Topband: Elevated Radials Questions

[Grant Saviers]

Thanks for the comments and pointers.  The land around the antenna is 
mixed grass and forested islands so on the ground radials would be 
partially buried and partially on the surface.  Digging through the 
trees and clearing the brush is not something I want to do. Also, based 
on prior experience with verticals on metal roofs, I'm a real fan of 
elevated radials.

I am relying on the credibility of the N6LF QEX series for how well/not 
well elevated radials will work (Mar - June 2012).  I realize this work 
was all analysis with EZNEC PRO, but it seems to be the similar to 
results of others I've read.  Googling "K5IU elevated radials" I did 
find the 2008 N6LF article which has the experimental data as well.  His 
analysis shows there isn't much difference in losses with more than 4 
radials between 0.15 and 0.27 wavelengths long.  I've heard conventional 
wisdom is to tune radials for resonance, but the analysis for 4 or more 
radials elevated > than a couple of feet seems to indicate it is a lot 
of work for little benefit.

I also found the 2005 thread "tuning elevated radials" on this reflector 
quite informative.

One thing that stands out is that I may be better off with more than 7 
shorter than 130' radials.

Grant KZ1W


On 12/13/2012 12:06 PM, Dennis W0JX wrote:
> Grant, you should consider putting in an additional 23 radials and put the radial system on or in the ground. This will eliminate any possible detuning by the big metal building and interaction with the RX 4 square. You said that your vertical T will go up to 85 feet. However, by elevating the radials 10 feet, your effective vertical distance is 75 feet which will allow you to shorten the top hat wires a bit. As an alternate, you could put down 1/8 wavelength radials on the ground but more of them and have a good system too.
>
> If you must go with an elevated radial system, I recommend that you read the articles by Dick Weber, K5IU, who strongly advocated elevated radials shorter or longer than 1/4 wavelength. If shorter, then the radials are loaded with a small coil. If longer, then they are tuned out with a capacitor. W5UN uses shortened elevated radials on his 160 meter 4 square with great results. They are about 70% of a quarter-wave in length.
>
> 73, Dennis W0JX/8
> Milan OH
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