Tim, I agree that most emissions (for physically small EUT's) will be found to be at maximum from 1 to 2 meters since at heights greater than 2 meters the antenna begins to distance itself from the EUT. But go to 4 meters height as called for in ANSI C63.4: 2003. Also, remember to bore-sight the antenna as you raise it and encompass the EUT within the beam width of the antenna as explained in the standard. Good quality cables and a properly placed pre-amp can eliminate problems associated with cable loss. Bill Stumpf D.L.S. Electronics
From: [email protected] List-Post: [email protected] Date: Thu, 22 Sep 2005 14:48:55 EDT To: [email protected] Subject: Above 1 GHz EMI testing with horn antenna Hello, A discussion has come up about the need to raise the horn antenna up to 4 meters when doing an EMI test above 1 GHz. ANSI states that the antenna height should be adjusted between 1-4 meters to maximize the emissions. Some labs are only doing this test at 1 meter or maybe 2 meters high, (probably to reduce cable loss issues). Normally, the emissions are worst case below 2 meters, but how can one be absolutely sure, without checking? What is the legal requirement for the antenna height? These questions apply to unintentional radiators, where measurement above 1 GHz is required. Regards, Tim Pierce - 2005 IEEE Symposium on Product Safety Engineering 3-4 October Schaumburg, IL http://www.ieee-pses.org/symposium ---------------------------------------------------------------- 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 - 2005 IEEE Symposium on Product Safety Engineering 3-4 October Schaumburg, IL http://www.ieee-pses.org/symposium ---------------------------------------------------------------- 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 - 2005 IEEE Symposium on Product Safety Engineering 3-4 October Schaumburg, IL http://www.ieee-pses.org/symposium ---------------------------------------------------------------- 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
