RE: Ethernet Decoupling
_ From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Tuesday, February 28, 2006 6:22 AM To: emc-p...@ieee.org Subject: Ethernet Decoupling I have a twisted-pair Ethernet receive and a twisted-pair Ethernet transmit set of 4 wires penetrating what would otherwise be a shielded box. Internal box noise, as low as 35 MHz, is getting out along this path. I put a 4700 pF feedthrough capacitor on each of the four lines. That worked pretty well, so well that the Ethernet shut down. Does anyone have a guideline about how much capacitance, L-L L-G, that is typically OK? I want to thank everyone for the many instructive comments and tips about Ethernet problems! It's obvious that Ethernet interfaces must give commercial compliance engineers a lot of grief. In my case, I had the advantage of machined aluminum equipment cases, shielded interface cables that looked like small fire hoses, and MIL-grade multi-pin circular connectors that cost as much as your mortgage payment. So, what went wrong? It all came down to a bad wiring practice by a sub-module vendor; they routed the 4 Ethernet wires, and the cable shield, through the pins of several connectors. Even worse, they didn't ground the shields at each connector. As a result, Ethernet data was coupling onto all the other wires in those connectors, as well as getting onto the outside of the Ethernet cable shield. A few changes got us a 35 dB reduction of the 100 MHz noise. 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
RE: Question on RF conversion
-Original Message- From: drcuthb...@micron.com [ mailto:drcuthb...@micron.com] Sent: Thursday, January 13, 2005 7:01 AM To: lisa_cef...@mksinst.com; emc-p...@ieee.org Subject: RE: Question on RF conversion Lisa, Rather than giving you one formula I will give you an algorithm (easier for me to remember).Assuming that the Walkie Talkie is really radiating 5 watts and we have an isotropic antenna: 1) Chose a distance. Let's say the distance is 1 meter. This is far-field at 430 MHz. 2) The area of the 1 meter radius sphere is 4(PI)(r^2) = 12.6 square meters. 3) 5 watts covers the 12.6 sq meters. The power density per square meter is 5/12.6 = 0.4 watts/sq m. 4) Using P = (V^2)/R, solve for V which is V = (PR)^0.5. R is 377 ohms and P is 0.4 watts. 5) V = 12 volts/meter at 1 meter distance from the Walkie Talkie Assuming a dipole pattern the antenna gain is 2.1 dB and the E-field will be 15V/m at 1 meter. Dave Cuthbert Micron Technology Dave's image of the power propagating outward through the surface of a sphere is my favorite way of explaining why and how field strength (and power density) decays with distance. Most non-technical people can comprehend an antenna emitting a certain amount of power, and then, if you wave your arms around and get them to imagine a big sphere around that antenna, then they can grasp that all the antenna's power has to pass through the surface of that sphere. If they imagine the radiating power to be like suffused light, shining equally strong in all directions, you have just given them the model of an isotropic radiator. Now, if you tell them that the antenna has the ability to move, or focus the radiating power, robbing some directions, and concentrating the energy in a certain direction, you have just moved them to the concept of directional gain. The next step may need a piece of paper. Remember how all the RF power radiates out from the point source of the antenna in the center of the sphere? The power passing through a unit area (like one square meter) spreads as it moves outward, passing through an infinite number of imaginary spheres. If you think of a second sphere, at double the first sphere's radius, then the radiating wave has to spread out to double the surface length on that second sphere. But since the wave still has the same power, that power is now stretched over double the distance. (In 2 dimensions, this can represent the E or H field strengths. How about that, double the distance, half the field strength. That's 1/r! In 3 dimensions, the area of sphere 2 is 4 times the area of sphere 1, so the same power is spread over an area that's now four times larger. And how about that, double the distance, and you get 1/4 the power density. That's 1/rr!) So with just a little geometry and some arm waving, you can show a lot about RF propagation. Ed 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/listserv/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 Mcantwell mcantw...@ieee.org For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Question on RF conversion
-Original Message- From: Pettit, Ghery [ mailto:ghery.pet...@intel.com] Sent: Thursday, January 13, 2005 8:14 AM To: lisa_cef...@mksinst.com; emc-p...@ieee.org Subject: RE: Question on RF conversion Lisa, That depends on the gain and efficiency of the antenna. However, for a single data point I measured an old amateur radio HT (Yaesu FT-727R) a number of years ago on both the 2 meter (144-148 MHz) and 70 cm (440-450 MHz) bands in a 10 meter RF semi-anechoic chamber. The HT was placed on an 80 cm high non-conducting table. I connected a speaker-mic so I could lock key the radio for the measurements. On both bands, at a distance of 10 meters, the measured field strength was 1 V/m. If one believes 1/R, then the field strength at 1 meter would have been 10 V/m. Just a data point for the discussion. Ghery S. Pettit, N6TPT Intel Corporation I can second Ghery's observations on personal electronic emitters. I spent some time standing on rapid transit platforms in the SF Bay area, measuring the station RF ambient. I set up my antennas about 2 meters to the side of the faregates, and the highest observed emissions came from cell phones, PCS phones, ham radios, and police handy-talkies. This was certainly not far-field conditions, as the passengers often crowded the area, the faregates were big slabs of stainless steel, and some of the stations were underground. Despite a frequency range of 150 MHz to almost 2 GHz, these passenger-carried devices created field strengths of about 5 to 10 V/M at 2 meters distance. Ed 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/listserv/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 Mcantwell mcantw...@ieee.org For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 400 Hz filter
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Thursday, November 27, 2003 6:55 PM To: emc-p...@ieee.org Subject: 400 Hz filter Hi All, looking for a filter for a shield room. Needs to be 400 Hz capable, and good for 230 Vac if possible. Anything above 30 Amps would be good. Anyone have one lying about on the shelf? Thanks, Derek N. Walton Owner, L F Research EMI Design and Test Facility Poplar Grove, IL 61065 Derek: When you say 400 Hz capable, it sounds like you intend to use it with other power frequencies (DC, 50 Hz, 60 Hz) as well as 400 Hz. Remember that at 400 Hz, the capacitive line current may be very significant (10 amps), and the usual remedy for this is a power factor correction coil for each filter line. (The inductive reactance is adjusted to match the capacitive reactance, creating a parallel resonant tank circuit. Line current will drop significantly.) If you use the filter just for 400 Hz, you can leave the PF coils permanently connected. OTOH, if you use it for 60 Hz (or lower), then you might want to make the coil switchable, so you can disconnect it. Regards, Ed 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
RE: Seminars
-Original Message- From: richwo...@tycoint.com [ mailto:richwo...@tycoint.com] Sent: Tuesday, November 18, 2003 6:54 AM To: emc-p...@majordomo.ieee.org Subject: Seminars A senior level EMC test technician is seeking training to enable his eligibility for promotion to an entry level EMC Test Engineering position. One of the requirements of the new position is to write test plans based upon the type of EUT and its configurations. The types of EUTs include, ITE, motor operated equipment, CCTV and radio equipment; and testing is to FCC and CENELEC standards. Is anyone aware of any USA based seminars in the development of test plans? Richard Woods Sensormatic Electronics Tyco International Rich: A formal Test Plan is a normal requirement for a military contract (and a full-blown one can easily surpass 150 pages). After submission to the customer (typically a command procurement office), the document is reviewed EMC specialists, and the document is either accepted or returned for modifications. Once the Plan is approved, it becomes the guiding authority for subsequent acceptance testing. But the FCC CENELEC don't do that, so who needs the test plans? If the Plans are for internal Tyco use, then you at Tyco are in the best position to train someone to write them. Aside from a need to understand the operation of a new test article, a senior EMC test technician ought to already be able to write a test plan with ease. All that remains is to decide on the level of the document (Will you say a conducted emission measurement will be performed... or will you say Locate the xxx-xx BNC coax cable and connect one end to Jack ZZ on the 123-999 input panel, then.?) Beyond that, it's just elements of style; avoid the 3rd person passive, identify acronyms, keep the grammar to 10th grade or so. Pardon me, but the hierarchy sounds terribly rigid. BTW, if you want, I'll give you a sample TP. Regards, Ed 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
RE: Leakage at Enclosure Seams
-Original Message- From: Chris Maxwell [ mailto:chris.maxw...@nettest.com] Sent: Monday, November 17, 2003 8:03 AM To: Jeff Chambers; emc-p...@majordomo.ieee.org Subject: RE: Leakage at Enclosure Seams You may expect a small improvement because the overlap forms a weak capacitor, which will short circuit some high frequency currents across the gap. I really can't fathom a guess at how much improvement. It would be an interesting mathematical experiment to model the capacitance of the seam. Chris Maxwell | Design Engineer - Instruments Group email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From:owner-emc-p...@majordomo.ieee.org [SMTP:owner-emc-p...@majordomo.ieee.org] On Behalf Of Jeff Chambers Sent:Monday, November 17, 2003 10:22 AM To: emc-p...@majordomo.ieee.org Subject: Leakage at Enclosure Seams I have been asked to comment on what improvement might be expected in changing the design of an equipment lid from: A flat lid sat on the edges of the box, where the gaps between fasteners can be modelled as a simple aperture, where the attenuation decreases linearly with log(f) to zero at a half wavelength. To: A stepped lid, with the lid sat on the edges, and with the projection extending below the inner edge of the box.This removes the 'line of sight' gap into the enclosure. Does this improve the attenuation? Intuitively it should, but if the leakage occurs because of the interruption in shielding conductivity and hence current flow at the seam, it won't. Does anybody have any references to analyses of the above, or comments, please? (No emi gaskets are used btw). Thanks, Jeff Chambers -- Dr Jeff Chambers Westbay Technology Ltd Main St Baycliff Ulverston Cumbria LA12 9RN England Tel: 01229 869 108 Fax: 01229 869 108 http://www.westbay.ndirect.co.uk Jeff: If the radiation were leaking out by propagating through the seam gap, which would have to be very high GHz emissions, as the gap is small, then a more labyrinthine gap would help a bit. At lower frequencies, where the gap creates an impedance discontinuity, and the radiation is caused by current across the impedance, then I don't think the gap shape would matter very much. OTOH, even if my guess is right, somebody will want quantitative data, so test a couple of cover gaps yourself. Regards, Ed 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
Legal Precedents
There are many times where one of my colleagues has suggested that the cause of regulatory compliance could be hastened by citing an appropriate legal horror story to management (aka The Bean Counters). In one of my less stable moments, I suggested that there ought to be a collection of court transcripts, or at least synopses, of court cases which could dramatically illustrate the ramifications of cutting corners on the compliance effort. I have been reminded that there is a British site (is it Nutwood's Compliance Club?) that does just that, under the title of Banana Peels. Is there any similar site that has a corresponding American theme (as our lawyers might not be sufficiently frightened by British case law)? Regards, Ed 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
RE: Product Certify For Airline Usage
-Original Message- From: LIM,JAMES-CH (HP-Singapore,ex6) [ mailto:james-ch@hp.com] Sent: Sunday, November 16, 2003 7:07 PM To: IEEE EMC/Product Safety (IEEE, EMC/Product Safety) Cc: LIM,JAMES-CH (HP-Singapore,ex6) Subject: Product Certify For Airline Usage Hi, We have some enquiry regarding what is the requirement needed how to get a product certify for airline usage. Your inputs advises will be much appreciated. Thanks in advance! Best Regards, James Lim CH Engineer, Product Safety Tel: (65) 6824 3516 Fax: (65) 6273 7429 / (65) 6273 8736 James: As a start, look at DO-160 for an idea of what USA commercial aviation would require. Beyond this, you need to define what your product is, what it does, and where it goes. There are standards for a vast number of characteristics, even down to the seat power jacks or the in-flight entertainment systems. Ed 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
RE: Grounding
-Original Message- From: Gary McInturff [ mailto:gmcintu...@spraycool.com] Sent: Friday, November 14, 2003 10:46 AM To: 'Crabb, John'; Ned Devine; IEEE EMC/Product Safety (IEEE, EMC/Product Safety) Subject: RE: Grounding John, You are correct, but you have just presented the conundrum of the thread. Reliably grounded can be determined through test - 25 or 30 amps for a minute. A new hinge will likely pass that test. A used one may likely fail because of the corrosion and wear discussed by others. So the conundrum is do you test to get through the standard or do you use the standard to help you design something which hopefully remains safe. Personally, I don't like hinges for grounds - PE or earth and for the very cost sensitive it can be a real issue with the management guys and bean counters. Gary FWIW, military practice doesn't allow grounding through a hinge. MIL-HANDBOOK-454A, Paragraph 4.5.2.2 says Ground connections to shields, hinges, and other mechanical parts should not be used to complete electrical circuits. It goes on to also say ...the ground should be continuous and permanent. Paragraph 4.5.2.3 specifically addresses hinged panels and doors, saying Hinges or slides should not be used for grounding paths. Panels and doors containing meters, switches, test points, etc., should be attached or hinged in such a manner as to insure that they are at the same ground potential as the equipment in which they are mounted, whether in a closed or open position. A ground should be considered satisfactory if the electrical connection between the door or panel and the system tie point exhibits a resistance of 0.1 ohm or less and has sufficient capacity to insure the reliable and immediate tripping of equipment over-current protection devices. Of course, this isn't a commercial requirement, but it defines what the military thinks is necessary to avoid problems. Ed 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
Equipment Calibration
In some ways, I have the luxury of having a Metrology Department that maintains the periodic calibration on all of my test equipment. OTOH, as a customer of this Metrology Department's product, I would like to have some control over my overhead costs. And my latest bright idea has me getting stomped by the gurus of the status quo. I need to get smarter about how a calibration system works, and how flexible it can be. My lab has about 500 pieces of capital equipment, and the way I see it, all my equipment falls into one of two categories. The first category consists of those instruments which are used to measure the parameters of our company's products, and determine if the performance of those products falls within a range of acceptable tolerance. Data from these measurements is often contractually reported to our customers. Every equipment within this category needs to be maintained on a program of periodic, traceable calibration. But then there's the second category; which consists of support and stimulus equipment. Items here are old analog signal generators, function generators, amplifiers, pulse generators, sweepers and power supplies. To me, none of this equipment needs ANY periodic calibration. I base this on practical usage. Who can accurately read a power supply mechanical 80-amp ammeter that has a 1.5 long scale? Who can set a function generator frequency control that covers 2 decades, logarithmically, in 270 degrees of rotation? If I need to apply a 100 kHz signal in bursts of 2 milliseconds at a 1 Hz rate, I'll use a calibrated, traceable oscilloscope to set the uncalibrated generator to exactly what I need. The same for that power supply; if I need to know the current to 2% or better, I'll use a calibrated resistor and a calibrated DMM. And I couldn't care less about the gain of an RF power amplifier, as long as it pumps out enough power to create the field I need. Now, I'm not trying to justify the use of distorted, unstable or junky equipment. I'm just trying to spend my calibration dollars the most efficient way. And the way I see it, about 1/4 of my equipment fits my definition of not needing periodic calibration because I can monitor the results with calibrated equipment. So I proposed that these items be tagged with some kind of uncalibrated or user verified or no calibration required label. The gurus of Metrology say this can't be done, our ISO9000 Quality System will not allow this. I can't understand how a customer-oriented quality system can't be crafted to meet the needs of all of the customers of that system. And I suppose I'm felling a bit squeezed, what with my customers expecting me to use COTS equipment to function in military environments. I have to get more out of what I have, and the old military concept of everything in sight is on periodic calibration has to yield to current reality. So, am I getting shoveled upon regarding the impossibility of having a category of officially non-calibrated equipment alongside my calibrated equipment? How have you dealt with calibration program costs? Regards, Ed 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
RE: RS-103 help
-Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Tuesday, November 04, 2003 4:03 PM To: Bill Stumpf; 'emc-p...@majordomo.ieee.org' Subject: Re: RS-103 help I am not sure if you are asking for specific equipment model numbers, or general guidance. I will leave the specifics to others. I would start with a high gain horn and a calculation of how far away the far field is developed (2D^2/wavelength). You can use the equation for power density as a function of gain, transmitted power and distance to figure out how much power you need at 1 meter or 2D^2/wavelength. Then you go looking for that TWT power amp. The reason for this approach is that those amps are expensive and hard to find. I don't know if you could rent one at all. If you could find a 1 Watt TWTA, that would work as long as you are satisfied with 2D^2/lambda and not aiming for 1 meter. Also the horn bolts directly to the TWTA waveguide output. You probably can't stand the loss of interconnect between signal generator and amp, unless you plumb the whole thing with rigid waveguide, which would be painful. I recommend the test operator be right in the room with the test sample. I bet I'll draw some flack for that, but that beam is so directional I wouldn't worry about it. If you are worried about it, build a bunker house out of spare foam absorber. Also if you are very close to the EUT there are a couple issues. One is VSWR, you don't want reflected power splashed back into the horn, so you cant the angle slightly (angle of incidence equals angle of reflection) so that the reflected beam is diverted from the horn aperture. A second issue is that with a small illumination spot size you have to have a lot of antenna positions to paint the entire test set-up. MIL-STD-5461E covers that. if you were going to do this all the time it would be worthwhile to plunk down $150K for the 40 Watt amp and get a lower gain horn back at 1 meter and spray the whole test set-up to save time. Like everything else, that decision comes down to time or money. From: Bill Stumpf bstu...@dlsemc.com Reply-To: Bill Stumpf bstu...@dlsemc.com Date: Tue, 4 Nov 2003 14:21:20 -0800 To: 'emc-p...@majordomo.ieee.org' emc-p...@majordomo.ieee.org Subject: RS-103 help Hello all. I need help locating equipment for rent that can achieve the following goals. RS-103 (MIL-STD-461E) testing from 18 GHz to 40 GHz @ 200V/m. If anyone could point me in the right direction I would be most grateful. Bill Stumpf William M Stumpf DLS Electronics 166 South Carter St. Genoa City WI 53128 ph: 262-279-0210 fx: 262-279-3630 email: bstu...@dlsemc.com Ken hits all the important points, so let me just amplify g on a few of them. I use a 20W TWT amplifier from 8GHz to 18GHz, with an EMCO 3115 double-ridged horn antenna. Since I only go up to 18GHz, I stay in coax. However, I mount the antenna to the coax output of the TWT, to minimize cable loss. I use a long coax (low-power rating, cheap, but very low loss, to run from my external signal generator to the TWT input. This makes best use of the available power, even if the amplifier is within the chamber. My amps are 20W Hughes (not available any more), but check out IFI and Amplifier Research. But once over 18GHz, the best way to go is waveguide. Build up a collection by watching eBay! And a couple of short sections of flex waveguide greatly simplifies your setups. If you have the time, you can easily build a pair (18GHz to 26GHz 26GHz to 40GHz) of pyramidal horns from a section of waveguide and a few sheets of copper (to make the flare). I think you might be able to do the job with 5W TWT's, but 10W units would give you a better margin. I'd guess amps would be in the $12,000 range. And you'll also need a signal source, and maybe PIN diode modulators. You might be able to find an old Gigatronix signal generator, with its external frequency doublers, on the surplus market. Signal sources to 40GHz are either very expensive or science projects. I don't like to use the calculated method of predicting RF exposure; I prefer to stick a bolometer sensor right into the real field. For a sensor, I use the IFI EFS-5 with an external Narda probe (covers 300MHz to 40GHz). New cost is about $4000, but I bought 2 of my EFS-5's off of eBay ($65 $95 each, hah!). Add another $1000 for a remote indicator and some fiberoptic cable. All the trade-offs come down to coverage area. As a rough rule, the 3dB down points of a horn antenna's field are about the same as the visual projection of it's flare; just sight along the antenna edges to see your coverage footprint. It wouldn't be too far off to say that your area of reasonable exposure might only be 6 long! This doesn't pose too much of a problem if you're testing a hand-held gadget, but if you have two 7-foot tall equipment racks, you'll have to make a lot of
FW: 47 CFR Part 90
From: Price, Ed Sent: Tuesday, October 28, 2003 7:03 AM To: 'ITL-EMC User Group' Subject: RE: 47 CFR Part 90 From: ITL-EMC User Group [mailto:itl-...@itl.co.il] Sent: Tuesday, October 28, 2003 12:03 AM To: Emc-Pstc Group (E-mail) Subject: 47 CFR Part 90 Dear All, Does anyone know where I can download the latest version of FCC Rule 47 Part 90 (47CFR90) in pdf format? I would prefer to download the whole part in one file. Thanks to anyone who can assist. Regards David Shidlowsky Technical Writer EMC Laboratory ITL (Product Testing) Ltd. Kfar Bin Nun Israel Tel: +972-8-9797799 Fax: +972-8-9797702 Email: dav...@itl.co.il http://www.itl.co.il http://www.i-spec.com This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. There's a copy dated 10/1/2002 at: http://www.access.gpo.gov/nara/cfr/waisidx_02/47cfr90_02.html http://www.access.gpo.gov/nara/cfr/waisidx_02/47cfr90_02.html It's a pain, because there must be a hundred Adobe files; they made a separate file of each section! I always try to search the files of the individual FCC Bureaus; they often maintain a copy newer than the GPO, although they warn you that it's not official info. The GPO only compiles the revisions maybe yearly (?); the FCC considers the official word to be the daily Federal Register. Ed 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
RE: metallic coatings
-Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Thursday, October 16, 2003 7:03 PM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. Ken: Some of our recent products for the Army Marines used plastic and composite materials for cases. We used electroless nickel, and had no problems. Of course, the need for shielding was known from the start, so the mechanical guys were able to design the cases without difficult internal corners and problematic sealing surfaces. Mating the MIL connectors to the shielding was a bit more difficult, but we used a combination of clamped surfaces, conductive elastomer gaskets and conductive epoxy. Ed 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
RE: Job Opportunity - Maryland
I don't think asking the age on an employment application is prohibited; however, it invites suspicion and leaves a paper trail that may haunt you. Defining a college graduation date is odd, and appears to be a silly way to gauge the applicant's age. (Really, was EE course content so much different in 1985 versus 1987?) If we assume a reasonable progression of educational experience, a typical engineer would graduate at age 22 in 1986; thus, there appears to be an age cutoff of 39. Here's a free legal opinion, for California (and if you don't like it, sue this lawyer): People under forty years old are not protected by age discrimination in the workplace laws. If an employer refuses to hire somebody because he or she is thirty-nine, and therefore too young, that is not illegal. But if it because he or she is forty and too old, that is illegal. http://www.discriminationattorney.com/age.html You can dig deeper at: http://www.hr-guide.com/data/073.htm And for the, uhhh, horse's mouth, see: http://www.dol.gov/oasam/regs/statutes/age_act.htm Is it too quaint to prefer a good applicant rather than a specific age applicant? Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty From: Tyra, John [mailto:john_t...@bose.com] Sent: Wednesday, October 15, 2003 11:07 AM To: 'Mike Cantwell'; Emc-Pstc Cc: Bryan Axmear Subject: RE: Job Opportunity - Maryland I thought asking a persons age on a job application for employment is illegalyes From: Mike Cantwell [mailto:mcantw...@leapfroginet.com] Sent: Wednesday, October 15, 2003 12:22 PM To: Emc-Pstc Cc: Bryan Axmear Subject: Job Opportunity - Maryland I received the following job opportunity from this recruiter: mailto:bryan_axm...@oxfordcorp.com bryan_axm...@oxfordcorp.com He has helped others on this list find employment in the past so if anyone is interested in this position or knows of someone interested in this position either contact him directly or you can contact me and I'll help them get through. Looks like the emphasis is on design and analysis and not on testing. For whatever reason, age seems to matter, I'm sure to reflect salary versus experience. Good luck to those interested. Job Description: I need a emi/emc ANALYSIS/DESIGN (opposed to a straight test) guy that graduated from college between the years of 1988-1992. Job in maryland. Emi analysis, pspice, mathcad, RF work of any kind. t1) a graduate that didnt graduate any earlier than 1986 2) the candidate knows that my manager may want to make him an offer after 9 months for perm placment 3) it is emc/emi analysis and design instead of straight emi/emc testing
RE: Magnetoic field test in DO-160
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, September 23, 2003 4:50 AM To: emc-p...@ieee.org Subject: Magnetoic field test in DO-160 Hi all, I'm looking into the best way to perform the magnetic field from equipment test in DO-160. I'm currently using a compass, but has any one got a better idea? If I have to stick with a compass, has anyone go a preferred Vendor/model? Thanks, Derek N. Walton Owner, L F Research EMI Design and Test Facility Poplar Grove, IL 61065 Derek: I assume that you are referring to Section 15 (Magnetic Effect) of DO-160. I always wondered about how RTCA expected somebody to read a 1 degree deviation on a mechanical compass! I started a spare-time project on that last year, but the program evaporated, and I set it aside. But here's the idea. I bought a couple of Honeywell HMC-1002 2-axis magnetic sensors (SOIC surface mount devices, so I soldered them to a pair of 0.1 SIP Surfboards). The Honeywell devices (about $20 each from Newark) are magnetoresistive devices with a sensing range of -2 Gauss to + 2 Gauss, a maximum field of 10,000 Gauss, and a resolution of 27 microGauss. You feed the chip with 5 VDC and get a linear output of 5 mV/Gauss. With a modest external op amp, you can get 2.5 V/Gauss. (I hadn't decided whether to read this DC voltage directly, or to use a voltage-to-frequency converter and use this to modulate an LED for a fiberoptic link.) I think Honeywell offers chips with built-in serial converters that give you an RS-232 output. The idea is to read the two magnetic field strengths, and calculate a trigonometric solution that is equivalent to the standard's allowable degrees of compass deviation. See the Honeywell web site: http://www.magneticsensors.com they have a bunch of application notes and suggested circuits for using magnetoresistive bridge devices. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Arcing Sparking
-Original Message- From: Ralph McDiarmid [ mailto:ralph.mcdiar...@xantrex.com] Sent: Monday, September 22, 2003 11:12 AM To: emc-p...@majordomo.ieee.org Subject: RE: Arcing Sparking I suggest that an arc is something continuous and producing light or illumination. A spark is something abrupt and short lived. Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc. I think that the main difference between an electrical arc and an electrical spark is the sense of time. An Arc is a Spark that decided to park. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Ferrite Sleeving
From: GARY MCINTURFF [mailto:mcinturff3...@msn.com] Sent: Monday, September 15, 2003 9:47 AM To: Chris Maxwell; lfresea...@aol.com; emc-p...@ieee.org Subject: Re: Ferrite Sleeving If I remember correctly from years ago -its fairly brittle stuff and problematic in areas that experience much shock or vibration. Gary - Original Message - From: Chris Maxwell mailto:chris.maxw...@nettest.com To: lfresea...@aol.com ; emc-p...@ieee.org Sent: Monday, September 15, 2003 7:12 AM Subject: RE: Ferrite Sleeving I have a sample of a flexible ferrite material from a company called Tokin. It is not a sleeving; but it is a thin (about .040) sheet, flexible enough to be rolled into a tubular shape. Personally, I haven't found an application for this stuff. Chris Maxwell | Design Engineer - Instruments Group email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | Chris: I think that material is supposed to be cut to size and applied as an RF absorber, in places like the top of an IC chip, or maybe a circuit cavity. You would have to glue or epoxy it in place. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Changes on Part 15
-Original Message- From: Carpentier Kristiaan [ mailto:kristiaan.carpent...@thomson.net] Sent: Monday, September 01, 2003 4:21 AM To: emc-p...@majordomo.ieee.org Subject: Changes on Part 15 Hello Group, I noticed that the Part 15 rules have been changed since August 26th. Instead of reading the complete document, is there any easy way to find out the latest changes? Thanks ! Vriendelijke Groeten, Best regards, Meilleures salutations, Kristiaan Carpentier Kristiaan: There may still be some commercial organizations (Pike Fischer comes to mind) that will give you a bulletin of FC RR changes on a weekly or maybe even daily basis. The cost is substantial. I use the following site: http://www.fcc.gov/oet/info/rules/ where the FCC OET maintains the latest copy of Part 15. I simply check the site every month or so to see if my pdf file has been superseded by a later file. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: antennas
-Original Message- From: Mike Hopkins [ mailto:michael.hopk...@thermo.com] Sent: Friday, August 29, 2003 6:34 AM To: 'drcuthb...@micron.com'; emc-p...@majordomo.ieee.org Subject: RE: antennas I believe amateur radio products are exempt from the EN's. someone correct me if I'm wrong. Best Regards, Michael Hopkins Manager, EMC Technologies Thermo Electron Control Technology Division EMC ESD Simulation Solutions One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Fax: +1 978 275 0850 michael.hopk...@thermo.com A recent USA FCC ruling allowing amateur operation near 5 MHz has an unusual requirement; the operator needs to know the gain of his antenna (or maintain calculations modeling the gain), so as to abide by an ERP limit. Perhaps some European hams must also do something similar. I wonder if ham antennas (and/or their supporting towers) in the EU might be considered as structures, and subject to some mechanical requirements. This might be similar in class to flagpoles, overhead signs or light poles. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Multiple postings re fuse replacement markings
From: richhug...@aol.com [mailto:richhug...@aol.com] Sent: Thursday, August 28, 2003 2:29 AM To: j...@jmwa.demon.co.uk; emc-p...@majordomo.ieee.org Subject: Re: Multiple postings re fuse replacement markings Folks, Apologies for bombarding you with the same Email. This was because AOL sent me a message that my message couldn't be sent and so I re-tried. If its any consolation, that means I got extra helpings of so-and-so is out of the office messages. Richard Hughes Just a hint to minimize those avalanches of OOF autoreplies; I set a mail rule to look for the words out of the office in the subject line, and to then delete those emails. This simple filter trashes almost every one of those autoreplies. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Insertion loss of an injection probe
-Original Message- From: Luke Turnbull [ mailto:luke.turnb...@trw.com] Sent: Wednesday, August 20, 2003 12:05 AM To: emc-p...@ieee.org Subject: Insertion loss of an injection probe Dear group, I have a BCI testing standard that states the insertion loss of an injection probe must be less than 7dB. Does anyone have an idea about what they mean by the insertion loss? Thanks, Luke Turnbull Luke: The insertion loss is a measure of the efficiency of the probe. To test this value, inject a signal into the current probe coaxial port. Let's assume the injected signal level is 100 dBuV (50 ohm coax system). Now put a loop of wire, terminated in a 50 ohm resistor, through the current probe window. Finally, put an oscilloscope across the resistor terminals. If you read 5 volts across the 50 ohm resistor, that means you have a current flowing, in the resistor, of 0.1 amps, or 100 dBuA. 100 dBuV input - 100 dBuA output = 0 dB insertion loss More typically, if you read 2.5 volts across the resistor, that would be 0.05 amps, or 94 dBuA. This would yield an insertion loss of 6 dB. Obviously, you need to specify the input impedance and the load impedance. And measurements are more accurate and repeatable if you use a current probe calibration jig, typically sold by Solar or others. Using the calibration jig, you can calibrate probes in both directions (for current probe factor for emissions insertion loss for immunity) using a spectrum analyzer with a tracking generator or just discrete test gear. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: CDMA Product Approvals
From: garymcintu...@aol.com [mailto:garymcintu...@aol.com] Sent: Monday, August 18, 2003 8:56 AM To: michael.sundst...@nokia.com; lothar.schm...@cetecomusa.com; cblac...@airspan.com; alex.mcn...@ingenicofortronic.com; emc-p...@majordomo.ieee.org Subject: Re: CDMA Product Approvals So now I'm curious, which came first Ethernet or cell phone. CDMA is also used on Ethernet. At least the original simplex versions - triple shielded coax, then cheaper net - essentially phone cables. It wasn't needed with full duplex PTP transmission, which some might argue isn't true Ethernet. I remember seeing those old brick sized cell (mobile?) phones but thought they were slightly behind LAN's and the precursor to the Internet ARPANET (probably have wildly misspelled that) seems to have been around much longer than that. So I'm curious what was CDMA originally designed for? Anybody know. Gary Gary: I seem to recall Titan / Linkabit using CDMA for military data links around 1978. And did you ever lug around one of those Motorola FM handy-talkies from back in the early 60's? IIRC, they operated around 50 MHz, and must have weighed 20 pounds. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Temperature effects on conducted emissions?
