David The uncertainty would be based on the calibration uncertainties of the respective antennas, plus any consideration for the phase center changes (measurement distance) related to the antennas used. For example if you used two biconicals to transmit and a bilog to receive then the phase center uncertainty would only apply to the biconical.
John Mowbray, P. Eng. Senior EMC Engineer NCR Canada, Ltd. 580 Weber St. N. Waterloo, Ontario N2J 4G5 519 884 1710 X5371 [email protected] _____ From: Sterner, David [S&FS] [mailto:[email protected]] Sent: October 11, 2006 9:58 AM To: Mowbray, John H; Grace Lin; [email protected] Subject: RE: Antennas for Volumetric Site Attenuation Measurement John, What is the effect on 'uncertainty' calculation if a different set of antennas is used for NSA? . Honeywell David W. Sterner Quality Assurance Engineering Security & Custom Electronics 165 Eileen Way P.O. Box 9035 Syosset, NY 11791 Phone: (516) 921-6704 x6970 Fax # (516) 364-6953 [email protected] <http://www.honeywell.com <http://www.honeywell.com/> > From: [email protected] [mailto:[email protected]]On Behalf Of Mowbray, John H Sent: Wednesday, October 11, 2006 9:45 AM To: Grace Lin; [email protected] Subject: RE: Antennas for Volumetric Site Attenuation Measurement Grace My experience is that VCCI will accept the use of a bilog hybrid when it is the recieving antenna for you normal measurements, but you need to use biconical, log-periodic, or their diplole antennas for transmitting during the validation measurements. John Mowbray, P. Eng. Senior EMC Engineer NCR Canada, Ltd. 580 Weber St. N. Waterloo, Ontario N2J 4G5 519 884 1710 X5371 [email protected] _____ From: [email protected] [mailto:[email protected]] On Behalf Of Grace Lin Sent: October 11, 2006 9:19 AM To: [email protected] Subject: Antennas for Volumetric Site Attenuation Measurement Dear Members, Does anyone have a successful experience in volumetric site attenuation (per ANSI C63.4, etc.) by using a pair of bilog hybrid antennas (30MHz to 2 or 3 GHz)? A VIP from VCCI told me that I would be challenged by using a pair of bilog hybrid antennas to perform volumetric site attenuation. For daily radiated emission measurement, bilog antenna are popular, especially using automation software for initial scan. For a manufacturer, it is hard to justify a pair of biconical (30MHz-300MHz) and log periodic (300MHz-1GHz) antennas just for site attenuation measurement, used once every three years (per FCC and Industry Canada). I did some research. There is a paper to address the measurement uncertainty of the bilog antennas, titled: "Understanding the measurement uncertainties of the bicon/log hybrid antenna" ( <http: /www.ets-lindgren.com/manuals/Chen_Bilog.pdf> http://www.ets-lindgren.com/manuals/Chen_Bilog.pdf) written by Zhong Chen of ETS-Lindgren. I spoke to the author. He told me when using bilog antennas, if the results do not meet 4 dB requirement, it might not mean the site was not good as the measurement uncertainty might cause the incorrect results. I am suggested to try to use a pair of bilog hybrid antennas to perform volumetric site attenuation after a chamber manufacturer completing its measurement and compare the results. The problem is: I am not sure if I can convince my manager to rent a bilog antenna to try it. I only plan to purchase one bilog antenna if it cannot be used for site attenuation measurement. I figure out it may be a good idea to ask for your experience. I appreciate your input. Best regards, Grace Lin Crestron Electronics, Inc. 6 Volvo Drive Rockleigh, NJ 07647 <http://www.crestron.com/> www.crestron.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 [email protected] 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 [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 - ---------------------------------------------------------------- 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/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 ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- 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/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
