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: [email protected] [mailto:[email protected]] Namens John Shinn Verzonden: dinsdag 7 oktober 2008 5:46 Aan: 'Pettit, Ghery'; '[email protected]' 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: [email protected] [mailto:[email protected]] On Behalf Of Pettit, Ghery Sent: Monday, October 06, 2008 2:24 PM To: Conway, Patrick R (Houston); Brian O'Connell; [email protected] 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: [email protected] [mailto:[email protected]] On Behalf Of Conway, Patrick R (Houston) Sent: Monday, October 06, 2008 2:20 PM To: Brian O'Connell; [email protected] 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. [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Brian O'Connell Sent: Monday, October 06, 2008 4:00 PM To: [email protected] 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: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Monday, October 06, 2008 1:27 PM To: [email protected] Cc: [email protected] 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" <brian_kunde@leco tc.com> To Sent by: "emc-pstc" <[email protected]> [email protected] cc Subject 10/06/2008 01:02 Microwave Oven Interference with PM 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. 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