Re: Anechoic chambers: risks of energy leaking out
Aircraft VOR (vhf omni-range) frequencies are from 108-118 MHz. Aircraft COMM to tower 116-152 MHz. Glideslope signal is 329-335 MHz. Marker Beacon is at 75 MHz. DME is 960-1215 MHz. These have been around forever. There may be newer stuff I haven't listed. Ken Javor Phone: (256) 650-5261 From: Gert Gremmen g.grem...@cetest.nl Date: Thu, 15 Jan 2009 07:17:18 +0100 To: Michael Heckrotte michael.heckro...@ccsemc.com, Frank Krozel fr...@electronicinstrument.com, emc-p...@ieee.org, emc-pstc@LISTSERV.IEEE.ORG Conversation: Anechoic chambers: risks of energy leaking out Subject: Anechoic chambers: risks of energy leaking out Right. But still reduces the screening of your chamber from 100 dB or so to 30...40 and thus may cause problems with immunity testing. That brings me to a related subject: The risks that go with RF energy leaking out. Well if you are in the middle of Texas, that may not be such a problem. But my chamber is located precisely below the landing path of Rotterdam airport, and civil aircrafts like B737 fly approx. 150m (500ft) above it. Any idea what may happen, if a substantial amount of the right frequency leaks out at the right (?!?) moment ? Well, in fact I don't know. Is there someone on this list with pertinent data on this subject ?? Someone that can provide risk frequencies ? Gert Gremmen -Oorspronkelijk bericht- Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens Michael Heckrotte Verzonden: donderdag 15 januari 2009 3:26 Aan: Frank Krozel; emc-p...@ieee.org; emc-pstc@LISTSERV.IEEE.ORG Onderwerp: RE: Anechoic Chamber: Pass-through on hydraulic lines All, As was stated some months or years ago on this list regarding this same topic: The waveguide pipe is an outer conducter, the wire going through it is a center conductor, and the combination of insulation/air is a dielectric; this configuration is also known as a coaxial cable = transmission line. If you absolutely must feed a wire or an ungrounded coax into a chamber, and the wire or coax ground cannot be filtered, then feed the wire or coax through two absorbing clamps, one inside the chamber and one outside the chamber. Place an absorbing clamp at each end of the waveguide pipe, butted up as close as possible to the waveguide pipe. This is effective over the frequency range at which the absorbing clamps provide decent common-mode decoupling. Best Regards, Mike Michael Heckrotte Director of Engineering Compliance Certification Services 47173 Benicia Street, Fremont, CA 94538 Main: (510) 771-1000 Direct: (510) 771-1121 Fax: (510) 661-0885 michael.heckro...@ccsemc.com -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Frank Krozel Sent: Wednesday, January 14, 2009 6:25 AM To: emc-p...@ieee.org Subject: Re: Anechoic Chamber: Pass-through on hydraulic lines All, Tim's comment made me think. In the past, I have seen hydraulic lines passed through waveguide feed-thrus that have re-inforced metal braid. Be aware of this if you need to pass hydraulic lines into your chamber or RF shielded enclosure. Alternatives do exist that are non-conductive. Regards Frank Krozel http://www.electronicinstrument.com - Original Message - From: Haynes, Tim (SELEX GALILEO, UK) To: emc-p...@ieee.org Sent: Wednesday, January 14, 2009 6:26 AM Subject: RE: Anechoic Chamber: Pass-through vs. Bulkhead Hi All, Conventional wisdom is, as stated, to bond the shield of a cable, hydraulic pipe, or any other electrically conductive - non-energised item that penetrates the shield wall. This is usually done with a purpose made bulkhead connector and is, again, usually done at a purpose made access plate in the shield room wall. Energised items cannot be connected to the shield and here the conventional wisdom is to connect the energised conductor via a filter that has its local ground connected to the shield wall. However, it might be acceptable to use a pass-through pipe where the pipe is long and can provide a sufficiently high capacitance to ground to form a functional filter at the frequencies of concern. The capacitance might be increased by stuffing the pass through pipe with conductive wire wool. I once had no option but to pass through a cable into the chamber. The project allowed me to remove the outer insulation at the pass through and I bonded the cable shield to the screened room by using a bolt to apply pressure to a shim of metal that held the cable firmly to the metal of the pass through pipe. That worked well. I hope the information helps. Regards Tim Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax : +44 (0)1582 795863 ) Mob: +44 (0)7703 559 310
RE: Anechoic chambers: risks of energy leaking out
