model.cfm?modelID=21481 http://www.nationaltestequipment.com/ offers a drop-in LCD replacement display that replaces your old analyzer's CRT, HV and driver circuits. Your analyzer will run cooler, last longer on battery and weigh a bit less. The cost is $1,795, installed, with a 6 to 12 month warranty. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
British MoD Crystal Ball
I'm currently using the British MoD DEF STAN 59-41 in a couple of programs. Both are Army Land equipments, so the Method DRE03.3 test method is invoked. The purpose of the DRE03.3 requirement is to ensure radiated emission protection to the CLANSMAN radio system. However, the CLANSMAN is pretty obsolete, and is being replaced by the BOWMAN radio system. Will DRE03.3 continue to exist? Perhaps it will be modified to include BOWMAN antenna components and an adjusted emission limit? Or perhaps the BOWMAN has much better immunity than CLANSMAN, and won't need the protection of a special test method? Can anyone hazard a guess on the future of this requirement? Thanks in advance! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Airborne Missile Protection System for Helicopters in Iraq
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Michael Loerzer Sent: Tuesday, October 21, 2008 10:49 AM To: emc-p...@ieee.org Subject: Airborne Missile Protection System for Helicopters in Iraq Hi Experts, does anybody know if „additional” safety/EMC aspects for the import of an “Airborne Missile Protection System for Helicopters in Iraq” are mandatory? Or has anybody a contact to “experts” in Iraq (ministries, authorities, …)? Our customer needs a obligatory answer. Mit freundlichen Grüßen Yours sincerely Dipl.-Ing. Michael Loerzer Managing Director Regulatory Affairs Specialist Michael: It all depends on your customers requirements. Military purchases define the specific quality assurance and/or compliance requirements, so you need only consult your contractual documents. I really doubt that there is an Iraqi civil authority that is buying helicopter anti-missile systems. If it is purchased by the Iraqi military, it is probably being contracted through the US military. Typically, the EMC requirements would be a suite of MIL-STD-461F and MIL-STD-464A tests. There might also be some MIL-STD-704 power quality tests. I'm not very familiar with any military safety standards, but they would be invoked by the equipment system specification document. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Kunde, Brian Sent: Monday, October 06, 2008 12:55 PM To: emc-pstc Subject: Microwave Oven Interference with 2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian You could suggest the IT guys try a different link standard that moves them out of the 2.45 GHz ISM band. You can also buy new microwave ovens, since publicly accessible ovens get a pretty horrible beating during use, and may be leaking from sprung doors or abused door seals. You can also get industrial microwave ovens that operate at 960 MHz. These ovens are often huge (imagine making taco filling starting with frozen slabs of beef and lard), but maybe some table models are available. (The 960 MHz penetrates food much deeper than the consumer 2450 MHz, so it lends itself to industrial cooking.) Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: DO-160 Section 15 - Calibration of Compass
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Luke Turnbull Sent: Thursday, October 02, 2008 9:30 AM To: emc-p...@ieee.org Subject: DO-160 Section 15 - Calibration of Compass Hi all, Maybe a little off-topic. Section 15 is a compass-safe-distance test. One measures the deflection of a compass (in degrees) caused by an EUT. I have been asked about how the compass should be calibrated to demonstrate that the number it gives (deflection in degrees) is traceable. Does anybody have any experience with this test and the calibration of the compass? Thanks, Luke Turnbull Luke: I had started to do that test a couple of years ago, but I couldn't figure out how to read a compass as accurately as needed. Even a large nautical compass is difficult to resolve to one degree! I began building an electronic compass, using a Honeywell HMC-1001 2-axis magnetoresistive sensor. This had the promise to easily resolve one degree of deviation due to external field influences. (Actually, the output is a pair of DC voltages, proportional to the magnetic field. I would have needed to solve the trigonometric solution for the deviation.) It all sounded like a great idea, but the project requirement went away before I even received the little bag of parts, so it remains another of those uncompleted projects. (The parts are cheap, all your really need is the HMC chip and a dual op amp, and a plastic case. Honeywell has a nice tech bulletin with suggested schematics, etc.) Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Lab Rat Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Immunity of commercial equipment to radar at frequencies over 5 GHz
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John McAuley Sent: Monday, September 29, 2008 2:18 PM To: emc-p...