In our OATS dome, we use a pair of large antistatic plastic Rubbermaid wheeled carts with a sheet of plywood laid across the tops. A tabletop host pc is set on that. How's that effecting the measurements? <groaner> Should these effects be part of the 'uncertainty'?
Kyle Ehler KCØIQE <mailto:kyle.eh...@lsil.com> Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321 -----Original Message----- From: umbdenst...@sensormatic.com [mailto:umbdenst...@sensormatic.com] Sent: Thursday, November 01, 2001 4:12 PM To: doug.pow...@aei.com; emc-p...@ieee.org; davi...@ece.umr.edu Subject: RE: EMC test table construction plans David, On a similar note I had heard that an EUT shelter might demonstrate a 6 dB variation between wet and dry conditions, or dirty vs. clean (pressure cleaned) condition. Did the papers comment on wood properties? Perhaps identifying soft wood vs. hard wood, minerals absorbed during growth, wet vs. dry, or other "conditioning" situations? I have only seen a handful of labs, but they all had wooden tables (defacto standard for the times -- past?). I wonder if the standards were written around the convention of wooden tables? You've raised an interesting issue. Best regards, Don Umbdenstock Sensormatic > ---------- > From: Pommerenke, David[SMTP:davi...@ece.umr.edu] > Reply To: Pommerenke, David > Sent: Thursday, November 01, 2001 4:15 PM > To: 'POWELL, DOUG'; EMC-PSTC (E-mail) > Subject: RE: EMC test table construction plans > > > Doug, > > For emissions and immunity you should not use any wood in the table. It > will > significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB > for > immunity up to 1 GHz) change the test result. My experience has shown that > Styrofoam is basicly the best material. There are a couple of published > papers on this issue. As surface material the following worked out fine: > > - Foamed PVC (rather stiff, low dielectric constant due to the foamed > nature), maybe 4 mm thick. > > - PE sheet, maybe 2 mm thick. > > David Pommerenke > > > > -----Original Message----- > From: POWELL, DOUG [mailto:doug.pow...@aei.com] > Sent: Thursday, November 01, 2001 11:38 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 > ----------- >
