In addition to the other responses, I would add that you need to understand what your magnetic emission standard is trying to protect. Since you are going down to dc, the strong implication is that you need to measure up close, as in the RTCA/DO-160 "magnetic effects" or "compass-safe distance" requirement. The MIL-STD-461 RE101 limit someone cited make a measurement at 7 cm from the test sample, using a a coil of diameter 13.3 cm. That gives you one kind of result, suitable for protecting a piece of sensitive equipment immediately adjacent to the test sample. An obsolete MIL-STD-461 requirement, RE04, made a measurement at one meter, but the limit was very tight. That limit protected a specific magnetometer. And a long time ago when commercial EMC was simple, that is before the simplification imposed by the 89/336/EEC EMC Directive, there was a VDE requirement for magnetic testing from 0.15 - 30 MHz, at three meters, outside your band of interest, but the purpose there was to protect radio reception, and the magnetic measurement was because they felt it was a better measurement at those frequencies than electric field.
The point being, with a near field magnetic measurement, you have to decide what and why you are making the measurement in order to design a good test, or pick the proper standard. > From: "Gordon,Ian" <[email protected]> > Date: Wed, 18 Apr 2007 09:06:10 +0100 > To: "'IEEE EMC & SAFETY PSTC'" <[email protected]> > Subject: Magnetic field testing > > All > Can anybody suggest a standard which describes how to perform magnetic field > emission testing from DC to at least 500Hz in addition to a guide as to what > instrumentation to use? Ideally we would like a plot of the field against > its level, similar to that from a receiver as in electric field emission > testing. > > > Ian Gordon > > . > > > *********************************************************************** > The information contained in this email and any attachments may be > confidential and is provided solely for the use of the intended recipient(s). > If you are not the intended recipient, you are hereby notified that any > disclosure, distribution, or use of this e-mail, its attachments or any > information contained therein is unauthorised and prohibited. If you have > received this in error, please contact the sender immediately and delete this > e-mail and any attachments. > > No responsibility is accepted for any virus or defect that might arise from > opening this e-mail or attachments, whether or not it has been checked by > anti-virus software. > > - > ---------------------------------------------------------------- > 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 ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