@ieee.org Subject: Immunity of commercial equipment to radar at frequencies over 5 GHz Dear Group I am seeking information on the immunity of commercial equipment to radar at frequencies over 5 GHz. The field strength will be in excess of 300 V/m. There is little information available on the immunity of commercial equipment to radar pulses at these high frequencies and levels. My guess is that equipment will be relatively immune given the bandwidth of IC technology. The rule of thumb for the bandwidth of IC technology is 10 or 20 times the bandwidth. There may, of course, be non linear out of bandwidth responses. From a search on the web it appears that PCs will not exceed 4 GHz for some time based on the current state of the art 45 µm and 65 µm technology. What is the upper bandwidth of a 3 GHz PC? I would also assume that the high frequency clock is contained within the processor and would be relatively well protected? I would be interested to hear from military test labs that have experience of testing immunity of equipment to pulsed fields up to 18 GHz. How frequently do conventional circuits fail high level EMI testing? Many thanks for any information provided. Best regards John McAuley Compliance Engineering Ireland Ltd John: Don't count on the semiconductors in your commercial equipment being non-responsive to GHz range energy. A susceptible response might be elicited just by the application of the RF, but more often, the RF couples into your device through apertures or other paths, and then non-linear circuit elements demodulate the RF, allowing the modulation rate to create the susceptible response. Paragraph A.4.3.10.4.2 of MIL-STD-461F says it more thoughtfully: Modulation is usually the effect that degrades EUT performance. The wavelengths of the RF signal cause efficient coupling to electrical cables and through apertures (at higher frequencies). Non-linearities in the circuit elements detect the modulation on the carrier. The circuits may then respond to the modulation depending upon detected levels, circuit bandpass characteristics, and processing features. Pulse modulation at a 1 kHz rate, 50% duty cycle, (alternately termed 1 kHz square wave modulation) is specified for several reasons. One kHz is within the bandpass of most analog circuits such as audio or video. The fast rise and fall times of the pulse causes the signal to have significant harmonic content high in frequency and can be detrimental to digital circuits. Response of electronics has been associated with energy present and a square wave results in high average power. The modulation encompasses many signal modulations encountered in actual use. The square wave is a severe form of amplitude modulation used in communications and broadcasting. It also is a high duty cycle form of pulse modulation representative of radars. There's a lot more after that, but to paraphrase it a bit, the RF is the vehicle and the modulation is the payload. I have tested a number of systems where the EUT is rock solid in the presence of CW, but goes nuts when you turn on the modulation. Let's add another fun effect; FM demodulation. I have seen a couple of EUT's where the sweep rate of the illuminating signal was the culprit. Sweep the RF frequency too fast or too slow, and the EUT is OK. Sweep at a moderate rate, and the EUT responds! Clearly, you can't test for every possible modulation and sweep rate, so following the guidelines of MIL-STD-461 by using a 1 kHz 1 Hz square wave modulation and sweep speeds compliant with Table III yields a conservative and prudent test regime. Getting back to your original question, I would be pessimistic about the chances of typical commercial equipment operating in the presence of 300 V/M, 1 kHz 50% modulation 5 GHz energy. I would expect susceptible responses, and I would not be surprised to encounter destructive effects too. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified Lab Rat Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send
RE: Shielding setup for conducted emission prescans
Don't forget to include a low-pass filter for the AC powerline where it enters your shielded work area. Another alternative might be to find a used TEM or GTEM cell. It will give you shielding, plus you can also do radiated emission and immunity pre-scans too. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, September 30, 2008 6:53 AM To: Untitled Subject: Re: Shielding setup for conducted emission prescans I'm going to go out on a limb here and disagree with Mr. Woodgate. Not that what he said was wrong, just overkill. If all you are worried about is conducted emissions from 150 kHz to 30 MHz, and if the AM BCB is the only licensed high power transmitter of concern (TV BCB starts at 54 MHz, and FM at 88 MHz), then all you need is some chicken wire stretched over that 2x4 frame. I wouldn't even worry about soldering or otherwise making an ohmic connection between different sections of the chicken wire, just assure yourself plenty of overlap. And make sure the door closes well and the metallic cladding goes all the way around from the outside to the edges and at least a little on the inside, and make sure the door frame is likewise coated and that coating makes a decent connection to the chicken wire. That is all you will need - no fingerstock, no gasket of any kind. AM is such a long wavelength it can't get through even the rather large chicken wire interstices of an inch or more. Ken Javor Phone: (256) 650-5261 From: Gelfand, David david.gelf...@ca.kontron.com Date: Tue, 30 Sep 2008 09:08:19 -0400 To: emc-p...@ieee.org Conversation: Quiet PC for RE Subject: Shielding setup for conducted emission prescans Hi all, I do conducted emission prescans, but do not have a shielded room. A few AM radio stations come in loud and clear. I was considering building a wooden frame and covering it with mesh to shield the setup. Our products are mostly smaller than a breadbox. Any suggestions would be appreciated! Thanks, David David Gelfand Conformity Specialist Kontron Canada Inc. 616 Curé Boivin Boisbriand QC Canada J7G 2A7 450 437 5682 x2449 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Heretical Views of Product Safety Orthodoxy
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Thursday, August 21, 2008 3:14 PM To: emc-p...@ieee.org Subject: RE: Heretical Views of Product Safety Orthodoxy Attending puts you at the risk of conversion to a heretical viewpoint of product safety. The Director of Engineering, sometimes refers to me as 'the heretic' and other times as 'the subversive'. Is the pariah existence my lot in life if I stay in compliance engineering ? Brian Really, really, really try to avoid the final label of martyr. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: RF What-if (was: RE: Another Cancer Scare?)
