Re: MEASURING VSWR WITHOUT A DIRECTIONAL COUPLER
Hi John, All, The answer to your question is in my original e-mail on the subject. I said at the end... "One error that may creep in, is if the "device leg" of the "T" is extended with co-ax or is relatively long (>lambda/20)" Having dealt with the fundamental of the problem, it is up to the user to determine if the error is too large. If the "T" piece is in "N" type - that's, say, 3cm per leg... I would estimate that there would not be a significant error intil the wavelength is greater then 60cm ~ 400MHz. Smaller "T" pieces could be used - e.g. TNC or SMA. By removing the "T" piece you would remove one source of error but will gave removed two interfaces - the effect of which is probably not determinable with the existing equipment. I would guess that removing the "T" piece may be a better IF it is a quality item, but it is probably a case of "suck-it-and-see". Thanks for "pulling me up" on the method though - it shows that somebody understood what I wrote! Anybody out there with another method? Regards Tim --- 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
Ian, All, With the equipment you have it is possible to get some measure of SWR or match of devices. I am not claiming it is accurate but with care should provide some useful information. Apart from your equipment you will need two good-quality attenuators -probably 20dB will be suitable, a good quality 50 Ohm load, a "T" piece and 2 bits of good co-ax of the shortest suitable length. For best accuracy you might need an attenuator at the signal source and the measurement receiver. Place the "T" piece on the device to be measured. Set any input attenuation on the device to whatever range you need to check the SWR.. Put the two attenuators on the other 2 legs of the "T". Feed one attenuator (att1) with a signal source. Measure the output of the other attenuator (att2). Sweep 1 - across the range in suitable steps, making amplitude measurements at each step. Record amplitude vs. frequency.(1) Disconnect the "T" from the device Sweep 2 across the range in same steps, making amplitude measurements at each step. Record amplitude vs. frequency.(2) Connect 50 Ohm load to "T" where device had been. Sweep 3 across the range in same steps, making amplitude measurements at each step. Record amplitude vs. frequency.(3) The theory behind it is this. You have a known source level (measurement 2 + att2) at the center of the "T" When you compare the level with the device in place (measurement 1 +att2), since att2 is common and if the device is a perfectly flat 50 Ohms, you should see a loss of 1.765dB on measurement 1 compared with measurement 2. You can check the system out by terminating the "T" with the 50 ohm load and this will indicate the quality of the "set up". By examining the delta amplitude change with frequency (measurement1-measurement2)F1 to (measurement1-measurement2)F2 you might be able to draw some conclusion regarding any reactive components (its unlikely that a pure resistance will actually change value with frequency). The attenuators are to reduce the effects of mismatched source / cable / measurement receiver. One error that may creep in, is if the "device leg" of the "T" is extended with co-ax or is relatively long (>lambda/20) e-mail me direct if you want any more info Regards Tim Haynes tim.hay...@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: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: EEC compliance for a ground based radar
Hi all, AFAIK, radar (in the UK) are certified by CAA or by DERA Portsmouth. (DERA was what they used to be called - but I don't know what they are called now - unless its QinetiQ) CAA do air traffic radar etc. while DERA did marine radar. MoD radar came under MoD rules and were probably checked out by DERA anyway. Again AFAIK, radar are covered by R&TTE but it only makes radar manufacturers dowhat they would have done under the old regime in the UK. Does this help? I think I am correct but reserve the right to be wrong. Regards Tim --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Equipment for own use (was gas appliance)
Hi Everybody... In the EU there is workplace legislation that in the UK is implemented under the "Provision and Use of Work Equipment Regulations" (PUWER) 1998. In these regulations anything that is provided for use at work is required to comply with the relevant Directives. If the equipment is "old" there are a set of equivalent requirements. Regards Tim --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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.rcic.com/ click on "Virtual Conference Hall,"
Requirements for Czech Republic
Hi everybody! I have been asked to find out what the requirements are for a rack of test equipment that will be used in the Czech Republic. In particular I am interested in the requirements for; EMC Will EU EMC Directive (self) certification suffice or are there requirements for third party certification? Safety Are there third party certification requirements here or will self certification to IEC 950 / BSEN 61010 (as applicable) suffice. Labels Do safety warning labels, where text is involved, have to be in native Czech language (I am cautious because I am not sure what language it is - indeed there may be more than one) Will IEC standards for the safety symbols suffice? I know there are differences between British Standard safety labels and IEC (either are acceptable in UK) what about Czech. Republic? Electrical What are the colour codes for mains wire in use in Czech. Republic? Are they the same as EU? Thanks in advance for all the replies. Tim Haynes --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: SLIM
Hi Gail Is there any possibility that you can let me know who is the "reliable source who attended the June meeting of the EU Commission on the SLIM Initiative..." and what the name of the forum was? I need to trace the forum etc. to determine if the comment has substance as far as the writing of the new Directive is concerned. However, there was no meeting of the SLIM Working Group in June, the meeting following that of February is 3/4 th July. I will let the group know if anything of substance turns up. Regards Tim Haynes --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: IEC 825 and Light Emitting diodes.
