Jeff, The calibration procedure will not change. The equipment requirements WILL change. You will still need all of the same type of equipment (field probe, amps, signal generator, power meter, etc.) but the power requirements will go up as a squared function of the field level, and the cost of the amplifiers will go up even more. Obviously, you will need an amplifier(s) with enough power. If you go much over 30v/m, you will need to pay attention to cables/connectors as well. Low loss cables (heliax, Utiflex, etc) will reduce the amplifier requirements somewhat, but the cable and connectors also need to be rated for the power, RG58 cable and BNC connectors won't do. Keeping the VSWR low is also important. The layout of the chamber and equipment is a factor. Moving the amp closer to the antenna (shorter cable, less cable loss) can buy you a few dB at the higher frequencies. High-gain antennas help, but the increased gain comes at the expense of beamwidth. From 200 MHz up, there are horn antennas that perform better than log-periodic antennas, but you need to make sure the beamwidth covers the required test area. I have seen horns that worked great at most frequencies, but had an extremely narrow beamwidth somewhere in the rated frequency range. I've seen 61000-4-3 applied to field levels up to 30v/m, but levels up to 200v/m usually have some other test method specified (mil-std, automotive, etc). Bob Richards, NCT.
jeff collins <jeffcollin...@yahoo.com> wrote: Group, I need to perform Radiated Immunity testing beyond the 61000- 4-3 limits. Section 5 of 61000-4-3 , Table 1 refers to this as the "Open Test Level" where the field strength may be any value. The question I have is: How do you calibrate and measure the field strength at levels above the 61000-4-3 requirements? I've seen emails in the past from folks making measurements at 200V/m and higher. I'm hoping someone will chime in and enlighten me on how the calibration and measurement was done at those levels. Are there any Mil -Spec's that cover how to achieve field calibration at these higher levels? Thanks, Jeff Collins Compliance & Reliability jcoll...@six9sreliable.com - ---------------------------------------------------------------- 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
