Hi Ed, I've been making antenna pattern measurements recently in our chamber and I too see a variation as you described. One theory I'm working on is that our turntable might not be as accurate in it's 5º increments as it could be. If the set point has a tolerance of 1-2º and that lies on the relatively "steep" side of a lobe then you might expect a large variation for a relatively small positional change.
With regards, James James Pawson Leading Hardware Engineer - EMC EchoStar Europe ________________________________ From: Ed Price [mailto:[email protected]] Sent: 25 February 2012 09:26 To: [email protected] Subject: Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz If you took a reference level at the start of a 180-degree rotation, after stepping 180 degrees CW, then 360 degrees CCW and then 180 degrees CW, sometimes you could go back to the original point and get a new level that was less than 0.5 dB different. And sometimes the level had changed 2 dB, so you got to repeat the test. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/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: Jim Bacher: <[email protected]> David Heald: <[email protected]>
