April 18, 2001
Dear Art:
I'm a retired EMC engineer but have always had a great interest in field-wire coupling and have also implemented A. Smith's formulas into a series of BASIC programs when I was at Boeing. At this time, I also verified these by use of MOM codes. If your program were available, I would very much enjoy examining it, as you appear to have gone further than I in providing a good user interface.
I am surprised that so few young engineers appear to be involved with writing their own programs for applications like these. There was always a great deal of satisfaction for me in creating standalone programs to solve things like field-wire, wire-field and cable-cable coupling problems and today the expectations seem to be considerably different. It was always my opinion that if you don't really understand the methods used by an analytical program, the results are likely to be misleading. Nowadays with the widespread use of composites, it's a lot more difficult to apply the old formulas with confidence. I'd be interested to hear how you approach these kinds of problems.
Best wishes,
Roger Modeen
Senior EMC Consultant,
Kistler Aerospace
modeen@qwest.net
Editor's Note: This letter was sent to Art Glazar, author of the practical paper titled "A Software Implementation of TL Field-to-Cable Coupling Equations" which appeared in the Fall 2000 Newsletter. Mr. Glazar offered the software to readers who contacted him at aglazar@ieee.org. This practical paper generated the most correspondence to date to the Newsletter. Readers from all over the world requested this software. In response to Mr. Modeen's letter, Mr. Glazar advised that he had forwarded a copy of the software to Al Smith and he was very pleased. In his reply to Mr. Modeen, Mr. Glazar speculated that perhaps today's engineers have ready access to programs like MATHCAD, so that analytical solutions are easier to obtain than by programming.
May 3, 2001
Todd,
I have kept the most recent EMC Newsletter open at my desk with the box on Signal Return visible. I adopted the idea when talking to people over here about "signal ground." I really believe that this kind of clear definition helps a lot when dealing with different problems. In our department we also deal with power issues and then we of course use the notation of return current. In addition, one of the things I still remember from the textbook on electromagnetism we used at University 35 years ago is (my translation): "Currents of any significant magnitude only occur in closed loops." Please also forward to those concerned that I enjoy reading the Newsletter.
Best regards,
Arne Wallers, Senior Specialist Physical Properties Division Multi Service Networks,
Access Networks
Infrastructure and Product Approvals
Ericsson Telecom AB, Stockholm
Telephone: +46 8 719 6636, Sweden Cellular: +46 70 519 6636
Email: Arne.Wallers@ericsson.com
Editor's Note: This letter was sent in response to Todd Hubing's Chapter Chatter column that appeared in the Winter 2001 issue. This column included the popular "Tom Van Doren Song" and a discussion on "Signal Ground vs. Signal Return."
June 29, 2001
Dear Editor:
Todd Hubing requested that I send the Chapter Chatter input to you until you appoint his successor. I have been dealing with the Central New England (CNE) Chapter input since the mid 70s. As you know, Charlie Anderson was the Chapter Chatter Editor until Todd replaced him about nine years ago.
Sincerely,
John Clarke
jclarke805@mediaone.net
Editor's Note: We wish to acknowledge and commend Mr. Clarke for his contributions to the Newsletter over the past two decades.
June 11, 2001
Dear Editor:
I found the article on the cover of the last Newsletter (Spring 2001) of particular interest, especially since I have been involved in EMI signal measurement for over 40 years. Frankly, I also found the article to be rather amusing, since solutions to the problems discussed have been resolved and published years ago. It sort of reminds me of the joke about the conversion from cycles to Hertz.
The so-called beyond 1 GHz problem has in fact existed from 30 MHz, but no one in the EMC community wants to admit it. Thus, my reference to the cycle/Hertz conversion. Although there is ample reference to measurement uncertainty, such uncertainty applies only to signals that have been detected and can thus be measured. The real problem is one of omission, not detecting signals. There is ample evidence of the existence of this problem but, as I said, it is being ignored. However, as frequencies increase above 1 GHz, the beam width of DUT radiated signals can and does become much narrower. This exacerbates the already existing problem, thus the sudden realization that the problem exists. Fortunately, my paper "A Theory to Optimize the Detection of EMI Signal Measurement" published in the November 1989 issue of the IEEE Transactions on EMC, addresses, as the title suggests, the problem of EMI signal detection. The paper shows, among other things, that the problem is frequency independent. Most importantly, it provides the basis for a solution to the error of omission. In brief, the paper concludes that in the general case where the probability of detection is unknown, the only available solution to increase the probability of detection is to take a large number of sweeps. This, by the way, is why the solution lies with the use of a spectrum analyzer using a max hold positive peak detector function. There is still a need to provide measurement procedures to a total solution. Such procedures could be frequency dependent, since as I have said the problem becomes more severe at higher frequencies. It may be of further interest that the above referenced theory has been incorporated in the EMI Commercial Measurement Program, EMICMP, which is currently available for Anritsu spectrum analyzers. These programs provide a method of increasing the probability of signal detection, a method to optimize the measurement of individual signals, and an option to include measurement uncertainty in the measured data.