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Shinn Sent: Sunday, August 17, 2008 5:35 PM To: emc-p...@ieee.org Subject: RE: RF What-if (was: RE: Another Cancer Scare?) Take a look at this. http://tinyurl.com/69na9 Regards, John Shinn, P.E. Appears to be England, Norfolk, some fields outside Hillington. Patterns on the fields appear consistent with linear harvesting techniques; doesn't seem shiny enough to be anything beyond a field of beans. What, is this a stealth solar array? Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: monopole recommendations
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Julian Jones Sent: Monday, August 11, 2008 3:36 AM To: emc-p...@ieee.org Subject: monopole recommendations we need to get a back up for our EMCO 3301, 41 inch rod antenna. looking for recommendations for what other labs are using. I've noted the changes MIL 461F brings with grounding the connector especially. I've almost finalised on the A H systems SAS-550-1B has anyone got / used this one ? any problems to report. Rgds Julian Jones Hursley EMC Services Tel: 023 8027 Mob: 07787 523 607 ju...@hursley-emc.co.uk mailto:ju...@hursley-emc.co.uk Unit 16, Brickfield Lane Chandlers Ford EASTLEIGH, Hampshire, SO53 4DP Company Registration 3301279 Julian: I have been using an SAS-550-1B for about ten years, and I like it quite a bit. It has an internal battery that gives about 8 hours operation, almost as long as the venerable old Stoddart 95010-1. The gain flatness isn't a smooth as the Stoddart, but the sensitivity is a little bit better (mine averages about -11.3 dB AF; I don't know if that's typical or I'm just lucky). (Ken Javor mentions the 0 dB factor, but that was available only when you used the capacitive top-hat and extended the rod to about 50; so when a standard calls for a 41 rod, active or passive, the old Stoddart could only give you a flat 8 dB antenna factor.) The slightly non-flat AF is no problem with modern acquisition systems; if your software can handle the wiggly factor of a biconical, the active rod will seem almost flat in comparison. A couple of years ago, I had AHS modify my active rod to allow me the ability to have an active loop antenna. They changed the top connector to a type N, added a switch on the side to select rod or loop, and added some circuitry inside the amplifier box. I can now connect either their 41 rod or 12 loop to the amplifier base. This is a good bargain if you need to do both electric magnetic fields. Reliability has been excellent. Battery life is long enough that I don't have to worry about external power. It is ESD sensitive, so no touching the exposed rod element! Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: monopole recommendations
-Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Thursday, August 14, 2008 6:32 AM To: emc-p...@ieee.org Subject: RE: monopole recommendations Ed is correct. The antenna factor of the 95010-1 is 8 dB/m when configured for MIL-STD-461 RE02/RE102. I was talking about the amplifier gain, not the complete antenna. BTW, one of my two 95010-1 antennas came from the UK. The bloke from whom I bought it shipped it with four dead dry cell type batteries - I paid to ship those dead batteries across the pond, plus they can break loose easily under stress and then damage the circuit board. I was lucky and only paid the penalty of the high shipping costs; the antenna worked flawlessly with good batteries. I only had one of those 95010-1's, but it did last for over 18 years! Battery life was so long that you began to forget that it had batteries. And that flat AF was so nice in the days before computers took over. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Commercial EMI test software, need opinions on
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Monday, July 21, 2008 8:57 PM To: Untitled Subject: Commercial EMI test software, need opinions on Forum Members, I am assisting in choosing automated software control for an EMI test facility. I’m old school – REAL old school – and am unfamiliar with any of the following: ETS Lindgren – TILE http://www.ets-lindgren.com/page/?i=Tile Teseq – Compliance 3 http://www.tese .com/com/en/products_solutions/emc_radio_frequency/software/index.php?navid=37 CKC – EMI Test http://www.ckc.com/emitest.asp If any of you have experience with any of these, or others, positive or negative, please let me know off-line. Thank you, Ken Javor I think that the most important decision is to determine what kind of testing you intend to perform. By that, I'm asking if you want to study the EUT, or are you looking only for pass/fail results? Automation is great, until you come up against test conditions that the automation didn't anticipate. For emission testing, find out how the software handles single-event emissions, or