I third this sentiment. I've seen wide variation in cable construction with respect to shell grounding and raw cable shield construction (foil types, braid % coverage).
HDMI cables with ferrite cores are available at places like Monoprice, but they are definitely in the minority. A web search similar to "HDMI cables with ferrite" yields some interesting and at times humorous A/V forum discussions. Also, if you search on 'ferrite' alone on the HDMI site, there's a vintage press release about a patented shielding can design which removes the need for ferrites and if you find the associated company's site, the technology (shell/can design) shows up on page one of their catalog. It seems as though the HDMI and DisplayPort interfaces have gone through change such that early cables more commonly had ferrites and later ones do not, perhaps due to what has been learned along the way about the transmitter and receiver PCBA/module designs. Cheers, Adam On Thu, Sep 4, 2014 at 4:51 AM, Pawson, James <james.paw...@echostar.com> wrote: > I'm with Ghery on this one. > > All HDMI cables are not created equal. > Screening of the backshell and connection of the cable shield is critical. > > James > > -----Original Message----- > From: Pettit, Ghery [mailto:ghery.pet...@intel.com] > Sent: 04 September 2014 08:46 > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: [PSES] FCC EMI Test and Ferrites on Cables > > You are highly unlikely to find the ferrite prayer beads at Best Buy. If > you don't specify which ones to get you have no idea what the result will > be. I think you are correct, the beads must be shipped with the product. > The right ones, to boot. > > Now, how does the designer know that he needs ferrite beads? My > experience has been that many (most?) HDMI cables do not have their shields > terminated properly, if at all. Once the shields are terminated correctly > problems go away. Could this be a better solution? > > Ghery S. Pettit > > -----Original Message----- > From: Scott Douglas [mailto:sdouglas...@gmail.com] > Sent: Wednesday, September 03, 2014 11:31 PM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: [PSES] FCC EMI Test and Ferrites on Cables > > Fellow List persons... > > Please help refresh a tired brain. A designer of a product tells us that > he passes FCC emissions testing if he puts ferrite sleeves (beads?) on the > four HDMI cables connected at the rear panel of the product. > > He tells us that all he needs to do is add a statement in the user manual > to the effect that the HDMI output cables must have ferrite sleeves > (beads?) on them. > > He says he does not need to specify manufacturer name and part number of > the ferrites. > > He says he does not need to provide the ferrites with the product. > > He also does not plan to include the HDMI output cables with the product > because every installation will have different length HDMI cables needed. > > Now, my old brain thinks the above is not acceptable and that the FCC says > that anything special needed to pass FCC testing must be provided with the > product. And I am thinking that ferrites are special as you can't get them > at Walmart or Radio Shack or Ace Hardware. And not all ferrites are the > same. > > Can anyone confirm my memory and maybe give a pointer to the part of the > FCC Rules that clarify this? Or have the rules changed over the years and I > just missed that part? > > Thank you in advance for any and all comments, on list or off. > > Best regards, > Scott > > - > ---------------------------------------------------------------- > 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 <emcp...@radiusnorth.net> > 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 <emcp...@radiusnorth.net> > 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 <emcp...@radiusnorth.net> > 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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
