Hello Ken,
Thinking aloud here: would such a factor exist as a generic formula? If I think about this the other way round, putting 1V of RF into the coax connector will generate 1V between the septum and ground (or between the septums? septii? in the case of a differential GTEM like a Laplacell). This 1V will be spread over the distance between septum and ground, dictating the overall field strength. This means cells with different dimensions will have different factors. This is leaving aside the frequency response / VSWR of the cell. I do recall seeing some formulae for correlation between GTEM and OATS/SAC but that was a while ago. A quick google on the subject shows a few papers with lots of big equations. I no longer have my old copy of EN 61000-4-20 but there might be some interesting reference material in there. This standard also notes that many of its provisions only apply to "small EUTs" which is anything below a certain size in relation to the GTEM volume or anything with cables attached (which are "under consideration") More practically, you could generate your own factors using an RF generator and an isotropic field probe and using reciprocity to flip this around to get a Volts out - field inside factor. Additional: There's also this NPL / York EMC guide on "The Use of GTEM Cells for EMC Measurements" which has some interesting info in. Its been a long while since I've read it in any depth though. https://www.npl.co.uk/special-pages/guides/gpg65_gtem Hope some of this is useful. All the best James James Pawson EMC Problem Solver Unit 3 Compliance Design for EMC / Pre Compliance / Problem Solving / EMC Testing / Consultancy / Environmental & Vibration <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk -- 07811 139957 Opening Hours: Tuesday to Friday, 0830 to 1800. Closed Monday. From: Ken Javor <ken.ja...@emccompliance.com> Sent: 12 August 2019 15:44 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] GTEM cell used for RE measurement Does anyone out there have a simple transducer factor that yields rf potential at the GTEM cell vertex coaxial connector for a given vertical electric field component coupling to the cell septum? Purpose is to calculate gain/noise figure specs for a preamplifier used between spectrum analyzer and GTEM cell to measure RE. Thank you. Ken Javor Phone: (256) 650-5261 - ---------------------------------------------------------------- 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 <mailto:emc-p...@ieee.org> > 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://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org <mailto:sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org <mailto:mcantw...@ieee.org> > For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org <mailto:j.bac...@ieee.org> > David Heald <dhe...@gmail.com <mailto:dhe...@gmail.com> > - ---------------------------------------------------------------- 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 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://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: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
