I "triple echo" Ken's suggestion. Back when I was managing the HP/Agilent test lab in Colorado Springs, we installed the "waffle-style" ferrite panels into the floor permanently, with plywood and carpeting over the top within our 3m chamber (3 or 4-foot conventional carbon-loaded absorber everywhere else). We did nothing different from normal - even continuing the antenna height scans (I know, not theoretically required), as well as full EUT rotations (360 degrees). We never bothered with correlation factors, because in our case, the correlation between the fully anechoic 3m chamber and 10m OATS was amazingly comparable.
We checked the correlation with comb generators, as well as real products with multiple cables fanned out. It did tend to read a little higher below 150 MHz in the chamber, but that was OK, knowing it would read lower at the OATS. Cheers, Ken (The Other Ken) _______________________ Kenneth Wyatt Wyatt Technical Services LLC Woodland Park, CO Email Me! | Web Site | Blog Subscribe to Newsletter Connect with me on LinkedIn On Dec 19, 2011, at 7:01 AM, Elliott Mac-FME001 wrote: > Season’s Greetings to all > > I agree with this – have had success with it in the past. > > Minimizes effect to RI setup as well of moving absorbers in and out. Leave as > calibrated. > > I did a correlation study with a reference radiator to develop the > correlation factor to the OATS > > > Best regards, > > Mac Elliott > > > [ ] General Public > From: Kunde, Brian [mailto:[email protected]] > Sent: Monday, December 19, 2011 9:01 AM > To: [email protected] > Subject: Re: [PSES] Semi-Anechoic Chamber Question > > I echo Ken’s suggestion. > > The Other Brian > > From: [email protected] [mailto:[email protected]] On Behalf Of Ken Javor > Sent: Friday, December 16, 2011 6:04 PM > To: [email protected] > Subject: Re: Semi-Anechoic Chamber Question > > Since it’s a pre-compliance scan, why not just leave the floor absorber in > place, use a fixed receive antenna height, and add 4-6 dB (or whatever number > is deemed appropriate) as a worst case adjustment factor? > > Ken Javor > > Phone: (256) 650-5261 > > From: Jim Hulbert <[email protected]> > Date: Fri, 16 Dec 2011 16:48:51 -0500 > To: "[email protected]" <[email protected]> > Conversation: Semi-Anechoic Chamber Question > Subject: Semi-Anechoic Chamber Question > > I have an older 3-meter semi-anechoic chamber that is fully compliant for > radiated immunity testing per IEC 61000-4-3. Occasionally I also use the > chamber to run a radiated emissions "pre-scan". When I use the chamber for > the pre-scan up to 1 GHz, I remove the foam absorbers and ferrite floor tiles > between the antenna and EUT to get a reflecting ground plane. The aborbers > are no problem but the floor tiles are quite heavy. As an easier option, > I'm thinking of coming up with a relatively light weight conductive surface > that can be easily placed over the floor tiles and easily removed again. > Something like a foil that could be rolled into place and then rolled up > again when done. I could connect the foil to the shielded room floor to > ground it. Does anyone have any experience doing something like this or > would I be wasting my time and better off continuing my practice of removing > the tiles? I'm not looking for compliance emissions measurements because I'm > limited to 3 meter distance and an antenna sweep height of 3 meters. > However, I would like to get the best pre-scan data I can to minimize > surprises when I do go out to an open area test site for the final test. > > Thanks. > > Jim Hulbert > - > ---------------------------------------------------------------- > > 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]> > > - > ---------------------------------------------------------------- > 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]> > > LECO Corporation Notice: This communication may contain confidential > information intended for the named recipient(s) only. If you received this by > mistake, please destroy it and notify us of the error. Thank you. > > - > ---------------------------------------------------------------- > 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]> > > - > ---------------------------------------------------------------- > 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]> > - ---------------------------------------------------------------- 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]>