-Original Message- From: Gordon,Ian [ mailto:ian.gor...@bocedwards.com] Sent: Monday, August 11, 2003 8:33 AM To: 'IEEE EMC-PSTC GROUP' Subject: Temperature effects on conducted emissions? All Can anyone suggest a means by which the indicated signal from a LISN + transient limiter + receiver combination can result in a 30dB change over one month? I used the same reference source and test configuration on both occasions to generate emissions. However, the source is merely a piece of standard equipment and not intended as a calibration reference. The temperature has varied considerably over the last month but I would not have thought this could result in a 30dB variation. Alternatively, can anyone suggest a means of constructing a reference source which may be connected to the LISN input? Thanks Ian Gordon Ian: You didn't say if the latest measurements were higher or lower than the original. However, 30 dB is a huge variation, and room temperature shifts shouldn't cause that at all. You need to build confidence in your setup. First, verify the cal of your analyzer. Easiest way is to use the front panel cal output at maybe 100 MHz or 300 MHz. Or inject a signal from a signal generator into the analyzer input. One thermal effect could be that you have fried the analyzer's input attenuator. Now, put the limiter on, and repeat the above. Now inject into the head end of your coax. You should be down only by the expected coax loss. Now, inject into the input of the attenuator that you normally use on the LISN. You should be down by 10 dB. Last, check your LISN. That's relatively easy. Assuming that you are using an LISN that works from 9 kHz to 10 MHz or so, just connect a 50-ohm signal source to the LISN power output terminal and the case ground. (You did disconnect the LISN input power?) Also connect a high impedance oscilloscope probe to this point. Now connect the second oscilloscope channel to the LISN signal output port, using the 50-ohm termination option in the oscilloscope. (I use a Tek TDS640A.) Inject enough RF signal to get a nominal value on Channel 1, typically 1 Vrms. Now look at the Channel 2 50-ohm signal port level. It should also be almost exactly 1 Vrms, except for the frequency range below about 100 kHz. If this reading is significantly lower than it should be, then you are seeing a bad coupling capacitor in the LISN. If too high, then a blown LISN resistor is the cause. BTW, as you sweep the injected signal down towards 9 kHz, you should see a rise in the signal port loss, until you see about 5 dB or so at 9 kHz. This is normal, and something that you should have been adding in to you acquired data. (It's the typical loss associated with the RC voltage divider. The loss will be very high at the power frequency, and infinite at DC.) The last thing to consider is the attenuator and limiter. Both of these may have been subjected to extreme physical shock (as in I dropped it on the concrete floor). This could cause an intermittent problem. You might want to tap or slap them while you watch the signal loss through them. Also try wiggling and moderately pulling on the various coax fittings and connectors. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Lightning Surge Characterization/Standards THANKS
-Original Message- From: John Woodgate [ mailto:j...@jmwa.demon.co.uk] Sent: Thursday, August 07, 2003 9:23 AM To: emc-p...@majordomo.ieee.org Subject: Re: Lightning Surge Characterization/Standards THANKS I read in !emc-pstc that Chris Chileshe chris.chile...@ultronics.com wrote (in 01c35ce5.8dbac680.chris.chile...@ultronics.com) about 'Lightning Surge Characterization/Standards THANKS' on Thu, 7 Aug 2003: Err.. should that read Ladies and Gentlemen? There may well be some ladies who are members of the group, but I don't recall any post recently that indicates a female source. Of course, your name is epicene Once again, John forces me to resort to deep references. However, I'm relieved, as I thought he implied that your name was horse-like. For mere mortals: Main Entry: ep·i·cene Pronunciation: 'e-p-sEn Function: adjective Etymology: Middle English, from Latin epicoenus, from Greek epikoinos, from epi- + koinos common List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 15th century 1 of a noun : having but one form to indicate either sex 2 a : having characteristics typical of the other sex : INTERSEXUAL b : EFFEMINATE 3 : lacking characteristics of either sex - epicene noun - ep·i·cen·ism /-sE-ni-zm, e-p-'/ noun Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Apples and ? comparison of dBuV/m
-Original Message- From: Eric Penne [ mailto:epe...@olug.org] Sent: Wednesday, August 06, 2003 8:44 PM To: emc-p...@majordomo.ieee.org Subject: Apples and ? comparison of dBuV/m I've been perusing some FCC test reports and had a question that I couldn't find an answer to. I'm trying to brush up on my skills so I can get a job in the EMC industry again. Funny thing my former employer told me. I had my picture in the Fall 2002 issue of the IEEE EMC newletter 4 times at the Minneapolis EMC Symposium. Unfortunately I was laid off 1 week after the show. :) Anyway, on a couple of the reports, measurements were taken to verify that a transmitter didn't exceed the limits of a band next to it. The EUT including antenna was tested in a chamber and the maximum value in average and peak testing was found in dBuV/m. The unit is operating above 1GHz. To verify the band edge measurements the transmitter was directly connected to a spectrum analyzer and power measurements were taken to find the overall peak and the peak in the restricted band. The difference of the direct connection Spec Analyzer test was subtracted from the maximum average value in the radiated emissions test to say that the EUT passed in the restricted band. What I couldn't understand was how an average value from the RE scan with a Res BW of 1MHz could subtract a peak value from the power scan that has a Res BW of 100kHz? Is an average value with 1MHz RBW equal to a Peak value with 100kHz RBW? Thanks, Eric Eric: I'm more concerned that the conducted measurements do not take into account the efficiency of the antenna at out-of-band frequencies. It is one thing to measure the RF power at the fundamental and other frequencies in a constant 50-ohm system. It is quite another to measure the field strength created by that RF power when radiated by a real antenna. Real antennas usually exhibit wide variations in efficiency and radiation pattern when you depart from the design frequency. While measuring in a controlled 50-ohm system, with various detectors and bandwidths may be interesting, the requirement you defined was suppression of RADIATION at an adjacent frequency. Unless you exhaustively define the characteristics of the antenna (and apply that as a correction factor to the 50-ohm power information), the only right way is to really measure the fields. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: apertures
-Original Message- From: drcuthb...@micron.com [ mailto:drcuthb...@micron.com] Sent: Thursday, July 10, 2003 11:59 AM To: emc-p...@majordomo.ieee.org Subject: apertures I have a question on apertures. You may recall the formula that is frequently given for signal attenuation through a small aperture in a large conductive sheet. It is 20LOG(I/2L), where I is the wavelength and L is the slot length. For example, if x is 1/2-wavelength then the attenuation is 0 dB. But I'm not 100% sure what the attenuation is referenced to. If they are referencing it to the E-field that would be present at the aperture location if the sheet were not there to the E-field across the length of the aperture then that makes sense. It seems that we now have a 1/2 wavelength aperture radiating only the signal energy that it has intercepted. Let's say it is referenced to the E-field that would be present with no sheet. Now to say that the E-field a large distance away from the 1/2 wavelength aperture has not been attenuated by the aperture is wrong, although this is implied by the formula. Only a fraction of the energy contained in the total incident wave has made it through the aperture. The aperture now acts as a dipole radiating this fraction of the total incident wave. So is the attenuation given by this formula to be referenced to the power that would be intercepted by a dipole? Dave Cuthbert Micron Technology Dave: Allow me to follow the power model. If the aperture has a long dimension of 1/2 wavelength, then the RF power illuminating the source side of the aperture will propagate through the aperture with very little loss. The total power propagating through the aperture is dependent on the area of the aperture, as the aperture allows through all of the power that the illuminating plane wave presents to the aperture area. For instance, if the plane wave had a power density of 1 mW/sq cm, and the aperture had a 1 sq cm area, then 1 mW would be propagating through the aperture, and that 1 mW would then radiate out the far side of the aperture. Now here the model gets a little foggy to me. Should I consider this 1 mW to now be an isotropic radiator? I don't think so, because the barrier (that contains the aperture) would block half the radiation. Indeed, the reflection off the barrier would look like gain over isotropic. Should I now model the 1 mW as applied to a dipole (the end of the 1/2 wave aperture)? Despite my floundering at the relaunching of the power that got through the aperture, at least I can now imagine this power propagating out in a hemispherical wavefront, spreading its 1 mW over greater and greater areas. Hmmm, did I answer anything along the way? Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Request for MIL-STD_461E CS101 tips for configuring a 400 Hz Delt a Power System.
-Original Message- From: kaan.l.greger...@l-3com.com [ mailto:kaan.l.greger...@l-3com.com] Sent: Wednesday, July 09, 2003 11:47 AM To: emc-p...@majordomo.ieee.org Subject: Request for MIL-STD_461E CS101 tips for configuring a 400 Hz Delt a Power System. Hello Group, I am looking for tips regarding how to configure a MIL-STD-461E CS101 test setup for a DELTA power system so as to reduce any safety concerns for the equipment (including the audio amplifier) and the operator (. . .me. . .). Does anyone have any experience(s) in this realm that they would like to share? Thanks in advance. . . Kaan Gregersen L-3 Communications / Communication Systems - West Voice: (801) 594-2560 Kaan: The first thing to check is to be sure your 10 uF capacitors can handle the capacitive current. If you have a Delta configuration, with perhaps 480 VAC at 400 Hz, you are going to put about 12 amps through each of the three capacitors. If you have a 208 VAC Wye configuration, then your capacitive current drops to only 3 amps through each capacitor. Consider the heating of the capacitors, and also remember that the current (in addition with the current needed to operate the EUT) will be drawn through the LISN's and the power source. If you use the setup shown in Figure CS101-5, then be very careful about the oscilloscope chassis. The chassis will be connected to one of the Delta phases. This is why the oscilloscope isolation transformer is necessary. But it's still an unsafe way to work. Instead. use a two-channel oscilloscope, with a differential probe setup. That way, you can ground the oscilloscope chassis. Much safer! Finally, consider the voltage that will be induced back into your AF power amplifier. Since the amplifier should have a 2-ohm impedance (the injection transformer is a 4:1 impedance step-down, presenting a 0.5-ohm source impedance to the EUT), initially put a 2-ohm resistor across the primary of the injection transformer, and read the voltage generated across this resistor when the EUT is energized. Check the AF power amplifier specs to be sure this is safe. You shouldn't have a problem with a 25-amp or less EUT phase current with any typical amplifier rated for CS101 duty. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Instrument Controller Software
-Original Message- From: John Cronin [ mailto:croni...@hotmail.com] Sent: Tuesday, July 08, 2003 11:29 AM To: emc-p...@majordomo.ieee.org Subject: Instrument Controller Software Hi I have a requirement to log the screens from a spectrum analyser over a period of between one day and one week. I have been using the DDDA software from Stanford research with some success. However, I need a slightly more sophisticated package that will allow me to dump screens as plots at 15 minutes intervals over a prolonged period unto a laptop using GPIB. I envisage using an Advantest 3265 or HP 8562 analyzer. Can anyone point me in the right direction? Mnay thanks John Cronin John: HP used to have a program called Benchlink, a simple controller and data dumper for their instruments. It was available by download, in a free 30-day trial version, from their website. Try the Agilent site now. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialt http://www.ieeecommunities.org/emc-pstc
RE: CISPR Receiver/SA
-Original Message- From: richwo...@tycoint.com [ mailto:richwo...@tycoint.com] Sent: Wednesday, July 02, 2003 5:43 AM To: emc-p...@majordomo.ieee.org Subject: CISPR Receiver/SA If you were purchasing a brand new, fully CISPR compliant EMC receiver/SA, and wanted to obtain the best value at the lowest cost, what would you choose and why? Likewise, if you decided to purchase a used receiver/SA, what would you choose and why? Richard Woods Sensormatic Electronics Tyco International Rich: I'd like to address the second half of your question, the lowest cost end. I wanted to have some kind of backup, a sanity check, for my fancy automated spectrum analyzer system. My solution was to buy old receivers on eBay. One particular system, the Eaton / Singer / Stoddart Series 7 receivers (NM-17/27 NM-37/57) can be used with the CCA-7 quasi-peak adapter, to give you a very nice back-up or pre-compliance measurement capability. You can run these in manual mode, or use internal sweeps with an external plotter. And the amazing thing is that you can get these for $200 or so off of eBay. (The usual disclaimers; don't buy what you can't fix; the operator has to be smarter than the machine; do you feel lucky?) My experience was; bought an NM-17 for $160, works perfectly; bought an NM-37 for $65, bad tuning voltage, took a few hours to fix it; bought a CCA-7 for $110, works perfectly; bought an NM-7 for $125, works but cal control is noisy; bought an NM-65 for $175, has a power supply problem but haven't had time to look at it. So, using your criteria of lowest cost (and I think the value is there too, since it does the job), I spent about $650, and got a measurement system that covers 30 Hz to 12 GHz (OK, the 1-12 GHz part isn't working yet), with a QP capability too! Another low-end solution is an HP-141T spectrum analyzer mainframe, with 8552 IF and 8555 8553 plug-ins. This will give you 10 kHz to 18 GHz coverage, but only with a Peak detector. Get an 8556 plug-in, and you can extend the range down to 30 Hz. I have a complete 141 system, but can't really suggest it too strongly, since the surplus units are all over the range in quality. Buying one of these is depending on luck a bit too much for even me. They are still repairable by humans, but it helps to have very small fingers and lots of patience. BTW, one other thing that's often overlooked in the total cost is the fact that you don't have to maintain any periodic calibration on these back-up systems. (My company operates with an internal Metrology department, and every piece of equipment I have has to have a calibration budget, or be declared non-calibrated support equipment. Some very reliable instruments may have been written off long ago, but their calibration budgets remain. I have to be careful that, when I acquire something, I also consider the ongoing calibration cost too.) Obviously, the above are not economically competitive systems for a full-time test lab. OTOH, it's a big improvement over an oscilloscope with a loop probe antenna, or waving a hand-held scanner over your product. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Do you realise how annoying it is?
-Original Message- From: Hudson, Alan [ mailto:alan.hud...@amsjv.com] Sent: Monday, June 30, 2003 6:41 AM To: EMC-pstc (E-mail) Subject: Do you realise how annoying it is? Rant on I know it's been mentioned before, but I'm having a bad day so I'll mention it again. You do someone the courtesy of replying to their enquiry in this useful group, or you post a query, and what do you get? Umpteen (16 in the last 3 hours) I'm out of the office messages from people you didn't know existed, never mind wanted to know if they were in or out. Alan: The bright side is that all of these out-of-office postings give you great leads as to where you can raid offices for office supplies. I haven't had to formally requisition paper or staples or pens in years. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: MIL-STD 461 C
-Original Message- From: Paolo Peruzzi [ mailto:paolo.peru...@esaote.com] Sent: Thursday, June 12, 2003 6:27 AM To: emc-p...@majordomo.ieee.org Subject: MIL-STD 461 C Dear group, I would like to get the old broadband and narrowband RE limit tables of the superseded MIL STD 461C, for teaching purposes. Could anybody tell me where to find a pdf of that standard? Thanks, Paolo ** Paolo Peruzzi Esaote S.p.A. Research Product Development - Design Quality Control via di Caciolle, 15 I- 50127 Florence tel: +39 055 4229469 fax: +39 055 4223305 e-mail: paolo.peru...@esaote.com ** Paolo: I'm sending you a pdf of the entire MIL-STD-461C. (If anyone else would like a copy, email me off-list. BTW, it's about 12MB.) Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Surge Suppressors on a UPS
From: Price, Ed Sent: Monday, June 02, 2003 8:19 AM To: 'EMC-PSTC List' Subject: Surge Suppressors on a UPS Hi Group! Last Friday, I got ambushed in a meeting. I hate it when that happens! A question was asked about whether it's OK to put a surge suppressor on the output of a UPS that is supplying power to some expensive equipment. I opined that I didn't think it should be necessary, but that it also shouldn't hurt anything either. So then somebody asks me why all the UPS manufacturer's sites say not to use a surge suppressor. I expertly reply that gosh, I don't know, but I'll take a look. The next question nails me again. Are there any standards for UPS output power quality? Uh, well, I'll look into that too. Now, the market is light industrial, USA, but are there any applicable EN standards also? Just for some background, here's a typical entry from Tripp-Lite's FAQ list for UPS's (not to pick on Tripp-Lite; they just said it most succinctly of several sites I looked at): http://www.tripplite.com/support/faq/tech_ups.cfm Can I plug a surge suppressor or extension cord into my UPS? No. Using an extension cord will void your equipment coverage warranty, as all equipment must be plugged directly into the UPS. Tripp Lite does not recommend plugging a surge protector into a battery backup outlet of a UPS either as this can overload it. Also, when some UPS systems switch to battery power they will output a waveform that a surge suppressor may see as a surge and short-circuit the UPS. Again, this setup will void the equipment coverage warranty. Now this is getting to be a big can of worms! What do they mean by some UPS? Is there one kind that does, and another kind that doesn't; and how do you know which is which? And if some UPS will create a voltage transient (is that what they mean?) sufficient to trigger a surge suppressor, then why is it OK to let the UPS apply that transient to my protected equipment? All this talk about uninterrupted power isn't worth anything if the UPS kills my equipment when it switches to battery power mode. And who's fault is this? I mean, a surge suppressor is pretty dumb; it just sits there waiting for the voltage to go over a certain level and then it conducts. What's this about the surge suppressor may see something as a surge? That's saying the surge suppressor could mis-interpret the waveform it sees. If the surge suppressor is conducting, then I think the UPS has just done something very naughty. I also don't understand the prohibition of an extension cord. Maybe this is a legal issue, as I can't see any valid safety or regulation issues here. We regularly put a UPS in the bottom of a rack system, and then wire a stripline outlet set for the height of the rack. Isn't that the electrical equivalent of an extension cord? What am I missing? Thanks in advance! Ed I'm replying to my own post because, so far, my question has not really been answered. It HAS generated a really large volume of private emails expressing concern about things like what happens when you use a UPS to power equipment with built-in surge suppression. Or questions about just what are these switching event waveforms that a surge suppressor might want to suppress, and why should they be allowed to be applied to equipment without surge suppressors (equipment designed with the assumption that the UPS is protecting it from the public mains). It looks like racking and stacking a UPS, with a power distribution strip (the moral equivalent of an extension cord?) feeding a group of discrete electronics boxes (most of which have built-in filters and suppressors) is quite common. Yet UPS manufacturers seem to be saying that this bad practice and will even void the UPS warranty. So far, all comments have been from USERS of a UPS. I would like to hear from the other side, the UPS designers. (Privately if you must, but I would like to be able to later post unattributed answers.) Thanks again! Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
Surge Suppressors on a UPS
