Late to the party - but agree with James. Look to the USB cable first (as an obvious source). Incidentally try to use a robust USB peripheral and avoid the USB memory sticks. We use external USB powered HDDs, for example).
-----Original Message----- From: James Pawson (U3C) <ja...@unit3compliance.co.uk> Sent: Saturday, November 28, 2020 4:41 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] SV: [PSES] Thoughts on what may be the emission source This message originated outside of DISH and was sent by: owner-emc-p...@listserv.ieee.org Derek, I agree with Amund. Narrowband 240MHz (high speed mode clock rate) and 480MHz (second harmonics from low differential pair matching) are classic USB emissions. There may be a little something at 960MHz of 1.44GHz as well. I've had good results from RasPi boards in the past with USB so my immediate line of inquiry would be any other USB devices in the test setup, followed by the cables. Happy hunting! James James Pawson The EMC Problem Solver Unit 3 Compliance Ltd EMC Testing / Design for EMC / Problem Solving / Pre Compliance / Consultancy / Environmental & Vibration www.unit3compliance.co.uk // 07811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 -----Original Message----- From: Amund Westin <am...@westin-emission.no> Sent: 28 November 2020 09:43 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] SV: [PSES] Thoughts on what may be the emission source Derek, 240/480MHz sound like USB 2.0 High speed .... It's 4 USB-ports on the RPi ? Br Amund -----Opprinnelig melding----- Fra: DEREK WALTON Sendt: 28. november 2020 00:49 Til: EMC-PSTC@LISTSERV.IEEE.ORG Emne: [PSES] Thoughts on what may be the emission source Hi Folks, I’m working on a product containing a Raspberry PI as the main controller. I see two very strong emissions at about 240 MHz and 480 MHz. They are obviously related. I’ve discounted video, but not having any details on the board it’s making it hard to pin down the source. Anybody make some suggestions as to what the source may be? Thanks, Derek. - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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>
