Hi All, I recently wrote an article on wireless interference, with microwave ovens being one source of that interference. Fortunately, the use cycle of microwave ovens is relatively short, so any interference is short-term. However, any leakage is certainly an issue for those standing nearby - maybe listening to popcorn, etc.?
http://www.edn.com/electronics-blogs/the-emc-blog/4438663/Wi-Fi-network-interference--analysis--and-optimization <http://www.edn.com/electronics-blogs/the-emc-blog/4438663/Wi-Fi-network-interference--analysis--and-optimization> In this article, I show a real-time spectral plot of microwave oven leakage at 12 inch distance from the oven. The peaks were around -20 dBm using a short “rubber duck” antenna on the Tek RSA306 analyzer. The leakage limit is 1 mW/cm^2 with a test load (water) and 5 mW/cm^2 without a test load (measured at 5 cm from the oven surface). I measured mine just now at 0.1 mW/cm^2 loaded and 0.5 mW/cm^2 unloaded. The Australian Government did a study on the subject in 2004 and includes some interesting background on the door interlock designs: http://www.arpansa.gov.au/pubs/emr/microwave.pdf <http://www.arpansa.gov.au/pubs/emr/microwave.pdf> Health Canada also did a survey of several new and used microwave ovens in the Ottawa area: http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/microwave_ovens-micro_ondes/index-eng.php <http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/microwave_ovens-micro_ondes/index-eng.php> Cheers, Ken _______________________ Kenneth Wyatt Wyatt Technical Services, Inc. 56 Aspen Dr. Woodland Park, CO Phone: (719) 310-5418 Email Me! <mailto:[email protected]> | Web Site <http://www.emc-seminars.com/> | Blog <http://design-4-emc.com/> The EMC Blog (EDN) <http://www.edn.com/blog/The-EMC-Blog> Subscribe to Newsletter <http://www.emc-seminars.com/Newsletter/Newsletter.html> Connect with me on LinkedIn <http://www.linkedin.com/in/kennethwyatt> > On May 15, 2015, at 9:00 AM, Ken Javor <[email protected]> wrote: > > My microwave oven used correctly interferes with wi-fi and Bluetooth, but > with blue tooth if I bring the devices close together I can overpower the > incidental oven radiation, right next to the oven. I can't do that with > wi-fi at home, because of the fixed location of the wi-fi base station at > the other end of the house from the oven. Obviously I can bring the wi-fi > device closer to the base station and at the same time farther from the oven > and make the problem go away, but that is hardly surprising. > > But the point of the news item was that it seemed the interference was tied > to the oven door opening, which is problematic, at least to me. I don't buy > the delay thing someone posited - I'm thinking that it is a switch > activating a relay interrupting power to the magnetron, and that happens > before any pressure on the oven door gasket has been released. > > Ken Javor > Phone: (256) 650-5261 > > >> From: Michael Derby <[email protected]> >> Reply-To: Michael Derby <[email protected]> >> Date: Fri, 15 May 2015 08:02:00 +0100 >> To: <[email protected]> >> Subject: Re: [PSES] Interference Caused by Microwave Oven >> >> This isn't a particularly helpful contribution, but when I use my microwave >> (used correctly, with the door closed), my Bluetooth speaker completely >> stops working and any WiFi activity grinds to a halt. >> >> I try to keep the kids away from the microwave when it's in use, as much as >> I can. >> >> >> Michael. >> >> >> -----Original Message----- >> From: John Woodgate [mailto:[email protected]] >> Sent: 14 May 2015 23:42 >> To: [email protected] >> Subject: Re: [PSES] Interference Caused by Microwave Oven >> >> In message <[email protected]>, dated Thu, 14 May 2015, Doug Powell >> <[email protected]> writes: >> >>> My question is this. If the RF generated inside the oven does not stop >>> prior to the opening of the RF seal on the door, which testing is >>> responsible to identify this problem, EMC or the Safety testing >> >> Not 'either/or': emission with the door open violates CISPR 11/EN 55011, >> it's also a violation of the Section of IEC/EN 60335-2 (too late here to >> look it up) and potentially a violation of the regulatory EMF exposure >> limits as measured according to IEC 62233. >> -- >> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk When I >> turn my back on the sun, it's to look for a rainbow 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 >> <[email protected]> >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities site at >> http://product-compliance.oc.ieee.org/ can be used for graphics (in >> well-used formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> Scott Douglas <[email protected]> >> Mike Cantwell <[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher: <[email protected]> >> David Heald: <[email protected]> >> >> - >> ---------------------------------------------------------------- >> 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 >> <[email protected]> >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities site at >> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used >> formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) >> List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> Scott Douglas <[email protected]> >> Mike Cantwell <[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher: <[email protected]> >> David Heald: <[email protected]> > > - > ---------------------------------------------------------------- > 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 > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> - ---------------------------------------------------------------- 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