Hi Gert, ILS (Instrument Landing System) operates in the VHF band (108-118 MHz). There is also DME (Distance measuring equipment) which operates in the 960-1215MHz band. Mvg, Willem Jan Jong From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Gert Gremmen Sent: donderdag 15 januari 2009 7:17 To: Michael Heckrotte; Frank Krozel; emc-p...@ieee.org; emc-pstc@LISTSERV.IEEE.ORG Subject: Anechoic chambers: risks of energy leaking out Right. But still reduces the screening of your chamber from 100 dB or so to 30...40 and thus may cause problems with immunity testing. That brings me to a related subject: The risks that go with RF energy leaking out. Well if you are in the middle of Texas, that may not be such a problem. But my chamber is located precisely below the landing path of Rotterdam airport, and civil aircrafts like B737 fly approx. 150m (500ft) above it. Any idea what may happen, if a substantial amount of the right frequency leaks out at the right (?!?) moment ? Well, in fact I don't know. Is there someone on this list with pertinent data on this subject ?? Someone that can provide risk frequencies ? Gert Gremmen Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens Michael Heckrotte Verzonden: donderdag 15 januari 2009 3:26 Aan: Frank Krozel; emc-p...@ieee.org; emc-pstc@LISTSERV.IEEE.ORG Onderwerp: RE: Anechoic Chamber: Pass-through on hydraulic lines All, As was stated some months or years ago on this list regarding this same topic: The waveguide pipe is an outer conducter, the wire going through it is a center conductor, and the combination of insulation/air is a dielectric; this configuration is also known as a coaxial cable = transmission line. If you absolutely must feed a wire or an ungrounded coax into a chamber, and the wire or coax ground cannot be filtered, then feed the wire or coax through two absorbing clamps, one inside the chamber and one outside the chamber. Place an absorbing clamp at each end of the waveguide pipe, butted up as close as possible to the waveguide pipe. This is effective over the frequency range at which the absorbing clamps provide decent common-mode decoupling. Best Regards, Mike Michael Heckrotte Director of Engineering Compliance Certification Services 47173 Benicia Street, Fremont, CA 94538 Main: (510) 771-1000 Direct: (510) 771-1121 Fax: (510) 661-0885 michael.heckro...@ccsemc.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Frank Krozel Sent: Wednesday, January 14, 2009 6:25 AM To: emc-p...@ieee.org Subject: Re: Anechoic Chamber: Pass-through on hydraulic lines All, Tim's comment made me think. In the past, I have seen hydraulic lines passed through waveguide feed-thrus that have re-inforced metal braid. Be aware of this if you need to pass hydraulic lines into your chamber or RF shielded enclosure. Alternatives do exist that are non-conductive. Regards Frank Krozel http://www.electronicinstrument.com From: Haynes, Tim (SELEX GALILEO, UK) To: emc-p...@ieee.org Sent: Wednesday, January 14, 2009 6:26 AM Subject: RE: Anechoic Chamber: Pass-through vs. Bulkhead Hi All, Conventional wisdom is, as stated, to bond the shield of a cable, hydraulic pipe, or any other electrically conductive - non-energised item that penetrates the shield wall. This is usually done with a purpose made bulkhead connector and is, again, usually done at a purpose made access plate in the shield room wall. Energised items cannot be connected to the shield and here the conventional wisdom is to connect the energised conductor via a filter that has its local ground connected to the shield wall. However, it might be acceptable to use a pass-through pipe where the pipe is long and can provide a sufficiently high capacitance to ground to form a functional filter at the frequencies of concern. The capacitance might be increased by stuffing the pass through pipe with conductive wire wool. I once had no option but to pass through a cable into the chamber. The project allowed me to remove the outer insulation at the pass through and I bonded the cable shield to the screened room by using a bolt to apply pressure to a shim of metal that held the cable firmly to the metal of the pass through pipe. That worked well. I hope the information helps. Regards Tim Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax : +44 (0)1582 795863 ) Mob: +44 (0)7703 559 310 * E-mail : tim.hay...@selexgalileo.com P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England Wales. Company no. 02426132
RE: Anechoic chambers: risks of energy leaking out
