Re: Stumped
I used a probe calibrated to 450 MHz. I am going to my local hardware store, they used to carry copper and brass stock tubing, and I am going to try your suggestion. Thank you! -- From: Cortland Richmond 72146@compuserve.com To: Ken Javor ken.ja...@emccompliance.com, ieee pstc list emc-p...@ieee.org Subject: Re: Stumped Date: Tue, Oct 15, 2002, 3:19 PM It looks like you've answered your own earlier question, Ken; yes, you CAN see a difference between a leaky coax and good coax. I don't know that you can rely on the usual clamp-on current probe up at 400 MHz, but the relative difference tells you a good deal. And at 400 Mhz you only need a few feet for most of the power in shield current -- where the leaks end up -- to radiate away. You may also have copper losses in the shield -- which is not designed to carry signal current, remember -- as well as radiation losses through it. However, 20 dB more than very little is not necessarily a lot. You can measure how much is lost to radiation by repeating your original test, but this time with a small-diameter - as tight as practical - copper tube replacing the braid, making an almost perfect shield. The power lost thorough radiation will no longer be dumped to space, and you should see that as decreased loss end-to-end. Cortland --- 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: Ferrites for GND
Should I be using 10 Ohm here? -Original Message- From: Wan Juang Foo [mailto:f...@np.edu.sg] Sent: Friday, October 11, 2002 8:29 PM To: Dan Pierce; emc-p...@majordomo.ieee.org Subject: Re: Ferrites for GND Dan, It is a lossy material and most commercially available ferrite beads are 'tuned' to peak around the 100 MHz (VHF band II ?). I suppose there must be lots of exception but I have not use any outside this region. Most of them have different Q to describe their individual characteristics. Obviously, there are lots of RFI from many FM radio stations making it a necessity for many design. The material's 'lossy' property are subjected to saturation etc... Here is how I suppose it works :-) or fail to work often..., the presence of a ferrite bead in the ground path increases the inductance of the return path at some frequencies, it also introduces a form of RF losses that can be modelled as an ac resistance. Hence, it is a differential mode filter of sorts, it will not work against CM interference if the bead is only in the path of the return lead (signal ground). There is always other grounds that RF breakthrough can come around. However, so much being said, pay careful attention to the layout (installation and placement) because in general reference designs often do not provide reference 'photographs' for best layout practices. Some do provide PCB layout but very often in the interest to avoid verbosity, the all important 'notes' are absent. Inter-conductor capacitance can ruin the performance of the ferrite bead. Just my 2 ¢ cheerio... Tim Foo Dan Pierce dpie...@openglobe.net To: emc-p...@majordomo.ieee.org cc: (bcc: Wan Juang Foo/ece/staff/npnet) Sent by: Subject: Ferrites for GND owner-emc-pstc@majordo mo.ieee.org 10/12/02 03:01 AM Please respond to Dan Pierce I have always been reluctant to place ferrite beads in the ground path, but I see them frequently in reference designs for USB and Analog Audio. What kind material should this be and what characteristics would this type of ferrite have. I am assuming this ferrite would not have 600 Ohm impedance @ 100MHz Thanks in advance, Daniel J. Pierce Sr. Design Engineer OpenGlobe, Inc. (An Escient Technologies Affiliate) 6325 Digital Way Indianapolis, IN 46278 mailto:dpie...@openglobe.net P: (317) 616.6587 F: (317) 616.6587 (See attached file: Dan Pierce.vcf) --- 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: Stumped
It looks like you've answered your own earlier question, Ken; yes, you CAN see a difference between a leaky coax and good coax. I don't know that you can rely on the usual clamp-on current probe up at 400 MHz, but the relative difference tells you a good deal. And at 400 Mhz you only need a few feet for most of the power in shield current -- where the leaks end up -- to radiate away. You may also have copper losses in the shield -- which is not designed to carry signal current, remember -- as well as radiation losses through it. However, 20 dB more than very little is not necessarily a lot. You can measure how much is lost to radiation by repeating your original test, but this time with a small-diameter - as tight as practical - copper tube replacing the braid, making an almost perfect shield. The power lost thorough radiation will no longer be dumped to space, and you should see that as decreased loss end-to-end. Cortland --- 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
