Dear All,
Where does 3V/m come from? I do not know but if I run some numbers… E(dBV/m)=P(dbW)+14.77+G+20log(1/Distance) How close would you put a 10kW transmitter to housing? 300m? what antenna gain? 6dB? E=40+14.77+6+20log(1/300) E=60.77-49.5 = 11.27 dBV/m =3.66V/m Try some other realistic examples then take a “view” on what number you would set as an immunity limit. There will be some occasions where 3V/m is too low but do you make all equipment meet higher levels or do you set levels that satisfies most situations most of the time? Remember, most of the equipment that these limits apply to are semi permanent as far as their location is concerned. Somebody in the thread mentioned cars. Now cars are different. EMC tests (as per standards) can NEVER be used for safety certification as the tests do not simulate the “real world”, either in maximum potential exposure levels, not in terms of the multiple exposures that can occur. If you want more on this, take a look at Keith Armstrong’s presentation at http://www.theiet.org/events/2009/digests/emcuk/armstrong-vehicles.cfm?type=pdf Regards Tim ************************ Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG * Tel : +44 (0)1582 886239 * Fax : +44 (0)1582 795863 * Mob : +44 (0)7703 559 310 * E-mail : [email protected] P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman ________________________________ SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. ******************************************************************** - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]>