low duty cycle pulses. Can you delete data point-by-point, or does a single improper data point invalidate the entire test scan? How easy is it to stop an automated scan and go manual, and then can you resume the automated scan? Can you call for multiple re-scans, or do you have to guess that before the first scan? How easy is it to edit the support files (antenna factors, etc)? How many support files can you use at one time (separate files for an antenna, cable, pre-amp, band-pass filter)? For susceptibility testing, how does the software control the field strength? Does it use real-time monitoring, or a level look-up table? How does the software allow for various modulations (CW, 80% AM, 50% square pulse, other PRR's and durations)? Can an automated scan be paused during a scan, allowing full and easy manual control, and then have the automated scan continued? For all software, find out how open the code is. Are you locked out of the code? For instance, could you prove the dwell times of a frequency stepped scan? What would you have to do if you wanted to buy some new hardware and control it with your existing software? Are data files archived in a format compatible with export to MS Word and Excel? Can support files be edited on a PC and loaded into the test computer, or must you use the test computer to perform all support functions (software support time can cut into operational availability)? For my testing, I have highly automated the emission testing, while deliberately keeping the susceptibility automation to a minimum. I only want my emission software to gather, present and archive the data; I don't want it to even attempt to create reports. I only want my susceptibility software to handle the drudge part of the work; I still want to be in close control of what's happening throughout a scan. In my opinion, complete lab automation is not yet achievable (or even desirable). I think the best way is to separately address the functions of emission and immunity, and apply sufficient automation to assist, but not replace, the EMC engineer. Certainly, my opinions are somewhat biased being based primarily on military testing. However, I become suspicious of highly automated EMC operations; the smoother it looks on the surface, the more likely there's a ground loop (or some other fascinating surprise). Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Low Loss Coax Cable
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Kunde, Brian Sent: Tuesday, July 15, 2008 1:20 PM To: emc-p...@ieee.org Subject: Low Loss Coax Cable What coax cable types do you recommend for a very low loss cable up to 6Ghz but also flexible? I need a good low loss cable to connect between my horn antenna and the floor connection of my Heliax. The cable only needs to be 5 or 6 feet long but flexible enough so I can change polarization on my antenna. I have looked at many cable types in catalogs and on-line but you cannot tell if it will be flexible without seeing it for real. I ordered a cable called “Helical Super Flex”. I liked the low loss properties but it was not at all flexible, let alone super flexible. It was barely semi-rigid in my book . I tried RG393/U but it is not very flexible and I prefer a lower loss cable if possible. What do you all recommend? What is the best? Where can I buy it in small quantities and possibly in custom lengths? Thanks to all in advance. The Other Brian Brian: I use United Microwave Type 190 coax cable; see: http://www.unitedmicrowave.com/52.gif This stuff is rated at about 20 dB/100 feet, and is reasonably flexible. I use it up to 18 GHz. The only negatives are that: 1. It won't handle more than about 10 watts in the upper GHz region. 2. It is not the toughest cable; don't step on it. 3. The factory attaches the connectors, so you can't buy in bulk and make your own custom lengths. You will find that the factory delivers quickly, that the cable works very well, and the cost is less than 10% of what a Gore cable would cost. For instance, a single piece, 24 cable, with SMA's on each end, costs about $80. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Power Spectral Density Measurement
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Grace Lin Sent: Friday, June 27, 2008 7:01 AM To: emc-p...@ieee.org Subject: Re: Power Spectral Density Measurement Dear Members, Thank you very much to those whe have commented. FYI. We found out the data discrepancy was caused by a test fixture/board (support test commands to set up channels and power level) and the length of power lead (from EUT to DC power supply). Best regards, Grace It's a bit difficult to understand how the length of the power cable affected the transmitter coaxial output port power spectral density? Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Mode Tuned RS?
