On 16 Jun 2008 at 8:48, Price, Edward wrote: > > I'm curious about the effect of using a gold (or silver) loaded epoxy > to bond a connector shell to a chassis box. If I measured a bond > resistance of about 1 Ohm from the connector shell to the chassis, how
> could I estimate the degradation in shielding effectiveness (frequency > range of interest is about 10 kHz to 5 MHz)? > > Maybe this has been thoroughly covered in some past Symposium papers. > Can anyone give me a hint about where to look? Of course, absolutely > definitive answers, which allow me to remain lazy, are also quite > acceptable. > > Thanks in advance! > > > Ed Price Ed, My first question is the degradation in shielding effectiveness compared to what? If you are comparing the conductive epoxy to a screw-fastened connection you need to know the exact resistance of both shield paths. I think if you took a good four-wire resistance measurement box-to-box for a typical cable length you could get a good comparison of relative resistance. If one construction had 5% higher total resistance the degradation would be at least 5% at the lower frequencies. Scott B. Lacey Scott: For a standard of comparison, maybe I could use the definition of a good conductive joint as one being less than 0.0025 Ohms. If I assume that the radiated leakage is proportional to the joint resistance, then a 1 Ohm value is 400 times higher than a "good" joint. That would imply that the leakage would be 52 dB greater than the "good" joint cable. Naahh, can't be that simple! Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military & Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
