dave wrote:
Jim Lux wrote:


Do you use a balun at the antenna
feedpoint? How do you tune the inverted-V?

Good RF chokes on the coax at the feedpoint and at the point of entry
would go a long way to eliminating any "RF in the shack" problems. A
couple 2.4" 31 mix cores with half a dozen turns on them, for instance.

Whether the V is tuned or not won't have any effect on RFI or grounding.

A BalUn would help a lot.

Balun/choke.. tomato, tomato.. they're really all the same thing. Keep
the RF off the outside of the coax.



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.

The communications system (be it CATV, net powered broadband, amateur,
etc.) would need to be bonded to any of the usual things that form the
grounding/bonding system,e.g, one could "ground" through the metal conduit.

A ground rod is, of course, not recommended in the current codes as a
made electrode, and in any case, the code doesn't necessarily require a
specially installed ground for this purpose. If you DO install another
ground, then it has to be bonded with AWG #6 copper (or bigger) (can't
use the conduit)

Telephone has different rules. Must have electrode/grounding means as
close as practicible to point of entrance, and the ground wire has to be
AWG14 or large, insulated, in as straight a line as possible.

Metal structure supporting outdoor antenna systems have to be grounded
with AWG10 or bigger copper, AWG8 aluminum, or AWG17 copperclad steel,
straight line. (the size requirement is for mechanical strength, not
conductivity, which is why the copperweld(r) can be smaller)

So you have these weird situations where the phone protection block has
to be connected with AWG14 insulated to a grounding electrode as close
as practicible, but then, because of the "bonding of electrodes" rules,
you have to connect that electrode to the "house ground" with nothing
smaller than AWG6.

CATV is even different.. grounding block for drop has to be grounded to
an electrode close to block and an *insulated* AWG14 or bigger run to
bond with the rest of the house's grounding system.


This sort of thing is why most ham installations aren't "code
compliant"... heck, you could go insane trying to wend your way through
the thicket of rules for the NEC. And that doesn't even begin to get
into the transient suppression guidelines and/or NFPA 780 lightning
protection rules.

dave wrote:
Jim Lux wrote:


Do you use a balun at the antenna
feedpoint? How do you tune the inverted-V?

Good RF chokes on the coax at the feedpoint and at the point of entry
would go a long way to eliminating any "RF in the shack" problems. A
couple 2.4" 31 mix cores with half a dozen turns on them, for instance.

Whether the V is tuned or not won't have any effect on RFI or grounding.

A BalUn would help a lot.

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.



and bonded from their to the electrical service grounding electrode
system with a number four or larger conductor.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison

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

On Mon, 04 May 2009 13:14:04 +0200, noname wrote:

Now, where (if any) should I add grounding to that setup? I was going
to add a lightning arrester to the coax just before it enters the
house (fed into two ground rods), but will forego that since none seem
overly thrilled about the idea.

Hi Stewart,

A very good description of your set-up. You are already grounded
through a the haphazard path of your AC outlet - if you chose to use
three prong connections, if your outlet is in fact grounded, if your
equipment actually has a safety ground to chassis. A lot of "ifs,"
hence my use of "haphazard."

By deliberately adding a ground wire going to an ad-hoc ground rod,
you can easily introduce problems. The worst of which could be
lethal, but that extreme is unlikely (except it might only be resolved
at the coroner's inquest).

Consult code for grounding requirements.

The minor problems include ground loops that can plague your listening
and/or your contacts asking what that strange music is in the
background of your transmission. The loops can burn out wiring in
your rig (actually, more like traces on cards). The oddities that
arise from ad-hoc grounding scroll out on a list of complaints that
many come here to find solution for.

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.

That sounds like a fantasy. If this thread doesn't grow suitably to
fill in the vacuum of information, you can do a search in google
groups, for this group, using the key word GROUND and CODE.

73's
Richard Clark, KB7QHC

In article ,
Richard Clark wrote:

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.

That sounds like a fantasy. If this thread doesn't grow suitably to
fill in the vacuum of information, you can do a search in google
groups, for this group, using the key word GROUND and CODE.