Harmonics - IEC/EN 61000-3-4 for equipment 16A
I have not been able to find any info on an EN version of the above, but there is a published IEC version. The Europa site does not list -3-4 as having been published in the OJ for the EMC directive. The IEC site contains the scope of the standard, including the following: These recommendations specify the information required to enable a supply authority to assess equipment regarding harmonic disturbance and to decide wether or not the equipment is acceptable for connection with regard to the harmonic distortion aspect. This document is not to be regarded as an International Standard. Questions: 1. This quote leaves me a bit puzzled. Does this standard contain test methods and pass/fail criteria, or is it somewhat less concrete than that? 2. Is anyone aware of a published or draft EN version? 3. Is there an upper limit to the current (e.g. EN61000-3-11 goes from 16A to 75A)? Thanks, Jim Eichner, P.Eng. Regulatory Compliance Manager Xantrex Technology Inc. phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. --- 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: RTTE - receive only equipment
The requirement for receivers depend on the classification of the receiver. As you may know most ETSI standards classify a receiver or send/receive combination into 3 classes, depending on the amount of hinder their failure may cause, in terms of 1 serious problem with risk for user (cellulars / marine / rescue equipment etc) 2 problems, easy to overcome (walki talkies) 3 failure causes no problem (car keyers babyphones etc) In Class 3 most tests do not need to be carried out. Some assessment need to be made however. When reading the text however, i cannot stop thinking that the authors thought of receivers being part of a transceiver combi, and not stand alone receivers. There is no reason however to exclude those receivers that upon failing may cause harm to a certain user or environment. In my opinion, commercial broadcast receivers for consumer use are definitely to be excluded (for now). The notification aspect is definitely only for intentional radiators, the scope of this may be taken wide, however. I personnally would never even think of notifying a radio receiver to the authorities. None of their business , and... Notification is related to effective use of the spectrum, unless your receiver is intentionally radiating, no impact on spectrum is to be expected. Gert Gremmen ce-test -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of richwo...@tycoint.com Sent: dinsdag 15 oktober 2002 19:09 To: emc-p...@majordomo.ieee.org Subject: RE: RTTE - receive only equipment Good question Amund. I found nothing in the Directive that provides a clear direction. I think that sound of silence from the rest of the group means that no one knows the answer. I checked the UK's notification form and there is only one place where they ask about the receiver: Duplex direction (if applicable) This should state simplex, ½ duplex or duplex operation. If duplex please quote, where applicable, transmit and receive frequencies and/or duplex split. It's a mystery. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Monday, October 14, 2002 8:43 AM To: emc-p...@majordomo.ieee.org Subject: RTTE - receive only equipment As far as I understand the RTTED, the directive also applies to radio receive-only equipment. But are we required to notify it for each member state within EU, if it use non-harmonized frequency bands ? Best regards Amund Westin, Oslo / Norway --- 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 --- 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 --- 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: Stumped
To try and verify your theory, I set up a signal generator at 100 and 400 MHz, -20 dBm into 50 Ohms. I drove a six foot section of RG-58 with bnc connections, and terminated in a shielded 50 Ohm dummy load. I repeated the same measurement using one of my twisted shielded pairs. I measured leakage current by placing a current probe around first the coax and then the TSP, sliding the probe up and down the cable looking for maxima. I did not see a significant difference at 100 MHz, but at 400 MHz there was 20 dB more leakage on the TSP than from the coax. Is it a good assumption that anything I measure with the current probe is essentially lost in transmission? -- From: Cortland Richmond 72146@compuserve.com To: Ken Javor ken.ja...@emccompliance.com, ieee pstc list emc-p...@ieee.org Subject: Re: Stumped Date: Tue, Oct 15, 2002, 12:59 PM Now that I've re-read the message, I see where you are coming from. I thought you were looking at common-mode loss of the cable (as a whole, shield included) *above ground*; you are looking at the center conductor common mode with respect to the overshield, almost as a coaxial cable itself. Yes, that seems a reasonable impedance for that configuration. Loss is from the conductor and from the dielectric. You have a relatively large, low-loss conductor -- but due to its high capacitance, I'd expect dielectric loss to predominate in the setup you are using. A question about the braid; you said it appears to be Kapton coated. Could it be that braid conductors are not making intimate contact with each other? In that case, radiation loss could still be a large part of what you saw. Cortland --- 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: Stumped
