Well, it isn't a "proposed CISPR 22 standard" anymore. Amendment 1 to CISPR 22:2005 was published in July and provides limits from 1 GHz to 6 GHz. The actual test methods, etc are provided in the CISPR 16 series of documents. See the amendment for the specific citations.
No height scan is required for CISPR 22 above 1 GHz IFF (remember the old algebra IFF - If and only if?) the EUT falls within the beam width of the antenna. Otherwise, some height scanning is needed. Again, look at the amendment and read the cited portions from CISPR 16-x. No bore sighting either way. Ghery S. Pettit Intel Corporation From: [email protected] [mailto:[email protected]] On Behalf Of Brent DeWitt Sent: Saturday, October 01, 2005 7:54 PM To: Dward ATCB; [email protected]; [email protected] Cc: [email protected] Subject: RE: Above 1 GHz EMI testing with horn antenna Possibly a wee bit harshly stated, but otherwise correct as previous posters have noted. That said, the other issues are beam width of antennas (unspecified in most standards) and "bore-sighting" (uspecified in most (all?) standards). If I remember correctly, the proposed CISPR 22 standard for emissions above 1 GHz does not have a height scan or bore sighting. Is this correct? With respect, Brent DeWitt > -----Original Message----- > From: [email protected] [mailto:[email protected]]On Behalf Of Dward ATCB > Sent: Saturday, October 01, 2005 5:54 PM > To: [email protected]; [email protected] > Cc: [email protected] > Subject: RE: Above 1 GHz EMI testing with horn antenna > > > Just because someone does something and 'gets away with it' does > not mean it > is right nor within the rules. The standards say raise and lower the > antenna 1-4 meter. That is what it means. Until such time as > the standards > and rules are written for a different antenna height, the only > way that you > can say you comply with the rules is to do what it says i.e. > raise and lower > the antenna 1-4 meters. IF you do not raise and lower the antenna 1-4 > meters then you are not compliant to the rules. It is as simple as that. > > > 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 or 209-966-2145 > 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. > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Eric Lifsey > Sent: Saturday, October 01, 2005 12:29 PM > To: [email protected] > Cc: [email protected] > Subject: Re: Above 1 GHz EMI testing with horn antenna > > Circa 1995 I saw plotted emission data taken at a semi-anechoic > chamber in Austin, Texas, that justified reducing the scan > height to a maximum of around 1.4 meters (IIRC) for emissions in > the GHz range. > > However, when I ran the first 1-2 GHz emissions measurements > where I worked I found maximums at 2.5 meter heights. (Using an > octave horn.) I suspect the other lab tested a physically small > source which would hide the effect of a real EUT of random > dimensions and apetures. > > I mounted the horn with a slight downward tilt to help insure > that the EUT emissions would be collected at the higher antenna > elevation and as frequency approached 2 GHz. The measurement > distance was 3 meters within a compact shielded room with cone > absorbers. This chamber was used primarily to pre-scan > emissions below 1 GHz at the time. > > IMO the best approach as suggested by others is to scan per the > written requirements. I'd add that I would have preferred to > collect emissions from greater than 3 meters to avoid the > concerns of the narrow field of illumination/sensitivity in the > octave horn. > > Best Regards, > Eric Lifsey > > [email protected] said: > > Hello, > > > > A discussion has come up about the need to raise the horn > > antenna up to 4 > > meters when doing an EMI test above 1 GHz. ANSI states that the > > antenna height > > should be adjusted between 1-4 meters to maximize the emissions. > > Some labs > > are only doing this test at 1 meter or maybe 2 meters high, > > (probably to > > reduce cable loss issues). Normally, the emissions are worst > > case below 2 > > meters, but how can one be absolutely sure, without checking? > > What is the legal > > requirement for the antenna height? These questions apply to > > unintentional > > radiators, where measurement above 1 GHz is required. > > > > Regards, > > Tim Pierce > > > > - > > 2005 IEEE Symposium on Product Safety Engineering > > 3-4 October Schaumburg, IL > > http://www.ieee-pses.org/symposium > > > > ---------------------------------------------------------------- > > 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 > > [email protected] > > > > Instructions: > > http://listserv.ieee.org/listserv/request/user-guide.html > > > > 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: > > > > Richard Nute: [email protected] > > Jim Bacher: [email protected] > > > > All emc-pstc postings are archived and searchable on the web at: > > > > http://www.ieeecommunities.org/emc-pstc > > > > > --- > http://www.relia.net/~elifsey/ > > - > 2005 IEEE Symposium on Product Safety Engineering > 3-4 October Schaumburg, IL > http://www.ieee-pses.org/symposium > > ---------------------------------------------------------------- > 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 [email protected] > > Instructions: http://listserv.ieee.org/listserv/request/user-guide.html > > 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] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > - > 2005 IEEE Symposium on Product Safety Engineering > 3-4 October Schaumburg, IL > http://www.ieee-pses.org/symposium > > ---------------------------------------------------------------- > 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 [email protected] > > Instructions: http://listserv.ieee.org/listserv/request/user-guide.html > > 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] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.344 / Virus Database: 267.11.9/116 - Release Date: 9/30/2005 > -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.9/116 - Release Date: 9/30/2005 - 2005 IEEE Symposium on Product Safety Engineering 3-4 October Schaumburg, IL http://www.ieee-pses.org/symposium 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 [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - 2005 IEEE Symposium on Product Safety Engineering 3-4 October Schaumburg, IL http://www.ieee-pses.org/symposium 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 [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