Hi all, Have a look at the following Hewlett Packard documents. Application Brief I-009 Application Brief I-015 Application Note 1109 These might help answer the questions. Regards Tim --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: EN standard for pacemaker immunity
Hi everyone, Except for "official" certification - it is not the standard that is the most important. Consider the field strengths that the person (hence pacemaker) will be exposed to. Are the standards realistic or were they created to give a MINIMUM level of confidence to some authority? What are the failure modes of the device and what form of harm would a failure cause? What are the product liability issues of an EMC induced failure? I have a friend with a pacemaker / defibrillator. He was told that this new device would give him a better quality of life than the old type. (No - I will not mention makes) However, the antitheft devices at the shop doors (here in the UK) cause him to be defibrillated! He has not been able to go shopping at the local center since his heart attack two years ago. The makers of the device say that it meets all the standards. His surgeon will change it to a different make but requires payment for the operation and the device. Nobody will tell him that any new device will be able to withstand the fields generated by the antitheft systems. B.T.W. The antitheft systems meet their requirements. My friend is wondering if he can go to litigation over this issue. Just a thought for the melting pot. All the above is a strictly personal view. Regards Tim --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Equipment for development
Hi Everybody, I have some equipment that is currently under development for an American company. While the design of the equipment still has to be finalised, the customer requires a set of units to run on a simulator for test purposes. Apart from the obvious requirement that these development units must not cause harm, are there any specific requirements for safety or EMC (etc.) that *must* be complied with? I don't know (at this time of writing) which State the company is located - is there any serious differences between States that must be considered? Regards Tim - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Equipment designed and manufactured for use in-house
Carlos Perkins wrote... >Dear All, >A question from UK: > >Does anyone have a strategy for handling the Low Voltage and EMC >Directive requirements relating to equipment made for use in-house? > >By this, I mean test boxes, power supplies, break-out boxes, etc. > >These products are not meant to be offered for sale (ie not 'placed >on the market'), but have been 'taken into service' by being switched >on and used. >I think, therefore, that the protection requirements of the >Directives must be met, but CE marking is not necessary. > >In terms of Safety, I think EN 60950 and EN 61010-1 are relevant. > >Does anyone have a view on this? > >Cheers, Hi Carlos, In the UK, apart from EU Directives for the market, there are is a complete set of requirements for Health and Safety at Work. When you start taking onboard the mandatory Hazard And Risk Assessment for the task and consider the reaction of the Health and Safety Executive if they come to investigate an accident - you may find that for many pieces of "home brew" equipment formal certification starts to look like a reasonable option. On the EMC side, although the EMC Directive might not apply (more in a moment) the 1949 Wireless Telegraphy Act does apply and causing interference to emergency services, navigation frequencies or telecommunication systems that make lots of money from providing high reliability radio links might work out expensive one way or another. The EC Guidance document says (my words) that, although the item is never placed on the market as such, the requirements for placing on the market apply when the item is taken into service... As you have decided that the equipment must meet the protection requirements I assume that it you will have some sort of evidence to support the concept. If you have the evidence and are happy with it, then is there a great leap to sticking the CE Mark on it? Note: When in the UK with uncertified equipment at a trade fair or exhibition - the Wireless Telegraphy Act still applies, as does civil liability. I hope that this helps? Tim >- My mind is my own, blame no other for my thoughts. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Feedback on EMC
Hm.. But who are you and who do I e-mail if I am interested?? Or did I miss something? Regards Tim Haynes - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: NSA (using acid)
Hi Folks, For what it is worth MURIATIC ACID Synonyms: Hydrochloric acid, Spirits of salt. Safety profile: A corrosive irritant to the skin, eyes, and mucous membranes. Mildly toxic to humans by inhalation, and moderately toxic by ingestion. A concentration of 35 ppm causes irritation of the throat after short exposure. Is it wise to "blow" the acid off with an airline as suggested in one of the other replies? Regards Tim Haynes - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Reducing magnetic influence on PC-monitors