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Cortland Richmond Sent: Tuesday, July 01, 2008 6:11 AM To: emc-p...@ieee.org Cc: cortland.richm...@ge.com Subject: Mode Tuned RS? I have a need to do DO-160/ED14 RS testing of a system with fairly large component EUT's. It seemed to me that the best way to do this is in a mode-tuned chamber, but there seems a paucity of such in the field, and those I've found so far seem too small for the system I wish to test. Have any of our group a recommendation where to look? Cortland KA5 I think that General Dynamics in Tucson has a decent drive-in chamber. Also, the US Army at White Sands Missile Range and the US Navy at Patuxent River. OTOH, maybe you don't need a chamber quite that big? Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: MIL-STD 461 vs. DSTAN 59-41
About three years ago, I made a short table that lists the additional requirements of DF 59-41 beyond 461E. It's not up to date, what with DF 59-411 461F existing now, but it still might be of some interest. I have already sent a copy to Dave, but I will provide a copy to anyone else who would like it. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Lab Rat Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of david.cole...@selex-comms.com Sent: Tuesday, July 01, 2008 8:07 AM To: Barker, Neil; 'Powell, Doug'; emc-p...@ieee.org Subject: RE: MIL-STD 461 vs. DSTAN 59-41 Thanks guys, but the question was not where can I get copies of these standards?, but a request for a technical comparison of the limits / levels / methods embodied within them. Which as you can appreciate, is no small task. So not wishing to possibly re-invent the wheel, I posed the question as I did. Best Regards, Dave Coleman AIIRSM SELEX Communications - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
HIRF Risk
I have had a fair amount of experience in making sure that military systems can meet the MIL-STD-461 RS103 requirement of 200 V/M. However, we are now seeing system requirements for levels from MIL-STD-464 (and other places). These new requirements invoke immunity to levels such as 8 GHz to 10 GHz at 21,000 V/M (peak pulse). I would like to get an idea of the amount of risk involved in going to that next level. Has anyone had any experiences with meeting the 461 200 V/M and then trying for the 464 levels? Does equipment that meets 461 usually meet those 464 levels? If not, what kind of failures do you see (cable arcing, internal component destruction)? Thanks in advance! Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: HIRF Risk
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Tuesday, July 01, 2008 10:18 AM To: emc-p...@ieee.org Subject: Re: HIRF Risk In message c48fcc88.204d4%ken.ja...@emccompliance.com, dated Tue, 1 Jul 2008, Ken Javor ken.ja...@emccompliance.com writes: Recall that coupling efficiency to circuits decreases with increasing frequency. 21,000 V/m at 10 GHz couples the same level as 2100 V/m at 1 GHz, which is like 210 V/m at 100 MHz. But then you need to look at modulation. Usually these high field intensities occur at short pulsed, low duty cycle modulations. For these types of tests, you are usually looking at flight critical equipment only. Eliminating bird-strike by cooking the fowls at 100 m range? (;-) -- That's an interesting marketing claim; we guaranty always hot pizza delivery. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: like your eggs raw /// mobile phone safety
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Tang, George Sent: Wednesday, June 18, 2008 5:40 PM To: Reginald Henry; dw...@atcb.com; James, Chris; emc-p...@ieee.org Subject: RE: like your eggs raw /// mobile phone safety Let’s see….. The popcorn package label says “Place bag in a 1000 watt microwave oven. Set power level to HIGH. Cook for 5 minutes……” When you take the popcorn out of the oven, it is HOT and it BURNS your finger to touch the popcorn. If you believe the power through this COLD RESISTOR can cook a popcorn, then I have a Golden Gate Bridge to sell you. Of course, what long term side effects cell phone has on the human body (ringing in ear due to one sided hearing, muscle cramps in the arm and neck, poor brain development in young children due to concentration to sound coming from only one ear, hormonal imbalance due to lack of exercise….) is unknown to people. But cooking popcorn with a cell phone radiated power is ridiculous. George My oven does the MIL STD popcorn bag in just a few seconds over 3 minutes. g I hate to guess the ratio of viewers of that video who analyzed the conditions (antenna direction, underlying physics) to those who now know they have proof that cell phones are more dangerous than ever. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Epoxy Bonding
