Hi Derek - Go Reds!! This is not a surprise to me. I have railed at much length a couple of years ago as to the latest FCC changes to the emissions qualification. I am sure you are familiar with it so I won't belabour the point. Fundementally the FCC PC emissions procedure has rendered the EMC discipline almost irrelevent. The new procedures coupled with the lack of enfocement makes it difficult to justify the increased costs of EMC design & test. It also makes the whole measurement uncertainty push ridiculous. After all if the procedures allow for prodcut that 20dB out of spec why bother with a couple of dB of error?? Lets give the emissions standards some teeth or eliminate it all together. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; <mailto:charles.gra...@echostar.com; > Email Alternate: chasgra...@ieee.org
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, March 25, 2003 1:05 PM To: emc-p...@majordomo.ieee.org Subject: OK, what's going on? Hi all, This e-mail has been prompted because of a number of things that have all come together. This may take a little reading, but please stick with it. Last note... this is not intended to pick on any individuals, or organization, but I do want to stir the pot. I operate an engineering lab, helping clients harden their designs to meet EMC requirements. In this particular instance, I was working for a small client, on a card that goes in the PC . In order to test I need a host PC. So, to save money, the card maker supplies 2 clones. Neither of the two PCs passed emissions testing with the card, in fact, above 100 MHz, they fail even the Class A limit: badly! So, before calling my client, I pull his card, the PC is no different, I pull the monitor, then the keyboard, then the mouse... No different. I test just the PC chassis one at a time. On their own, booted and then the peripherals removed. Not even close to passing. Disgruntled, I get my office PC... Fail. I get my kids PC.. over 20 dB over the limit! So, I think so much for clones... I buy 2 Dell ( sorry, no point trying to hide names... ) desktops, both fail, quite badly. However, they have very similar noise profiles... Can 5 PC's all fail? I think my measuring system is set -up wrong. So I verify this. I am within 1 dB of what I expect when I inject a signal from a signal generator and account for antenna factors. Here lies the question: why can I not find a PC that passes? Worse, since they don't pass, who is chasing them down to enforce the requirements? I'm unhappy, because I am taking a clients money to make him meet the requirements, when it seems no one else is. Now, what's making this worse for me, is that I am an EMC Lab assessor. So, I go to labs and make them jump through hoops so that they produce, as consistently as possible, data the characterizes a product. Exercises, like those performed by USCEL, show that labs can have very consistent results. Anyone that stands up and says EMC is not a field where consistency can be achieved, should not be in the compliance business: please close your lab. So if the test are consistent, why the HUGE variations? In the 20+ labs I have assessed, I feel that almost every one had an ethical approach. Ironically, I felt that the bigger companies I visited like HP and Intel were exceptional: both ethically and technically. The rest of the labs were between good to very good. So cheating is unlikely.. I have now spent about 60 man-hours looking for a PC that passes FCC Class B emissions. Something that I should just be able to go to the store and get. As yet, I have no PC. Our field, it appears, is not a level playing field. It appears more like a rugby game in which we have no referee! So why are there no fines being levied? Especially since it seems I can find non-compliant products everywhere! Is the self policing approach out of control? I intend to take this up with the FCC. Is there anyone out there that is supportive of this action ( which means you must be doing things right.. )? Am I wasting my time ( in which case if this is all lip service... why should we even test!!!! )? Or am I missing something ( I listen to 2 by 4's )? Derek Walton Owner of an EMC Lab EMC Lab Assessor NARTE EMC Engineer 30 years of EMC experience
