I see very little response at those frequencies and levels. Recall that coupling efficiency to circuits decreases with increasing frequency. 21,000 V/m at 10 GHz couples the same level as 2100 V/m at 1 GHz, which is like 210 V/m at 100 MHz. But then you need to look at modulation. Usually these high field intensities occur at short pulsed, low duty cycle modulations. For these types of tests, you are usually looking at flight critical equipment only. The bandwidth of these subsystems is very slow relative to the duration of these pulses. You will see some issues, but very few in my experience. One thing you need to do with flight and engine controls is superimpose a low frequency modulation to which these systems can actually respond, like 1 or 3 Hz. This is written up in the modulation section of the MIL-STD-461 appendix. Ken Javor
Phone: (256) 650-5261 ________________________________ From: "Price, Edward" <[email protected]> List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: Tue, 1 Jul 2008 09:47:45 -0700 To: <[email protected]> Conversation: HIRF Risk Subject: HIRF Risk I have had a fair amount of experience in making sure that military systems can meet the MIL-STD-461 RS103 requirement of 200 V/M. However, we are now seeing system requirements for levels from MIL-STD-464 (and other places). These new requirements invoke immunity to levels such as 8 GHz to 10 GHz at 21,000 V/M (peak pulse). I would like to get an idea of the amount of risk involved in going to that next level. Has anyone had any experiences with meeting the 461 200 V/M and then trying for the 464 levels? Does equipment that meets 461 usually meet those 464 levels? If not, what kind of failures do you see (cable arcing, internal component destruction)? Thanks in advance! Ed Price [email protected] <mailto:[email protected]> <mailto:[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 - ---------------------------------------------------------------- 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
