Ken, Good point and well noted. I appologise if I muddied the waters. I probably should have kept my mouth (keyboard?) shut because most of my background is FCC/EU emissions and antenna design/modeling. I didn't take well enough into account the specific MIL standard you quoted and your well stated directivity issue. With respect, Brent DeWitt
From: Ken Javor [mailto:[email protected]] Sent: Thursday, October 28, 2004 9:31 PM To: [email protected]; Gary McInturff; [email protected] Subject: Re: Vertical monopole with counterpoise radiation pattern One minor caveat to Mr. DeWitt. I was careful to talk about directivity and not gain. Gain implies power flowing into the antenna on a transmission line and power flowing out as a traveling wave. The ratio of power flowing out to in is the antenna efficiency, and that multiplied by the directivity is the gain. As I noted, the type of rod antenna used in MIL-STD-285 is electrically short, presents a very high impedance to the power source and hence does not radiate power, just electric field lines. From: "Brent DeWitt" <[email protected]> Reply-To: <[email protected]> List-Post: [email protected] Date: Thu, 28 Oct 2004 20:16:51 -0700 To: "Gary McInturff" <[email protected]>, <[email protected]> Subject: RE: Vertical monopole with counterpoise radiation pattern Gary, The vertical monopole over counterpoise (or image plane) has the same radiation pattern as a vertical dipole in free space. If I remember correctly, it has 2.15 dB gain over isotropic at the maximum. Brent DeWitt From: [email protected] mailto:[email protected]]On Behalf Of Gary McInturff Sent: Thursday, October 28, 2004 4:19 PM To: [email protected] Subject: Vertical monopole with counterpoise radiation pattern Folks, I'm guessing that for a given dimension above the ground plane the above antenna radiates isotrophically, correct. (No - I'm not much of an antenna guy). Just trying to figure out a little about the shielding integrity test for e-fields in Mil-std- 285. Thanks Gary ---------------------------------------------------------------- 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: Ron Pickard: [email protected] Scott Douglas [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: Ron Pickard: [email protected] Scott Douglas [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
