Thanks! Ken Javor Phone: (256) 650-5261
From: Ken Wyatt <[email protected]> Date: Tue, 13 Aug 2019 10:41:29 -0600 To: Ken Javor <[email protected]> Cc: "[email protected]" <[email protected]> Subject: Re: [PSES] GTEM cell used for RE measurement Hi Ken, You might try contacting Dr. Diethard (Andy) Hansen, inventor of the GTEM. He can be reached at [email protected] LI: https://www.linkedin.com/in/dr-diethard-hansen-032b28155/ Cheers, Ken _______________________ I'm here to help you succeed! Feel free to call or email with any questions related to EMC or EMI troubleshooting - at no obligation. I'm always happy to help! Kenneth Wyatt Wyatt Technical Services LLC 56 Aspen Dr. Woodland Park, CO 80863 Phone: (719) 310-5418 Web Site <http://www.emc-seminars.com> | Blog <https://design-4-emc.com> The EMC Blog (EDN) <https://www.edn.com/electronics-blogs/4376432/The-EMC-Blog> Subscribe to Newsletter <http://www.emc-seminars.com/Newsletter/Newsletter.html> Connect with me on LinkedIn <https://www.linkedin.com/in/kennethwyatt/> > On Aug 13, 2019, at 10:34 AM, Ken Javor <[email protected]> wrote: > > Re: [PSES] GTEM cell used for RE measurement > I¹m working for a customer. The customer bought the GTEM cell used. I¹m sure > the manufacturer would be willing to sell the software at a price, but right > now my goal is to figure out if he needs a low noise preamplifier to augment > his spectrum analyzer, and if so, what noise figure and gain. For that I need > a transfer function between field intensity and rf potential at the GTEM cell > EMI port. > > Complicating this is the customer is working to CISPR 25, i.e., automotive, > which measures emissions at one meter, whereas the typical GTEM cell software > for predicting emissions assumes a far field at three or more meters > distance... > > Ken Javor > Phone: (256) 650-5261 > > > > From: John Woodgate <[email protected]> > Reply-To: John Woodgate <[email protected]> > Date: Tue, 13 Aug 2019 15:46:19 +0100 > To: <[email protected]> > Subject: Re: [PSES] GTEM cell used for RE measurement > > > > Won't the manufacturer tell you? > > > Best wishes > John Woodgate OOO-Own Opinions Only > J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> > <http://www.woodjohn.uk> <http://www.woodjohn.uk/> > Rayleigh, Essex UK > > On 2019-08-13 15:27, Ken Javor wrote: > > >> Re: [PSES] GTEM cell used for RE measurement I understand how the GTEM cell >> works for immunity. That is quite simple, as you say. It¹s not as simple for >> emissions. I think an analogy is the equation for transmitting from an >> antenna is not reciprocal with receiving. One is simply a function of gain, >> the other involves frequency/wavelength. I too worked with GTEM cells in the >> past and understood better, and I too did a search and found the very complex >> formulae (!) but now I need to be able to get from a field intensity limit to >> the coupled potential at the cell coax connector, and I¹m not finding that, >> nor a way to get there. >> >> Ken Javor >> Phone: (256) 650-5261 >> >> >> >> >> From: "James Pawson (U3C)" <[email protected]> >> <mailto:[email protected]> >> Reply-To: "James Pawson (U3C)" <[email protected]> >> <mailto:[email protected]> >> Date: Tue, 13 Aug 2019 07:47:56 +0100 >> To: <[email protected]> <mailto:[email protected]> >> Subject: Re: [PSES] GTEM cell used for RE measurement >> >> 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 ³small EUTs² which is anything below a >> certain size in relation to the GTEM volume or anything with cables attached >> (which are ³under consideration²) >> >> >> 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: There¹s also this NPL / York EMC guide on ³The Use of GTEM Cells >> for EMC Measurements² which has some interesting info in. Its been a long >> while since I¹ve 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 >> www.unit3compliance.co.uk <http://www.unit3compliance.co.uk> >> <http://www.unit3compliance.co.uk> <http://www.unit3compliance.co.uk/> >> <http://www.unit3compliance.co.uk/> -- 07811 139957 >> Opening Hours: Tuesday to Friday, 0830 to 1800. Closed Monday. >> >> >> From: Ken Javor <[email protected]> >> <mailto:[email protected]> >> Sent: 12 August 2019 15:44 >> To: [email protected] >> 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 >> <[email protected]> <mailto:[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://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 <[email protected]> <mailto:[email protected]> >> Mike Cantwell <[email protected]> <mailto:[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher <[email protected]> <mailto:[email protected]> >> David Heald <[email protected]> <mailto:[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]> <mailto:[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://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 <[email protected]> <mailto:[email protected]> >> Mike Cantwell <[email protected]> <mailto:[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher <[email protected]> <mailto:[email protected]> >> David Heald <[email protected]> <mailto:[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://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 <[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://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 <[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://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 <[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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
