Station With Center-Fed Dipole - Best Grounding Technique?
 

"dave" wrote

A BalUn would help a lot.

For what? If the antenna system is balanced (as are dipoles, inherently), I
seriously doubt a balun would be good for anything.

Station With Center-Fed Dipole - Best Grounding Technique?
 

Howard Lester wrote:
"dave" wrote

A BalUn would help a lot.

For what? If the antenna system is balanced (as are dipoles, inherently), I
seriously doubt a balun would be good for anything.



He's feeding it with coax, so it's not just a good idea, it's required.

The antenna is balanced, the feedline is not. He stated the feedline is
RG-8X.

tom
K0TAR

Station With Center-Fed Dipole - Best Grounding Technique? [Salting ground rods]
 

"Jim Lux" wrote in message ...
By the way, a Yeasu technician once recommended salting ground
rods to resolve a poor grounding situation at the time, so I've
been doing that ever since (can't hurt), especially during the
dry summer months. Adding water is pretty obvious, so didn't
think I needed to spell that out, Dave.

Hmm. and that Yaesu technician has what training and experience
in grounding systems for lightning protection (other than what's
printed in the front of the manuals)?

And did the salting improve anything? if so, what? adding
grounding is almost always the wrong solution to operational
problems (RFI, for instance), since the purpose of grounding
systems is to deal with abnormal events (short circuits,
transients, etc.).


I will have to second Jim's statements here. Anyone that thinks that salting ground rods will provide a better radio frequency ground is fooling himself. Charged ions in water move at relatively slow speeds that are determined by, among other things, the temperature, the size of the ions, and the viscosity of the solution. At low frequencies, the period of the AC voltage allows the ions to migrate a considerable distance. But at higher frequencies, the period becomes shorter and the ions can move only slight distances before the polarity, and hence the direction of the ion migration, changes. The conductivity of the solution follows a reciprocal relationship with frequency.

By the time we get to radio frequencies, the dissolved salts do little to increase the ground conductivity. What is important, however, is the moisture content. This is why moisture retaining clays such as bentonite are sometimes used.

In areas where the ground is frozen. it is difficult to get a good radio frequency ground. This is because the dielectric constant of ice is low while that of water is high. In this special case, adding salt might help as it lowers the freezing point of water.

At the WYFF transmitter site on Caesar's Head, SC, there is an 800 foot tower atop a 3100 foot granite mountain. To get a decent ground for lightning protection, they ran three 1/4" thick copper sheets about a foot wide out from the base of the tower to where the guy wires attached. This provides an effective capacitive grounding system as the granite itself is not very conductive. They get hit by lightning frequently. Previous station engineers have related many stories about ball lightning rolling around the floor in the transmitter room.

--
73, Dr. Barry L. Ornitz WA4VZQ

Station With Center-Fed Dipole - Best Grounding Technique?
 

dave wrote:
Since we are sticklers for the NEC, Homey needs a #6 wire from where the
transmission line enters the dwelling to an 8' copper clad rod driven
into the earth, as close as practicable.

What if it is 1/4WL long?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Station With Center-Fed Dipole - Best Grounding Technique?
 

Cecil Moore wrote:

What if it is 1/4WL long?

Then not only will he not be worried about insurance problems and nearby
lightening strikes, but he won't be bothered with interference complaints,
and all those annoying "Donald Duck" voices and beeps on the radio, etc.

:-)

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Station With Center-Fed Dipole - Best Grounding Technique?
 

Cecil Moore wrote:
dave wrote:
Since we are sticklers for the NEC, Homey needs a #6 wire from where
the transmission line enters the dwelling to an 8' copper clad rod
driven into the earth, as close as practicable.

What if it is 1/4WL long?

"as practible" leaves some wiggle room. Charts of lengths to avoid are
available.

Station With Center-Fed Dipole - Best Grounding Technique?
 

"Tom Ring" wrote

He's feeding it with coax, so it's not just a good idea, it's required.

The antenna is balanced, the feedline is not. He stated the feedline is
RG-8X.