Hi Group! Last Friday, I got ambushed in a meeting. I hate it when that happens! A question was asked about whether it's OK to put a surge suppressor on the output of a UPS that is supplying power to some expensive equipment. I opined that I didn't think it should be necessary, but that it also shouldn't hurt anything either. So then somebody asks me why all the UPS manufacturer's sites say not to use a surge suppressor. I expertly reply that gosh, I don't know, but I'll take a look. The next question nails me again. Are there any standards for UPS output power quality? Uh, well, I'll look into that too. Now, the market is light industrial, USA, but are there any applicable EN standards also? Just for some background, here's a typical entry from Tripp-Lite's FAQ list for UPS's (not to pick on Tripp-Lite; they just said it most succinctly of several sites I looked at): http://www.tripplite.com/support/faq/tech_ups.cfm Can I plug a surge suppressor or extension cord into my UPS? No. Using an extension cord will void your equipment coverage warranty, as all equipment must be plugged directly into the UPS. Tripp Lite does not recommend plugging a surge protector into a battery backup outlet of a UPS either as this can overload it. Also, when some UPS systems switch to battery power they will output a waveform that a surge suppressor may see as a surge and short-circuit the UPS. Again, this setup will void the equipment coverage warranty. Now this is getting to be a big can of worms! What do they mean by some UPS? Is there one kind that does, and another kind that doesn't; and how do you know which is which? And if some UPS will create a voltage transient (is that what they mean?) sufficient to trigger a surge suppressor, then why is it OK to let the UPS apply that transient to my protected equipment? All this talk about uninterrupted power isn't worth anything if the UPS kills my equipment when it switches to battery power mode. And who's fault is this? I mean, a surge suppressor is pretty dumb; it just sits there waiting for the voltage to go over a certain level and then it conducts. What's this about the surge suppressor may see something as a surge? That's saying the surge suppressor could mis-interpret the waveform it sees. If the surge suppressor is conducting, then I think the UPS has just done something very naughty. I also don't understand the prohibition of an extension cord. Maybe this is a legal issue, as I can't see any valid safety or regulation issues here. We regularly put a UPS in the bottom of a rack system, and then wire a stripline outlet set for the height of the rack. Isn't that the electrical equivalent of an extension cord? What am I missing? Thanks in advance! Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Bad Fuse vs. Good Fuse
-Original Message- From: POWELL, DOUG [ mailto:doug.pow...@aei.com] Sent: Friday, May 23, 2003 3:57 PM To: EMC-PSTC (E-mail) Subject: Bad Fuse vs. Good Fuse Hello all, Recently, in my company, we've been discussing what exactly constitutes a good or bad fuse. In this industry we often hear that the trouble with a defective product was, the fuse was bad. I occurred to me that the fuse is not bad, it performed exactly intended. In fact if the problem that caused the fuse to operate is still present, then the fuse is still good even though it is now an open circuit. The only time it can be a bad fuse is if it did not operate, resulting in shock or a fire. I have now have my ears tuned-in to this concept of a bad fuse and find it is commonly used all over the industry. In fact you can go to any number of websites that provide trouble shooting notes, and find instructions on how you can measure a bad fuse from a good fuse using an Ohm meter, photos included. And some of these instructions are from reputable manufacturers. Another term often used is defective fuse, which in some way sounds more scientific, but is still fundamentally wrong. I recently saw a newspaper article that gave the explaination why electrical service was lost for over 100,000 people as a bad fuse. An investigation was under way to determine why the fuse went bad. This is a little like hearing the technologically uninitiated say it must be a short somewhere, when the television set stops working. Maybe I am finicky, but this affects how companies view real product defects. When the defect is the bad fuse, then the real problem may be covered up. Often the answer is, increase the fuse size to prevent nuisance trips. The risk, of course, is that for every incremental increase in fuse value, you increase the risk of fire proportionally. Any thoughts or experiences? BTW - To all US citizens in the group, have a relaxing Memorial Day weekend. -doug Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO 80535 USA Doug: I would submit that a fuse can be bad if it opens at too low of a current, thus creating an improper denial of service. A fuse may also be bad if it does not follow the expected curve of energy operation for both conductive and interrupted states. An open fuse may be considered a successful application of protection, but, suppose it was a one-amp rated fuse, was subjected to a 20-amp fault current, yet required 30 seconds to melt and create the interrupted condition. I suspect that most engineers would expect a one-amp fuse to blow much faster than that. As usual, it's always more complicated the closer you look at it. Regards, Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Graphing Software
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Friday, May 16, 2003 9:45 AM To: emc-p...@majordomo.ieee.org Subject: Graphing Software Hi All, I'm looking at plotting the response of devices on a polar plot, either 2D or 3D. In this cases it's the response of a field probe. Several plots will be used for different frequencies. Does anyone have suggestions of what package to use? I know or Origin, but it's very expensive. Cheers, Derek N. Walton Owner L F Research EMC Design and Test Facility Poplar Grove, Illinois, USA www.lfresearch.com Derek: You can do this for free, right from Excel or MS Word. If you choose Excel, then just enter two columns of data, XY pairs of degrees and magnitude. Then, click the chart wizard, and choose the radar style, either 2D or 3D. That's it. I always have trouble setting up new charts, what with MS's non-scientific orientation of chart data formats. Once I build a chart or plot that I like, I usually copy it, and just stick in new data and labels for subsequent charts. Anyway, it's free, colorful, and seduces you into spending more time than you should building a dumb chart. Regards, Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: TEMPEST regulations
-Original Message- From: Alexandru Guidea [ mailto:gui...@cae.com] Sent: Friday, May 09, 2003 8:35 AM To: 'emc-p...@majordomo.ieee.org' Subject: TEMPEST regulations Dear colleagues, I am looking to procure an UK (or NATO) TEMPEST standard/regulation -- JSP 480. Any help in finding a source for this doc will be greatly appreciated. Whether some confidentiality restrictions exist, they can be resolved by our library, as it has similar docs. Thanks, Guidea Alexandru CAE Inc. Montreal, CANADA Alexandru: A JSP is a British Ministry of Defence (MoD) Joint Services Publication. You might try the MoD homepage at: http://www.dstan.mod.uk/index.html but many Comsec documents are classified, so you might have trouble getting a copy (as in not exactly a pdf on the web g). Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Correction factors
From: Franck GALVIN [mailto:franck.gal...@e-labs.fr] Sent: Tuesday, May 06, 2003 8:36 AM To: emc-p...@majordomo.ieee.org Subject: Correction factors Dear all, I perform conducted or radiated emission test with HP8594EM spectrum analyser or HP8656A receiver. To not have measurements errors I must enter correction factors (antenna or LISN, cable and other ...). My questions are: 1/ When you enter data to antenna factors for example, you write ''frequency'', ''amplitude'' and what about ''frequency scale'' (log or lin) ? 2/ Does frequency scale depend of correction type (cable, amplifier, antenna, LISN, transient limiter...)? Thanks in advance for your answers. Franck GALVIN eLAbs (France) Franck: I have somewhat older HP hardware software than your setup, but here's how the HP software works for me. When you are creating an equipment calibration table, you are asked to declare the number of data pairs (frequency amplitude) that define a curve which represents the response of the equipment. For example, an external attenuator might be defined by only two pairs, say, 0.01 / 20 18000 / 20 (data units are MHz dB). However, for something like a current probe or antenna, you might have a file of 50 pairs or so. You also choose LIN or LOG, which specifies the interpolation method used between the data points. I always choose LOG, since the completed emission plots usually use a logarithmic frequency scale. I don't think this makes any practical difference, but then I always enter enough data pairs so that the delta dB from one pair to another is 1 dB or less. After setting up a calibration file (you need a transducer, cable and limit set of files), be sure to test the expected accuracy by injecting a known signal into the coax cable head-end to verify that the factors are being added correctly to the raw spectrum analyzer data. IIRC, the HP convention was to always subtract the correction factor value from the raw data. Thus, you have to make the attenuator data a negative number, so that subtracting a negative yields adding a positive! (Hope you don't think I'm joking!!! Read you software manual very carefully.) Regards, Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: ELF (E and H) survey equipment
-Original Message- From: John Harrington [mailto:jharring...@f2labs.com] Sent: Monday, May 05, 2003 7:44 AM To: 'emc-p...@majordomo.ieee.org' Subject: ELF (E and H) survey equipment Does anyone know where I might be able to rent (and failing that purchase) some E and H field survey eqipment? I need it to range from sub 1Hz to 10kHz, to read E and H fields separately, and to be portable. Thanks John Harrington EMC Technical Manager F-Squared Laboratories That's an interesting task! I noticed that an old Stoddart NM-40A, which could measure to microvolts from about 20 Hz to 50 kHz, just sold on eBay for under $100. An old NM-40A, an active E-field probe and an H-field loop antenna could get you much of the way to doing your measurements. But, getting a bit more modern, you could also use a decent digital oscilloscope with FFT capability. That would cover from 10 kHz down to sub 1 Hz all by itself. Then, all you need are probes. Now here, I'm getting a little bit out of my range, so I invite any assistance or corrections. But it seems that you could get E-field by using something like a 41 rod counterpoise, which is electrically 1/2 meter. Use a very high impedance, bandwidth limited FET amplifier, calibrate the gain, and remember to add 6 dB for the 1/2 meter electrical length. For H-field, sub 1 Hz loops are a bit of a problem, but still a classical solution. You might try to get exotic with something like reading the voltage across a low resistance in series with a loop coil. You might try researching natural radio, where hobbyists have done a lot of work on low-noise, ultra low-frequency receivers and active antennas. Look at http://www.auroralchorus.com/natradio.htm Regards, Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: FCC Limits
From: Andre, Pierre-Marie [mailto:pierre-marie.an...@intel.com] Sent: Tuesday, April 29, 2003 7:00 AM To: lfresea...@aol.com Cc: emc-p...@majordomo.ieee.org Subject: RE: FCC Limits You can visit : http://www.access.gpo.gov/nara/cfr/waisidx_01/47cfr15_01.html Good luck Pierre-Marie Andre Senior Approval Engineer Unfortunately, the official Government Printing Office site is playing a rather cosmic joke, since the copy available there is dated 1 October 2001. A much more recent revision, 13 March 2003, is available at http://www.fcc.gov/oet/info/rules/ This is also a pdf file of the entire Part 15, whereas the GPO site has a separate pdf for each section of Part 15! Regards, Ed This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: FCC Limits
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, April 29, 2003 7:34 AM To: pierre-marie.an...@intel.com Cc: emc-p...@majordomo.ieee.org Subject: Re: FCC Limits In a message dated 4/29/2003 9:01:17 AM Central Daylight Time, pierre-marie.an...@intel.com writes: You can visit : http://www.access.gpo.gov/nara/cfr/waisidx_01/47cfr15_01.html Good luck Pierre-Marie Andre Senior Approval Engineer Thanks, but this is the old limits. The new conducted limits are being lowered to 150 kHz I believe. It's this info I'm looking for. Derek N. Walton Owner L F Research EMC Design and Test Facility Poplar Grove, Illinois, USA www.lfresearch.com Yes, it's disconcerting that the GPO, which should be the final arbiter of what's official US government paperwork, is actually well behind the curve on FCC info. I use the FCC web site, http://www.fcc.gov/oet/info/rules/ and then drill down to the files for the individual Bureaus. The latest info they publish is the 3-13-03 edition. I make it a habit to periodically visit and download the latest revisions. Don't know why the GPO (Printing?) can't do the same. Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: Check list for PCB Layout
-Original Message- From: james.free...@infineon.com [mailto:james.free...@infineon.com] Sent: Friday, April 25, 2003 10:00 AM To: tkrze...@genius.org.br; emc-p...@majordomo.ieee.org Subject: RE: Check list for PCB Layout Is this for real? is there actually in institute for geniuses? This would explain why we are all really in the dark. No geniuses to lead us. I dream of genii... Ed Price (TD, Janitor, College of Complexes) ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Symbols vs. text - was EN61010-1, Symbol 14
-Original Message- From: pat.law...@verizon.net [mailto:pat.law...@verizon.net] Sent: Tuesday, April 22, 2003 10:59 AM To: EMC-PSTC Subject: Re: Symbols vs. text - was EN61010-1, Symbol 14 On Mon, 21 Apr 2003 08:28:19 -0700, ed.pr...@cubic.com wrote: -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Friday, April 18, 2003 11:49 AM To: richhug...@aol.com Cc: peperkin...@cs.com; emc-p...@majordomo.ieee.org Subject: Re: Symbols vs. text - was EN61010-1, Symbol 14 Hi Richard: You said We in the product safety industry must be very careful that we use symbols in strict accordance with their definitions. SNIP Allow me a couple of observations on safety, from my viewpoint as a consumer rather than a safety specialist. I find the universal alert symbol (the exclamation point within a triangle) to be rather useless at best and even distractive. It's the equivalent to shouting Hey!, with no hint of what the true danger is. Sure, it puts you on guard, but while you are looking for the sharp edge to avoid, do you instead get burned from a hot surface? I would much rather have a specific hazard depicted so I know right away what the hazard is. Further, I think symbols should have a hierarchy of warning. There's only a few ways that the human body reacts to nasty outside stimuli (i.e., you bleed, burn, freeze, have pieces fall off). The top-level safety symbol should express the major danger category. Then, for people who haven't yet fled the area, you can have all kinds of very graphic depictions of trauma (superheated radioactive acidic steam). SNIP Regards, Ed Price ed.pr...@cubic.com Hi Ed (and group): Maybe these labels are what you have in mind? I think the top half of the page are ISO symbols. Are they too 'busy'? Would they get the message across to the majority of product users? http://www.bay-labels.com/safety_symbols.htm Pat --- Pat: Yes, those labels at http://www.bay-labels.com/safety_symbols.htm are a good example. #1 just shouts at you, but doesn't tell you anything. Your reaction is Huh! What, where, slippery floor or high voltage? #2, #11, #13 #18 are really good specific hazard symbols; to me, they clearly define an immediate threat. I wish I could say that #7 #25 were good symbols, but I understand them by training only. #7 might mean bright light and #25 might mean no bare hands to someone else. #31, #32 #33 are all nice symbols, but the hazard is quite similar. It's nice to be specific, but do you really care if the symbol differentiates a cog wheel from a pulley from a gear? #5 almost looks like a bullet hole at first. Finally, #3 is my choice for a truly improper warning symbol, and should not be included with any set of hazard symbols. A fuse advisory, of all things! Honestly, without the text, did anyone guess this one? CAUTION: My personal impressions only g. Regards, Ed Ed Price ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Low signal switching
-Original Message- From: djumbdenst...@tycoint.com [mailto:djumbdenst...@tycoint.com] Sent: Monday, April 21, 2003 10:28 AM To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic Don: The only ones I trust are the HP (now Agilent) coax relays. As for low-level reliability, this is what is used in my HP automated data acquisition system, and I have also seen them used in Watkins Johnson receivers. Both applications are small-signal (-110 dBm), low-loss, high isolation, high reliability applications. Did I mention that they're expensive? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Symbols vs. text - was EN61010-1, Symbol 14
-Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Friday, April 18, 2003 11:49 AM To: richhug...@aol.com Cc: peperkin...@cs.com; emc-p...@majordomo.ieee.org Subject: Re: Symbols vs. text - was EN61010-1, Symbol 14 Hi Richard: You said We in the product safety industry must be very careful that we use symbols in strict accordance with their definitions. No issue with you there. However, the paper states that some of these misuses were perpetrated by people not even connected with electrical engineering, let alone safety. Indeed. We need to keep such people from learning about our safety symbols (except when we use them in the proper venue and context). :-) This brings me to another of your statements The fact of misuse of symbols dilutes the meaning of the symbol. The more the misuse, the less valuable the symbol is for safety purposes. Perhaps this is true, let's assume it is for the moment. What then are the options available to us? Either we have to find a way of policing the use safety symbols or we have to face the possibility that every symbol described in IEC 60417 could become unusable due to misuse. Any suggestions on how to police (internationally, of course) the incorrect use of IEC and ISO symbols? We need to first make sure our house is in order. First, do we have clear, unambiguous definitions for our safety symbols? Based on the very short definitions in 417, I think not. I believe we need much more work on the definitions. Second, we need to make sure we only use the symbols in accordance with the definition. We can police ourselves through our traditional third-party safety certification of products. So what do we do as regards written words? We look at the context in which the word is used. If I were to pronounce that an object is cool then the chances are that I would mean that it is below room temperature - but if my daughter were to pronounce an object cool then the chances are that it would be the latest 'in thing'. Confusing? In theory maybe, in practice not really. Of course, the standards for word definitions (which, for the sake of simplicity, I'll call dictionaries) do describe multiple common uses of individual words (including examples of their contextual usage, if they're any good). The preceding is a very good statement of the problem of multiple definitions for both words and symbols. Let's back up a step and ask the purpose of the symbol (or even the set of words). I submit that the purpose is to invoke an action on the part of the reader. If the symbol/words is in regard of safety, then I submit that the action invoked is because of lack of a suitable safeguard. Products should be designed so that no safety symbols/words are required (at least for the user/operator). If you look at your monitor, keyboard, and computer, you probably will see no symbols or words relating to safety. So, products CAN be designed without the need for safety symbols. You ask So what do we do as regards written words? My response is design the product so that no words or symbols are needed insofar as safety is concerned. Best regards, Rich Rich: Allow me a couple of observations on safety, from my viewpoint as a consumer rather than a safety specialist. I find the universal alert symbol (the exclamation point within a triangle) to be rather useless at best and even distractive. It's the equivalent to shouting Hey!, with no hint of what the true danger is. Sure, it puts you on guard, but while you are looking for the sharp edge to avoid, do you instead get burned from a hot surface? I would much rather have a specific hazard depicted so I know right away what the hazard is. Further, I think symbols should have a hierarchy of warning. There's only a few ways that the human body reacts to nasty outside stimuli (i.e., you bleed, burn, freeze, have pieces fall off). The top-level safety symbol should express the major danger category. Then, for people who haven't yet fled the area, you can have all kinds of very graphic depictions of trauma (superheated radioactive acidic steam). Now, about keyboards. How about CAUTION: May induce repetitive stress injury? That symbol is gonna take some hard thought! Remarkably, on something truly dangerous (razor blades), I have never seen a warning etched on each blade. Is there some product category for them, something like Generally Recognized As Doggone Dangerous (GRADD)? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To
RE: Bulk current injection method for CS101
-Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, April 21, 2003 1:10 PM To: Price, Ed; 'EMC-PSTC List' Cc: 'Low, Aaron S' Subject: Re: Bulk current injection method for CS101 The reason Mr. Low can't use the -461E figure Ed suggested is that Solar's highest current capacity CS101 transformer handles 100, not the required 150 Amps. As I said in an earlier posting, such a high current load would get an almost direct feed from the generator, which would eliminate any significant ripple in the frequency range where IR drop dominates IZ drop. I would say that would be from at least 1 kHz and below, but depending on how short that common path is, it may extend to an even higher frequency. When verification requires unobtainable test equipment, it behooves engineering to consider why that might be. Ken: I agree with your explanation about the probability of a dedicated power source. (I would also question the nice, roundness of the 150 Amp value; is this rated or the REAL current draw?) However, a 50% current overload on a Solar injection transformer is not a major problem. If you keep that shorting bar on the secondary at all times other than when you are actually generating the AF injection power, you can minimize transformer heating. And, a tip of the hat goes to the designers of that old Solar stuff; they designed in a big safety margin. Test quickly, although thoroughly, and get a really big fan. And if that can't keep the thermal rise down, then get a big tank of CO2. BTDT g, anybody smell smoke? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Bulk current injection method for CS101
