Doug, You might want to look at a paper that was presented at the Montreal IEEE EMC Symposium by HP on measurements that they made on a table when starting to test above 1 GHz. As you know, the FCC (ANSI C63.4) and CISPR 22 requirements simply call out that the table should be non-conducting. That's about all that is said. Measurements made by HP in Vancouver, WA show that this might just be an inadequate specification for the table due to reflections from the table/air boundary. Their table was wood with no metal fasteners of any kind, with a plastic sheet on the top. It meets the "non-conducting" requirement, but demonstrated that this minimal standard is inadequate to ensure accurate and repeatable results. I am certain that the results of their tests will cause some interesting discussions in various standards bodies over the next few years.
That said, a wood or fiberglass table should meet your needs quite nicely. I've seen a number of construction techniques over the years that have all had minimal metal content (our tables have two swivel casters under the legs at one end and metal axels for the wheels at the other end as their total metal content). These range from all wood, to PCV pipe frame with a wood top to fiberglass construction. All are sturdy enough to hold 200 pounds and all are "non-conductive". I'm not sure what to suggest for your swivel mount, but I have seen turntables built with a single metal pivot in the middle with a race of pool balls used for ball bearings further out on the table. Quick, simple and elegant. Non-conductive, except for the pivot in the middle. Good luck and have fun. Based on HP's paper, I suspect that a lot of us will be building new tables of a yet to be determined material in the next few years. Should make for some interesting conversations. Ghery Pettit Intel -----Original Message----- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, November 01, 2001 9:38 AM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length & width? -doug ----------- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com ----------- _________________________________________ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