On 16 Jun 2008 at 8:48, Price, Edward wrote: I'm curious about the effect of using a gold (or silver) loaded epoxy to bond a connector shell to a chassis box. If I measured a bond resistance of about 1 Ohm from the connector shell to the chassis, how could I estimate the degradation in shielding effectiveness (frequency range of interest is about 10 kHz to 5 MHz)? Maybe this has been thoroughly covered in some past Symposium papers. Can anyone give me a hint about where to look? Of course, absolutely definitive answers, which allow me to remain lazy, are also quite acceptable. Thanks in advance! Ed Price Ed, My first question is the degradation in shielding effectiveness compared to what? If you are comparing the conductive epoxy to a screw-fastened connection you need to know the exact resistance of both shield paths. I think if you took a good four-wire resistance measurement box-to-box for a typical cable length you could get a good comparison of relative resistance. If one construction had 5% higher total resistance the degradation would be at least 5% at the lower frequencies. Scott B. Lacey Scott: For a standard of comparison, maybe I could use the definition of a good conductive joint as one being less than 0.0025 Ohms. If I assume that the radiated leakage is proportional to the joint resistance, then a 1 Ohm value is 400 times higher than a good joint. That would imply that the leakage would be 52 dB greater than the good joint cable. Naahh, can't be that simple! Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Epoxy Bonding
I'm curious about the effect of using a gold (or silver) loaded epoxy to bond a connector shell to a chassis box. If I measured a bond resistance of about 1 Ohm from the connector shell to the chassis, how could I estimate the degradation in shielding effectiveness (frequency range of interest is about 10 kHz to 5 MHz)? Maybe this has been thoroughly covered in some past Symposium papers. Can anyone give me a hint about where to look? Of course, absolutely definitive answers, which allow me to remain lazy, are also quite acceptable. Thanks in advance! Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
GPS Signal Simulator
Would anyone know of a source for a GPS signal simulator test set? I would like to be able to simulate the L1 and L2 RF signals from several satellites so as to be able to evaluate the performance of a GPS receiver. So far, I have found only two vendors: Spirent and CAST. Seems like with so many manufacturers of GPS receivers, there must be more than a few makers of GPS signal sources. Thanks in advance! Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: FCC Immunity Requirements
This message has been converted via the evaluation version of Transend Migrator. Use beyond the trial period specified in your Software Evaluation Agreement is prohibited. Please contact Transend Corporation at (650) 324-5370 or sales.i...@transend.com to obtain a license suitable for use in a production environment. Thank you. br -br From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Grace Lin Sent: Friday, May 02, 2008 5:12 AM To: emc-p...@ieee.org Subject: Re: FCC Immunity Requirements Ian, Years ago, I had an oppotunity to ask an FCC officer this question at the FCC booth during an IEEE symposium. The officer told me FCC cares if a product produces high emission to the public. It is not FCC's resposibility for a product that doesn't work properly in a noisy environment. For this reason, FCC is not likely to post any immunity requirement on unintentional radiators. Please note Bob's and Ted's comments. Last March, I had an oppotunity to sit with an EU policy maker for a dinner. I expressed FCC's position about immunity requriement. He agreed with it. However, it maybe not easy to withdraw the immunity requriements from the EMC Directive. For manufacturers, it is not a big deal to meet both emission and immunity requriements (since EU requirements are self declaration). However, if other countries follow up and post in-country testing requriements, this would be a big issue for manufactrurers. Sincerely, Grace Grace: I think that the general lack of immunity requirements in the USA originates from a traditional basis. The US has long controlled emitters (intentional unintentional), but has never assumed any right of good reception. (Uhh, let's not get into encrypted and cell phone emissions right now.) OTOH, Europe has licensed receivers, and thus has an obligation to ensure a certain quality of service to those licensed users. The argument was made that the US market would reject poorly performing consumer equipment with lousy immunity, and that regulatory control was an unnecessary intrusion on that market. That logic carried the day for a long time, regardless of what you think of it's truth. However, the US market has become just about as regulation-controlled as the European market, so I expect that someday we will see immunity standards imposed on US consumer electronics. (Since many products sold in the US market are already compliant with EN, there is a de facto immunity requirement already in place. g) Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