I know that, and just because it's balanced to unbalanced, it's not
*required.* The antenna system can work just fine without one. In some
cases, at least according to the late Lew McCoy, it can do more harm than
good. If the antenna system is inherently unbalanced due to one leg being,
say, in greater proximity to metal and other objects, then I would consider
using some kind of balun or choke system.

Station With Center-Fed Dipole - Best Grounding Technique?
 

On Mon, 04 May 2009, dave wrote:

Do you have metal water pipes upstairs with continuity to a spot
near the ground rods downstairs? If so you can run a strap to
your shack upstairs, and another from the water pipe to the
ground rods downstairs.


Nope, nothing anywhere near the radio. All the water pipes in the
house are on the opposite side, fifty feet or more from the radio. The
shortest path to any ground whatsoever is directly out the window and
down to the soil roughly ten feet below.


You need an RF ground (as the safety ground is the 3 prong Edison.)
MFJ makes an artificial ground. Do you use a balun at the antenna
feedpoint? How do you tune the inverted-V?

Nothing is permanently installed at the moment, so it's a fairly clean
slate. The antenna (Alpha Delta Model DX-EE 40-20-15-10 meter dipole)
was pre-installed to drill the hooks needed to hold it up, but it's
now a pile of wires on the living room floor. The antenna doesn't have
a balun of any type.

While the antenna was up, I used an MFJ-207 Antenna/SWR Analyzer to
get some very quick readings just to make sure the antenna would work.

stewart / w5net

Station With Center-Fed Dipole - Best Grounding Technique?
 

Howard Lester wrote:
"Tom Ring" wrote

He's feeding it with coax, so it's not just a good idea, it's required.

The antenna is balanced, the feedline is not. He stated the feedline is
RG-8X.

I know that, and just because it's balanced to unbalanced, it's not
*required.* The antenna system can work just fine without one. In some
cases, at least according to the late Lew McCoy, it can do more harm than
good. If the antenna system is inherently unbalanced due to one leg being,
say, in greater proximity to metal and other objects, then I would consider
using some kind of balun or choke system.



http://www.bunkerofdoom.com/lit/bal_...baltransys.pdf

Station With Center-Fed Dipole - Best Grounding Technique?
 

On Mon, 04 May 2009, Jim Lux wrote:

Where are you located? The recommendation will vary
substantially if you are in Southern California (almost no
lightning) or Orlando Florida (Lightning capital of the US,
for all intents and purposes).


Heidelberg, located in central Germany. Lightning is not a huge
problem here, but one can perhaps never be too safe in that regard.

By the way, the soil here is just fine as well and certainly doesn't
lack moisture. Thus, since so many are fosusing on it, I'm sorry the
salt was even mentioned. It's not needed in any way. It's just
something I've gotten into the habit of doing.


Hmm. and that Yaesu technician has what training and
experience in grounding systems for lightning protection
(other than what's printed in the front of the manuals)?

And did the salting improve anything? if so, what? adding
grounding is almost always the wrong solution to
operational problems (RFI, for instance), since the purpose
of grounding systems is to deal with abnormal events
(short circuits, transients, etc.)


The salt did indeed help in that particular situation. At the time, I
was living on a hillside in Bremerton Washington, with the immediate
countryside mostly small rock incapable of holding water for any
length of time.

The situation was so bad, my radio (Yaesu FT-847) would often
instantly shut off due to high SWR readings, in spite of my ground
plane antenna being fully functional with several (at one point eight)
ground rods installed. The only way to prevent that was to add water
around the ground rods each day, which usually worked only until the
next day.

Since adding more ground rods did nothing (and watering my antenna
each day was quickly getting tedious), I called Yaesu thinking the
radio might be defective. The technician recommended salt after
agreeing my ground rods should be sufficient for the task.

I was skeptical, but did as he suggested. Dug a hole (about a foot
deep) around each ground rod, drove the rods in a bit deaper, poured
in a generous helping of rock salt, and then watered the area long
enough for the salt to spread into the soil.

Of course, the radio was fine immediately after adding the water, but
the real test was the next day once the water drained away. The radio
did operate just fine that next day, and the day after that. In fact,
the rock salt added to the soil (more added every two to three months)
resolved the problem entirely the remainder of my time at that
location.

stewart / w5net