The braid looks pretty tight to me, but since real coax is always coated with opaque insulation, I can't make a direct comparison. If it were a leaky coax effect, would I be able to pick that up with a current probe placed around the cable? If I compared the current probe reading from a leaky coax to a good one, could I see the difference that way? -- From: Cortland Richmond 72146@compuserve.com To: Ken Javor ken.ja...@emccompliance.com, ieee pstc list emc-p...@ieee.org Subject: Re: Stumped Date: Tue, Oct 15, 2002, 12:59 PM Now that I've re-read the message, I see where you are coming from. I thought you were looking at common-mode loss of the cable (as a whole, shield included) *above ground*; you are looking at the center conductor common mode with respect to the overshield, almost as a coaxial cable itself. Yes, that seems a reasonable impedance for that configuration. Loss is from the conductor and from the dielectric. You have a relatively large, low-loss conductor -- but due to its high capacitance, I'd expect dielectric loss to predominate in the setup you are using. A question about the braid; you said it appears to be Kapton coated. Could it be that braid conductors are not making intimate contact with each other? In that case, radiation loss could still be a large part of what you saw. Cortland --- 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: Stumped
Now that I've re-read the message, I see where you are coming from. I thought you were looking at common-mode loss of the cable (as a whole, shield included) *above ground*; you are looking at the center conductor common mode with respect to the overshield, almost as a coaxial cable itself. Yes, that seems a reasonable impedance for that configuration. Loss is from the conductor and from the dielectric. You have a relatively large, low-loss conductor -- but due to its high capacitance, I'd expect dielectric loss to predominate in the setup you are using. A question about the braid; you said it appears to be Kapton coated. Could it be that braid conductors are not making intimate contact with each other? In that case, radiation loss could still be a large part of what you saw. Cortland --- 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: post from 'shbeard' contains a virus in the attachment
I also received the E:Mail, but it did not originate from me (at least not recently). I do not recognize the E:Mail shbe...@iglou.com, although, some time ago (6/6/02), I did start a thread with the same subject. I did not open the attachment for fear that it was a virus. Susan Beard Ted Rook t...@crestaudio.com@majordomo.ieee.org on 10/14/2002 05:53:30 PM Please respond to Ted Rook t...@crestaudio.com Sent by:owner-emc-p...@majordomo.ieee.org To:emc-p...@ieee.org cc: Subject:post from 'shbeard' contains a virus in the attachment my terminal found W32bugbear and quarantined the file --- 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 --- 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: RTTE - receive only equipment
Good question Amund. I found nothing in the Directive that provides a clear direction. I think that sound of silence from the rest of the group means that no one knows the answer. I checked the UK's notification form and there is only one place where they ask about the receiver: Duplex direction (if applicable) This should state simplex, ½ duplex or duplex operation. If duplex please quote, where applicable, transmit and receive frequencies and/or duplex split. It's a mystery. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Monday, October 14, 2002 8:43 AM To: emc-p...@majordomo.ieee.org Subject: RTTE - receive only equipment As far as I understand the RTTED, the directive also applies to radio receive-only equipment. But are we required to notify it for each member state within EU, if it use non-harmonized frequency bands ? Best regards Amund Westin, Oslo / Norway --- 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 --- 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: Stumped