Hi again, Covering comments since I last posted - yes chokes may provide sufficient attenuation for the purpose - but to confirm this all the possible issues need to be considered. With a waveguide beyond cut off, filling the hole with a dielectric effectively increases the frequency that it will pass. 3mm at 40GHz gave 100dB. Fitted with PVC coated fibre the attenuation dropped to 60dB - we ended up with 1.5mm fibre through the waveguide. In the EU - the EMC Directive now explicitly places requirements on Fixed Installations. Now I know I will get some disagreement, but in my opinion, we all work in fixed installations therefore an EMC facility is either a fixed installation in its own right OR it is part of a bigger fixed installation. The radiated immunity signal is - by definition - a transmission. If this is done in a screened room, then the radiation is suppressed radiation. Strangely, there is a UK Statutory Instrument regarding Suppressed Radiation which dictates the limits of radiation detectable outside the suppression. If these limits are met, and operation is contained within the frequency range, then no license is required. It would therefore seem that, if the limits are exceeded or the frequencies in use extend beyond the frequency range in the regulations - then a licence IS required. The table for the UK is given below. I have no idea what other Member States require in the way of limits and frequency ranges -or indeed whether they have any regulations of the nature of the UK regulations. However, returning to the EMC Directive, there is a requirement for the fixed installation to meet the protection requirements of the Directive AND for record to be kept. My Company - the Company I work for - lies underneath the flight path for London Luton airport. ALL engineering (not just the EMC) is carried out inside screened rooms - about 3,000 sq.m. of them. The EMC Support equipment, the high power amplifiers and the project support equipment is all contained within their own screened rooms - that is the emc facility is a suit of four screened rooms. The screening is maintained so that is does not fall below a level that maintains the emissions at levels lower than those given in the table. You will smile when you look up SELEX Galileo - Sensors and Airborne Systems - as you will see why we go to so much trouble to stop signal leaking out. An alternative view, would be to treat the fixed installation (the EMC Facility) and apply the limits of a well known EN for radiated emissions - at 10m from the screened room. If you have 10V/m in the screened room at 3m from the antenna, that is 140dBuV/m at 3m, then it is easy to calculate the level at, say, 16 or 20m from the antenna. The minimum screening that this approach would give would be, say 140 - 20log(20m/3m)-37dBuV (for frequencies above 230MHz) = 140 - 16.5 -37 = 86.5dB. Below 230MHz, on the same basis, 93.5dB attenuation would be required. If this can be obtained via through connections, filters, the grade of screening on the coax, etc. then there should be no problems being under the flight path of an airport. Food for thought. Regards Tim Statutory Instrument 1989 No. 1842 SCHEDULE Regulation 5 TERMS, PROVISIONS AND LIMITATIONS OF EXEMPTION 1.Use of relevant stations and relevant apparatus for emission shall be limited to use - (a) on a frequency within a frequency band specified in table 1 below; and (b) where the maximum field strength of the emission does not exceed the limit specified in relation to that frequency band when measured at the distance specified in relation thereto. TABLE 1 Frequency Band (MHz) Limit for maximum field strength (dB.013 V/m) Distance at which measurement taken (m) 0.150 - 0.2835 34 100 0.5265 - 1.605 34 100 1.605 - 2.1735 48 100 2.1905 - 3.950 48 100 22.00 - 29.999 34 100 30.00 - 70.5030 30 71.50 - 74.6030 30 75.40 - 80.0030 30 84.00 - 108.00 30 30 137.00 - 143.00 30 30 144.00 - 146.00 30 30 148.00 - 153.00 30 30 156.8375 - 225.0030 30 400.00 - 405.50 30 30 406.50 - 450.00 30 30 453.00 - 464.00 30 30 467.00 - 960.00 30 30 2.Relevant stations and relevant apparatus shall not radiate, in any frequency band, spurious emissions of a maximum field strength in excess of the limit, when measured at the distance specified in table 2 below in relation to each frequency band - TABLE 2 Frequency Band (MHz) Limit for maximum field strength (dBV/m) Distance at which measurement taken (m) below 30 23 100
RE: Anechoic chambers: risks of energy leaking out -ERRATA
Sorry - errata where I said filling the hole with a dielectric effectively increases the frequency that it will pass that should read filling the hole with a dielectric effectively decreases the frequency that it will pass regards Tim Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax : +44 (0)1582 795863 ) Mob: +44 (0)7703 559 310 * E-mail : tim.hay...@selexgalileo.com P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England Wales. Company no. 02426132 This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Anechoic chambers: risks of energy leaking out
In message 201048ea81ba0745aca78e4cc883900104290...@desmdswms201.des.grplnk.net, dated Thu, 15 Jan 2009, Haynes, Tim (SELEX GALILEO, UK) tim.hay...@selexgalileo.com writes: Strangely, there is a UK Statutory Instrument regarding Suppressed Radiation which dictates the limits of radiation detectable outside the suppression. But it isn't, it seems, Statutory Instrument 1989 No. 1842, which is about *exemptions* from Article 1 of the Wireless Telegraphy Act, and doesn't include the table of frequencies, distances and levels. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Anechoic chambers: risks of energy leaking out
