View Single Post
  #10   Report Post  
Old February 25th 05, 12:06 AM
Gene Fuller
 
Posts: n/a
Default

Mark,

In the article quoted, Cebik was describing a half-wave "L" fed at the
corner; basically a bent half-wave dipole in an odd orientation.

He fully agrees that the more typical base-fed quarter-wave "L" would
benefit from radials.

73,
Gene
W4SZ

wrote:
KC1DI wrote:


Cebik says concerning the Inverted L antenna- which is similar to the



vertical Dipole that : "There is little evidence, despite the


vertical

position of one arm of the antenna, that the inverted-L would benefit



from a ground plane beneath the antenna. The actual low-angle gain of



the inverted-L will, however, vary with the quality of the soil in


the

region of reflection at a distance from the vertical arm. All


patterns

were taken over average soil, and soils that are either poor or


better

than average will tend to show a higher gain and lower take-off


angle,

at least on the fundamental frequency."

You might do well to read his articles at :


http://www.cebik.com/radio.html

He has quite a few dealing with the effects of different radial


systems

for vertical antennas.



I'd have to look at the articles later...But, as it is, I would
have to disagree with that. An inv-L is nothing like a 1/2 wave
vertical. He may be referring to an extended version, but normally,
an inv -L is a single wire loaded, 1/4 wave vertical,
and relies on the ground connection.
Max current is still at the base, and you can lose a lot to ground,
if it's poor. A longer 3/8, etc L would show lesser losses, but
radials would still help some.
MK