Re: Microwave Oven Interference with 2.4Ghz Wireless LAN
In message , dated Tue, 7 Oct 2008, Gert Gremmen writes: >It's a typical example of international frequency regulators (ISO/ERC) >failing. Who the heck decided it was a good idea of allocating the 2.4 >GHz band (ISM frequency) to Wireless LAN's ? Of course the actual >decision was made by the standardization committee that wrote IEEE (!!) >802-b/g (any family?)to make sue of a licencse free band) I don't think those bodies are responsible (or not entirely). Frequency allocations are agreed internationally by ITU (but are not necessarily agreed on a world-wide basis, but by regions). > but this by lack of a suitable "free frequency". Or at least they were >thinking that a LAN would never approach a MicroWave oven. Good luck >that these devices operate on a rectified AC power without any >capacitance, so they switch off every half period, They have full-wave rectifiers, so it's the 2.45 GHz that switches off when the rectifier output voltage is too low, but the mains current doesn't switch off. On the other hand, the switching-off creates a comb of sidebands around the oscillation frequency at frequency separations equal to the mains supply frequency and its harmonics. So it's difficult indeed to avoid the emissions by selecting a particular carrier frequency (or frequencies) within the band for LAN use. > during which the LAN has the time to transfer some data. > >Many GHZ go unused currently, reserved to some non-operating system or >defense applications that may or may not be used one day. > >Take for example the 2900-3100 Mhz band could have been allocated at >the time to short range devices in a similar way as 2400-2483.5 has >been allocated today. But regulation agencies are always too late in >recognizing the market... Like the US Senate, the maxim is 'with all deliberate speed'. The decisions have to take in very many interests and be as 'future-proof' as possible. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Either we are causing global warming, in which case we may be able to stop it, or natural variation is causing it, and we probably can't stop it. You choose! John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
It's a typical example of international frequency regulators (ISO/ERC) failing. Who the heck decided it was a good idea of allocating the 2.4 GHz band (ISM frequency) to Wireless LAN's ? Of course the actual decision was made by the standardization committee that wrote IEEE (!!) 802-b/g (any family?)to make sue of a licencse free band) but this by lack of a suitable "free frequency". Or at least they were thinking that a LAN would never approach a MicroWave oven. Good luck that these devices operate on a rectified AC power without any capacitance, so they switch off every half period, during which the LAN has the time to transfer some data. Many GHZ go unused currently, reserved to some non-operating system or defense applications that may or may not be used one day. Take for example the 2900-3100 Mhz band could have been allocated at the time to short range devices in a similar way as 2400-2483.5 has been allocated today. But regulation agencies are always too late in recognizing the market... Gert Gremmen Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens John Shinn Verzonden: dinsdag 7 oktober 2008 5:46 Aan: 'Pettit, Ghery'; 'emc-p...@ieee.org' Onderwerp: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Hi Gherry: Just remember that when you pull back on the yoke (stick), the houses get smaller, but if you keep pulling back they get bigger again. John From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Pettit, Ghery Sent: Monday, October 06, 2008 2:24 PM To: Conway, Patrick R (Houston); Brian O'Connell; emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Nothing much of interest. It's about as interesting as getting a sports car up to about 75 mph and pulling back on the wheel. Not much happens. Now, do that in a small airplane and pull back on the wheel. Yippee! From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Monday, October 06, 2008 2:20 PM To: Brian O'Connell; emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN ...circling back to an old thread: What would happen if we placed 8 access points in a circle around some popcorn? YouTube here we come! Best Regards, Patrick. p.con...@hp.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Monday, October 06, 2008 4:00 PM To: emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Recently we added two new food blasters to the lunch room and noted that some office areas no longer had reliable network connect. Installed some isolation transformers between building mains and the food blasters - no more complaints from the sales/accounting dweebs, or whatever they do. Also noted that some of the power to the lunch room does not have a separate ground wire - uses the metal conduit, which probably does not help much. As for the specific ID of these iso transformers, hmmm... we no longer make this particular model. But I am going to upgrade my tin-foil hat, as I very much suspect that the space aliens are using the 2.4GHz carrier to link our brains to the NSA computers... luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interfe
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
