Bob:
Not every Figure in the MIL-STD shows every detail, and you can try very hard to generate inconsistencies if you want. For instance, my setups track Figure 2 very closely, but I never go to the trouble to run little strings with pointed ends, painted with alternating segments of invisible paint, in order to replicate the dashed dimensional lines in the Figure. Also, my LISN’s are not cubes, but I don’t despair that my data will not be accepted. Another thing that is hard to reconcile is the positioning of the ground plane table in Figure 2 (right against the shielded enclosure back wall) with Figure 1, which calls out absorber material right down the walls all the way to the ground plane. If you followed Figure 1 exactly, you would lose a whole lot of ground plane space to the 24” thick absorbers sticking out from the walls. Maybe the Figures will be rationalized in Revision G, but until then, you get to use your tailoring authorization to smooth out those inconsistencies. You also said that your equipment was used “below the waterline”, which is not important, as you then said it was used “below decks”, which is important. Assuming that the vessel is metallic, then a compartment (above or below the waterline) will have inherent shielding and poor damping. Further, most substantial equipment will either be rack mounted or bolted to the deck and bulkhead. (Remember that your “table-top” equipment will likely be on the deck in a real ship unless it is secured to that table.) You are correct to use Figures 2 or 4 for your main guidance, but just as clearly, Figure 5 can be ignored (uhh, unless you equipment also drives around in that below-decks compartment). Ed Price [email protected] <blocked::mailto:[email protected]> WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, August 30, 2011 1:52 AM To: [email protected] Subject: Re: RE102 Vertical Ground Plane And Figures 2 and 3 of the Figures 1 through 5 clearly show a vertical back plane with the tabletop horizontal ground plane bonded to it (or at least it implies a vertical back plane). It is either a vertical back plane or the floor back plane bent up at a 90 degree angle. If there wasn't any confusion since 1993 then there should have been. : ) The equipment I have is tabletop equipment to be mounted below the water line (i.e., below deck). The reference is to Figures 1 through 5 (all of them), not just Figure 1. Bob Heller St. Paul, MN 55107-1208 Tel: 651-778-6336 Fax: 651-778-6252 ================================= [email protected] wrote on 08/29/2011 01:13:33 PM: > From: > > Ken Javor <[email protected]> > > To: > > Untitled <[email protected]> > > Date: > > 08/29/2011 01:17 PM > > Subject: > > Re: RE102 Vertical Ground Plane > > Sent by: > > [email protected] > > This is a recap and expansion on my original response on this > subject, which clearly didn’t take. > > Figures 2 & 3 are about the tabletop set-up, as per my original post > and that below from WL. The reference in MIL-STD-461 RE102 about > the set-up says, verbatim: > > “5.17.3.3 Setup. > > The test setup shall be as follows: > > a. Maintain a basic test setup for the EUT as shown and described in > Figures 1 through 5 > and 4.3.8...” > > Figure 1 shows the required minimum absorber treatment in the test > chamber. You don’t get to “pick and choose” the parts of the > standard that are applicable. It’s “and”, not “or.” > > And these figures were all brand new in MIL-STD-462D (1993), and are > unchanged since then. > > To my knowledge, there has been no confusion about this topic since 1993. > > > Ken Javor > > Phone: (256) 650-5261 > > > From: <[email protected]> > Date: Mon, 29 Aug 2011 05:16:59 -0500 > To: <[email protected]> > Subject: Fw: RE102 Vertical Ground Plane > > > > From: > > Robert E. Heller/US-Corporate/3M/US > > To: > > "Steve Ferguson" <[email protected]> > > Cc: > > [email protected] > > Date: > > 08/29/2011 05:11 AM > > Subject: > > Re: RE102 Vertical Ground Plane > > > > Thanks Steven. that was my take as well. The problem comes in > > because the RE-102 procedure references the Figures and a reference > > is a reference unless it states that portions of the reference are > > to be ignored. If we are allowed to start to "pick and choose" the > > parts of the procedures or references that we like or dislike then > > there is no sense in writing the procedure. > > > > Bob Heller > > 3M EMC Laboratory, 76-1-01 > > St. Paul, MN 55107-1208 > > Tel: 651-778-6336 > > Fax: 651-778-6252 > > ================================= > > > > > From: > > "Steve Ferguson" <[email protected]> > > To: > > <[email protected]> > > Cc: > > "Mike Violette" <[email protected]> > > Date: > > 08/28/2011 03:26 PM > > Subject: > > RE102 Vertical Ground Plane > > > > Bob, > > > > I reviewed the test configuration MIL-STD-461F figures (Figure 1 and > > Figure 2) you mentioned and in my opinion it was not the intent to > > imply a vertical ground plane. The figure are carry-overs from > > early revisions and the goal was to provide a generic sketch of the > > ground plane layout. The vertical portion represents the anechoic > > chamber wall (note that there is no RF absorber in the sketch). > > Reading the associated text, there is no mention of a vertical plane. > > > > If a vertical plane were incorporated, the desired effect for the > > anechoic material would be negated. I believe that the generic > > sketch used in the standard should be used for layout guidance only. > > > > Please contact me if you want to discuss or need more information. > > > > Steven G. Ferguson, iNCE > > Executive V.P. > > Washington Laboratories, Ltd > > 7560 Lindbergh Drive > > Gaithersburg, MD 20879 > > [email protected]\ > > V 301-216-1500 x 112 > > C 240-401-7177 > > F 301-216-1590 > > > > Please check our website (www.wll.com <www.wll.com> ) for Wl > Academy Seminars or > > contact me with any questions! > > - - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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