I fully agree with Chas, For further guidance on this issue please check out ANSI C63.7:Para.6.3 (1992) "American National Standard Guide for Construction of Open Area Test Sites for Performing Radiated Emission Measurements".
It states: "Thick (several mm or more) dielectric material such as Sand, Asphalt, or wood on top of metal ground planes (....) may result in unacceptable site-attenuation characteristics in certain frequency ranges, especially in vertical polarization measurements" In a prior life I was forced to use a site that had a thin layer of asphalt over the ground plane. It was a nightmare to use. The NSA was all over the place in vertical. For what it worth. Regards, Michael Taylor Loveland, CO From: [email protected] [mailto:[email protected]] On Behalf Of Grasso, Charles Sent: Tuesday, March 15, 2005 1:30 PM To: '[email protected]'; '[email protected]' Subject: RE: OATS Ground Plane Material HI Keith - Well the EMC Society goes back a long way and papers were written in the early days of the relative performace of different OATS constructions. The conclusion - do NOT cover the screen. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: [email protected] Email: [email protected]; Email Alternate: [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, March 15, 2005 8:55 AM To: [email protected] Subject: OATS Ground Plane Material Has anyone attempted to imbed an OATS ground screen in asphalt? A new parking lot is going in near our lab and I have a chance to install an OATS. The stack-up will be gravel with 3" base asphalt and a 1" asphalt cap. I have plenty of copper screen and was considering putting it between the asphalt layers. Another alternative would be to use galvanized hardware cloth. Any advise? Keith 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/listserv/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: Richard Nute: [email protected] Jim Bacher: [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/listserv/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: Richard Nute: [email protected] Jim Bacher: [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/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