I measured impedances of 15 - 25 Ohms. The separation between twisted shielded pair center conductor(s) and shield is the thickness of the center conductors' insulation - very thin. This makes the capacitance higher than for 50 Ohm coax. At the same time the close proximity of center conductors and shield reduces the inductance, relative to 50 Ohm coax, and since the impedance is the square root of the ratio of inductance by capacitance, it seems clear to me that the impedance has to be lower than 50 Ohms. But the impedance is not the major issue here. How am I getting so much loss in the very thin conductor insulation? Or is there another loss mechanism of which I am unaware? -- From: Cortland Richmond 72146@compuserve.com To: Ken Javor ken.ja...@emccompliance.com, ieee pstc list emc-p...@ieee.org Subject: Re: Stumped Date: Tue, Oct 15, 2002, 2:52 AM Ken, a few thoughts. Did you account for radiation resistance? You have described not merely a single-wire transmission line but ALSO, a fairly good antenna. The impedance is probably higher than you calculate. A coax cable with the same ratio of shield radius (height above ground) to inner conductor size will be higher impedance tan your 15-25 ohms. You have greater spacing -- the ground isn't concentric -- and the impedance HAS to be higher. For all but the lowest frequencies in the range you mention, the chamber prevents current on the cable from flowing as on a transmission line; its resonances couple differently to the line than operating over an unenclosed ground plane. But assuming your matching is correct, you SHOULD see only a travelling wave on the cable, and current or voltage that does not vary along the line (except due to loss). If the match is incorrect, you will have standing waves, and this you can confirm pretty easily with a current probe. The chamber resonances may obscure this. It is possible to find loss in common mode simply by measuring common-mode current at a peak near one end of a suspended conductor and again at a peak near the other end. The location of current nodes will depend (outside a chamber!) on wavelength, but the difference between them over length will depend on radiation and other losses. Cortland --- 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: 95/54/EC Automotive Directive Conflict
Alex, I believe you can market based on the French decision. However, you should at the same time appeal your case to the people in Europe responsible for the Automotive Directive and obtain a ruling. How this is done, maybe someone else in the group can divulge this information. 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. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Tuesday, October 15, 2002 12:44 PM To: emc-p...@majordomo.ieee.org Subject: 95/54/EC Automotive Directive Conflict Hi Forum, I have a French ITE product destined to be used in the UK. Primarily this was not intended to be used in a vehicle but now we want to make this possible. We have created a 12V lead accessory so that it can also be used in a vehicle e.g. a taxi or bus. Our French colleagues got the OK from their Vehicle Authority, UTAC, that the Directive 95/54/EC did not apply quote Your terminal is not designed mainly for use in cars. Therefore, Directive 95/54/EC is not applicable for terminal, but Directive 89/336/EEC is applicable. They now ship these for use in the French Market. The UK vehicle authority, VCA, has stated Directive 95/54/EC is Mandatory for this same product. Can I ship these products for use in the the UK based on the French decision without fear of prosecution from the UK authorities? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: LED's and laser safety?
Folks, Having now communicated with UL and others on this matter, I understand that there is no agreement between UL and their European counterparts that all LEDs are Class 1 (which is what I infer from the comment below). Even if such an agreement been in existence, its significance for companies wishing to use compliance with Harmonised Standards to support their declaration of conformity with the LVD or RTTED would be highly questionable. However, it seems that UL do not (in general - it's impracticable to make a categorical statement about such large organisations) mention those LEDs that are of the surface-emitting type (known as SLEDs) in their reports. However, not all LEDs are of this type and so the generalised statement is inaccurate. For further information about the safety of SLEDs and some other types of semiconductor optical emitter you may be interested in the statement published by the International Commission on Non-Ionising Radiation Protection (ICNIRP): http://www.icnirp.de/documents/led.pdf UL's stance on the safety of SLEDs can be seen to be in line with this statement by the international body on non-ionising radiation. Note also that IEC 60825-1, although mentioning in the Note to Clause 9.1 that single-fault condition testing is not needed for SLEDs, does not go as far as to say that all SLEDs are inherently Class 1. I hope that the above clarifies rather than confuses. My own opinions as always, Richard Hughes -Original Message- From: Warren Birmingham [mailto:war...