hurrumph, I'd never admit to modifying some accessory equipment, I'd get the other guy to do it. Now where did I put those spring fingers and Cu tape?? He's going to need them.
- Bill Indecision may or may not be the problem. --- On Wed, 4/22/09, Conway, Patrick R (bNB Houston) <[email protected]> wrote: From: Conway, Patrick R (bNB Houston) <[email protected]> Subject: RE: [PSES] SV: "Quiet" Laptop To: "Price, Edward" <[email protected]>, "[email protected]" <[email protected]>, "E. Robert Bonsen" <[email protected]> Cc: "Brent G DeWitt" <[email protected]>, "[email protected]" <[email protected]> Date: Wednesday, April 22, 2009, 2:14 PM Ed- You make some good points. Most notably, that in your world the laptop is chosen based on functional performance, but is then used for EMC testing. Sounds like a common problem. Sort of like buying a Yugo because it is cheap, and then using it to haul rocks in a granite mine. Someone is wanting to do some heavy lifting with that low-cost COTS hardware – most likely they will be unhappy somewhere down the road. (am I mixing metaphors?) Professionally, I would never recommend an ITE product be placed next to analyzers/receivers, etc., and that goes for any ITE: desktop, laptop, server, monitor, modem, music player, etc. I also don’t recommend placing a cell phone in a shirt pocket if you have an implanted defibrillator. In both cases I know there will have been extensive testing to show coexistence is possible, but why take the chance! I expect that there are a lot of people in your position: not getting much choice in the selection of the support hardware. But, is the solution to pass the responsibility for the problem over to the COTS ITE manufacturers? Educating the purchaser may get better results. Better yet, why not take a COTS laptop and modify it up to the levels you need? Screws on the back of the laptop make it easy to disassemble. And I doubt anyone on this list requires much instigation to start taking things apart!! If engineers in the Mil world can upgrade their own hardware, then they will always have a “quiet laptop”. I wonder if anyone has stories having done this? Interesting suggestion on publishing compliance data. Could be a possibility in the future. In the EU we already publish acoustic noise data, power consumption data, and others. Maybe EMC compliance data will be next. Stay tuned… Best Regards, Patrick. [email protected] <http://us.mc01g.mail.yahoo.com/mc/[email protected]> 281-514-2259 From: Price, Edward [mailto:[email protected]] Sent: Wednesday, April 22, 2009 12:16 PM To: Conway, Patrick R (bNB Houston); [email protected]; E. Robert Bonsen Cc: Brent G DeWitt; [email protected] Subject: RE: [PSES] SV: "Quiet" Laptop Importance: High Pat: Almost every military product that I test needs support equipment to make it function. I may have to create external signals, monitor operation, send commands, log data or command other support equipment. Laptops have become the controller of choice for exercising the military hardware during development and test phases. The laptops are not just running software, they are intimately (for me, usually way too intimately) connected to the military hardware by USB, Ethernet and serial busses. Even worse, the laptop is usually placed right next to a big collection of commercial test equipment (spectrum / modulation / network analyzers, power supplies, signal sources), consumer media equipment (we use video discs to stream dummy data through the military hardware) and a junkbox of non-deliverable switchboxes, hubs, patch cords and blinky lights. You see, I'm not testing the laptops, but they are electrically present in my real test environment. I want the laptops to be as quiet as possible, and as immune as possible. OTOH, I have to work with what a program brings me, and the programs don't really ask me about which laptops to buy. And, as our discussion has shown, there is no publicly available data about EMC quality for typical commercial laptops. It's great that an "insider" speaks up to offer help, but my point was about availability of data and how that might affect a buyer's choice. Getting back to my own preferences, I suppose it's a question of how good is good enough? I'm always looking to use less lossy coax, or find a microwave pre-amp with a 0.7 dB noise figure. If I was selecting a laptop for my lab, or recommending one, I would like to be able to choose the best EMC performance I could find (and afford). Of course I recognize that I represent a very small and stingy market, so I don't expect laptop manufacturers to worry too much about me. However, I still would like to be able to see compliance data, not just a statement, at a manufacturer's site. Some manufacturers do things just for good customer relations, or brand image. For instance, Agilent maintains a site where you can download service manuals for many totally obsolete HP equipments. A company that thinks like that may just well see the value in showing the real EMC performance of their products. Hint! <g> Ed Price [email protected] 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: Conway, Patrick R (bNB Houston) [mailto:[email protected]] Sent: Wednesday, April 22, 2009 7:27 AM To: [email protected]; 'E. Robert Bonsen' Cc: 'Brent G DeWitt'; Price, Edward; [email protected] Subject: RE: [PSES] SV: "Quiet" Laptop Last week I offered my “professional assistance” to help find quiet laptops. Now I will offer my (less) helpful “philosophical assistance”… Is our community too close to this topic to see it clearly? Is it the “Can’t see the forest for the trees” phenomena? For instance- when was the last time we had a wide spread EMC problem in the consumer electronics community? We all know of “little” problems, but when was the last time there was a pervasive problem? Our community, and the EMC Professionals that came before us, should take credit for this achievement. Same goes for laptops- They are designed, built and manufactured to run software. As an EMC professional I agree that there there is value in owning a laptop that never, ever looses it’s EMC performance. But where do I buy one? We build a good product (pick one), it performs to spec, and customers are happy. We should be happy, but alas, we are too close to the topic. We know it could perform better if only… Best- Patrick. OOO- and for amusement purposes only! - ---------------------------------------------------------------- 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
