The following answer is predicated on the assumption that the antenna is either a quarter-wave or a slightly shorter stub. If the metal box surface area is such that a radius from the antenna to the edges of the box is equal to or greater than the stub length, you will get much better performance than if there is no effective ground plane.
> From: "Jim Eichner" <[email protected]> > Date: Wed, 18 Oct 2006 10:25:27 -0700 > To: <[email protected]> > Subject: Wi-Fi antenna location > > Question for the RF types in the crowd: > > Consider 2 scenarios involving a product that uses an 802.11 radio for > remote monitoring. The product is a large metal box, and the radio is a > separate plastic box containing the 802.11 module and its antenna > connector. > > Scenario 1: The antenna is mounted on the plastic radio box and the > radio connects to the host via cable and is mounted remotely (several > feet away or more). For the sake of discussion, assume the radio box is > mounted on a non-conductive surface (drywall typically). > > Scenario 2: The radio is located inside the host product, and the > antenna is mounted on the metal skin of the host and connects to the > radio via an antenna cable. > > Questions: > > 1. Should one of these scenarios theoretically have better range than > the other? > > 2. Should one of these scenarios theoretically have less directionality? > > > Thanks in advance for your help, > > Jim Eichner, P.Eng. > Compliance Engineering Manager > Xantrex Technology Inc. > e-mail: [email protected] > web: www.xantrex.com > Any opinions expressed are those of my invisible friend. > Confidentiality Notice: This email message, including any attachments, > is for the sole use of the intended recipient(s) and may contain > confidential and privileged information. Any unauthorized review, use, > disclosure or distribution is prohibited. If you are not the intended > recipient, please contact the sender by reply e-mail and destroy all > copies of the original message. > > - > ---------------------------------------------------------------- > 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/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] > > 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/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
