On Sun, 12 Nov 2006 19:25:38 -0000, "Dave" wrote:

in context of the message i was replying to the writer implied that rf
flowed 'into' the earth and that was the end of it, more correctly it could
be said that rf flows 'through' the earth, but it doesn't dissappear 'into'
the earth.

Hi Dave,

True, but knowing Bill, I doubt his description was meant to be so
literal as to having current disappear into the earth.

In the sense of RF ground, already described by me earlier, ground is
a pool of infinite charge and as such current into it does disappear.
Otherwise, it would perturb and become less than a ground, its
potential would elevate and that elevation would be in reference to
some other ground.

This is a true picture of the reality of ground as such perturbation
does just this, and is evidenced by local variations of potential to
other "grounds." However, this reduces the discussion to one of
infinite regression and over-qualifies an answer to the primary
question.

i have been told before that i have very long trains of thought, usually i
am just trying to be descriptive enough for someone else to follow along...
and i just like ellipsis.

Up to the ellipsis was fine. The better part of writing is what you
leave behind after you trim off the fat.

it relates to the common assumption that the radio case, coax shield, and
other items connected to a common 'ground' are at 'rf ground'. ignoring the
'earth', there is also the common misconception that things tied together to
the often discussed 'single point ground' are all 'grounded'... something
that is not necesssarily true when dealing with rf.

I can follow the argument for concern, but you really don't offer any
context. There are far more examples of grounding working than not;
and your brush has tarred them all equally.

There is the practical answer to the question of RF ground, and there
is the literal answer (or academic, if you prefer). The practical
answer might have the user elevated hundreds of volts above academic
RF ground. That user might never perceive it in any way because the
user may have contrived to build a virtual ground that satisfies all
the requirements for operating without suffering themselves or any one
else.

73's
Richard Clark, KB7QHC