From: Gary McInturff [mailto:gmcintu...@spraycool.com] Sent: Thursday, October 28, 2004 4:19 PM To: emc-p...@ieee.org 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 The radiation pattern of a vertical monopole (around the horizon) is uniform, so you could call it omni-azimuthal. However, the pattern is a bit like a donut dropped over the monopole. Maximum radiation is at an elevation angle somewhat above the horizon. There is a minimum directly above the monopole, and the field on the horizon is also slightly weaker. Since these antennas are useful for multi-point communication, or fixed location to mobile. As most users tend to be at ground level, the monopoles are often made a bit longer than resonance, which has the effect of depressing the angle of maximum radiation downward toward the horizon. To continue the fast-food analogy, sort of like a squashed donut. OTOH, a vertical monopole is not the optimum choice for aerial communication; antennas for GPS are a good example of an alternate to vertical monopoles. Regards, Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty 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 emc-p...@ieee.org 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: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc