I went to the EMC Test Systems website and looked at the 3106 half power beamwidth:
http://www.emctest.com/productpage.cfm?model=3106&producttype=Antennas At around 850 MHz, it dips to a low of just under 30 degrees, which means that a 1.5 m square has its edges at the half power point (with the antenna-EUT spacing of 3 m). So it may just barely work. But if you look at a log periodic such as the 3144: http://www.emctest.com/productpage.cfm?model=3144&producttype=Antennas the beamwidth minimum is nearly 50 degrees and you get a more uniform field intensity. The disparity is not as much as my gut reaction. I am used to working at 1 meter separations and the directionality of the DRG horn is a greater problem than at three meters. ---------- >From: John Woodgate <j...@jmwa.demon.co.uk> >To: emc-p...@majordomo.ieee.org >Subject: Re: RF Field Uniformity and Antenna location >Date: Fri, Jan 18, 2002, 3:38 PM > > > I read in !emc-pstc that Ken Javor <ken.ja...@emccompliance.com> wrote > (in <20020118175519.JJOG20810.femail29.sdc1.sfba.home.com@[65.11.150.27] >>) about 'RF Field Uniformity and Antenna location', on Fri, 18 Jan > 2002: >> Assuming >>it is, I can't imagine using a horn, which is a constant aperture antenna >>with gain increasing with increasing frequency. You need a constant gain >>antenna, a log periodic. > > The non-uniform gain makes the measurement more complicated, but I don't > see that it rules out the use of a horn. What have I missed? > -- > Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk > After swimming across the Hellespont, I felt like a Hero. > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: pstc_ad...@garretson.org > Dave Heald davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the old > messages are imported into the new server. > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