@comfortjets.com] Sent: 11 October 2002 23:06 To: emc-p...@ieee.org Subject: Re: LED's and laser safety? Gary, I was recently in conversation with UL about LEDs whereas I am now being told that UL has convinced the European counterparts that LEDs are no longer considered Class I Lasers and the requirements for them to be tested as such has been dropped. UL no longer treats them that way in their CB Reports. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Thursday, Oct 10, 2002, at 08:53 US/Pacific, Gary McInturff wrote: IEC-825 has incorporated LED's into the safety standard but, from what I can tell, left a great deal of confusion. I typically deal with the 5 - 10 mcd devices and haven't been required to provide any IEC-825 conformity proof for the Western European test house. We may be jumping up to about 60 mcd and non-focused devices and I don't know where the standard starts to become concerned. I hate to buy the standard if it doesn't provide any clarity for these types of parts. Could you folks clue me in? Gary --- 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
95/54/EC Automotive Directive Conflict
Hi Forum, I have a French ITE product destined to be used in the UK. Primarily this was not intended to be used in a vehicle but now we want to make this possible. We have created a 12V lead accessory so that it can also be used in a vehicle e.g. a taxi or bus. Our French colleagues got the OK from their Vehicle Authority, UTAC, that the Directive 95/54/EC did not apply quote Your terminal is not designed mainly for use in cars. Therefore, Directive 95/54/EC is not applicable for terminal, but Directive 89/336/EEC is applicable. They now ship these for use in the French Market. The UK vehicle authority, VCA, has stated Directive 95/54/EC is Mandatory for this same product. Can I ship these products for use in the the UK based on the French decision without fear of prosecution from the UK authorities? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Stumped
Ken, a few thoughts. Did you account for radiation resistance? You have described not merely a single-wire transmission line but ALSO, a fairly good antenna. The impedance is probably higher than you calculate. A coax cable with the same ratio of shield radius (height above ground) to inner conductor size will be higher impedance tan your 15-25 ohms. You have greater spacing -- the ground isn't concentric -- and the impedance HAS to be higher. For all but the lowest frequencies in the range you mention, the chamber prevents current on the cable from flowing as on a transmission line; its resonances couple differently to the line than operating over an unenclosed ground plane. But assuming your matching is correct, you SHOULD see only a travelling wave on the cable, and current or voltage that does not vary along the line (except due to loss). If the match is incorrect, you will have standing waves, and this you can confirm pretty easily with a current probe. The chamber resonances may obscure this. It is possible to find loss in common mode simply by measuring common-mode current at a peak near one end of a suspended conductor and again at a peak near the other end. The location of current nodes will depend (outside a chamber!) on wavelength, but the difference between them over length will depend on radiation and other losses. Cortland --- 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: Stumped (screw shaped inner 'coax' conductor, CEM simulation WAS: TSP or FTP ... )
which means that whatever the impedance actually is, if properly matched, mismatch losses may be bounded. Base on the significant electrical length per turns, I cannot see how mismatch losses can be 'bounded' especially at 1GHz. Perhaps at a higher frequency for a much shorter electrical length LAMBDA. If it were mismatch loss wouldn't the loss be strongly frequency dependent in a periodic fashion? The usual type of mismatch losses is indeed periodic, for resons to do with the defined location of the 'mismatch' or 'physical boundary' in the Tx line. This physical boundary remains the same as the electrical length of the cable changes with frequency. The losses I measured increased with increasing frequency, and the nature of the increase was identical to that specified for the RG-XX coaxial types (with larger magnitude as previously noted). Speaking