[Antennas] Ground Planes

Tue Apr 5 22:45:04 EDT 2005

One would think this would be the ultimate approach... but.... I have made 
a study of radial installations, and the law of diminishing returns comes 
into play very fast as the coverage of the radial dimension increases. 
Notable pioneers in broadcasting of the mid- 1930's pretty much got it right 
in their experiments... for recap, see the July 2000 QST article by Rudy 
Severens on "verticals, grounding systems and some history". What you find 
is that once you get past a specific radial coverage/ density, the marginal 
improvement per radial (read that coverage) is very very small... and in 
some cases immeasurable.
In my case, I installed a mil. Shakespeare 222 in my antenna-challenged 
community as a stealth device. I designed a radial burying device for my 
medium sized tractor (which I now sell commercially) to bury radials. As I 
began burying radials, I made measurements on the resulting system (they are 
quarter wave for 80 meters)... impedance measurements on the antenna on 
80-10 meters, and distant/ elevation field strength measurements. I reached 
the limits of my test equipment when I hit 240 radials... and basis my 
threshold, about 120 radials was really optimum given the cost of the wire.
Meshing your back yard... while it may give you wood... isn't really cost 
practical.
Sincerely,
Dr. William J. Schmidt, II K9HZ
Trustee of the North American QRO - Central Division Club - K9ZC
Email: bill at wjschmidt.com
WebPage: www.wjschmidt.com
"If computers get too powerful, we can organize them into a committee; that 
will do them in." -- Bradley's Bromide
----- Original Message ----- 
From: "Mel Vance" <icra at galaxynet.com>
To: <antennas at mailman.qth.net>
Sent: Tuesday, April 05, 2005 4:53 PM
Subject: Re: [Antennas] Ground Planes
>> Let me set up the parameters. I have a back yard some 50-75 ft by
>> 50-75ft. I am going to have it resodded. I want to go to Lowes or
>> Home Depot and buy copper screening. , Roll it out and solder each
>> section together. After the screening is in place, it will be covered
>> by sod. It I put a mast in the center and bond it to the screen and
>> place an all band vertical on the mast, will this satisfy the ground
>> plane requirements of a vertical. This would be great to anyone
>> building a new home and in need of an excellent ground plane for a
>> vertical. Any comments would be appreciated and should help others on
>> the reflector.
>>> Boy...thought I was the only one who had thought of this........
>> Well....part of this will depend on how much you have to spend.........
>> If the funds are available, I would put 2 or 3 layers, over-lapping the 
> seams, and solder it all
> together well. This will make it last longer than just a single layer.
>> I would also use some copper stakes about every foot and solder to the 
> screen. Just a foot
> long would do it. These will help bond it all to your soil (electrically), 
> and help keep it from
> working to the surface due to freezing and thawing. You still may need to 
> add soil from time
> to time due to settling or erosion.
>> An idea I had was to add 1/4" copper pipe with very small holes drilled 
> used to dribble water
> through the ground mat area.....more erosion potential, but better soil 
> conductivity...I hope.
> Could catch rain from your down spouts in a barrel to feed the system.
>> Just my thoughts..........
>> Mel
> N7OKL
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