-Original Message- From: Low, Aaron S [mailto:aaron.s@lmco.com] Sent: Thursday, April 17, 2003 1:24 PM To: emc-p...@majordomo.ieee.org Subject: Bulk current injection method for CS101 I am wondering if any of you have had experience using a current probe to inject current into a power line for a modified MIL-STD-461 CS101 test? I am trying to envision how I am going to run CS101 on a 150 Amp system without blowing up the test equipment amplifiers. I cannot use two identical transformers and two identical loads to help protect the amplifiers. Thanks Aaron Aaron S. Low Systems Engineer Naval Electronics and Surveillance Systems EP5 D5 MD45 Syracuse, NY 13221-4840 Phone: (315) 456-1203Fax: (315) 456-0509 Aaron: A current probe is a very inefficient coupler at the very low frequencies that CS101 covers. I don't think it's possible to use a current probe to do this. Using the technique described in Figure A-5 of 50.7 of MIL-STD-461E, you only need two transformers and ONE dummy load. I don't understand why you say you cannot do this. One further thing you could do is use an older, vacuum tube amplifier. These amplifiers tolerate load-impressed voltages better than newer, solid-state amplifiers. I'm not sure about how much a given amplifier will tolerate, but, as a benchmark, I have done CS101 on 80 Amp, 400 Hz powerline using a single Solar 6220 transformer and a McIntosh MC-60 (tube) amplifier. I have also done 50 Amp 400 Hz lines with a McIntosh MC-100 (solid-state) amplifier. I suggest you get a few more opinions; contact Solar Electronics and maybe Fischer Custom Components. Watch out for on/off transients; you may want to put a shorting bar across the injection transformer secondary winding terminals during turn-on turn-off. You could try to design a high-pass filter for the circuit between the amplifier output and the injection transformer. I'm assuming that your power is 400 Hz, so the CS101 test starts at 800 Hz. That might be a very interesting filter design, but anything would help. Finally, try brute force! Get a variable speed motor generator, and adjust the frequency by generator RPM. This method might carry you up to several kHz, where you could then switch over to an electronic generator protected by a more reasonable high-pass filter. Wow; what a science project! Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: high immunity
-Original Message- From: drcuthbert [mailto:drcuthb...@micron.com] Sent: Thursday, March 27, 2003 8:00 AM To: 'robert Macy'; drcuthbert; 'emc-p...@majordomo.ieee.org' Subject: RE: high immunity Robert, I figured 5 kV/m for a distance of 100 meters, over ground. Using commonly available lab items (and a 100 kV power supply) I should be able to generate 5 kV/m at 3 meters during a 1 ns pulse width. Wonder what this would do to a cell phone? Dave Cuthbert Micron Technology Dave: How would you generate a pulse like that? Direct capacitor discharge to an air gap? And how would you launch the EM wave? Dipole arms at a spark gap? Parallel plate antenna? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calibrating police radar guns
-Original Message- From: Hjálmar Árnason [mailto:hjal...@mi.is] Sent: Thursday, March 27, 2003 3:14 PM To: emc-p...@majordomo.ieee.org Subject: Calibrating police radar guns Hi Forum I can recall back in November 2000 there was some discussions here in this group on how to fight speeding tickets and many of you had good advices. I'm about to start on a project which includes calibrating and repairing police radar guns. This will probably involve setting up a semi-anechoic chamber or OATS. I have access to a room which can be used to set-up a chamber and want to restrict the set-up to the radar freq. around 25 and 35 GHz. I would appreciate if you could give some advice and direct me to the right websites to get information. I need both test equipment and material for the chamber. The budget is low so second hand equipment is my goal. Anyone selling his set-up ?. Thank you kindly, Hjalmar Arnason Reykjavik Iceland hjal...@mi.is Hjalmar: The only calibration performed on police radar guns that I am aware of is verification of the Doppler shift response. This is done by whacking a factory-supplied tuning fork, and holding the tines in the radar beam. The vibrating tines reflect a Doppler-shifted signal, and the gun display counter is adjusted to read the appropriate speed. For the US market, the only tuning forks I have ever seen were designated for 55 MPH. To independently verify the calibration, you could measure the audio frequency of the tuning fork and relate that to peak velocity of the tuning fork tine. (I'm not certain, but, IIRC, the velocity of the tine should also be 55 MPH. Maybe we should dig out our high-school Physics book.) AFAIK, no measurements are made on such interesting things as RF power output, beam width, range, multipath rejection or rejection of undesired signals. Further, I don't know about Iceland, but in the USA, I would want malpractice insurance if I was certifying the performance of devices that regularly served as trial evidence. Who would want to enter a market like that? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Help wanted with succinct subject description for non-special ists
-Original Message- From: King, Richard [mailto:richard.k...@uk.thalesgroup.com] Sent: Monday, March 24, 2003 3:07 AM To: 'emc-p...@majordomo.ieee.org' Subject: Help wanted with succinct subject description for non-specialists Dear all, I am working on an article about EMC for an internal newsletter. The aim is to increase awareness of the EMC related projects on which my colleagues and I are currently engaged. The target audience is largely composed of engineers specialising in other subject areas (software, systems and hardware), managers and support staff. To put the piece in context I would like to succinctly describe what EMC is in an opening couple of paragraphs. However I am struggling to do so in language that is easy to read and not full of techno-jargon. My questions to the list are: What are your experiences of producing similar material? How well was it received and what is your advice for people producing similar text? Are there any examples of good summaries available, on the web or elsewhere, that people in my position can draw upon for inspiration? My current draft is copied after my signature. Comments or alterations, either by direct e-mail or to the list, will be gratefully received. Thanks in advance, Richard King Systems Engineer Thales Communications UK. I pitch it low and slow: The whole idea of Electromagnetic Compatibility is to produce a product that operates in complete electronic harmony with its environment. Ideally, our product will cause no harm to any existing electronic system. We don't want our product to accidentally retract the landing gear or crash the payroll computer. And just as importantly, our equipment will continue to work reliably, shrugging off RF fields and powerline noise. That's all you need for the executive level description. If you want to go to the next level, then loop through: We ensure the compatibility of our product by creating a model of the real electronic environment, either from an established standard or by analysis. We use this model to define a set of electronic environmental tests. When our product is made to operate successfully in these model environments, we maximize the probability that our product will operate harmoniously in its market environment. If they want even more information, see if they might like a summer intern job in your lab. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Help wanted with succinct subject description for non-special ists
-Original Message- From: C N [mailto:abx...@hotmail.com] Sent: Monday, March 24, 2003 10:48 PM To: emc-p...@majordomo.ieee.org Subject: Re: Help wanted with succinct subject description for non-specialists For non-technical people ... in other words KISS. EMC is two things: I respectfully disagree. Here's what I'd say. Take it as you wish. EMC or Electromagnetic Compatibility is the products ability to pass a variety of electromagnetic product testing requirements demanded by different countries or customers. Doug: I think that the ability to pass the tests is more correctly called Compliance. Compatibility is achieved only if the compliance requirements accurately portray the real world. Assuming that the compliance requirements have been set reasonably well, achieving Compliance will reasonably assure Compatibility. Yet, carried to extremes, it's certainly possible to not be in compliance, yet be compatible most of the time. And sometimes, you can be compliant, without always being compatible. Regards, Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Racing Car EMC
-Original Message- From: Peter Conboy [mailto:peter.con...@piresearch.co.uk] Sent: Monday, March 17, 2003 1:50 AM To: 'emc-p...@majordomo.ieee.org' Subject: Racing Car EMC Anyone out there got an opinion on what standards should be applied for the electronics fitted to racing cars - F1, CART, IRL etc.? Because of the environment, the need for absolute reliability, and the safety critical application (e.g. throttle, clutch, steering, chassis control) we take things seriously, but do not actually CE or e mark. The tests I do generally cover e and exceed most standards as actually I try and break the box rather than just go to the standards limit. I am having a bit of a debate inside my company, because 95/54/EC refers to only vehicles on rhe road, and racing cars are off road and therfore implies CE as a catch all This to me is wrong as patently its a vehicle, CE may be broader on the immunities, but is less severe on the radiated stuff. Given the self contained nature of the car, it is the radiated immunities I feel I should be most concerned with once I'm sure engine sourced interferences have been dealt with. Also CE and e are EU, whats the legal U.S. position? - I stress legal because the teams themselves don't care. Thanks Peter Peter: What kind of an RF environment does a race car experience? There's an audio link to the driver, a telemetry link for structural data, and possibly a video link for a car camera. And then all the similar links for the other cars. Does the car see any special exposures on the course (Doppler radar?) or in the pits (noisy service tools)? And, are there any unusual operational conditions, like running without a battery (saves weight, more ripple) or operation of heavy actuators or solenoids? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: antenna port conducted emissions
-Original Message- From: Low, Aaron S [mailto:aaron.s@lmco.com] Sent: Wednesday, March 19, 2003 11:49 AM To: emc-p...@majordomo.ieee.org Subject: RE: antenna port conducted emissions I'd like to thank all those who replied so far. According to MIL-STD-462D: 4.9.2 Operating frequencies for spread spectrum equipment. Operating frequency requirements for two major types of spread spectrum equipment shall be as follows: a. Frequency hopping. Measurements shall be performed with the EUT utilizing a hop set which contains a minimum of 30% of the total possible frequencies. This hop set shall be divided equally into three segments at the low, mid, and high end of the EUT's operational frequency range. b. Direct sequence. Measurements shall be performed with the EUT processing data at the highest possible data transfer rate. Can I interpret this section to mean that when scanning for emissions, standard MIL-STD scanning methods apply? Aaron Aaron S. Low Systems Engineer Naval Electronics and Surveillance Systems EP5 D5 MD45 Syracuse, NY 13221-4840 Phone: (315) 456-1203Fax: (315) 456-0509 L I interpret 4.9.2.a as trying to ensure that you are not playing tricks with the selection of frequencies. For instance, at the low end of your hop range, your circuit might generate higher harmonic content, so you decide to choose a hop set that's all in the upper 1/3 of the range. No, uh-uh, not prudent, shouldn't do that. If by methods, you mean scanning speed, in MHz per second, then remember that Paragraph 4.3.10.3.1, Table II is only a set of maximum speed limits. Notice that 4.3.10.3.3 says For equipment that operates such that the potential emissions are produced at only infrequent intervals, times for frequency scanning shall be increased as necessary to capture any emissions. As I said earlier, you may have to scan much slower than the speed limit. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: antenna port conducted emissions
-Original Message- From: Low, Aaron S [mailto:aaron.s@lmco.com] Sent: Wednesday, March 19, 2003 7:44 AM To: emc-p...@majordomo.ieee.org Subject: antenna port conducted emissions Folks, I am interested in your opinions regarding antenna port conducted emissions (MIL-STD-461D CE106) on a spread spectrum/frequency hopping device. Is it practical to automatically measure (using a swept scan EMI receiver) emissions from such a device? I would think that when using spread spectrum and a swept scan receiver, the receiver has some large probability of missing the emissions caused by a particular harmonic when using swept scanning systems. The limit for CE106 (transmitters) is derived from the power of the fundamental (there is no fundamental, only a band of operation), how do you measure that power on the EMI receiver? Does anyone have any experience/advice they would be willing to part with? Thanks Aaron Low ps. I am relatively new to this field, so my question may seem very basic to many of you; please excuse me. Aaron: First question is are you sure you should be working to 461D? 461E came out 20 August 1999. Now, to address your technical situation. Yes, you do have a fundamental. Just because it's hopping doesn't mean it's not there. Granted, 461 CE06 (later CE106) originated in the era of non-hopping systems, and may address them better in a future revision, but it does say that your reference will be the peak power level of the fundamental. You can measure the peak power by using a spectrum analyzer in peak hold, using sufficient bandwidth to ensure the detector actually charges to the peak during the time that the fundament dwells in the SA resolution bandwidth. Sometimes you can sweep a small portion of spectrum, or you can go to zero span width and just sit at some frequency waiting for the fundamental to hop there. You may find that the fundamental amplitude varies across the hopping range, so you might need to disable the hopping and fix the fundamental to one or more specific frequencies. Remember when looking for harmonic content, the hop sizes will be n x the fundamental hop size. Probabability of intercept is a problem, and I usually scan very slowly and do several overlaid sweeps of the spectrum. Many of the transmitters that I see have a short duty cycle (like 7 uS on and 993 uS in standby), so this makes the signal acquisition even more challenging. Sometimes I set automated scans to run 16 hours overnight, or over a weekend. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: RADIATED IMMUNITY REQUIREMENTS FOR EN61326
-Original Message- From: Mike Hopkins [mailto:michael.hopk...@thermo.com] Sent: Monday, March 03, 2003 1:32 PM To: 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: RE: RADIATED IMMUNITY REQUIREMENTS FOR EN61326 Sorry, but I must be missing something Transmitting antennas are designed to radiate power, and the field strength of any signal being radiated will be at it's highest close to the antenna in fact, depending on frequency and distance, one might even be in the near field effects Antennas may be made directional, which results in power being concentrated in one direction, but if you're talking broadcast antennas, they are generally omni-directional arrays that achieve gain by keeping fields concentrated at low angles so power radiated towards the sky is minimized. Such antennas would clearly produce their highest levels of radiation close to the antenna structure itself; however, directly above or below the antenna fields would be less. I cannot guess why the radiated levels for these frequencies would be lower than for other frequencies. The only thing I can think of is that maybe it isn't expected that one would be close enough to a broadcast antenna at these frequencies for it to be an issue (antennas are mounted atop very tall buildings and towers) -- on the other hand, a piece of lab equipment or control equipment in a process plant could certainly be very close to other sources or radiation from, say, 5W walkies used by security personnel -- how much of a field can you get a 150MHz a foot from a 5W transmitter?? Mike Hopkins Thermo KeyTek Mike: About 10 V/M. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Hospital Cell Phone Ban?
Listmembers: Here's an interesting letter in The Lancet, with several UK physicians calling for the deletion of the general ban on cell phones in hospitals. http://www.thelancet.com/journal/vol361/iss9359/full/llan.361.9359.correspon dence.24777.1 Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Sharp Object
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, February 27, 2003 11:41 AM To: emc-p...@majordomo.ieee.org Subject: Re: Sharp Object I read in !emc-pstc that Joshua Wiseman jwise...@printronix.com wrote (in f503cb4657afd4119b9400508bb0d6540695c...@irvmail.printronix.com) about 'Sharp Object' on Thu, 27 Feb 2003: I am looking for the symbol for sharp objects. So far I have had little success in finding it. I have an out of date edition of IEC 417 in my office but I don't see it in there. Can someone point me in the right direction. 'Sharp objects' is in an ISO standard, not IEC 60417. I'm not sure whether it is in ISO 7000 or a special medical equipment standard. I suggest that you go to http://www.iso.org and search. Or to your local hospital! -- Regards, John Woodgate, OOO - Own Opinions Only. Josh: Here's a page with the Sharps warning symbol. I don't know how authoritative this is, but the page is Australian, and it's the same symbol I have seen used here in California. http://www.safetyline.wa.gov.au/../pagebin/pg002646.htm Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: IEC 61010 requirements
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Saturday, February 22, 2003 12:05 AM To: emc-p...@majordomo.ieee.org Subject: Re: IEC 61010 requirements I read in !emc-pstc that peter merguerian pmerguerian2...@yahoo.com wrote (in 20030221231714.74613.qm...@web14806.mail.yahoo.com) about 'IEC 61010 requirements' on Fri, 21 Feb 2003: The other day, I called a surgeon and he happened to be in the operating room with his cellphone performing an operation. Does that make his cellular comply with IEC 601-1? Maybe not, but there are VERY serious EMC issues. No cell-phone should be switched on in an OR. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk I would be even more concerned about fire explosion hazard. The cell phone is most likely not gas-tight. A couple of years ago, I talked with an anesthesiologist, who related his worries about oxygen and anesthesia gasses being trapped in folds of the patient's blankets (patient heat loss on an operating table is a concern) or the draping of the procedure site, thereby creating little flame or explosion zones. That surgeon's phone would just about in the worst place relative to the gasses. And another thought just arises; how did he take your call? Hard to see how he could do that without violating the isolation of the operating site. If this becomes a common practice, we'll soon hear a tale about somebody loosing a cellphone inside a patient, like what happens when they mis-count the sponges. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Swissair 111
Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Fred Townsend [mailto:f...@poasana.com] Sent: Wednesday, February 19, 2003 12:42 AM To: Ken Javor Cc: Gary McInturff; EMC-PSTC (E-mail) Subject: Re: Swissair 111 - long winded even by my standards but an interesting article Scary! I squirmed in my seat as I read the article. You see I did the electrical design part of a similar system. Our system had a critical design flaw. It was a mechanical error so I was not responsible for the error but it could have crashed the airplane. Luckily we did not use a contractor for certification. We submitted straight to the FAA. The FAA spotted the problem and it was soon fixed. It makes me wonder what would have happened if we used a contractor to certify. In another vein, did anyone else pick up the error in the article? It related to the disk drive. It probably was the reporter's error. I see errors of this kind so frequently when you have a journalist or English major writing about scientific issues. They are not equipped to do the job. Fred Townsend Do you mean: Aboard an airplane, the hard drives would probably get 10-20 degrees Celsius (50 to 68 degrees Fahrenheit) hotter than in a laboratory, he said. I just assumed that it was the reporter having a problem with arithmetic. I was more interested in the comment that the heat rise observed in the laboratory would probably have been even hotter in a real installation. So why didn't they get a typical seat, stick it in an altitude chamber, and find out what the heat rise really was? I'm not very familiar with the certification process for adding a gadget to an aircraft. But, it seems to me that the aircraft modifiers, like SBA, are supposed to use only accepted or certified parts in the modification. It seems like there's a gap, from the time that the manufacturer's first FAA consultant bailed out of the job, and the time when SBA started installing the systems onto aircraft. I didn't see anywhere in the story that the entertainment systems were ever certified or whatever they call it, to be used by anyone. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: OATS Building
-Original Message- From: Wan Juang Foo [mailto:f...@np.edu.sg] Sent: Friday, February 14, 2003 5:47 PM To: emc-p...@majordomo.ieee.org Subject: Re: OATS Building Walt, I don't think an inflatable structure is going to be a good candidate to be a 'radome' (sp?) unless there is something about it being able to stand to gale force winds that I am not aware about. :-) I must admit that it is a good idea. On a lighter note, a PVC/fiber-glass enclosure not too much unlike the one shown in the URL below will fit the bill. http://www.yorkemc.co.uk/Images/Castleford/collage.jpg It was taken from http://www.yorkemc.co.uk/Emc_testing/castleford.htm Tim Foo A couple of words of caution about an inflatable cover for your OATS, based on my experience with a 30' wide by 100' long by about 15' high air-inflated range cover here in San Diego. 1. It's HOT. I don't know why, but it seems like the infrared portion of sunlight is intensified inside the inflatable. It feels like standing under those marquee heaters. Blowing only ambient 95F air made the inside temp go to at least 115F. You should consider an air chiller circulating fan as well as a pressurization fan, or your techs will quit. 2. If the flexible skin is ever allowed to go unpressurized, especially by accident, you have to plan ways to support the skin without tearing it. You may have to remember to always lay down antenna masts, build safety frames over your test equipment, etc. 3. The UV really degrades the flexible fabric skin. After about 4 years, my structure skin was so degraded, with many little holes and tears and thin spots, that I couldn't get full inflation with the originally very adequate fans. 4. Wind storms are not nice to inflatable structures. The wind can put much force against the side of the bubble. I saw the skirt of my building pick up multiple sand-bags, fly a short distance, and roll up in a big ball. My experience was that inflatables are nice to visit, but you wouldn't want to live there. IMHO. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: best screw/washer choices for attaching PCB to Chassis?
