It’s a trade-off. The more directional the antenna is, the harder it is to meet uniformity over the 1.5x1.5m area at higher frequencies. OTOH, you don’t have to have as large an amp. For the lower frequencies the bilog is probably worse, depending on the specific antenna.
Regards, Rob From: Bob Richards [mailto:[email protected]] Sent: Thursday, August 26, 2010 10:11 AM To: [email protected] Subject: Re: [PSES] Field Uniformity Calibration per 61000-4-3 What would be considered worst case? A bicon - log periodic pair, or a bilog hybrid? I think the less directional the antenna, the worse the uniformity may be, but, I'm no expert on antennas. Bob R. --- On Thu, 8/26/10, John Woodgate <[email protected]> wrote: From: John Woodgate <[email protected]> Subject: Re: Field Uniformity Calibration per 61000-4-3 To: [email protected] Date: Thursday, August 26, 2010, 2:57 AM In message <1347744851.367114.12827814 [email protected] <http://us.mc565.mail.yahoo.com/mc/comp se?to=1347744851.367114.1282781476042.J [email protected]> .comcast.net>, dated Thu, 26 Aug 2010, [email protected] <http://us.mc565.mail.yahoo.com/mc/[email protected]> writes: > Shouldn't the chamber user's antenna be used for the field-uniformity test? Otherwise I don't see how the results would apply if a different Tx antenna is later used. The radiation cahracteristics, including the coupling with the chamber, will be different. I think so, too, but there are possibly two stages: - check the chamber for freedom from non-uniformity [1] using a reference antenna; - check that acceptable uniformity can be achieved with the user's antenna. [1] e.g. due to one or more quasi-specular reflections. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - ---------------------------------------------------------------- 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] <http://us.mc565.mai .yahoo.com/mc/[email protected]> > All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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] <h tp://us.mc565.mail.yahoo.com/mc/[email protected]> > Mike Cantwell <[email protected] <htt ://us.mc565.mail.yahoo.com/mc/[email protected]> > For policy questions, send mail to: Jim Bacher: <[email protected] <http: /us.mc565.mail.yahoo.com/mc/[email protected]> > David Heald: <[email protected] <http:/ us.mc565.mail.yahoo.com/mc/[email protected]> > - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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]> - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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]>
