RE: Humidity and Radiated Emissions Tests
Mac, The biggest effect I've seen was due to the fire retardant in the old cones absorbing moisture and subsequent dielectric changes. We had to put in a humidity controller to keep the chamber and cones at the same RH all the time to get consistant measurements. Bill Barron, Manny manny.bar...@ngc.com wrote: Hello Mac, I don't know the actual physical effect, but there is a requirement in the ANSI C63.4, para 6.1.9. Sincerely, Manny Barron, EMC Engineer Northrop Grumman Mission Systems Intelligence Systems Division Electromagnetic Systems Laboratory 6! 377 San Ignacio Avenue San Jose, California 95119 Phone: 408-531-2430 Email: manny.barron@ mailto:manny.bar...@ngc.com ngc.com Web: www.ngc.com http://www.ngc.com/ _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Elliott Mac-FME001 Sent: Friday, January 13, 2006 11:20 AM To: emc-p...@ieee.org Subject: Humidity and Radiated Emissions Tests Colleagues, What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? Just curious as to the thoughts out there [or experiences] Best regards, Mac - 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 _ Yahoo! Photos – Showcase holiday pictures in hardcover Photo Books http://us.rd.yahoo.com/mai _us/taglines/photobooks/*http://pa.yaho .com/*http://us.rd.yahoo.com/mail_us/ta lines/photos/evt=38088/*http://pg.photo .yahoo.com/ph//page?.file=photobook_splash.html . You design it and we’ll bind it! - 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: Humidity and Radiated Emissions Tests
In message 20060113213741.90815.qm...@web36805.mail.mud.yahoo.com, dated Fri, 13 Jan 2006, Hans htm...@yahoo.com writes There are formulae for calculating the ERP/EIRP power loss due to moisture content in the air. Typically used when calculating point to point microwave links over several miles and especially over a water body. It seems the loss is near neglible within a 10m distance. It isn't so much power loss in beamed emissions that counts (usually), it's distortions of radiated field patterns. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - 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: Humidity and Radiated Emissions Tests
There are formulae for calculating the ERP/EIRP power loss due to moisture content in the air. Typically used when calculating point to point microwave links over several miles and especially over a water body. It seems the loss is near neglible within a 10m distance. Hans Best Regards Hans Mellberg San Jose, CA 95128, USA __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - 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: Humidity and Radiated Emissions Tests
You might see effects due to moisture on covers over turntables at OATS facilities. One more argument for 10 meter RF semi-anechoic chambers. :-) Wish we had one. :-( Ghery _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Marko Radojicic Sent: Friday, January 13, 2006 11:42 AM To: Elliott Mac-FME001; emc-p...@ieee.org Subject: RE: Humidity and Radiated Emissions Tests Interesting question! Water is a dielectric with absorptive properties that are frequency dependant. The most well-known peak absorption is the microwave oven 2.4GHz frequency. If you are having EMI issues in this frequency area, you may want to wait for a high-humidity day. 8-) In practice however, I cannot imagine that you would see much variation due to atmospheric RH. Certainly other measurement variation factors would outweigh the water contribution, IMHO. …Marko _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Elliott Mac-FME001 Sent: Friday, January 13, 2006 11:20 AM To: emc-p...@ieee.org Subject: Humidity and Radiated Emissions Tests Colleagues, What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? Just curious as to the thoughts out there [or experiences] Best regards, Mac - 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.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: Humidity and Radiated Emissions Tests
Is the site near the ocean? Salt plays havoc in moist air. Also, if in a dirty environment where particulates are high it could affect readings. These issues however should be able to be accounted for in your uncertainty budget. Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703-847-4700 fax 703-847-6888 direct - 703-880-4841 cell - 209-769-8316 NOTICE: This E-Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Elliott Mac-FME001 Sent: Friday, January 13, 2006 11:20 AM To: emc-p...@ieee.org Subject: Humidity and Radiated Emissions Tests Colleagues, What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? Just curious as to the thoughts out there [or experiences] Best regards, Mac - 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: Humidity and Radiated Emissions Tests
In message 54ffbe24c443bc45b8deb804650d2d2ba3a...@ct11exm64.ds.mot.com, dated Fri, 13 Jan 2006, Elliott Mac-FME001 fme...@motorola.com writes What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? The phases of the moons of Neptune can affect radiated emissions tests, or so it seems, sometimes! On an open-air site, there certainly can be effects, especially if surfaces are damp. It's not only condensation, and not only the EUT, that matters. Indoors, I suspect you can find effects if you go looking for them, but usually RH doesn't change very much in the short term. If you measured an EUT at 25% RH and then at 95% RH, the results should only be compared if they were obtained at the same temperature. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - 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: Humidity and Radiated Emissions Tests
Interesting question! Water is a dielectric with absorptive properties that are frequency dependant. The most well-known peak absorption is the microwave oven 2.4GHz frequency. If you are having EMI issues in this frequency area, you may want to wait for a high-humidity day. 8-) In practice however, I cannot imagine that you would see much variation due to atmospheric RH. Certainly other measurement variation factors would outweigh the water contribution, IMHO. …Marko _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Elliott Mac-FME001 Sent: Friday, January 13, 2006 11:20 AM To: emc-p...@ieee.org Subject: Humidity and Radiated Emissions Tests Colleagues, What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? Just curious as to the thoughts out there [or experiences] Best regards, Mac - 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: Humidity and Radiated Emissions Tests
Hello Mac, I don't know the actual physical effect, but there is a requirement in the ANSI C63.4, para 6.1.9. Sincerely, Manny Barron, EMC Engineer Northrop Grumman Mission Systems Intelligence Systems Division Electromagnetic Systems Laboratory 6377 San Ignacio Avenue San Jose, California 95119 Phone: 408-531-2430 Email: manny.barron@ mailto:manny.bar...@ngc.com ngc.com Web: www.ngc.com http://www.ngc.com/ _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Elliott Mac-FME001 Sent: Friday, January 13, 2006 11:20 AM To: emc-p...@ieee.org Subject: Humidity and Radiated Emissions Tests Colleagues, What is your opinion - does relative humidity have an effect on radiated emissions testing [as long as there is no condensation on the EUT]? Just curious as to the thoughts out there [or experiences] Best regards, Mac - 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