-Original Message- From: Kim Flint [mailto:kfl...@inkra.com] Sent: Monday, February 10, 2003 6:15 PM To: emc-p...@majordomo.ieee.org Subject: best screw/washer choices for attaching PCB to Chassis? Hi- We have a fairly straightforward requirement of mounting a PCB into a steel chassis. The chassis has PEM type standoffs and the PCB is held to them with machine screws. These connections provide an electrical ground path between the PCB and the chassis. In other words, we have what seems to be the fairly ordinary and common set of requirements. We need to have mechanical reliability (so the PCB is held in place), nothing should break during assembly, the screws should not be able to work themselves out, and electrical conductivity should be low for a low impedance ground path. Seems simple, yet all of us here have a different opinion about how to do this properly, we've all done it a variety of ways in our past, and none of us seems to have the right expertise to really claim to know the definitive answer. I'm hoping to get some expert opinions from this group, or at least some idea of what others do assuming there is some reasonable justification for it. Can you help? Or perhaps point me towards some good discussion on the subject? (I did search the 2+ years of mail I have from this group, since the archives don't seem to be online...) The questions are: Screw/Washer choice: - should a washer be used or not? - if a washer is used, should it be a locking washer? - Is it possible for a locking washer to cause unwanted damage to the PCB? - Is an adhesive like Loctite a reasonable alternative to lock washers in this case? - should the screw be zinc plated? or some other plating? PCB layout: - Should we use a plated through-hole with ground planes connected inside the hole? - or a non-plated hole with vias in the surface layer pad connecting to the ground plane? - What electrical or reliability concerns relate to this choice? - how large should the surface pad be assuming a 4-40 screw? anything else we should be considering? Thanks for any input you have! kim Kim: For the board, I would use a plated-through hole. The pad on top should be a bit larger diameter than the bolt head. The pad on the bottom should be a bit larger diameter than the PEM stand-off face. For the bolt, use a machine bolt with a pan style head. Put one lockwasher under the bolt head. You don't need a flat washer (unless your board is oddly fragile); keep it simple. But if you do use a flat washer, put it between the lockwasher and the board top pad. The lockwasher should be a split-ring style. True, a toothed lockwasher will cut into the board pad, but you want axial compressive force, not torque withstanding ability. Besides, the toothed washer might leave some FOD in your box. Use bright nickel plated hardware. Put a dab of Locktite into the female thread on the PEM before assembly. Don't worry about conductivity loss from male to female threads; your primary ground path is from the lower pad of the board to the face of the PEM stand-off. (And I'm assuming that the PEM will mashed into the baseplate with an excellent bond.) Make sure the PEM faces are clean before dropping the board on them. Avoid getting finger oils on the mating faces of PEM and board. Torque bolt till the washer is flat. Regards, Ed This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: GPIB filtered bulkhead connectors.
-Original Message- From: drcuthbert [mailto:drcuthb...@micron.com] Sent: Monday, February 10, 2003 8:12 AM To: 'Luke Turnbull'; Subject: RE: GPIB filtered bulkhead connectors. Simply terminating the shield at the screened room wall eliminates common mode shield current. No more filtering needs to be done. Dave Cuthbert Micron Technology -Original Message- From: Luke Turnbull [mailto:luke.turnb...@trw.com] Sent: Monday, February 10, 2003 7:38 AM To: Subject: GPIB filtered bulkhead connectors. Group, Does anyone know where I can buy filtered bulkhead connectors for running GPIB cables through screened room walls. Approximate cost? Alternatively, does anyone know suppliers and cost for GPIB fibre-optic extenders. Thanks, Luke Turnbull Filtering of signal or I/O lines at a penetration port is often required. In the case of radiated immunity testing, the applied fields may penetrate the EUT, then travel through the I/O lines, and upset support equipment. This will result in excessive test time at the best, or improper indications of test failure at the worst. In the case of emission testing, support equipment will often inject noise onto the I/O lines, which is then conducted into the EUT. There, it may couple onto the EUT powerlines or be directly radiated. This will result in improper indications of emissions which do not truly originate from the EUT. All test chamber penetrations should be filtered as heavily as possible, consistent with not impairing the integrity of the data signals. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Power Supply Vendor Reference
Group: I had a project engineer ask me if I could suggest any vendors for a modular power supply for his project. I say project, because it's a ground-portable box that does something or other which he didn't think I needed to know about. All I know is that he expects to put about 1kW of 208V, 50/60 Hz, Delta power into the power supply, and get 270 VDC, 48 VDC, 28 VDC, +/- 15 VDC and 8 VDC out of it. Anyone care to recommend their favorite PS vendor (or themselves)? Thanks, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Multi - Lingual Markings For Industrial Equipment in the U.S.
-Original Message- From: Duncan Hobbs [mailto:duncan_ho...@xyratex.com] Sent: Tuesday, February 04, 2003 7:51 AM To: emc-p...@majordomo.ieee.org Subject: Multi - Lingual Markings For Industrial Equipment in the U.S. Group, Does anyone know if there are any state or federal regulations that may require bilingual markings for certain regions in the USA? I am thinking of certain states where Spanish is a widely used language. The equipment is industrial test equipment, of the sort that would be installed in a factory (i.e. not consumer equipment) Many thanks in advance, Duncan. Duncan Hobbs, Senior Compliance Engineer Xyratex Product Compliance Lab. Havant, Hants, U.K. 02392 496444 duncan_ho...@xyratex.com Duncan: I don't know of any product marking requirements. I expect California to be on the forefront of any such requirements. I was able to find some references to forms, examinations and assistance being required to be provided in Spanish to Hispanic California workers by the California OSHA (Cal-OSHA) at: http://www.dir.ca.gov/samples/search/query.htm But I didn't find anything about products, either consumer or industrial, needing bilingual labeling. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: red tape
-Original Message- From: Ravinder Ajmani [mailto:ajm...@us.ibm.com] Sent: Monday, February 03, 2003 12:55 PM To: emc-p...@majordomo.ieee.org Subject: Re: red tape Red Tape is a very common term used for describing the bureaucracy of Government of India (perhaps a legacy from British). Delays and inaction by Indian bureaucracy have often been blamed to the Red Tape in the government offices (which signifies a cloth ribbon tied around a file folder to hold the papers in place). One result of the criticism was that the red tape was subsequently replaced with a white tape. Although it is anybody's guess, if this actually improved the working at the government offices. Regards, Ravinder PCB Development and Design Department But DUCT TAPE is your friend, regardless of color! Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: single fault conditions
-Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Friday, January 31, 2003 4:17 PM To: j...@jmwa.demon.co.uk Cc: emc-p...@majordomo.ieee.org Subject: Re: single fault conditions Hi John: For example, at a previous employer, I observed several instances of FETs (in a 3kVA instrument) exploding and sending molten metal (mostly from the leads and the lead's solder pads) through chassis vents, that subsequently caused the surrounding cheesecloth to ignite. WOW! I wouldn't have though that there would be enough energy in the droplets after their flight through the air to cause ignition. Did you treat the cheesecloth with potassium nitrate solution before the test? Molten metal has: high temperature high stored energy high thermal conductivity A small drop (1-2 mm diameter) of molten copper falling through about 0.4 meter will ignite non-flame-retardant plastic material (I've done the test and have the pix). Very much smaller pieces would ignite unalduterated cheesecloth. Best regards, Rich Rich: I first performed this test in 1965, albeit with certain modifications. I applied a molten glob of 60/40 alloy solder, through a 0.5 meter fall from a soldering iron, into the interstitial space between my leather shoe and Orlon sock. I did not experience synthetic fabric ignition, but I certainly did achieve lift-off (as I hopped around the lab trying to rip off my boot). In addition to pioneering this test method, I also think I invented disco that day. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 7:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon OK, less drama and more numbers. In a Helmholtz, the sweet spot or volume, should be limited to 1/3 the distance between the coils. So that means that coil separation should be 150cm to yield a test volume of 50cm. And, the definition of a Helmholtz is two identical flat coils, in plane, and separated by the radius of the coil. So, the radius of the coil is also 150cm. Now, the Helmholtz equation, re-arranged to find necessary current when the field (Gauss), turns (N), radius (a, in cm) and separation (cm) are known. I= [((5)^^(1.5)) x a x 10 x Gauss] / [ 32 x Pi x N ] So, lets try with a 150 cm radius separation coil, with 50 turns, looking for 50 Gauss (which is equivalent to your 5 milliTeslas). I = [((5)^^(1.5) x 150 x 10 x 50] / [ 32 x Pi x 50] (please don't let me mess this up) I = 838526 / 5026 = 167 Amps The only variables you can work with are number of turns and current. What size power supply have you got? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 7:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon Gordon, are you sure your numbers are correct? 5 milliTesla is equivalent to: 50 Gauss 4014 A/M 192 dBuA/M 194 dBpT and, if it were the H-field component of a plane wave: 1.5 million V/M 243 dBuV/M 6 x 10^^9 Watts/sq Meter I have a spreadsheet that calculates these values. I'll send you a copy off-line. Verify your requirements, and then we can find what you need to build. Ed This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Korean Spectrum Allocations or Band Plan
Hello Groupies! Is there a location where I may be able to download an English language version of Korea's RF spectrum allocation scheme (sometimes called a band-plan)? This would likely be similar to the USA FCC RR, Part 2. I believe that I may have found the information I need at: http://www.mic.go.kr/eng/jsp/res/res_100_01.jsp which is the Radio Waves Act. Unfortunately, I can only find Hangul versions of this information. Thanks, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
OT: Help with German Industrial Abbreviations
Hi group! I would like to ask if some of our list members, who are familiar with German industrial marking practices, to help settle a discussion. I am trying to determine the significance of markings on an auto radiator ID plate. The plate caries the markings: Hans Windorf A.-G. 4 Berlin - Schoenberg63 Werk Nr.16602 Lfd. Nr.413 I somewhat assume that the 4 and the 63 refer to the fourth month of 1963 as a date of manufacture. But what is the English equivalent of Werk Nr. Lfd. Nr.? Might these refer to a contract number, a plant ID, or a design drawing number? Thanks! Ed (restoring an Amphicar really getting weird about it) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Video Cameras for EMC Test Monitoring
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, January 16, 2003 1:28 AM To: emc-p...@majordomo.ieee.org Subject: Video Cameras for EMC Test Monitoring I read in !emc-pstc that Price, Ed ed.pr...@cubic.com wrote (in b78135310217d511907c0090273f5190d0b...@curly.ds.cubic.com) about 'Video Cameras for EMC Test Monitoring' on Wed, 15 Jan 2003: I wish there was some remote way to suppress the IR illuminators. Can't you just put duct tape over them, if you are not expecting to use them? Already tried that, John. The problem is that the Ramsey camera is about 1.5 diameter, and has a glass window over the end of the aluminum tube. There are 12 IR LED's distributed around the camera lens. I tried several masks, which effectively block the IR from projecting into the room. Unfortunately, the masks also reflect some IR back into the camera, causing the camera's AGC (or whatever) to darken the scene. Thus far, masks hurt more than help. Further play is indicated! Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Video Cameras for EMC Test Monitoring
-Original Message- From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com] Sent: Wednesday, January 15, 2003 4:27 PM To: djumbdenst...@tycoint.com; emc-p...@majordomo.ieee.org; smcen...@ustech-lab.com Subject: RE: Video Cameras for EMC Test Monitoring Hire one of the media's courtroom sketch artists - they aren't really doing anything useful anyway or promote one of your lab techs to sketch artist - and send him in. (You might want to have a list of lucky promotee's in place after the first one fails) Gary I guess that I have developed such a fearsome reputation at my plant that nobody even wants to come into my lab area, let alone go inside the chamber. About the only people who you can get to sit in there during a mild RS test are program managers, who figure they can avoid a direct charge for a technician. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Correlation of MIL-STD-461C and MIL-STD-461E
-Original Message- From: Mazzola, Santo [mailto:santo.mazz...@baesystems.com] Sent: Wednesday, January 15, 2003 12:21 PM To: 'Ken Javor'; emc-p...@majordomo.ieee.org Subject: RE: Correlation of MIL-STD-461C and MIL-STD-461E Ken, I mixed up some of the procedures in my e-mail. I think you inherently figured that out. My specific question would be comparing the MIL-STD-461E CE102 Basic curve performance (28 volt system) compared against results gotten against MIL-STD-461 class A1b (28 volt system). I think you answered it by saying that the limits are very close and that with different impedances it will still depend on how your test item reacts to the new LISN impedance. I guess the general question would be: Has MIL-STD-461E turned out to be more difficult then MIL-STD-461C or are the pass/fail rates similar. As always really appreciate your technical expertise. Thank You Sandy Mazzola BAESYSTEMS Inc -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, January 15, 2003 2:33 PM To: Mazzola, Santo; emc-p...@majordomo.ieee.org Subject: Re: Correlation of MIL-STD-461C and MIL-STD-461E In general the two versions are very close where they overlap, but specific answers must be on a case-by-case basis. Comparing CE03 with CE102 is complex in terms of how the test item interacts with a LISN as opposed to a a feedthrough capacitor, but the limits are very close. For RE102, there are several different curves, dependent on platform and Service usage, so more specificity is necessary before rendering a judgment. I served on the committee which drafted MIL-STD-461E and can likely answer any specific questions. Ken Javor -- From: Mazzola, Santo santo.mazz...@baesystems.com To: emc-p...@majordomo.ieee.org Subject: Correlation of MIL-STD-461C and MIL-STD-461E Date: Wed, Jan 15, 2003, 12:27 PM To all, I was wondering if anyone has any experience in the correlation of results of MIL-STD-461 C RE02 versus MIL-STD-461E RE102. MIL-STD-461 C uses a current probe and measures current while MIL-STD-461 E uses LISN's and measures voltage. More specifically, would a power supply that met MIL-STD-461C RE02 meet MIL-STD-461E RE102 if all other things were unchanged. Also has anyone any experience with correlating MIL-STD-461C CS01 versus MIL-STD-461E CS101. I think what I am trying to find out is; has the MIL-STD-461E version turned out to be more stringent or less stringent in the areas of RE102 and CS101. Thank You in advance for any responses. Have a great day Sandy Mazzola BAESYSTEMS Inc From the view of compliance with Test Methods CS101 and RE102, I would generally say that 461E is not more stringent than 461C. Our stuff usually passes CS101 and fails RE102, just like we always do (we're traditionalists; that is, we always make the same mistakes from program to program). OTOH, 461E is a more (justifiably) paranoid document than 461C, requiring the lab to perform and document things like automated data acquisition system calibration. In that respect, 461E is harder to perform. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Video Cameras for EMC Test Monitoring
From: Sandi McEnery [mailto:smcen...@ustech-lab.com] Sent: Wednesday, January 15, 2003 10:35 AM To: emc-p...@majordomo.ieee.org Subject: Video Cameras for EMC Test Monitoring We are in the process of purchasing video cameras for monitoring EMC Immunity testing up to 10V/M. Pricing for cameras designed to withstand 20V/M is way high do any of you successfully use cameras that are not as sturdy? Or ... does anyone know where we might purchase a used system?? Sandi McEnery US Technologies 770-740-0717(ph) 770-740-1508 (fax) smcen...@ustech-lab.com I can suggest two paths. I have been using an aged Sony Hi-8 Handycam. This yields an NTSC color video output and an audio output. It has autofocus. Nothing special about the camera (it was passed along to me from our corporate PR guys when the built-in tape deck died). By itself, this camera would never withstand the fields I can develop (I do the 200 V/M, 10 kHz to 18 GHz military), so shielding was needed. So, here's Path 1. I bought a 1-gallon size paint can (metal, of course). I mounted a Corcom powerline filter (with built-in male powerline connector) into the bottom of the paint can. I also mounted two BNC feed-through connectors (one each for video audio). Connect the camera power pack, and connect the camera outputs to the BNC connectors. I then stuffed the camera power pack and the camera into the can using stiff foam rubber. After checking the camera positioning, I cut a 1 diameter hole in the paint-can cover. Press the cover in place, and you are finished. I didn't use any screen across the open hole in the cover. I also didn't bother with any mounting hardware for the can (I use traditional military duct tape for almost everything). The paint can makes an excellent RF shield, since all the seams are soldered. The cover, when pressed in place, also yields a perfect RF seal. (Caution; fancy paint cans come with an internal plastic film to prevent corrosion. If you get this kind, you will have to use a wire wheel and buff off the plastic around the cover seal.) My gamble about no lens-hole shielding was successful, but you could always solder a patch of copper screen onto the rear surface of the cover hole. Also, the audio is transmitted through the can walls pretty well. (Audio is really great, as it lets you verify continued operation of the UUT, and allows correlation of observations with UUT operational events. And it gives you a one-way intercom.) This paint-can technique is great for shielding other support devices during a test; and the cans are available in quart and pint sizes also. Finally, the shiny paint-can makes a great statement about the frugality of your lab. But, even Sony Handy-cams must die sometime, so now Path 2. After 6 years of use, it became intermittent enough to force me to get a quick replacement. I bought a color CCD video camera, color LCD, power pack and a 65' camera cable from Ramsey Electronics. http://www.ramseyelectronics.com/ You can download their video products sub-catalog at: http://www.ramseykits.com/catalog/pdf/2003-103.pdf I bought their CCD322 camera package for $430. At the worst, I figured I could always use the paint-can shielding technique. But the CCD322 camera looked promising, as the case was made from a tubular section of aluminum. Aside from the open lens end, there is only one circumferential seam, and that could always be covered with conductive aluminum tape. All signals and power flow through a single 65' long control cable (about a 1/4 diameter). The camera runs in color mode when there's enough ambient light, and switches to IR with its own LED illuminators as ambient light decreases. Picture quality on the associated monitor is fine, although the viewing angle restriction of the LCD (and a really cheap bracket/stand) are small drawbacks. I set the camera on a cheap plastic tripod (the camera has a cheap little mounting bracket), and ran the cable through a hole in my penetration port. I didn't do any shielding to the camera housing, and I didn't even try to ground the cable at the port. (I did route the cable as close to the floor and walls as possible, and I minimized the length of cable in the enclosure.) With this off-the-shelf configuration, I was very pleased to find that I could do 50 V/M exposure without any camera problems. In the couple of months that I have been using this system, I have done exposures up to 150 V/M at some frequencies. I noticed that the camera began to exhibit some sync problems at 150 V/M in the 600 MHz region. So, it looks like I will have to do a few things, like tape the camera body seam and ground the cable at the penetration port (and maybe examine the cable-to-camera-body ground technique), if I want to get a 200 V/M capability. The camera does a great job at high light levels, but if it decides to turn on its IR illuminators, you get a serious reflection problem. I suppose the IR LED's are only On or Off, so, if
RE: Fiber optic cable testing per EN 55022:1998 ?
