On Thu, 12 Jan 2012 15:09:13 -0500, Grace Lin <[email protected]> wrote:
> I have a contractor performing NSA today. When the center of the biconical > antenna is located right at the 2 meter peripheral, NSA doesn't meet the 4 > dB requirements. In order to meet the 4 dB requirement, the antenna must > be moved inward until the tip of the biconical antenna element is right at > the peripheral. The contractor tells me this is the way suppose to. Do > you agree with the contractor? Which polarization? For horizontal, ANSI C63.4-2003 clause 5.4.6.5 says: For horizontal polarization measurements in the left and right positions, if the distance between the construction or absorbing material on the side walls and the EUT periphery is at least 1 m, **the center of the antenna may be moved toward the center position so that the extreme outside tip of the antenna is either at the test volume periphery or at a distance inward from the periphery by not more than 10% of the test volume diameter.** See also the Figure 8b. > For vertical polarization, the diagram from ANSI C63.4 shows the center of > the biconical antenna is not right at the peripheral. I cannot remember > how NSA was performed when the chamber was built four years ago. For vertical polarization, I think Figure 8a and 8c shows antenna rigth at the peripheral of diameter p, although the peripheral is smaller than the outer circle in the figure. Regards, Tom -- Tomonori Sato <[email protected]> URL: http://homepage3.nifty.com/tsato/ - ---------------------------------------------------------------- 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://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]>
