In message <c3ece0f6.1198d%ken.ja...@emccompliance.com>, dated Thu, 28 Feb 2008, Ken Javor <ken.ja...@emccompliance.com> writes:
>If you have two different serial numbers of the same model antenna, and >the antenna factors one to the next vary as much as shown below, then >either the antenna quality control is very poor, or (much) more likely >the antenna calibration tolerances are just that bad (OATS-to-OATS NSA >can vary 8 dB, right?). Agreed. > I would have thought that a free space antenna factor would be more >like 30 meters, especially at 30 MHz, but I?m not an expert on that. I would agree. Obviously it depends on how accurate you want to be, but 10 m seems too close unless the antenna is very small, when it will anyway have a high antenna factor at 30 MHz. > But if the comparison is valid, meaning your colleague?s ten meter >antenna factor should correlate to your free space factor, then just >use your colleague?s three meter numbers and be done with it. Yes: the uncertainty of your measurements for other reasons is likely to be quite a lot greater than the difference between the 10 m and 3 m numbers. >You will gain nothing by paying for a three meter calibration of your >antenna, aside from appeasing some accreditor whose understanding is >limited to checking calibration stickers and record books. Too true. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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