Hi Gherry: Just remember that when you pull back on the yoke (stick), the houses get smaller, but if you keep pulling back they get bigger again. John From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Pettit, Ghery Sent: Monday, October 06, 2008 2:24 PM To: Conway, Patrick R (Houston); Brian O'Connell; emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Nothing much of interest. It's about as interesting as getting a sports car up to about 75 mph and pulling back on the wheel. Not much happens. Now, do that in a small airplane and pull back on the wheel. Yippee! From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Monday, October 06, 2008 2:20 PM To: Brian O'Connell; emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN ...circling back to an old thread: What would happen if we placed 8 access points in a circle around some popcorn? YouTube here we come! Best Regards, Patrick. p.con...@hp.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Monday, October 06, 2008 4:00 PM To: emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Recently we added two new food blasters to the lunch room and noted that some office areas no longer had reliable network connect. Installed some isolation transformers between building mains and the food blasters - no more complaints from the sales/accounting dweebs, or whatever they do. Also noted that some of the power to the lunch room does not have a separate ground wire - uses the metal conduit, which probably does not help much. As for the specific ID of these iso transformers, hmmm... we no longer make this particular model. But I am going to upgrade my tin-foil hat, as I very much suspect that the space aliens are using the 2.4GHz carrier to link our brains to the NSA computers... luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
> -Original Message- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf > Of Kunde, Brian > Sent: Monday, October 06, 2008 12:55 PM > To: emc-pstc > Subject: Microwave Oven Interference with 2.4Ghz Wireless LAN > > I have just received and interesting call from our IT guys in > our production facility. They have installed a 2.4Ghz > wireless LAN system in our production and stock room areas, > which is a huge area, and which includes 13 Access Points and > a couple dozen wireless devices such as bar code readers, > computers, and printers. > > They discovered that they are having a major interference > problem which they have narrowed down to the Microwave Ovens > in the two break areas. > Evidently, Microwave Ovens run at 2.45Ghz. > > It would be very difficult to remove the ovens or to move the > break areas. > > Have any of you experts have experience with this issue? Any > suggestions? Are new ovens better then older ones? Are the > microwave ovens that run at a different frequency? Would it > help to try and shield the ovens better? Please help. > > The Other Brian You could suggest the IT guys try a different link standard that moves them out of the 2.45 GHz ISM band. You can also buy new microwave ovens, since publicly accessible ovens get a pretty horrible beating during use, and may be leaking from sprung doors or abused door seals. You can also get industrial microwave ovens that operate at 960 MHz. These ovens are often huge (imagine making taco filling starting with frozen slabs of beef and lard), but maybe some table models are available. (The 960 MHz penetrates food much deeper than the consumer 2450 MHz, so it lends itself to industrial cooking.) Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military & Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
Nothing much of interest. It's about as interesting as getting a sports car up to about 75 mph and pulling back on the wheel. Not much happens. Now, do that in a small airplane and pull back on the wheel. Yippee! From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Monday, October 06, 2008 2:20 PM To: Brian O'Connell; emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN ...circling back to an old thread: What would happen if we placed 8 access points in a circle around some popcorn? YouTube here we come! Best Regards, Patrick. p.con...@hp.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Monday, October 06, 2008 4:00 PM To: emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Recently we added two new food blasters to the lunch room and noted that some office areas no longer had reliable network connect. Installed some isolation transformers between building mains and the food blasters - no more complaints from the sales/accounting dweebs, or whatever they do. Also noted that some of the power to the lunch room does not have a separate ground wire - uses the metal conduit, which probably does not help much. As for the specific ID of these iso transformers, hmmm... we no longer make this particular model. But I am going to upgrade my tin-foil hat, as I very much suspect that the space aliens are using the 2.4GHz carrier to link our brains to the NSA computers... luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules:
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
...circling back to an old thread: What would happen if we placed 8 access points in a circle around some popcorn? YouTube here we come! Best Regards, Patrick. p.con...@hp.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Monday, October 06, 2008 4:00 PM To: emc-p...@ieee.org Subject: RE: Microwave Oven Interference with 2.4Ghz Wireless LAN Recently we added two new food blasters to the lunch room and noted that some office areas no longer had reliable network connect. Installed some isolation transformers between building mains and the food blasters - no more complaints from the sales/accounting dweebs, or whatever they do. Also noted that some of the power to the lunch room does not have a separate ground wire - uses the metal conduit, which probably does not help much. As for the specific ID of these iso transformers, hmmm... we no longer make this particular model. But I am going to upgrade my tin-foil hat, as I very much suspect that the space aliens are using the 2.4GHz carrier to link our brains to the NSA computers... luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEE
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
Recently we added two new food blasters to the lunch room and noted that some office areas no longer had reliable network connect. Installed some isolation transformers between building mains and the food blasters - no more complaints from the sales/accounting dweebs, or whatever they do. Also noted that some of the power to the lunch room does not have a separate ground wire - uses the metal conduit, which probably does not help much. As for the specific ID of these iso transformers, hmmm... we no longer make this particular model. But I am going to upgrade my tin-foil hat, as I very much suspect that the space aliens are using the 2.4GHz carrier to link our brains to the NSA computers... luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