BIG SNIP! >OK, if it is primarily a radiated path, then some aluminum foil >wrapped around the victim will produce some good results if the path >is the electric field. If the path is the magnetic field, this will >help slightly, but maybe not enough. But don't forget to let it breath! It can get very hot, very quickly without air. SNIP! Also, it may be worth looking at the field strength produced by the transformer. If it is too high, there may be a risk to health. In the UK the limits are set out by the National Radiological Protection Board and are current in the form of a booklet "Documents of the NRPB Volume 4 No 5 1993). I would expect that other countries have there own limits, or adopt these as a guide if you want. BTW The NRPB limits are only given the status of "guidelines" in the UK - but the Health and Safety at Work Act make them a defacto requirement. Tim My mind is my own - blame no other for my thoughts. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: More on Signatory for US based Manufacturer
Hi All, DoC requirements of the EMC Directive are only a general statement of requirement. The actual implementing legislation is that of each of the member countries. In the UK, the implementing legislation is the "UK EMC Regulations" Statutory Instrument No: 2372 1992. What I think this says (UK law is only an interpretation until a Judge rules on the interpretation!) is The manufacturer (or his agent/ representative) resident on UK soil is responsible for making the DoC. In this instance, Me (USA) make something that is marketed in the UK by Me (UK)- then it is Me(UK) that must make and hold the DoC. If the product is imported by someone who is not employed or contracted to the original manufacturer (other than to receive and pay for the manufacturers product), then it is the importer who must take responsibility and make the DoC. It might be (technically) different in other countries but the fundamental should be the same - that is the EU Authorities need an identifiable individual to sling in jail if the need arises! I hope this helps Tim My mind is my own - blame no other for my thoughts. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Laser pointers
# From: Rick Cooper # Subject: RE: Laser pointers # Date: Wed, 11 Nov 1998 09:43:19 -0500 # To: "'emc-p...@majordomo.ieee.org'" # # #> All, #> #> The seaside resort town of Ocean City, Maryland passed #> an emergency ordinance this past summer banning the use of these devices #> in public. Hefty fines, and, I think, jail time, could be imposed for #> what the city termed improper use. Mostly the city just wanted to stop #> the aiming of these devices at their bus drivers. #> #> Rick # #I wonder if they explored the possibility of adjusting the reflectivity of the bus drivers? # #Ed Is this why the bus companies round here are making enquiries about tinted windows? Tim - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Room grounding
h many room installers. I suggest that if you have #specific questions, contact the folks that made yours. Although the suppliers may provide good information, it is the company's responsibility (certainly here in the UK) to ensure that the workplace is safe. I would make sure that I understand what is happening in terms of grounding and carry out a hazard analysis and risk assessment. I would not rely on any single source of information and I would _double check_ any contradictory advice. I hope this is some use... Regards Tim Haynes tim.hay...@gecm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Method CS114
Ed Price wrote: And what is an "Amp per Watt"? Is that a "mho", a unit of conductance? Or is it a unit of admittance, a Siemen? hm... Wasn't mho one of the Three Stooges or am I thinking of something else?! No - I won't admit to anything - (no 4th over here) (I'm sorry - it's Tuesday and for some reason I'm feeling happy!) :-) Tim
Re: Video and computers in racks
Hi, Anyone who sells (or in any way supplies to another) an assembly of certified parts (with or without additional uncertified parts) that are intended to form a system, is considered to be the manufacturer of a new product. The size or complexity of the system is not significant until you start talking about assembling a whole building full The EMC Directive applies, as do, I believe, any other applicable directives such as LVD. (This is where I get shot down in flames!) The only remaining question is - does your equipment connect directly to a TV transmitter? If so, you may need to check whether the authorities in the destination country consider your equipment as "wireless telegraphy apparatus" as if could form part of the transmitter chain. If they do, they will probably require your equipment to be "type approved". This will invoke a whole heap of broadcast standards - depending on the destination country (no harmonisation for this aspect - yet!) The key factor in determining the application of "type approval" (in the UK at least) seems to be whether the equipment concerned can influence the nature of the radiated signal - which in the case of broadcast transmitters includes the picture quality. (Hmm.) A source of information would be the ITC (http://www.itc.org.uk) Oh - by the way - if your equipment IS classified as wireless telegraphy apparatus (because of it's intended use) then the EMC Directive requires that the EMC compliance is determined by a 3rd party "Notified Body" and a "type examination" obtained. This would be in addition to the "type approval certificate" ! I hope that the information is a) accurate and b) not too off-putting.. Regards Tim Haynes My mind is my own, blame no other for my thoughts. === #I have a perplexing question for anyone... # #If we purchase CE compliant computers and monitors, and CE compliant #anything, and place them in a rack, do we have a new "product" that has to #be re-certified? # #What if there are 16 computers in the rack (with a switcher for the #monitor/keyboard), and 16 video cameras many feet away all connecting to #these computers? I'm talking about systems such as DELL or HP #(off-the-shelf). # #What if there are only 3 computers, etc.? # #Would this "product" need all directives satisfied, or only some of them? # #Any input would be appreciated since we are trying to determine our effort #needed to achieve the CE mark. # #As always, thanks in advance! # #* #Ray Kester #Hardware Systems Manager #MTC #Fairfax, VA #
Re: Emissions or not?
WoW! Replies! Rather than respond in person I acknowledge all replies with thanks and comment here. BTW the 144.8 MHz tx is 100W e.r.p. Reflections from the Green Italian car? Why not all the other cars? Over all the other days, weeks, years that I have been using these frequencies? Too much coincidence. I like the idea that it might be the radio receiver in the Italian car kicking out a spurious response. Fault on my receiver? NEVER! :-) Oh well - possibly, but why only in relation to this Italian car? Third harmonic? 144.8 x 3 = 434.4 + 3xdeviation... not equal 433.325 by a long way. BTW 3rd harmonic is neg 74dBc on my old HP 8566a. I think it rules out the rusty bolt syndrome as well. The idea that it is an alarm system (the "here I am - I've been stolen" type) is possible though the chances are pretty low - there are not too many users of that alarm system here in the UK. Resonating car...? Hmm? Possibly but I streaches my imagination. Duff (Duff is UK slang for faulty/bad) electronics! Well - this was my first thought. Nice processor with lots of harmonics of clock frequencies and the subdivisions. Lots of switches changing the terminating impedance of the tracks (don't forget I am assuming a duff design). Now that really would modulate an incoming signal! Rating of the proposed causes? No I will let you all decide which is the most likely. Me? I am looking for a Green Italian car to experiment on. Oh, the make? I do't want to upset Fiat so I won't tell you..:-) Regards to all Tim
Re: Poll, Changes to the EMC directive
Whoa! and hello! The changes proposed are under the heading of SLIM - an acronym for simpler legislation ! However, even if the EC EMC legislation was rescinded would it remove the absolute responsibility of the manufacturer in the following areas? to make the product safe and to supply instruction to allow the safe use? to not cause interference to safety of life and navigation frequencies or any other radio link? to make a product that will work in the real electromagnetic environment? to take all reasonable precautions to ensure that the product was fit for purpose? Moreover, would the manufacturer be safe from litigation if he fails to address these points? Possibly the question is, "Do you want a tightly regulated EMC regime or a framework within which industry can manage risk?" - in which case I vote for the latter! Regards Tim tim.hay...@gecm.com Disclaimer My mind is my own, blame no other for my thoughts. G8PTP Peter Wrote:- Hello everybody A new discussion has started in Europe about redesigning the EMC directive. Im intrested to know of this groups opinion. The proposal is to remove the functional demands on products and only have security demands for immunity testing. To check the opinion of this group please reply to this mail direct to me (not the list) with one of the following lines and Ill post a compilation of the results. 1. YES , I agree with the removal of fuctional demands from the EMC directive. 2. NO , Funktional demands should continue to be a part of the EMC directive. Ill start compiling the results at the end of this week (june 19) and mail the results next week. Thank you Petter Gärdin ENATOR Communications AB P.O. Box 360 S-83125 ÖSTERSUND SWEDEN Email: petter.gar...@enator.se Amateur Radio Callsign: SM3PXO Phone: +46 63 156233 Fax: +46 63 156199
Emissions or not?
