On Thu, 6 Apr 2023 11:32:20 +0900, Youngsik Kim <fs741fs...@gmail.com> wrote:
> According to FCC part 18.305 FIELD STRENGTH LIMITS, a test article of Any > type unless otherwise specified has a measurement distance of 300 meters, > but I want to measure it at a distance of 3 meters because I need to > measure it in a chamber. > In this case, what is the limit at 3 meters? > > If we use Any non-ISM frequency, the measurement distance is 300 meters and > the limit value is 15 uV/m, We have a limit of 63.5 dBuV/m when measuring > at 3 meters. > However, other laboratories apply a limit of 103.5 dBuV/m. > Depending on the RF power of the test device, can I use a 40 log instead of > a 20 log conversion? > Is the conversion different depending on the power of the test device? See note 2 in the section, which says: Testing for compliance with these limits may be made at closer distances, provided a sufficient number of measurements are taken to plot the radiation pattern, to determine the major lobes of radiation, and to determine the expected field strength level at 30, 300, or 1600 meters. Alternatively, if measurements are made at only one closer fixed distance, then the permissible field strength limits shall be adjusted using 1/d as an attenuation factor. With the former method above, attenuation factor larger than -20 dB/decade may be used if measurements at closer distances justified that. Regards, Tom - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html 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: Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
