Home |
Search |
Today's Posts |
#11
![]() |
|||
|
|||
![]()
On Aug 30, 7:21*pm, Jeff Liebermann wrote:
On Sun, 30 Aug 2009 14:54:05 -0700 (PDT), Art Unwin wrote: Tom, W8ji *apparently is an expert with antennas *having lectured at Dayton and has authored many technical articles around antennas, states that radiators must be straight for maximum efficiency, He might have been talking about small antennas: That may have been at the back of his mind but he did not stipulate that http://www.w8ji.com/radiation_resistance.htm "Small antennas require extraordinary care to obtain high efficiency." Very true for electrically small antennas with emphasis on electrically. The 2004 Dayton PowerPoint presentation is at: http://www.w8ji.com/Dayton/Limited%20Space%20Antennas.ppt Using Google, I couldn't find any statement resembling the "straight radiators" claim. I never said this is a quote from the Dayton lecture. Tom has numorous dissertations with regard to antennas Ummm... fractal antennas are anything but straight and have the best gain for their size of any antenna. http://www.fractenna.com That is what Chip states for his company but I have no idea how a fractal would work on top band. Most on this group deride the claims of Chip with more than a handful of insults Also, efficiency isn't everything. *For example, the efficiency of the typical mobile HF antenna is fairly lousy because the antenna is a small fraction of a wavelength long. Exactly because it takes a WL or multiple there of to attain equilibrium * Still, it's the best that can be done on HF without trailing a long wire to a balloon, and dragging a grounding plate. * No. You are incorrect in my eyes! A multiple of a wavelength does not require a ground plain and can be condensed into any shape or form whilst retaining the required equilibrium. This is per the laws of Maxwell when considering all forces involved in radiation for maximum efficiency. Regards Art http://www.k0bg.com/eff.html -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558 |