TopBand: Re: Elevated Radials
km1h @ juno.com
km1h@juno.com
Mon, 09 Mar 1998 15:52:26 EST
On Mon, 09 Mar 1998 14:45:06 +0000 Tom Rauch
<10eesfams2mi@mass1-pop.pmm.mci.net> writes:
>> 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!
So mail me the pertinent data and lets get it off the reflector. I will
PAY ALL copy and mail costs.
>
>> >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.....
Here is NOT why ... who approved/requested that test configuration? The
station owner, the consultant or the FCC?
>
>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?
VERY well known by who? Reference real publications, Not QST, 73, etc.
>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!
Certainly just a bit over 1/4 wave but not 4dB worth.. I would surmise
that the station went to that length to improve the daytime coverage.
You neglect to mention the other towers in the array, the mutual coupling
AND the desires of the station owner. All I have heard from you is a
jumble of numbers but I dont see them on MY desk.
Were the other towers connected in a common ground interconnect ? What is
the actual configuration?
>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!
I do not remember economics entering this discussion but since you
mentioned it, I also thought that the reason for FCC involvement in the
subject was to offer stations an economic alternative to a massive ground
system. The BCB industry is full of stories of those stations who had to
truck in hundreds of yards of soil to cover the radials. Not all are
blessed by ideal soil or availabe real estate. I have never questioned
the importance of soil conductivity, but I do accept the idea that it
becomes somewhat less important with elevated radials. ...dont ask me to
apply a constant to "somewhat".
In any event you are misleading again since the short radials were only
for a test...otherwise they would be 120 1/4 wave radials in an FCC
accepted station...a LOT more dollars and acerage.....and impossible to
accomplish in some potential BCB station locations....thus the reason for
the exercise in the first place.
>
>Finally....
>>From the famous Lewis, Brown, and Epstein data
References please so all those interested may follow along.
.. 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.
>
I didnt realize that your back yard extended several miles. How about a
map and test documentation proof please.
>> > 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.
IMO we are even further apart...at least until you submit uncontestable
proof.
Rhetoric and long E-mail mesages with readers falling asleep just do not
cut it....sorry.
And y'all know..the only reason I opened my mouth was to understand my
own system better and make improvements if necessary. I am even further
from that goal than when I started!
Meanwhile, with the Administrators approval, I will continue to act as a
conduit for Mr X.
73 Carl KM1H
PS: in the interest of BW it would be a good idea to post replies of
group interest just to the reflector...I'm sure the server would
appreciate it.
>
>73, Tom W8JI
>w8ji.tom@MCIONE.com
>
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