Brian, Can you change the WLAN to operate in 802.11a mode which uses the 5GHz band? 11b/g is in the 2.4GHz band. The Access Points will most likely be able to support 11a but older clients may not. BTW - I've worked in the WLAN space for a couple of years and never heard of such a large issue with microwave ovens. I wonder if you have particularly bad models? (Although from Don's comments, this may not be so uncommon.) ...Marko From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of don_borow...@selinc.com Sent: Monday, October 06, 2008 1:27 PM To: emc-p...@ieee.org Cc: brian_ku...@lecotc.com Subject: Re: Microwave Oven Interference with 2.4Ghz Wireless LAN Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.i
RE: Microwave Oven Interference with 2.4Ghz Wireless LAN
Brian I have experienced two microwave production systems. Shielding helped a little, however, because product had to pass through it was not possible to completely mitigate the EMI and the situation was very difficult. In your case it is from commercial microwave ovens. The biggest source of emissions from these is the door. A new oven would help. If the door is in anyway loose they leak quite heavily. Shielding around the door would help. John McAuley www.cei.ie john.mcau...@cei.ie * DISCLAIMER: The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorised. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Kunde, Brian Sent: 06 October 2008 20:55 To: emc-pstc Subject: Microwave Oven Interference with 2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Microwave Oven Interference with 2.4Ghz Wireless LAN
Except for rebuilding the break rooms with foil-lined dry wall, metal flooring, screened windows, filtered power, waveguide-beyond-cutoff ventilation grills, and RF tight doors, I don't know there is much for a solution. I was told that in one major Boeing plant, communications as 2.4 GHz is all but impossible -- there are microwave ovens scattered around the various break rooms running off of all three phases of the electrical power (120/208 volts "Y"); and due to variety of manufacturers, generating RF during both polarities of each phase. In other words, continuous 2.4 GHz RF. Except for specialize industrial units, I don't think you will find microwave ovens running at any other frequency. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Kunde, Brian" To Sent by: "emc-pstc" emc-p...@ieee.org cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM2.4Ghz Wireless LAN I have just received and interesting call from our IT guys in our production facility. They have installed a 2.4Ghz wireless LAN system in our production and stock room areas, which is a huge area, and which includes 13 Access Points and a couple dozen wireless devices such as bar code readers, computers, and printers. They discovered that they are having a major interference problem which they have narrowed down to the Microwave Ovens in the two break areas. Evidently, Microwave Ovens run at 2.45Ghz. It would be very difficult to remove the ovens or to move the break areas. Have any of you experts have experience with this issue? Any suggestions? Are new ovens better then older ones? Are the microwave ovens that run at a different frequency? Would it help to try and shield the ovens better? Please help. The Other Brian LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Microwave Oven Interference with 2.4Ghz Wireless LAN
Brian As you know, the operation frequency of Microwave-oven uses same ISM band including 2.45GHz by which "Magnetron", main component of microwave oven is oscillated. It means, even though you use another new one, a little EMI will happen between Microwave oven and Wireless LAN. Best way is to reduce the use time of microwave-oven or remove it from LAN areas or isolate it >from areas by perfect shielding around microwave-oven. But these ways are not realistic or expensive. Instead of this, you can reduce the interference by general EMI noise reduction techniques. Basically, Microwave has a resonance space to heat food and Magnetron as source. You have to consider these things for microwave itself. 1. Impedance matching (filtering) between source (Magnetron) and resonance space. 2. Shielding effectiveness for preventing from emission at heating space (e.g. door screening, edge gap) 3. Radiation control through conducted power lines (conducted filter) To reduce your time, itll be better way to buy a new one considering the above things; it means new one must be compliant to CISPR 11. Best regards, Hocheol Kwak The Clemson Vehicular Electronics Laboratory, Department of Electrical & Computer Engineering, Clemson University, Clemson, SC, 29634-0915, Office: +1-864-656-7202 Homepage: http://people.clemson.edu/~hkwak CVEL site: http://www.cvel.clemson.edu/ Kunde, Brian wrote: > I have just received and interesting call from our IT guys in our > production facility. They have installed a 2.4Ghz wireless LAN system in > our production and stock room areas, which is a huge area, and which > includes 13 Access Points and a couple dozen wireless devices such as > bar code readers, computers, and printers. > > They discovered that they are having a major interference problem which > they have narrowed down to the Microwave Ovens in the two break areas. > Evidently, Microwave Ovens run at 2.45Ghz. > > It would be very difficult to remove the ovens or to move the break > areas. > > Have any of you experts have experience with this issue? Any > suggestions? Are new ovens better then older ones? Are the microwave > ovens that run at a different frequency? Would it help to try and shield > the ovens better? Please help. > > The Other Brian > > > > LECO Corporation Notice: This communication may contain confidential > information intended for the named recipient(s) only. If you received this > by mistake, please destroy it and notify us of the error. Thank you. > > - > > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list.Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to emc-p...@ieee.org > > Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/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:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
