This is ~true only for a "far field" analysis (as defined by NEC software)
for a vertical monopole -- which includes the propagation losses present
in
the radiated fields from that monopole, over an infinite, FLAT, real-earth
ground plane.
However that is not reality.
I think what is going here is we have a bunch of anecdotal results based on
one unknown compromised system compared to another compromised system when
dozens of things are changed, and we are trying to generate physics to
support one thing as being the cause.
I am 100% sure, based on dozens of comparisons with three stations located
not too far from me, that it is "pretty difficult" to make an antenna of
reasonable size and construction -20dB based on ground system shortfalls.
Some of this has gone beyond reasonable or logical, and is poisoning our
knowledge base.
In Toledo, a good friend lived on a small city lot behind a restaurant. His
backyard, the only place for an antenna, was just a few feet deep and maybe
100 feet long. He tied in everything he could; heating ducts, plumbing,
short radials, a short chain link fence. He was consistently, over many
years, within a few dB of my full size quarter wave in an ideal soil and
ground system. This was night after night, DX or local, over and over again.
Another fellow in a neighborhood had a short TV tower with inverted L, and
his radials ran to a sidewalk maybe ten or fifteen feet away. He had radials
crossing the ceiling of his basement. His signal was the same way.
Another station, W8KWN, just had driven rods.
NONE of these stations were even close to 20 dB down. It was more like 5 dB
to maybe a just little more at times, and a little less at times. The driven
rods were the worse system, but even they were not -20 dB.
Now there was one station who had bad luck. He had bigger back yard, and it
was just full of wires and antennas. He had all these bamboo supports and
quads and other things, a yard full of "stuff". His signal was so weak he
actually would swear and cuss at the other guys and accuse them of illegal
power because his antennas "were so good" in his own mind that there was not
way these other guys would beat him so badly unless they were cheating. No
amount of conversation could convince him he had the problem.
In my experience, it is more about having a neat, clean, uncluttered
installation and not doing things grossly wrong, like using coaxial stubs
for loading inductance or packing 900 pounds of antennas into a two pound
back yard area, than any sort of grounding issue.
The only -10 dB or -20 dB things I ever see are people who jam too much in
small area, or have some other serious system error they created but just
cannot see.
My ten foot tall mobile antenna with a pickup truck for a ground is about 20
dB down from my TX antenna. If someone else has that issue with a 50 foot
tall inverted L, they better look at something other than a compromised
ground system. They have a more serious issue.
73 Tom
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Topband reflector - topband@contesting.com
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