Gert: I don't think you'll find a list of important frequencies . If there were such a thing it would be like the terrorist handbook on how to bring down an airliner. I can tell you a lot of EMI immunity goes into every Boeing airplane. Fred Townsend From: Gert Gremmen g.grem...@cetest.nl To: Michael Heckrotte michael.heckro...@ccsemc.com; Frank Krozel fr...@electronicinstrument.com; emc-p...@ieee.org; emc-pstc@LISTSERV.IEEE.ORG Sent: Wednesday, January 14, 2009 10:17:18 PM Subject: Anechoic chambers: risks of energy leaking out Right. But still reduces the screening of your chamber from 100 dB or so to 30...40 and thus may cause problems with immunity testing. That brings me to a related subject: The risks that go with RF energy leaking out. Well if you are in the middle of Texas, that may not be such a problem. But my chamber is located precisely below the landing path of Rotterdam airport, and civil aircrafts like B737 fly approx. 150m (500ft) above it. Any idea what may happen, if a substantial amount of the right frequency leaks out at the right (?!?) moment ? Well, in fact I don't know. Is there someone on this list with pertinent data on this subject ?? Someone that can provide risk frequencies ? Gert Gremmen Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens Michael Heckrotte Verzonden: donderdag 15 januari 2009 3:26 Aan: Frank Krozel; emc-p...@ieee.org; emc-pstc@LISTSERV.IEEE.ORG Onderwerp: RE: Anechoic Chamber: Pass-through on hydraulic lines All, As was stated some months or years ago on this list regarding this same topic: The waveguide pipe is an outer conducter, the wire going through it is a center conductor, and the combination of insulation/air is a dielectric; this configuration is also known as a coaxial cable = transmission line. If you absolutely must feed a wire or an ungrounded coax into a chamber, and the wire or coax ground cannot be filtered, then feed the wire or coax through two absorbing clamps, one inside the chamber and one outside the chamber. Place an absorbing clamp at each end of the waveguide pipe, butted up as close as possible to the waveguide pipe. This is effective over the frequency range at which the absorbing clamps provide decent common-mode decoupling. Best Regards, Mike Michael Heckrotte Director of Engineering Compliance Certification Services 47173 Benicia Street, Fremont, CA 94538 Main: (510) 771-1000 Direct: (510) 771-1121 Fax: (510) 661-0885 michael.heckro...@ccsemc.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Frank Krozel Sent: Wednesday, January 14, 2009 6:25 AM To: emc-p...@ieee.org Subject: Re: Anechoic Chamber: Pass-through on hydraulic lines All, Tim's comment made me think. In the past, I have seen hydraulic lines passed through waveguide feed-thrus that have re-inforced metal braid. Be aware of this if you need to pass hydraulic lines into your chamber or RF shielded enclosure. Alternatives do exist that are non-conductive. Regards Frank Krozel http://www.electronicinstrument.com From: Haynes, Tim (SELEX GALILEO, UK) To: emc-p...@ieee.org Sent: Wednesday, January 14, 2009 6:26 AM Subject: RE: Anechoic Chamber: Pass-through vs. Bulkhead Hi All, Conventional wisdom is, as stated, to bond the shield of a cable, hydraulic pipe, or any other electrically conductive - non-energised item that penetrates the shield wall. This is usually done with a purpose made bulkhead connector and is, again, usually done at a purpose made access plate in the shield room wall. Energised items cannot be connected to the shield and here the conventional wisdom is to connect the energised conductor via a filter that has its local ground connected to the shield wall. However, it might be acceptable to use a pass-through pipe where the pipe is long and can provide a sufficiently high capacitance to ground to form a functional filter at the frequencies of concern. The capacitance might be increased by stuffing the pass through pipe with conductive wire wool. I once had no option but to pass through a cable into the chamber. The project allowed me to remove the outer insulation at the pass through and I bonded the cable shield to the screened room by using a bolt to apply pressure to a shim of metal that held the cable firmly to the metal of the pass through pipe. That worked well. I hope the information helps. Regards Tim Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax: +44 (0)1582 795863 ) Mob: +44 (0)7703 559 310 * E-mail : tim.hay...@selexgalileo.com P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher
RE: Anechoic chambers: risks of energy leaking out
