I'm not smart enough to add to the topic, but I sense something not to be over looked:
MIKE SHERMAN wrote: > I'm not an EE and > We're rating RF output as 0 mW (i.e., rounding off, it's a lot closer to 0 mW > than to 1 mW). and Heckrotte, Michael wrote: > Digital devices that have a power consumption not exceeding 6 nW are exempt > from specific technical standards per FCC Rules 15.103(f). Not to over looked is the disparity in unit. Thinking between 0 mW and 1 mW is in linear unit. However radio frequency emissions are usually expressed in logarithmic unit. The commonly encountered range of RF power expressed in logarithmic term is between -100 dBm to +60 dBm. In linear terms they are 10 nW to 1 kW. That's a huge range, and more specifically, there is a lot of difference between 0 mW and 1 mW. From what Michael wrote about, 6 nW is more about 160,000 times smaller than 1 mW and yet is not exempted. Heckrotte, Michael also wrote: > There are no such exemptions for intentional radiators. See FCC Rules 15.225 > for radiated emission limits applicable to radio devices operating on 13.56 MHz And an NFC device intentionally radiate RF energy in order to communicate wirelessly. Sincerely, Alfred Lee On October 19, 2018 3:22:50 PM PDT, MIKE SHERMAN <msherma...@comcast.net> wrote: >Esteemed fellow listers -- > > >I'm looking at a very low power, intermittent NFC card reader/writer. >Alkaline battery operated device. NFC is only energized for 10 seconds >at a time on demand, and range to read/write is less than 1 cm from the >surface of the device. > > >I'm not an EE, but my simplified thought process is: "I can barely get >this to couple magnetically with a card sitting on its surface. How >could I possibly interfere with broadcast services or other equipment?" > > >So, oh wise ones, from your experience what actions with respect to FCC >are reasonable to do? For example, radiated emissions testing seems to >me like a total waste of time and money. > > >More technical details: maximum input power to the NFC chip is 17 mW. >Chip is coupled to a flat 30mm x 40mm "NFC Ferrite Antenna (13.56 MHz)" >that my EE describes as "zero gain." We're rating RF output as 0 mW >(i.e., rounding off, it's a lot closer to 0 mW than to 1 mW). > > >Looking forward once again to interesting wisdom from this group. > > >Mike Sherman > >Graco Inc. > >- >---------------------------------------------------------------- >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> -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. - ---------------------------------------------------------------- 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>