-Original Message- From: Hans Mellberg [mailto:emcconsult...@yahoo.com] Sent: Thursday, January 09, 2003 4:59 PM To: John Woodgate; emc-p...@majordomo.ieee.org Subject: Re: Fiber optic cable testing per EN 55022:1998 ? As a matter of fact the local SCV EMC society paper next week is about EM radiation from fiber optics. No, not from the glass or plastic itself!, but from the metalized reflector coating and also from the proximity of the Tx diode next to the connector. Actually measurable radiation! --- John Woodgate j...@jmwa.demon.co.uk wrote: I read in !emc-pstc that Tom Cokenias t...@tncokenias.org wrote (in v04205511ba4377eaa41d@[10.10.10.79]) about 'Fiber optic cable testing per EN 55022:1998 ?' on Thu, 9 Jan 2003: I'm wondering how to handle fiber optic cables under the new EN55022 going into effect August 2003. Measurements are supposed to be made on telecommunications cables, and fiber optic cables are being used for telecommunications. From my reading of the standard I don't see that they would be excluded, but neither do I see how they should be tested. Can you see any mechanism by which they would emit EM radiation below 400 GHz, or conduct it, or lack immunity to it? You don't have to do tests that are clearly not sensible. -- Regards, John Woodgate, OOO - Own Opinions Only. Here's a link to a steel armored fiberoptic cable. I suppose the steel is a ribbon wrapped in a helix around the cable, somewhat like the old BX electrical cable. Currents induced in the steel would have to flow along the helix, which would electrically present as an inductor. Random conductive paths would link one turn of the helix to the next, shorting out the voltage from turn to turn. With sufficient induced current, a bit of corrosion, and maybe a little motion, this has the potential to create some interesting noise. http://www.mohawk-cdt.com/main.html Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Korean Frequency Allocation
Would anyone know if Korea allocates 210 MHz to 216 MHz to TV VHF Channel 13 (as is the USA convention)? If not, then what emissions are authorized for that band? Thanks in advance! Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Vehicle Mounted PCB
Dave: I just found a url for that vehicle EMC spec. Notice that Ford, GM Daimler Chrysler are setting up a lab accreditation scheme too. http://www.fordemc.com/ http://www.fordemc.com/ Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: Monday, December 09, 2002 2:57 AM To: EMC-PSTC Subject: Vehicle Mounted PCB Thanks to all those who responded to my posting. Some responses were helpful, some were amusing, and some were both, but all were gladly received. Best regards, David Sproul,
RE: Vehicle Mounted PCB's
You could look to the SAE J1113 Surface Vehicle standard. This covers EMC, ESD and physical environmental requirements for vehicle equipment. Further, the major auto companies have internal standards. (The only one I can recall is Ford's ES-XW7T-1A278-AB EMC specification.) Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com] Sent: Friday, December 06, 2002 11:17 AM To: David Sproul; EMC-PSTC Subject: RE: Vehicle Mounted PCB's sprays bank notes with red ink when it believes a robbery is taking place. And you want to sell it the US - heavens forbid! The new government administration is already putting our money in the red fast enough and doesn't need the additional help! I don't know what standards are involved but it seems customers not buying the product because of these problems would would drive a re-design pretty darn quickly. Gary -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: Thursday, December 05, 2002 11:19 AM To: EMC-PSTC Subject: Vehicle Mounted PCB's Dear group, A customer has been asked to redesign a board to stop it malfunctioning due to vibration, temperature and radio interference. They have been given a control PCB which they are told is the main culprit for the malfunctions. They circuit is mounted in an armoured vehicle as part of a security system which sprays bank notes with red ink when it believes a robbery is taking place. Apparently it sprays ink if it gets too hot, too cold, gets bumped, or if a radio or mobile phone is operated too close to it. The bad news is that this is on the market and being used by security firms within the UK and mainland Europe, with no real evidence of previous compliance with anything. Should this comply with any of Vehicle directive requirements? Are there any peculiar EMC requirements other than the usual 61000 series? What standard is likely to cover this device for use in vehicles? Although they haven't asked, what would be the most appropriate standard to cover safety requirements for this device. (Although is runs of only 12V, I am concerned about a fault causing a short across the battery, for example)? There was mention of selling it in the US too. If any has thoughts on what such a device should comply with there, all comments would be gratefully received. If you are thinking of writing back and suggesting the device be thrown in the bin, then I'm sorry to say that someone else has beaten you to it. Best regards, David Sproul,
RE: Radiated immunity testing above 1 GHz
-Original Message- From: richwo...@tycoint.com [mailto:richwo...@tycoint.com] Sent: Wednesday, November 13, 2002 6:00 AM To: emc-p...@majordomo.ieee.org Subject: Radiated immunity testing above 1 GHz I need to make a decision on an amplifier for radiated immunity testing in the 1-2 GHz range. The choices appear to be a new solid state amplifier ( I have not located a used one) or a used TWT amp. Is anyone using a TWT amplifier for radiated immunity testing above 1 GHz? Do I need to be concerned about protecting the tube from damage caused by excessive VSWR cause by, perhaps, chamber effects? Is there anything else I need to know about TWT amps (yeah, I know - throw it way if the tube dies)? Richard Woods Sensormatic Electronics Tyco International Rich: A 1 Watt TWT octave-band amplifier is fairly common, and I have seen them sell on eBay for a few hundred dollars. But 1 Watt (depending on antenna performance system losses) just barely gets you in to the lowest end of immunity testing. A 10 Watt amplifier might cost under $7k new, and would be a rare find at an auction or from an inventory reduction at an equipment rental company. But 10 Watts will let you do most commercial immunity work. A 20 Watt amplifier takes the edge off of trying to get the fields, and also lets you do military work (with some patience). I use a set of Hughes 8050 20 Watt amps that cover 1 GHz to 18 GHz. In a previous life, I had the luxury of 200 and 300 Watt TWT amplifiers. They were the Varian VZ series, and I seem to recall they cost around $30k each (in 1980 dollars). I don't know if anyone even makes new equipment like that any more; maybe you can't even replace the TWT's in them. Whatever you get, try to be sure that the amps have circulator protection. TWT's don't like reflected power, and immunity setups almost guarantee ranges of lousy VSWR. The circulator routes that reflected power away from the TWT and into a termination. Most lab amplifiers will either come with a circulator as standard, or have it as a factory option. If you get an amp that doesn't have an internal circulator, endeavor to get an external one ASAP. Re TWT amp operation. The tube makes up maybe 80% of the amplifier cost. Every time I flip on the TWT amp switch, my finger twitches a little. TWT amps don't seem to ever die while in use; rather, they die just as you start them up. I'm very cautious about protecting the amp from physical shock, and I always let the main power stay on for about 5 minutes after RF operation to let the TWT cool down as much as possible. One further suggestion; place the TWT amp as close as possible to the antenna. Since a TWT amp will have about 40 dB of gain, you can usually afford to lose a few dB in a long coax between the signal source and the amp, and still be able to drive the TWT to its limit. This arrangement will but maximum power to your antenna. All of the TWT amps I have ever used would withstand whatever RF was inside the shielded room, maybe since they were relatively dumb amplifiers. You might have a problem with this technique if your TWT amp has a microprocessor controller or some other fancy features. And, even for the 1 GHz to 2 GHz range, don't use even good coax, like RG-214. Get either semi-rigid solid wall coax, or get the superb flexible stuff from Gore or Storm. Finally, make sure that your leveling pre-amplifier will control the entire frequency range you are going to use. Some systems (like my IFI LPA-5) might require an optional variable-gain amplifier deck for frequencies above 1 GHz. (Maybe this isn't an issue for you, if you are controlling level by computer control of the signal source amplitude.) Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: docopocoss
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, November 06, 2002 2:01 AM To: emc-p...@majordomo.ieee.org Subject: Re: docopocoss I read in !emc-pstc that Price, Ed ed.pr...@cubic.com wrote (in b78135310217d511907c0090273f5190d0b...@curly.ds.cubic.com) about 'docopocoss' on Tue, 5 Nov 2002: In view of the elegance of docopocoss, drawing quartering comes to mind. Look, I didn't invent 'date of cessation of presumption of conformity of the superseded standard' - that's probably down to someone in the Commission's legal department. I just balked at typing it out over and over again, so I just copied the 'doa', 'dop', 'dow' system. The initials might have produced an even less elegant 'word'. -- Sorry, John. Try to remember that linguistic pioneers sometimes catch an arrow. I had also done a Google search, and found your name at the top of a very short list of references. The first thing about getting a newly minted word into general usage is to have a snappy pronunciation. Let's take a hint from Spanish, and accent the second syllable. That yields an English-friendly doh coh' poh caws. Maybe we could come to admire DOCOPOCOSS more if we could rhyme it with something. Hmmm: DOCOPOCOSS Don't forget to floss A dirty double-cross Help an old lady across A rock with no moss Here comes the boss And on that note, I realize I better get back to work. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: docopocoss
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Tuesday, November 05, 2002 1:04 PM To: emc-p...@majordomo.ieee.org Subject: Re: docopocoss I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in 200211051744.jaa26...@epgc264.sdd.hp.com) about 'docopocoss' on Tue, 5 Nov 2002: docopocoss This word was unknown to me. I checked an American dictionary and could not find it. Then, I called up the Google search engine and entered the word, hoping to find an English dictionary. Google immediately came back with the definition. We just put a new word into English! We should get an award for that. (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. In view of the elegance of docopocoss, drawing quartering comes to mind. g Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Shield Room Lighting
I think that another factor in shortening the life of incandescent lights is the fact that they are usually mounted in a heavy glass protective fixture. These glass globes offer a bit more safety from physical damage, and also look nicer than a bare light bulb in a socket. But the light bulb runs a lot hotter when you use the globe. I think this shortens the bulb life too. In my chambers, I have gone to bare bulbs in sockets. Of course, since my chambers are 9 feet tall, the bulbs are fairly safe even when people are moving large objects around (I have never had anyone accidentally hit a bare light bulb). I now use ordinary 100 W bulbs in open fixtures, and, over the past two years, my bulb life has improved to a point where I don't even think about it any more. BTW, my facilities guys wanted me to use some exotic industrial grade bulbs. IIRC, they were rated at 135 V for 100 W (so I suppose they were NOT 100 W bulbs at 120 V g). These bulbs were slightly longer and larger than an ordinary bulb, and had an anti-breakage Teflon film on the bulb surface. This gave then a satin appearance. However, those bulbs burned out just about as fast as ordinary bulbs (I was using them within globes at the time), and I since they cost several times more, I stopped using them. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: richwo...@tycoint.com [mailto:richwo...@tycoint.com] Sent: Thursday, October 31, 2002 12:00 PM To: emc-p...@ieee.org Subject: RE: Shield Room Lighting We have the same frequent burn out problem and we also have attributed it to the filters. We just keep replacing them. Has anyone tried the rugged bulbs marketed for use with garage door openers or ceiling fans or have tried the extended life bulbs? Do they last longer in chamber use to justify the cost? Richard Woods Sensormatic Electronics Tyco International -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, October 31, 2002 12:49 PM To: EMC-PSTC (E-mail) Subject: Shield Room Lighting Greetings all, I wanted to share an experience and I hope benefits someone else. My past experience with shield room lighting is that incandescent bulbs frequently burn out, about once every 2-3 months. I tried ruggedized lamps of various sorts, still with the same results. Obviously, I wanted to avoid florescent lighting because of the huge fields they radiate. After some investigation and discussions with co-workers, it became apparent that the problem is the line filter for service power in the room and the tungsten filament in the bulb. These line filters are typically have a really large line to neutral capacitance which significantly lowers the source impedance of the line. Coupled with this, tungsten experiences a fairly high in-rush current owing to it's very dynamic negative temperature coefficient. I toyed with idea of using inrush limiters but I thought there had to be a reliable low-tech solution. And at all costs, whatever solution I used, I wanted to avoid injecting unwanted RF noise into the room. I discovered traffic light signal bulbs. Available from a few sources, these bulbs have at least 5 filament supports, heat dissipaters and reflectors and are designed for continuous on/off operation in all sorts of weather conditions. They even keep working when the hanging fixtures bang into each other in wind storms. I also learned that these bulbs have about a 1 to 2 year life expectancy in these conditions, so I tried it out in my room. So far, I've logged a full year of use on 4 x 150W bulbs with no burn out. And no, I don't just leave them turned on. If you want to try this, do it soon because it appears that these bulbs may become a thing of the past and prices may be driven up. Over the last few years, many cities and counties are replacing their incandescent bulbs with the new LED bulbs and with great success. As soon as a white LED light becomes available I may try it out, although I guess I could use red LED lamps since I used to be in the navy. Best regards, -doug Douglas E. Powell Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO 80535 USA --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Temp/Humidity Meter
-Original Message- From: HALL,KEN (HP-Roseville,ex1) [mailto:ken_h...@hp.com] Sent: Wednesday, October 30, 2002 4:32 PM To: 'POWELL, DOUG' Cc: 'g...@microprecision.com'; Emc-Pstc (E-mail) Subject: RE: Temp/Humidity Meter Hello, We buy Radio Shack and others and have them calibrated by MicroPrecision Regards, Ken Hall Hewlett-Packard http://www.microprecision.com/index.html There's just something about the above statement that makes me feel so ancient obsolete. g Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question on Receiver EMI testing..
Adding a bit to Ken's comments. I agree, but I have seen many times when surprise emissions have been created by equipment that was never supposed to do that. Even a simple receiver can have a spurious problem, and I have encountered complicated receivers where T/R switches or electronic clamping circuits have created noise of their own (and very far out-of-band). I would need a good reason to NOT exercise the receiver. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Tuesday, October 29, 2002 5:36 PM To: Grasso, Charles; emc-p...@majordomo.ieee.org Subject: Re: Question on Receiver EMI testing.. I'm not going to claim to be an expert on this one, but this is my two cent's worth. From the point of view of what rf might leak from the EUT, it seems that an LO or IF would be the main concerns. I don't see how the absence/presence of a receivable signal would affect LO emissions. The amplitude of the IF signal would be proportional to received signal strength, so if the IF were in the band controlled by your emissions limit, that might be important. -- From: Grasso, Charles charles.gra...@echostar.com To: emc-p...@majordomo.ieee.org Subject: Question on Receiver EMI testing.. List-Post: emc-pstc@listserv.ieee.org Date: Tue, Oct 29, 2002, 5:47 PM Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. 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;nbsp;%20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: VSWR FROM ATTACHED DATA
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Tuesday, October 29, 2002 3:25 AM To: 'IEEE EMC SAFETY PSTC' Subject: VSWR FROM ATTACHED DATA People You may remember that you helped me a few weeks ago with VRC/VSWR assessments. As part of the same work I am attempting to assign a VRC/VSWR for a coupling de-coupling device (CDN) but have not been able to get a typical value from the manufacturer of the device. However, I have been sent the attached data. Are you able to help again by telling me how to calculate the VSWR or VRC from this data? Thanks Ian Gordon Ian: You could calculate the VSWR in two step from the data you have. For instance, at 150 kHz, the reported input impedance of the CDN was about 130 Ohms (output port shorted or open). Now, I'll assume that the driving RF generator had a source impedance of 50 Ohms. First, you can find the reflection coefficient, r, from: r = [(Zl - Zo)/(Zl + Zo)] Where the source impedance, Zo, is 50 Ohms, and the load impedance (the CDN reported data) is 130 Ohms, then: r = 0. Then, you can find the VSWR from: VSWR = [(1 + r)/(1 - r)] So, the VSWR at 150 kHz is 2.6! All that should be explained in your lab's #2108 Test Procedure. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: RFI/EMI requirements for the automotive industry
-Original Message- From: Denomme, Paul S. [mailto:paul.deno...@viasystems.com] Sent: Tuesday, October 29, 2002 6:16 AM To: 'emc-p...@majordomo.ieee.org' Subject: RFI/EMI requirements for the automotive industry Hi All, Can someone please inform me of the standards RFI/EMI standards that are required in the automitive industry. This would be for a microprocessor controlled item that is part of the vehicle. My customer stated that EMI/RFI specifications are Standard Automotive. What I am trying to figure out is what is Standard Automotive EMI/RFI requirements. Thank you for your help. Paul Denomme Viasystems Paul: I'm often confused by these types of problems. I usually ask my customer what the specific standards are, and, if I never heard of documents, can they give me a copy. It gets really strange when my customer has to admit that they don't know either, and will get back to me after they ask THEIR customer. I like to think that it helps to build a better relationship with my customer if I admit right away that I don't know what the heck he's asking for. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: definitions?
-Original Message- From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: Friday, October 25, 2002 12:35 PM To: 'Jacob Schanker'; Bill Flanigan; emc-p...@majordomo.ieee.org Subject: RE: definitions? Or we could simply do as a friend of mine does and refer to dB(dollar). What's that 10 meter chamber cost? About 126 dB(dollar). ;) Ghery But I always thought that money was power. Maybe you meant 63 dB$. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Definition ?
