Topband: Current Distribution on Buried Radials Used With Vertical Monopoles & Brown paper

[Bill N6MW]

The famous Brown et al. paper from 1937 on buried radials ground losses 
-- a brief summary


Thanks to TB posts and R. Fry, I have been tempted down a path to 
ancient paper analysis. The essential results from this have been given 
before in terms of trades of height, number and lengths of radials. 
Generally, not surprising, more and longer radials are better, with 
various qualifications and considerations. A brief version of that most 
relevant to hams is provided here in simple tabular form. Only two 
vertical heights are considered, ~1/4 and ~1/8 wavelength (88 and 44 
degrees) in comparison with the stated theoretical ideal of perfect 
ground. Only results for radial lengths of 90 and 45 feet are given. 
They are in dB loss (or gain if you don't like the minus sign) and might 
be interpreted as the ground loss as measured by the signal at a mile 
(1609 meters) away but near the ground (not sky wave). Since the data 
translation from 0.3 miles to 1 mile assumed the perfect ground scaling, 
the loss results are really those out to 1/3 mile all at 3 MHz.


dB loss using n 45' radials

n 88deg 44deg

2   -4.17 -6.30

15 -2.29 -3.57

30 -2.18 -3.43

60 -1.95 -3.16

113 -1.84 -3.03

Ideal 0.00 0.00


dB loss using n 90' radials

n 88deg 44deg

2    -4.17 -6.02

15 -1.25 -2.29

30 -1.05 -1.71

60 -0.85 -1.12

113 -0.65 -0.81

Ideal 0.00 0.00


So more is always better but how much you are willing to pay for the 
next dB always

becomes the question.  Impedances are in the paper.


Full painful story at http://n6mw.ehpes.com/BrownNotesFinal.pdf