Topband: Quarter wave sloper ?

[Jim Brown]

On 7/27/2024 6:59 PM, jim.thom jim.thom at telus.net wrote:
> Quarter wave sloper ?
> 
> Just to be xtal clear, when I said 1/4 wave sloper,

Yes, and that's been a popular way to do it. I chose another, and 
described it. It is, indeed, a quarter wave, and it slopes.

BTW -- those rods under the tower are an effective earth connection for 
lightning. But they are NOT a low-impedance path for RF, simply because 
the earth is a big resistor.

The only function of an earth connection for transmitting antennas is 
lightning protection. The earth is a big resistor. The functions of 
radials are 1) to SCREEN (shield) the field produced by the antenna from 
lossy earth; and 2) to provide a low resistance path for the antenna's 
return current. A counterpoise provides only the second function.

N6LF has been publishing some excellent work on radial systems, 
describing an interactive research process wherein he models various 
conditions, then built and measured them extensively, revising his model 
or modeling different variables, depending what he learned in the 
measurements, and so on. It is excellent engineering, and has given me 
many new understandings/insights of why radial systems behave the way 
they do. Many of us consider it the most important work on LF antennas 
in fifty years.

https://www.antennasbyn6lf.com/

The 2009 series on ground systems and the 2012 series on elevated radial 
systems are the material I find so worthwhile. Grab them and settle in 
with a nice Scotch.

73, Jim K9YC