off the cuff, (I should expect) the twisting profile (number of twist per unit physical length) would translate to number of 'smooth humps/bumps' per electrical length to decrease as frequency increases. :-) Considering the frequency of interest (80MHz-1GHz in IEC 1000-4-3) there may not be a substantial number of twist per electrical length. Due to the nature of the original intend of the insulation, I expect epsilom_r to be 'resonably' constant. We may not have to deal with the uncertainty associated with the dielectric medium. Making a (hazardous ?) guess, at 1GHz (LAMBDA_0 = 30 cm) LAMBDA= 30 cm/sqrt_epsilon_r Assuming epsilon_r =5 (I believe this will not be an unresonable figure), then LAMBDA=13.4 cm I suppose at a twist rate, say 80 t/meters (having no idea about you cable specs, I pull a figure of approx 12 mm pitch :-) it is roughly 11 or so t/LAMBDA. This will probable be closer to be 'distributed' at 100MHz being then 110 t/LAMBDA. (Ken, I need to corrected my statement I made a few min earlier ...) This I suppose needed some kind of MoM simulation to see the loss characteristics. I would like to hear from anyone handy with a CEM code like NEC, but on some hindsight, the proximity effect of the closely spaced conductors may be a problem for NEC. I suppose at the lower frequency the pair of twisted conductor will start to look like a short circuit at 80MHz. Does anyone out there know of a suitable CEM 'code' or technique to simulate the EM behaviour of such a conductor? I think SPICE is out for this kind of cable. regards, Tim Foo --- 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: Stumped (TSP or FTP (Foil screened Twisted Pair) )
The cables in question all used braided shield construction and were aerospace quality. The individual center conductors are insulated, of course, but there is nothing else between the insulated wires and the shield braid. The shield braid itself appears to be Kapton coated. It is indeed true that the twisted pair as a center conductor has an irregular shape relative to a single coaxial conductor. However there is an expression for the characteristic impedance of just such a cable (except for the twist) in the Reference Handbook for Radio Engineers. In my 1953 copy this type of transmission line is termed wires in parallel - sheath return. It is a complex formula but the point is that even with an irregular center conductor there is a defined transmission line characteristic impedance, which means that whatever the impedance actually is, if properly matched, mismatch losses may be bounded. If it were mismatch loss wouldn't the loss be strongly frequency dependent in a periodic fashion? The losses I measured increased with increasing frequency, and the nature of the increase was identical to that specified for the RG-XX coaxial types (with larger magnitude as previously noted). I can send a test data attachment to anyone interested. -- From: Wan Juang Foo f...@np.edu.sg To: Ken Javor ken.ja...@emccompliance.com, emc-p...@majordomo.ieee.org Subject: Re: Stumped (TSP or FTP (Foil screened Twisted Pair) ) Date: Mon, Oct 14, 2002, 9:11 PM Ken, I am only making a guess in the absence of the cable's specifications. Is your TSP a FTP (Foil screened Twisted Pair) type of cable constructed from copper wires coated with polyethylene and wrapped by Mylar tape (a transparent and mechanically tough film) between the TP and the screen? I think it is just mismatch losses due to the eccentricity of the cable. Imagine what kind of performance one would expect from a coax with an inner conductor that exhibit irregular cross sectional radius. IMHO, it's the inherent 'mismatch' losses of the 'cable' to CM signal. Given the inherent twisting (eccentricity) of the conductors within the 'screen', it is more like a coax with a screw shaped (how would I describe it???) distribution of Zo along the length of the cable. The TP configuration in the CM situation should be low loss only to circularly polarised electromagnetic waves (if there is such a phenomenal in electromagnetic propagation within a Tx line). For propagation modes of anything else approaching something that may represent a substantial fraction of Lambda would be, (or shall I say, should be) presented (or seen) as a lossy line due to the changing cross sectional characteristic of a FTP. I expected losses that would be on the same order or lower than that associated with off-the-shelf coax types like RG-58. Instead my losses were dramatically higher. In terms of CM performance (e.g. input impedance, losses, etc... ), a FTP due to it's eccentricity, I suppose cannot be compared to a RG-58. I have come across some FTP with 0.52 mm i.d. copper with a final diameter of 6.1 mm for the cable. Let me know if this description fits your bill. I have some information on their fabrication. Just another of my 2 ¢ ... regards Tim Foo Ken Javor ken.javor@emccomplian To: emc-p...