To: <topband@contesting.com>
> Date: Mon, 09 Mar 1998 11:52:45 -0500 (EST)
> From: km1h@juno.com (km1h @ juno.com)
I have this data also Carl. Boy do I have stacks and stacks of this
stuff I've spent hundreds of hours going over!
> >system in lieu of the elevated radial system. During the period of
> >November 20 through November 23, 1993, 120 copper radials of size
> >#10 and approximately 100 feet in length were equally spaced around
> >the No. 3 tower of the WVNJ array.
That's a pretty poor test. I would never use data like that. Here's
why.....
1.) At 1160 KHz, 100 feet is only .117 wavelengths. So the radials
were only .117 wl long! Installing a much less than ideal ground to
compare to another ground proves nothing, except they are
equally poor grounds.
It's VERY well known when radials are only .125 wl long more than 30
radials is a waste of time and effort. Any 160 op worth his salt
knows that! With radials LESS than 1/8 wl long, what was the point
in using 120 radials?
2.) Tower number 3, the tower tested, is the tallest tower and is top
loaded!
The electrical height of the top loaded tower is 110 degrees, so the
base resistance is very high. We all know that electrical height (and
taller physical height) renders that particular tower much less
dependent on a good ground than the other towers (that are shorter
and NOT top loaded) in that array! If I wanted to test that array, I
would have put the ground on the shortest tower, since that is the
tower that needs the best ground!
But even with all that going for the test, the thing still didn't get
any weaker when the very short radials were used instead of the long
high expensive elevated system!
Finally....
>From the famous Lewis, Brown, and Epstein data.. 30 (or even 100) 1/8
wl radials are about 3 or 4 dB down from ideal. All that test proves
is 120 1/8 wl radials (which might as well have been only 30
radials, for all the good extra radials do when they are so
short), which are know to be insufficient, are equal to six elevated
radials and probably the system is about 4 dB short of ideal.
IMO, that data just proves out what I measured in my back
yard! It agrees almost exactly with what I would expect from my own
test.
> > If ANYONE has any measurement data to the contrary compiled by a
> >competent consulting engineer, that data should be provided
> >IMMEDIATELY to you. Absent such data, I would consider the issue
> >settled and the discussion closed.
His own data conflicts with his own claims and clearly agrees with
what I measured. I feel better now that yet another measurement
confrms my own.. that being....
a full size elevated system is about equal to a very small ground
mounted system, both of which are about 4 dB short of a larger ground
mounted or elevated system employing 60 full size radials.
Thanks Carl and mystery friend. It appears we are reaching agreement.
73, Tom W8JI
w8ji.tom@MCIONE.com
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