John, All, The table at the bottom of my early e-mail IS from the Statutory Instrument - It is THE SCHEDULE referred to in the SI and is published (in the paper format) along with the SI. If you are looking at a web version, you should find a link to the schedule. John, I will send the HTML pages that I downloaded from Ofcom under a plain cover J Regards Tim Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax : +44 (0)1582 795863 ) Mob: +44 (0)7703 559 310 * E-mail : tim.hay...@selexgalileo.com P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Thursday, January 15, 2009 9:21 AM To: emc-p...@ieee.org Subject: Re: Anechoic chambers: risks of energy leaking out *** WARNING *** This mail has originated outside your organization, either from an external partner or the Global Internet. Keep this in mind if you answer this message. In message 201048ea81ba0745aca78e4cc883900104290...@desmdswms201.des.grplnk.net, dated Thu, 15 Jan 2009, Haynes, Tim (SELEX GALILEO, UK) tim.hay...@selexgalileo.com writes: Strangely, there is a UK Statutory Instrument regarding Suppressed Radiation which dictates the limits of radiation detectable outside the suppression. But it isn't, it seems, Statutory Instrument 1989 No. 1842, which is about *exemptions* from Article 1 of the Wireless Telegraphy Act, and doesn't include the table of frequencies, distances and levels. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England Wales. Company no. 02426132 This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Anechoic chambers: risks of energy leaking out
Further to my last e-mail, http://www.opsi.gov.uk/si/si1989/Uksi_19891842_en_1.htm Is the Statutory Instrument, at the bottom of which is a link with the word continue that links to the table at http://www.opsi.gov.uk/si/si1989/Uksi_19891842_en_2.htm Regards Tim SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England Wales. Company no. 02426132 This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Anechoic chambers: risks of energy leaking out
In message 201048ea81ba0745aca78e4cc883900104290...@desmdswms201.des.grplnk.net, dated Thu, 15 Jan 2009, Haynes, Tim (SELEX GALILEO, UK) tim.hay...@selexgalileo.com writes: John, I will send the HTML pages that I downloaded from Ofcom under a plain cover J Thanks. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Anechoic chambers: risks of energy leaking out
In message 860439.96457...@web83107.mail.mud.yahoo.com, dated Thu, 15 Jan 2009, FRED TOWNSEND ftowns...@sbcglobal.net writes: I don't think you'll find a list of important frequencies . If there were such a thing it would be like the terrorist handbook on how to bring down an airliner. I can tell you a lot of EMI immunity goes into every Boeing airplane. They are in the ITU Frequency Allocation Table, Article 5 of the Radio Regulations. http://www.itu.int/publ/R-REG-RR/en There is an on-line access at: http://www.icc-uk.com/efat.php -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Anechoic chambers: risks of energy leaking out
This approach compels good practice; some radiated susceptibility tests approach oven level at peak power. Cortland KA5S - Original Message - From: Haynes, Tim (SELEX GALILEO, UK) mailto:tim.hay...@selexgalileo.com To: emc-p...@ieee.org Sent: 1/15/2009 4:00:40 AM Subject: RE: Anechoic chambers: risks of energy leaking out ... An alternative view, would be to treat the fixed installation (the EMC Facility) and apply the limits of a well known EN for radiated emissions - at 10m from the screened room. If you have 10V/m in the screened room at 3m from the antenna, that is 140dBuV/m at 3m, then it is easy to calculate the level at, say, 16 or 20m from the antenna. The minimum screening that this approach would give would be, say 140 - 20log(20m/3m)-37dBuV (for frequencies above 230MHz) = 140 - 16.5 -37 = 86.5dB. Below 230MHz, on the same basis, 93.5dB attenuation would be required. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Anechoic chambers: risks of energy leaking out
Worldwide aviation frequencies are still a matter of public record. The most critical frequencies that come to mind where you are would be those used in Instrument Landing System/Glide Slope operation, sometimes linked to flight controls for fully automatic landings, and those just above 1 GHz used for navigation, identification, and collision avoidance.Some precision navigation down to landing threshold if I recall correctly now uses GPS at 1575 MHz, and a more precise level offered by a differential GPS signal sent by means ranging from delivery along with the GPS signal, to (for Europe) VHF FM broadcast station RDS subcarriers ( http://www.tecnogps.com/rasant_eng.htm) . One of course does not want to interfere with air/ground comms, either. Regards, Cortland Richmond [Original Message] From: Gert Gremmen g.grem...@cetest.nl Any idea what may happen, if a substantial amount of the right frequency leaks out at the right (?!?) moment ? Well, in fact I don't know. Is there someone on this list with pertinent data on this subject ?? Someone that can provide risk frequencies ? - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
