On Jul 14, 8:49 pm, Owen Duffy wrote:
For a multi mode RF / AC protective / Lighting ground, shallow buried
radials might be more effective than one or several driven electrodes
anyway. A driven electrode (or any vertical electrode) is not very useful
for RF.
I was considering this the other day... Seems to me, a good set of
radials on/in the ground are about the only system which could
cover all three jobs. Course, it would be kind of silly to use that
ground as the wiring safety ground, but it could work, as long
as the earth connection at the center of the radials is good.
I can't really think of any other systems that can provide a good
RF ground system, and lightning at the same time. Of course,
from the lightning end, it again assumes a good earth connection
at the center of the radials.
Some might be surprised that my ground rods are not very long
at all. And all are copper tubing, not rods..
My longest one is probably only about 4 ft long. But I have
several spaced around the mast, and tied together underground.
But all are pretty close to the mast. Not even close to being 8 ft..
More like 3 ft across...
That then also ties to the steel water pipe which is about 2-3 ft
away. So far, that ground seems good enough as far as a
lightning return. And I've had two strikes with me sitting here to
be able to say that. Seemed to be a good ground connection.
How can I tell? The sound..
A strike to my mast is very quiet. All you hear is an arc, which
sounds like a light bulb being thrown on the ground and breaking.
Course, you hear the overhead sonic boom, but that doesn't
count.. :/ That's not the real sound of the strike.
In comparison, a poor ground return will cause the strike to be
very loud, with a real loud "CRACK" to it. Then again, the
overhead sonic boom...
Trees make for a noisy strike..
My ground outside is for lightning return only. Does nothing
else. I use no RF ground. All my antennas are complete.
If a certain antenna requires an RF ground, that will be provided
as part of the antenna design.
My safety ground is provided by the house wiring.
So my outside ground scheme is a one trick pony.. :/
MK