Anyway, the one thing I did not find in the article was an address for the author, Mr. Windler. My intention is to provide him with the solution to most of these problems.
Roger Southwick
rasouthwick@zianet.com
Editor's Note: This letter from Mr. Southwick was sent to the Newsletter and also on to Mr. Windler once his e-mail address was provided. Mr. Windler subsequently provided the following reply.
July 9, 2001
Hi Roger,
Thanks very much for your input. The symposium presentations were not covering "new ground" per se and were not advertised as new. Our standards are in need of updating in this area. The purpose of the special session Mr. Heirman organized was to review the status of the standards changes being developed and the issues to be addressed. I am the chairperson of one such activity. ANSI Accredited Standards Committee C63, Subcommittee 1, Working Group 1-13.2 is drafting requirements for test sites making measurements above 1 GHz. We would welcome your joining our working group if you are interested. I will try to find the paper you referred to in the IEEE archives. If you can, send a copy for me to share with the ANSI Working Group at next week's meeting.
Thanks again for your input.
Michael J. Windler, PE
Underwriters Laboratories, Inc.
International EMC & NEBS Services
E-mail: Michael.J.Windler@us.ul.com
July 1, 2001
Dear Editor,
I wish to comment upon Peter Staecker's article in the Spring 2001 EMC Society Newsletter. I've been an IEEE member for over 30 years and a very active EMC Society member for over 15 years. I served on our EMC Society's Board of Directors for much of that time. I was Society Treasurer from 1986 until 1994. I participated in formal IEEE administrative/financial training for two consecutive years. I've never met Peter, though I recall voting for him. Today, just prior to writing this, I had a fairly lengthy discussion with him regarding his article. I believe, after this discussion with him, that we agree on much more than we disagree. But having said that, his article still very much upsets me. Why?
I think the key issue is best illustrated by the lead sentence in his concluding remarks: "First, deficit budgeting is part of a plan to increase the value of our products and services to members, while remaining competitive in the marketplace." This statement can be interpreted differently from what I believe he meant: Increasing value by artificially pricing it. IEEE corporate decides to grow by pricing some new, or enlarged product line at an artificially low (subsidized) price. One possible example: I have IEEE insurance. I'm very happy with it. But a question: Is my insurance priced such that the total cost to IEEE of running this program is covered? After all, is it fair to require members, who don't want insurance, to pay for infrastructure costs to support my getting cheap insurance? What about our recent experience with book publishing? Our "closing" of our book-publishing endeavor seems to indicate that IEEE seriously underestimated the cost of publishing. Another example: Several years ago, IEEE artificially lowered their production/printing costs. They admitted that they did this to encourage Societies to have IEEE produce their newsletter. The tax paying, private firm we had been using was not able to compete with this artificially low price. We switched to IEEE. Now our Society seems committed to IEEE, though there is some question as to whether IEEE is competitive. Yes, our Newsletter is better than ever, but I wonder if it is only due to the volunteer editor's hard work and improved technology. Some Newsletter issues have been late and errors have been made in production. I could give a couple more examples, but I hope my point is made.
IEEE employees are very good people. I work closely with a number of them. It is not the individual's performance that I address. As Parkinson so eloquently described some 50 years ago, people systems constantly seek to grow (at a predictable rate of about 5% annually, I recall). Restraining and/or channeling that "need to grow" is a management job. Our Institute is a very complicated organization of Regions and Societies with Chapters and Sections with an equally complicated governance process. This complexity tends to disenfranchise the true customers (the average IEEE members). Anything that dis-empowers or alienates customers usually fosters bad management.
Cordially,
Richard (Dick) Ford
EMC4D@aol.com
July 10, 2001
Dear Editor:
In reference to Peter Staecker's article "Comments on the IEEE Fiscal State of Affairs", I am left with serious apprehension that the IEEE will never recover financially while it's on the path he has described. Mr. Staecker failed to mention that the IEEE was intending to tax the EMC Society over $100,000 per year to cover their shortfall, and probably are taxing many other groups and Societies 12% of their net assets, in order to cover their deficit budget. This, of course, limits the benefits that the Society can provide to its members. What I would like to have read is that the IEEE is re-organizing, changing some of the old guard, and restructuring "our business" just like any company of similar size in industry would do. They should be frequently revisiting their budget for 2001 and making additional cuts as necessary. If a comparable private company had a corporate infrastructure deficit of about 30 million dollars and a net loss of about 11 million dollars, there would be major changes in personnel, structure and policy. Unless there are significant attitude and other changes made, I fear for the viability of the insurance and other benefits which makes membership in the IEEE so worthwhile.
Sincerely,
Robert D Goldblum
IEEE Life Fellow
rgoldblum@RBitem.com
EMC