@majordomo.ieee.org ce.comcc: (bcc: Wan Juang Foo/ece/staff/npnet) Sent by: Subject: Stumped owner-emc-pstc@majordo mo.ieee.org 10/15/02 05:31 AM Please respond to Ken Javor Forum, I have made some measurements and gotten results which are at odds with my intuition. I am wondering if someone out there can shed some light on this subject. I was interested in the losses associated with rf traveling on a twisted shielded pair cable. The scenario is that a length of this TSP cable is exposed to an rf environment (as in a test chamber during IEC 1000-4-3 testing) and then the cable penetrates a bulkhead using a grounded connector that provides excellent shield termination, and the cable continues on the other side in the pristine rf environment of a shielded control chamber, say for several meters. The question is, how much rf signal is at the final destination point vs. at the bulkhead. The concern is common mode, not differential mode. Meaning that the twisted pair can be looked at like coax, with an identical signal on both inner conductors relative to the shield. I expected losses that would be on the same order or lower than that associated with off-the-shelf coax types like RG-58. Instead my losses were dramatically higher. Following is my measurement technique. snip
Re: Stumped (TSP or FTP (Foil screened Twisted Pair) )
Ken, I am only making a guess in the absence of the cable's specifications. Is your TSP a FTP (Foil screened Twisted Pair) type of cable constructed from copper wires coated with polyethylene and wrapped by Mylar tape (a transparent and mechanically tough film) between the TP and the screen? I think it is just mismatch losses due to the eccentricity of the cable. Imagine what kind of performance one would expect from a coax with an inner conductor that exhibit irregular cross sectional radius. IMHO, it's the inherent 'mismatch' losses of the 'cable' to CM signal. Given the inherent twisting (eccentricity) of the conductors within the 'screen', it is more like a coax with a screw shaped (how would I describe it???) distribution of Zo along the length of the cable. The TP configuration in the CM situation should be low loss only to circularly polarised electromagnetic waves (if there is such a phenomenal in electromagnetic propagation within a Tx line). For propagation modes of anything else approaching something that may represent a substantial fraction of Lambda would be, (or shall I say, should be) presented (or seen) as a lossy line due to the changing cross sectional characteristic of a FTP. I expected losses that would be on the same order or lower than that associated with off-the-shelf coax types like RG-58. Instead my losses were dramatically higher. In terms of CM performance (e.g. input impedance, losses, etc... ), a FTP due to it's eccentricity, I suppose cannot be compared to a RG-58. I have come across some FTP with 0.52 mm i.d. copper with a final diameter of 6.1 mm for the cable. Let me know if this description fits your bill. I have some information on their fabrication. Just another of my 2 ¢ ... regards Tim Foo Ken Javor ken.javor@emccomplian To: emc-p...@majordomo.ieee.org ce.comcc: (bcc: Wan Juang Foo/ece/staff/npnet) Sent by: Subject: Stumped owner-emc-pstc@majordo mo.ieee.org 10/15/02 05:31 AM Please respond to Ken Javor Forum, I have made some measurements and gotten results which are at odds with my intuition. I am wondering if someone out there can shed some light on this subject. I was interested in the losses associated with rf traveling on a twisted shielded pair cable. The scenario is that a length of this TSP cable is exposed to an rf environment (as in a test chamber during IEC 1000-4-3 testing) and then the cable penetrates a bulkhead using a grounded connector that provides excellent shield termination, and the cable continues on the other side in the pristine rf environment of a shielded control chamber, say for several meters. The question is, how much rf signal is at the final destination point vs. at the bulkhead. The concern is common mode, not differential mode. Meaning that the twisted pair can be looked at like coax, with an identical signal on both inner conductors relative to the shield. I expected losses that would be on the same order or lower than that associated with off-the-shelf coax types like RG-58. Instead my losses were dramatically higher. Following is my measurement technique. snip --- This message is from the IEEE EMC Society Product Safety
post from 'shbeard' contains a virus in the attachment