Hello everybody! Isn't experience a wonderful thing? Well, I have just experienced something that makes me wonder about the validity of EMC emission regulations... I am a radio ham and operate on VHF and UHF bands from the car. The other night I was transmitting on 144.8MHz while the UHF receiver was tuned to 433.325MHz (my local UHF repeater). Suddenly, I started hearing a weak signal on UHF and, as it got rapidly stronger, I realised that it was me! At first I thought that somebody was fooling around, but that thought went when I realised that every time I caught up with the green Italian sports machine the signal got stronger and when it pulled away, the signal got weaker. When I stopped transmitting, there was no signal on UHF - no repeater or spurious. I have two thought on this... 1 The Italian car mixed my 144.8 with something internal to it, and retransmitted the resulting product. 2 It has a strong emission that caused mixing in the UHF receiver. I tend to discount the third theory, that the VHF transmitted signal overloads the UHF radio, because I use a duplexer and can receive very weak UHF signals while transmitting VHF. So - any ideas on this matter - and should we start doing emission measurements during immunity tests so that we know what the real world performance of the products will be? Regards Tim tim.hay...@gecm.com
Re: Shielded power cord, seeking source for
#Hi Rick. # #You wrote: # # #Not as far as I am aware, and I have been designing mains powered stuff #since I was too young to know better... But then I'm not aware of any #manufacturers of Moulded Screened Mains Cable assemblies, they are #invariably home made. # #Screened mains cable is freely available on the reel (in the UK from people #like RS Components for instance) and I have used it when I have had #problems with radiated emissions or susceptibility on long mains cables. #Usually when a filter demonstrates a particularly arkward resonance. # #Any component which is safety or EMC critical, and which may be changed by #a subsequent user can be made a condition of compliance by a relatively #simple statement in the instructions. i.e. under the general heading of #'Using as intended'. Use of the equipment without the particular cable is #therefore 'Not as intended' and therefore shouldn't be expected to comply #(and shouldn't be put into service). # #A thruppence worth perhaps. # #Chris Dupres #Surrey, UK. If screened mains cable is used, then surly it acts like a coax (a poor one possibly) and transfers the energy, contained within, to a point where the cables are not shielded. This would probably be at the mains wall socket - where the energy could (would?) then radiate! If the intention is not to cause interference to radiocommunications etc. then how has the screened mains cable helped? The test might seem OK but how is "due diligence" served? Just thought that I would ask! Regards Tim Haynes (tim.hay...@gecm.com) Disclaimer My mind is my own - blame no other for my thoughts.
Re: Do you need a license
#Paul Rampelbergh wrote: #> #> Is there a need to have a license to posses and operate EMC #> measurement tools? #> #In the UK... none that I know of. #-- #Regards, #Phil Ford You might like to check the situation with the following person; Steve Hewitt of the Radiocommunications Agency, Test and Development Licence section Phone +44 (0) 171 211 0008 The situation may change depending on the frequency of radiation within the screened room - the breakpoint being 1GHz I think. I applied for a licence - and this was granted (for 150 UKP / annum) - I was NOT told that a licence was not needed. My licence covers 9kHz to 100GHz and for pulse / FM / AM modulations. If you do not use a screened room - then you Do need a licence! Regards Tim Haynes Regards Tim Haynes (tim.hay...@gecm.com) Disclaimer My mind is my own - blame no other for my thoughts. Num festinat tempus quando ludes
