Wayne wrote:
"John Smith" wrote in message
...
David wrote:
What would you define RF ground as? There seem to be a lot of different
ideas.
David:

Ground can be a relative thing. What I have always found to be good
advice is that EVERY ground, at some point, be allowed to reach a low
ohmic earth ground (best possible if it all occurs at the exact same earth
ground point--or no current flows and there is no voltage potential
between such grounds.) For example, although a dipole needs no rf ground
directly at the point it connects to the feed-line, the rig hooked to such
an antenna and feed-line should be given a good earth ground.
snip

Regards,
JS

When you refer to hooking the rig/dipole to a good earth ground, are you
still talking about an rf ground, or a safety ground?
I see no requirement to connect a nicely matched dipole to an earth ground
for rf purposes. For example, a battery operated transmitter feeding a
dummy load wouldn't need one either.



Wayne:

Both. Only a dummy would think he needed an rf ground for a watt burner
of proper impedance.

However, there always is that "special case;" if the nitwit was running
a kw off a forklift battery, he just might want that rf ground.

JS

"John Smith" wrote in message
...
Wayne wrote:
"John Smith" wrote in message
...
David wrote:
What would you define RF ground as? There seem to be a lot of different
ideas.
David:

Ground can be a relative thing. What I have always found to be good
advice is that EVERY ground, at some point, be allowed to reach a low
ohmic earth ground (best possible if it all occurs at the exact same
earth ground point--or no current flows and there is no voltage
potential between such grounds.) For example, although a dipole needs
no rf ground directly at the point it connects to the feed-line, the rig
hooked to such an antenna and feed-line should be given a good earth
ground.
snip

Regards,
JS

When you refer to hooking the rig/dipole to a good earth ground, are you
still talking about an rf ground, or a safety ground?
I see no requirement to connect a nicely matched dipole to an earth
ground for rf purposes. For example, a battery operated transmitter
feeding a dummy load wouldn't need one either.

Wayne:

Both. Only a dummy would think he needed an rf ground for a watt burner
of proper impedance.

However, there always is that "special case;" if the nitwit was running a
kw off a forklift battery, he just might want that rf ground.

JS

Well, my question is in the context of rf ground being a function of the
antenna subsystem. It wasn't clear why you recommend use of a transmitter
rf ground, if the antenna system doesn't require it. Yes, I would run some
sort of rf ground at the rig if I were using a random wire fed with a tuner
in the shack, because the antenna system requires it.

My own setup is a ground mounted vertical with a modest 10 foot diameter
ground system. The "rf ground" is at the base of the antenna (as is a
separate lightning ground). The shack is on the second floor, and has only
a safety ground at the rig.

Wayne wrote:
"John Smith" wrote in message
...
Wayne wrote:
"John Smith" wrote in message
JS

Well, my question is in the context of rf ground being a function of the
antenna subsystem. It wasn't clear why you recommend use of a transmitter
rf ground, if the antenna system doesn't require it. Yes, I would run some
sort of rf ground at the rig if I were using a random wire fed with a tuner
in the shack, because the antenna system requires it.

My own setup is a ground mounted vertical with a modest 10 foot diameter
ground system. The "rf ground" is at the base of the antenna (as is a
separate lightning ground). The shack is on the second floor, and has only
a safety ground at the rig.


Wayne:

I see...

An antenna design requiring a system of underground ground radial(s) to
function correctly (or at least as designed), (or, for that matter,
above ground radial(s) running though bushes) would only be a "complete
antenna" if such were taken for granted had already been installed
(meaning the "rf ground-establishing" radials.)

And, if there were any chance at all I would be running a kw, and
touching both the ground radials and the ground at the same time AND
wanted to cover all special case/weird/worst-possible-cases (and I do
propose everyone should plan on this)... I would provide a nice low
ohmic earth ground for such radials (possibly useful for safety only.)
But then I am a sissy and find rf burns painful.

I didn't realize you were asking me, "If the guy has only installed half
of the antenna, should he install the "other half?" The answer to that
is all too obvious.

Yanno, those trick questions always throw me!

Regards,
JS