my terminal found W32bugbear and quarantined the file --- 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: NEBS Level 3 Plus
Also for clarification, NEBS Level 3 Plus means all of GR-1089-CORE and all of GR-63-CORE. Also known as NEBS Level 3 Plus other criteria Both terms are borne from SR -3580, although not contained within in it. The confusion arises from the fact that not all the criteria in GR-1089 and GR-63 appear in NEBS Levels 1, 2, and 3 levels of SR-3580. There are several that fall into another category that are basically other miscellaneous criteria. Since each RBOC typically requires evaluations to all the criteria in GR-1089-CORE and GR-63-CORE, not just those in Level 1, 2, and 3, the term NEBS Level 3 Plus was used by people around industry to mean NEBS Level 3 plus other miscellaneous criteria in SR-3580 that are not contained in levels 1, 2, and 3 or all of GR-1089 and GR-63 But as Dave pointed out be careful. The deviations in test procedures or test labs required by some RBOC's can have a significant influence on whether you comply with a given criteria. So you may be NEBS level 3 Plus with one RBOC and not be NEBS Level 3 Plus with another depending upon how the test was performed or who performed it. Also be aware that some RBOC's and CLEC's accept testing to some of the new ANSI standards that are being developed. For instance the earthquake test was revised in ANSI T1.329-2002 and the Fire test was revised in ANSI T1.319-2002. The materials requirements for fire in GR-63 are from ANSI T1.307 which is up for ballot currently and should be accepted by November. All three of these are base documents for GR-63 earthquake and fire tests. These were not used when GR-63 was revised last April. Since three RBOC's and a couple CLEC's participated in the development and approved these ANSI standards, they tend to let manufacturers use these in place of the outdated GR-63 tests. But make sure you discuss with your customer first as Verizon for instance does not accept the new T1.329 fire standard. There seems to be significant interest to have Telcordia revise GR-63 to address these and other issues, and anyone interested should contact Richard Kluge at Telcordia to express interest that a project be opened to update GR-63 with the newest ANSI documents and fix other issues that labs and manufacturers know exist. Good Luck, Jim Jim Wiese NEBS Project Manager/Senior Compliance Engineer ADTRAN, INC. 901 Explorer Blvd. P.O. Box 14 Huntsville, AL 35814-4000 256-963-8431 256-963-8250 fax jim.wi...@adtran.com -Original Message- From: Dave Lorusso [mailto:d...@lorusso.com] Sent: Monday, October 14, 2002 4:19 PM To: Georgerian, Richard; IEEE emc-pstc Subject: RE: NEBS Level 3 Plus Richard, Verizon does not recognize NEBS Level 3 as called out in Telcordia/Bellcore SR-3580. They had input into this document, but later regretted it. What Verizon does recognize is their own checklist at www.verizonnebs.com http://www.verizonnebs.com/ . The confusion comes from the fact that the SR-3580 requirements are scattered throughout Verizon's checklist. At the NEBS 2002 Conference last week, Verizon introduced their latest revision of their checklist. They are trying to incorporate all of the other RBOC's and ATT requirements into this document. I caution everyone to obtain the specific checklists/requirements from each or your potential customers and comply with them. NEBS Plus is mentioned in an article I wrote for Evaluation Engineering What Every Startup Needs to Know About NEBS: http://www.evaluationengineering.com/archive/articles/0502emc.htm http://www.evaluationengineering.com/archive/articles/0502emc.htm The intent was to highlight that just meeting NEBS Level 3 was not enough to get equipment into your customer's central offices. In summary, there is no NEBS Level 3 Plus requirement, there are only customer requirements. Best regards, Dave Lorusso Lorusso Technologies, LLC Your NEBS, Product Safety and EMC Solution http://www.lorusso.com/ www.lorusso.com www.nebs-faq.com http://www.nebs-faq.com/ 512.695.5871 (phone) 512.233.2939 (fax) -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Georgerian, Richard Sent: Monday, October 14, 2002 11:10 AM To: IEEE emc-pstc Subject: NEBS Level 3 Plus Greetings All, Does anyone know the specifics regarding Verizons NEBS Level 3 Plus requirement. I have checked the Verizon web pages, the archives of the emc-pstc, and the word search on the internet, with no luck. Otherwise, I believe this is just another name for the checklist document that Verizon uses and can be downloaded from their website. Thanks in-advance. Richard Georgerian Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 USA Tele: 303-218-5748 Fax: 303-218-5503 mailto:rgeorger...@carrieraccess.com mailto:rgeorger...@carrieraccess.com
