[Antennas] Diminishing Returns

[David C. Hallam]

To amplify a bit on my radial problem.  I have the usual 1/4 acre city 
lot.  On this lot there are 7 medium size Live Oak trees.  On the lot 
line adjoining my neighbor there are 4 more.  The only place I have to 
put the vertical is an area between the house and the lot line.  This 
area is approximately 95x20.  The antenna is placed approximately 65 ft 
back on this strip.  The radials will have to run in two pie shaped 
wedges about 180 degrees apart.  The maximum I can get at the end of the 
wedge is about 20 ft.

 From the replies I have received, I gather I am wasting my time putting 
radials down.  I have put in two 8 ft ground rods.  I guess I will just 
go with that.  Because of trees and overhead wiring, I can not elevate 
the antenna.  Living in coastal FL I do not want to roof mount anything.

David
KC2JD/2

Merv Stump wrote:
> David, just asking this question may start a religious war.  However, I
> believe the most efficient use of radial wire occurs when the tips of the
> radials are about 0.025 wavelengths apart.  For example, on 80 meters a
> wavelength is about 260 feet.  0.025 X 260 = 6.5, so the tips of your
> radials should be about 6.5 feet apart.  If you use quarter wavelength
> radials on 80 meters they will be about 65 feet, and thus the diameter of
> the circle they cover will be 130 feet.  The circumference of this circle
> will be pi X 130 or approximately 408 feet.  408 divided by 6.5 is 62, so
> about 60 radials is optimal if they are a quarter wavelength long.  
> 
> This is not to say that adding radials beyond this will not show
> improvement.  It is to say that if you want to improve on the 60 quarter
> wave radial system, you are better served to begin making the radials
> longer. Notice that if you follow the above logic and go for one-half
> wavelength radials you end up with about 120 radials.
> 
> So your first statement is correct.  You can't have too many, and more and
> longer is always better.  However, for a fixed amount of wire there does
> appear to be an optimum tradeoff between length and density.
> 
> Regards, Merv W2OE   
> 
> 
> 
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