There seems to be more than a few instances of odd differences in British and American technical terms. One that I especially like is the name for that little butterfly valve in a carburetor; we call it a choke, but the British call it a strangler. The odd thing is that the American preference for words like hood and choke implies a preference for Old English or Germanic roots. The British preference for bonnet and strangler implies a preference for Middle French and Latin. I wonder if they means anything? Regards, Ed (Eduoard or Eadvard?) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From:Ken Javor [SMTP:ken.ja...@emccompliance.com] Sent:Thursday, October 24, 2002 10:48 AM To: lisa_cef...@mksinst.com; emc-p...@majordomo.ieee.org Subject: Re: Definition ? Screen is the Queen's English for what Americans call shield. As in Brit usage windscreen for American windshield. -- From: lisa_cef...@mksinst.com To: emc-p...@majordomo.ieee.org Subject: Definition ? Date: Thu, Oct 24, 2002, 8:15 AM Hi all, Could anyone explain the definition of a screened cable as it is applied in EN61000-4-6 (and perhaps elsewhere) Thank-you in advance Regards, Lisa --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: 160 Amp Triax
-Original Message- From: Ted Rook [mailto:t...@crestaudio.com] Sent: Friday, October 11, 2002 7:04 AM To: Subject: 160 Amp Triax maybe you could try the DOD, they probably have something like this to feed the deep space antenna at Arecibo ;-) seriously now, I'm very curious to know the application, or have we been missiled by a typo? Best Regards Ted Rook, Console Engineering, ext 4659 Please note our new location and phone numbers: Crest Audio Inc, 16-00 Pollitt Drive Fair Lawn, NJ 07410 USA 201 475 4600 telephone receptionist, 8.30 - 5 pm EST. 201 475 4659 direct line w/voice mail, 24 hrs. 201 475 4677 fax, 24 hrs. Ted: Having had a little chuckle about the implications of needing 160 Amp, 2000 V triax, I think we need to clarify the OP's requirements. I'm gonna stick out my neck a bit, but I don't think the OP was looking for an RF triax cable, where the usual application of putting DC power on the line (by using a bias tee and blocking capacitor) is to support a remote RF pre-amplifier. The humor for we RF guys is that the implied power being transferred is vastly higher than reasonable for a pre-amp. I think the OP meant that he was looking for a power cable that was built in a triaxial manner, and that the central core and the inner shield layer would have to carry the 160 Amps with a 2000 V potential. And, that the insulation between the inner shield and the outer shield also had to withstand 2000 V potential. He didn't say anything about the current capacity of the outer shield, nor anything about the quality of any external insulation. So what he wants is a power transmission line built in a specific manner, not an RF line that also will carry current. I don't think it's an off-the-shelf product, but it sure is possible to build. I wonder if twisted shielded pair would work just as well? Hmmm, two strands of # 1/0, with heavy insulation. That would end up maybe 2 OD. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: High Voltage Equipment/Appliance Wire
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, October 10, 2002 12:23 PM To: emc-p...@majordomo.ieee.org Subject: Re: High Voltage Equipment/Appliance Wire I read in !emc-pstc that POWELL, DOUG doug.pow...@aei.com wrote (in B44016F6854CD511A6470003476B45E43825EF@FTCEXC01) about 'High Voltage Equipment/Appliance Wire' on Thu, 10 Oct 2002: I need to locate a resource for High Voltage Triax cable. It should be rated to 2000V AC/DC on both the center conductor and the 1st shield. The 2nd shield will be grounded and then an overall jacket. In addition it needs to be rated for 160 Amps continuous. This is for you esoteric hi-fi vinyl disc player tone arm? -- Regards, John Woodgate, OOO - Own Opinions Only. Yes; I believe he has an incredibly high-gain, liquid argon cooled, pick-up coil. Pressurized oil bearings are also giving him a problem. g Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: EMI suppression for fiber-optic thru-hole ...
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, October 10, 2002 1:10 AM To: emc-p...@majordomo.ieee.org Subject: Re: EMI suppression for fiber-optic thru-hole ... I read in !emc-pstc that Doug McKean dmck...@corp.auspex.com wrote (in 011101c26fe3$e97937d0$cb3e3...@corp.auspex.com) about 'EMI suppression for fiber-optic thru-hole ...' on Wed, 9 Oct 2002: Now the cable is of course non-conductive, but is there some emi grommet for the gaping hole in such a construction that plugs up a large diameter hole while at the same time allowing for a small thru-hole? I've seen a cheap standard mechanical metal part used for that. It's a domed top with spring fingers dangling below it (think 'jellyfish'). It was modified by the user by having a bite taken out of the edge, using a simple press tool, allowing the fibre to pass through. Far cheaper than a conducting grommet and worked well. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! John may be talking about (what's called in the USA) a knock-out plug. These are commonly available in most hardware stores, and come in several sizes to match the conduit holes in metallic wiring boxes. If you make a mistake and knock out too many holes, you can put a knock-out plug in to fill up the unused hole. These plugs are often zinc or nickel plated, and have a series of spring fingers that hold the plug very firmly in the hole. They do a pretty good job as an RF plug, as long as they are clean and you make sure the finger tension is strong. To accommodate a fiber cable, you will have to make a small notch at the perimeter to avoid stressing, or even cutting, the cable. If you are doing a production quantity, this will be an operation that needs a special mechanical jig. If it's just a few pieces, you can cut a little radial notch with a hacksaw blade. If you really want to get fanatical about the RF joint, you can try tack soldering a few bonds around the perimeter of the plug (but don't melt your fiber cable). Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Explosive Atmosphere Safety Question
I have recently been pondering the safety design of the typical automobile gasoline tank fuel quantity sensor (or sender) assembly. The several examples that I have seen consist of a float attached to a mechanical pivot arm. As the fuel level varies, the arm moves, changing the resistance of the sensing element. My first question is how is the mechanical sliding resistive contact isolated from the explosive fuel/air mixture? Certainly, when the tank is nearly full, the entire sensor element is submerged in the fuel. But what happens when the tank is nearly empty, and external air replaces the fuel. The sensor is then hanging in the fuel/air mixture. In short, how are sparks avoided at the mechanical sliding sensor contact? Secondly, how is the problem of sensor self-heating (during a single-fault condition) avoided? I can imagine a scenario where the hot vehicle bus is faulted to the sensor lead. Since a typical sensor element varies between about 100 Ohms to just a few Ohms, the sensor element could dissipate 25 Watts or more. This would cause rapid heating of the sensor element, possibly ending in the burn-out of the resistive element (inside the fuel tank). Again, how is this ignition scenario prevented? I am hoping to get a few informed comments before I go out and buy one for a sacrificial dissection. (I think I became an engineer because I never could get those frogs to work again after re-assembly.) Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: FCC information
-Original Message- From: Neil Helsby [mailto:nei...@solid-state-logic.com] Sent: Tuesday, October 08, 2002 2:55 AM To: emc-p...@majordomo.ieee.org Subject: FCC information Further to my recent queries, I was pointed at a couple of web sites. These are: ecfr.access.gpo.gov frwebgate.access.gpo.gov Checking both I find different versions of the FCC documents. Looking at, for example, 15.107 conducted limits, the first site includes a heading this data current as of the Federal Register dated September 19, 2002 and the second Revised as of October 1, 2001 The text of both bear little commonality. There are also small discrepancies between the versions of 15.109, radiated emissions. As the ecfr data appears to be more up-to-date, do I ignore the frwebgate pages and is there any official document to say that would be correct? Thanks for your help, Regards, Neil Helsby Neil: It bothers me that I can often find information that's more recent by going directly to the FCC's OET site. For instance, look at: http://www.fcc.gov/oet/info/rules/ where there is a Part 15 release dated 8/23/2002. You would think that the official version would be at the Government Printing Office's Code of Federal Regulations, but that doesn't seem to be the case. I seem to have found a comment that the CFR is updated only on a periodic schedule, and that the latest components are only then published in the CFR. I also recall that US law becomes effective (or official) when it is published in the daily Federal Register. So, there may quite often be a considerable time lag between the daily Register appearance and the next GPO CFR revision. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: information safe
-Original Message- From: Lucian [mailto:y...@ht.rol.cn.net] Sent: Thursday, October 03, 2002 5:27 AM To: emc-p...@majordomo.ieee.org Subject: information safe Dear Sirs, We know it's very important to keep information safe, while PC and its monitor emit signals always. One method to deal with it is shielding, another method is to place an emitter besides PC emitting signals to interfere with PC's signals. Does anybody know any information about the latter method? Thanks a lot in advance. Best regards, Lucian Lucian: You could employ a noise emitter of sufficient ERP to actively destroy the front ends of sensitive listening devices. However, EN FCC compliance will be a problem. Best (End-of-week) Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis
RE: preplated steel
-Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, October 02, 2002 3:23 PM To: emc-p...@majordomo.ieee.org Subject: Re: preplated steel I read in !emc-pstc that Ted Rook t...@crestaudio.com wrote (in sd9b1823@peavey.com) about 'preplated steel' on Wed, 2 Oct 2002: I believe that if you want edges that don't corrode you can get the right material by coordination between your engineers and purchasing people. The stuff that would protect sheared edges was 'Terneplate' in UK. The plating is an alloy (tin/lead?) and the process is not all that cheap, IIRC. But the overall cost can be at least competitive with post-plating and is perhaps more environmentally-friendly. It may be that lead-free platings are now used, and these may be less effective at protecting sheared edges. -- Regards, John Woodgate, OOO - Own Opinions Only. Terne plated steel is cold-rolled steel that has a thick layer of 92% lead / 8% tin. I think the process is a continuous hot-dip technique, not electro-plating. The lead/tin coating allows the steel to be deformed or stamped without the coating breaking. The plating also lubricates the forming equipment, allowing for less tool wear and more extreme formations of the steel sheet. The most common use in the USA is the making of vehicular fuel tanks. The terne coating provides an excellent barrier to prevent the gasoline or diesel oil from contacting the steel. All that said, I don't think terne is desirable for electronic work. The high-lead alloy looks dingy, and the lead rubs off onto your fingers. Also, the process doesn't do anything for the cut edges of the steel sheet. You would still have to use something like a folded joint (for mechanical strength) and then reflow the plating in a soldering operation, to wet and re-plate the exposed surfaces. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: MEASURING VSWR WITHOUT A DIRECTIONAL COUPLER
Everybody I need to assess the uncertainty of radiated emission and immunity measurements and thus need to measure the mismatch between components in the systems. The frequency range of interest is 30MHz-1GHz) Is there a way in which I can measure the VSWR of a cable-antenna-receiver/amplifier combination without having to purchase a directional coupler or network analyser? The equipment I have at my disposal is: two power amplifiers (150kHz-30MHz 80MHz-1GHz), a spectrum analyser with tracking generator (9kHz-2.6GHz), signal generator (150kHz-1GHz), RF power meter (9kHz-1GHz) and a receiver (9kHz-2.6GHz). Any suggestions would be appreciated. Thanks Ian Gordon Ian: It's a request that may be intellectually stimulating, but for a real-world answer, go get a directional coupler. Since you already have invested multiple thousands in equipment, there's no excuse to not buy a directional coupler. Check out eBay, go to your closest electronics surplus store, check out Pasternack Mini Circuits Werlatone, or try a rental company. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: EMC Prosecution in UK
-Original Message- From: Alan E Hutley [mailto:nutwoo...@nutwood.eu.com] Sent: Wednesday, September 25, 2002 11:43 PM To: Emc-Pstc Discussion Group Subject: EMC Prosecution in UK EMC Prosecution, the company mentioned in the report Hot UK Ltd is owned by Helen of Troy based in El Paso Texas. For full story go click below http://www.compliance-club.com/TS%20Prosecution.doc http://www.compliance-club.com/TS%20Prosecution.doc Alan E Hutley EMC Compliance Journal www.compliance-club.com http://www.compliance-club.com HOT was fined $9,000 by the British magistrates. HOY FY 2001 sales were $361M. Hair dryers are a hot market! http://www.helenoftroylp.com/index.htm http://www.helenoftroylp.com/index.htm Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis
RE: Difference between Receivers and Spectrum Analyzers
Muriel: The biggest difference is the first stage of the spectrum analyzer. The typical SA presents the signal (possibly through a bandpass filter and attenuators) to the first stage mixer. A receiver typically has a tuned RF section, which improves selectivity. A SA thus has a higher noise figure, and it is more vulnerable to overload and mixer burn-out. Now, if your SA has a tunable pre-selector, it starts to look a lot like a receiver. And, if your receiver can be swept in frequency, it begins to look like a SA. Modern SA's and receivers are not all that different in performance. More importance is being given to processing beyond the RF/IF signal chain, and BOTH now look more like computers than anything else. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Muriel Bittencourt de Liz [mailto:mur...@eel.ufsc.br] Sent: Wednesday, September 25, 2002 11:51 AM To: Lista de EMC da IEEE Subject: Difference between Receivers and Spectrum Analyzers Hello Group, For EMC measurements (conducted and radiated emissions), electromagnetic fields measurements (via antennas), what is the difference between using a EMI Receiver or a Spectrum Analyzer?? Some guesses that I've been thinking are: - The Receiver is more accurate than the Spectrum Analyzer, so it is more suitable for EMC measurements that aim to respect the EMC standards. - For measuring electromagnetic fields (eg electric field) for safety (human safety standards for man-made electromagnetic fields, like ICNIRP) the Receiver is suitable because it can give an accurate value to a particular frequency that is being studied. - The spectrum analyzer is qualitative, i.e. it gives an idea of how the spectra measured is distributed in the frequency range. The receiver is quantitative, i.e. it gives accurate amplitude for each frequency swept. Well, I think this subject is very controversial, and it will generate a lot of discussions, that will be good for us all. Best Regards, Muriel B. de Liz --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Current from Car 12V cigarette lighter socket / 42 VDC
-Original Message- From: Jim Eichner [mailto:jim.eich...@xantrex.com] Sent: Wednesday, September 18, 2002 1:36 PM To: 'Ken Javor'; Jim Eichner; 'EMC-PSTC - forum' Subject: RE: Current from Car 12V cigarette lighter socket Thanks. The solution you propose is in the works. The SAE is working on a completely different style connector for power connections to 12Vdc, and 2 other styles for 42Vdc and 120Vac connectors. This effort is just getting off the ground however. Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Pardon the slight topic shift, but when will we be seeing 42 VDC automotive systems? I understand that there has already been some fleet vehicle production with the 42 VDC standard, but when will it be introduced to the consumer market? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: New EU regulations - civil aviation
This discussion is touching on several aspects of Personal Electronic Devices (PED's) aboard aircraft. Bruce Donham, of Boeing, has a two-year-old paper with some hard data at: http://www.boeing.com/commercial/aeromagazine/aero_10/interfere_story.html Also, here's a cross reference to PED Electronic regulations: http://aviation-safety.net/events/ped/ped-regl.htm And, 106 pages of Aviation Safety Reporting System PED related history, current to May 2002, at: http://asrs.arc.nasa.gov/report_sets/ped.pdf This whole subject is about as confusing as EMF's and cancer. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, September 16, 2002 6:33 AM To: andrew.p.pr...@baesystems.com; emc-p...@majordomo.ieee.org Subject: Re: New EU regulations - civil aviation I do realize there is a big difference in the use of cable shielding/screening between general and commercial aviation practices. However the same general aviation aircraft that get by with little or no cable shielding/screening also have no electronic critical flight controls, so it is a wash. Any aircraft with flight controls qualified to RTCA/DO-160A will also have its maximum degree of automation limited to using the autopilot, possibly in conjunction with navigation inputs from aircraft NAV receivers. Both the rf (coax) and the base-band signal inputs into the autopilot would be shielded in my experience. I would definitely NOT expect personal electronics to interfere with such control systems (except for that all-important radio link). I would also expect that as an older aircraft gets avionics upgrades, with avionics qualified to RTA/DO-160D, that the cables connecting to the new avionics must be upgraded if the certification is to maintain validity. Specifically, if a new avionics upgrade were form, fit and function compatible with the old part, but required a shielded harness to meet RTCA/DO-160D, then that cable would have to be retrofitted along with the equipment. Am I being overly idealistic and out of touch here? In any case I reiterate: basic systems engineering practices mandate that a (non-rf) signal that carries flight critical information should be piped through the aircraft such that neither cross-talk nor stray emissions from other electronics cause interference. Along these lines, there are those who mourn the passing of the old term, rfi, because the term evoked the concept of RADIO interference, rather than the general term electromagnetic interference, which is global in its meaning. We need to consciously retain the idea that stray (unintentional) rf emissions from non-antenna connected electronics have the potential to create only rfi. -- From: andrew.p.pr...@baesystems.com To: emc-p...@majordomo.ieee.org Subject: Re: New EU regulations - civil aviation Date: Mon, Sep 16, 2002, 1:57 AM Firstly all avionic equipment is qualified to RTCA/DO-160 (European equivalent EUROCAE ED-14). All new equipment is test to DO-160D however there is still equipment installed on aircraft that was originally tested to DO-160A. Overtime the DO-160 has become more stringent with tighter emission levels and high immunity test levels which includes HIRF testing. There is one problem that arises from this as most of the cabling installed on the aircraft is unscreened. This is for weight saving reasons. Therefore with alot of older aircraft having a mixture of new and old equipments installed using cabling that is unscreened it is reasonable to assume that some Passenger Portable devices such as Gameboys, Laptop Computors, Mobile Phones, etc. will if that passenger happens to be sitting above a cable run cause interference with one or more aircraft systems. The UKCAA keeps a log of all reported incidents. Regards Andy Andrew Price Principal Development Engineer (EMC Specialist) BAE SYSTEMS Avionics A125 Christopher Martin Road Basildon, Essex SS14 3EL tel: +44 (0) 1268 883308 email: andrew.p.pr...@baesystems.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at:
RE: electricity and water
-Original Message- From: Ted Rook [mailto:t...@crestaudio.com] Sent: Friday, September 13, 2002 8:05 AM To: Subject: electricity and water my 2c The audience are children. Children do not even know what electricity is. This would seem to require education in more than one topic if it is to be understood by the children For example first: what is electricity? the difference between the wall outlet, the car battery and the overhead power lines. second: how does electricity travel from place to place? the concepts of conductors and insulators. third: why is electricity dangerous? electric shock, what is it? is the body a conductor or an insulator? are some parts of it are most sensitive to damage? fourth: why wet places and things are hazardous: water can change things from insulators to conductors eg wood, paper, cloth, skin. Good Luck Ted Rook Ted: All good points. You want to aim your pitch to 80% of the target audience. So, to provide some atypical guideposts, I got a skip loader and excavated some recollections of my early projects. When I was 4, my parents found that I was able to defeat child-proof power outlets. At 7, I knew batteries and motors worked better with copper wires than cotton strings. I was soldering at age 10. At 11, I was doing electroplating. At 12, I was building kits with tubes. And at 13, I learned about power dissipated in a load by measuring the DC resistance of a big flashbulb. YMMV! regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