73's
Richard Clark, KB7QHC

It really depends on the area that your trying to build the RF Ground
on, or into. Here in Alaska much of the earth (Dirt) is just plain
Silica Sand, and rock, with very little mineralite in it, and is about
as effective an RF Ground as a piece of Glass. We use Dipoles a lot just
for that reason as they don't required an RF Ground to work against to
radiate effectively. In some areas where Marconi type Antennas are used,
and one MUST have an effective RF Ground, we have used Chicken Wire
panels laid flat out from the base to 1/4 Wave at the lowest Frequency
of intended use, and then Salted the dirt to add to the effective
conductance of the Ground plane untill the chicken wire Rusts to the
point of leaving just the conductive material in the top of the dirt.
The Commercial AutoTune Antenna Tuners really don't work well without an
effective RF Ground to work against, as the Microcode that runs them,
can't deal with the very non-stable RF Grounding Systems. There are a
number of ways to get single-ended Autotuners to tune Balanced Dipole
type Antennas, and those are used as well. Much of the work done in the
commercial MF/HF Communications Antennas Systems here in Alaska, was
pioneered by the Engineering Staffs of the old Northern Radio Company,
and then continued by Stephens Engineering Associates. (SEA) Both
outfits were leaders in Bush Communications here in Alaska, in their day.

--
Bruce in alaska
add path after fast to reply

On Mon, 04 May 2009, Richard Clark wrote:

A very good description of your set-up. You are already
grounded through a the haphazard path of your AC outlet
- if you chose to use three prong connections, if your outlet
is in fact grounded, if your equipment actually has a safety
ground to chassis. A lot of "ifs," hence my use of "haphazard."


Okay, I have checked each of those. The house was recently inspected
ensure compliance with recent building code requirements, with the
outlets and overall grounding system checked for proper wiring at that
time. The house wiring exceeded current building requirements, which I
was indeed happy to hear.

The radio uses a three-prong cord (a requirement here), with the
chassis apparently connected at several points to the ground of that.
It appears the antenna shield side of the connector is also bolted
directly to that chassis.


By deliberately adding a ground wire going to an ad-hoc
ground rod, you can easily introduce problems. (snip)


So you recommend no additional grounding?

stewart / w5net

On Tue, 05 May 2009 17:10:16 +0200, noname wrote:

On Mon, 04 May 2009, Richard Clark wrote:

A very good description of your set-up. You are already
grounded through a the haphazard path of your AC outlet
- if you chose to use three prong connections, if your outlet
is in fact grounded, if your equipment actually has a safety
ground to chassis. A lot of "ifs," hence my use of "haphazard."


Okay, I have checked each of those. The house was recently inspected
ensure compliance with recent building code requirements, with the
outlets and overall grounding system checked for proper wiring at that
time. The house wiring exceeded current building requirements, which I
was indeed happy to hear.

Hi Steve,

So, in fact your three prong plugs find their way to the panel ground.
Can YOU find that ground?


The radio uses a three-prong cord (a requirement here), with the
chassis apparently connected at several points to the ground of that.
It appears the antenna shield side of the connector is also bolted
directly to that chassis.

So, by this explicit statement, your "balanced" antenna has been
unbalanced at the rig (which only further enforces the unbalance by
virtue of the coax connection).

By deliberately adding a ground wire going to an ad-hoc
ground rod, you can easily introduce problems. (snip)


So you recommend no additional grounding?

This is a loaded question because there are TWO grounds which
discussion often gets mixed. They may both go to the same point of
zero potential, but their paths are what distinguish them. The TWO
grounds are safety ground and RF ground. Any wire that is
significantly long at a wavelength of your operation, will qualify
more as a radiator than it will as a ground wire.

Consider you are sitting at your transmitter, it has a dedicated newly
applied ground wire that runs the shortest distance to what you think
of as ground. Maybe that is all of 10 feet. You are operating on
10M. Ground is a quarterwave away. That puts your equipment at the
high potential end of a wire with zero potential at ground. How
grounded does that sound?

The solution there is to add an artificial ground tuner to move that
potential away from you (this would be an attempt to "balance" the
distribution so that your equipment sits at an artificially imposed
neutral - ground of another mother).

Thing is, as I said, you already have a ground connection. The safety
ground is a necessity unless you are very practiced in the art of
isolation. You can add another path, and, again, that path may be a
different length to the one you already have. Given that situation,
you may find one path now spilling current into the new one - as
dependant upon the wavelength of operation and the physical path
lengths. When this spilling from one path into the other occurs,
strange things happen compared to if you hadn't added that new path.

More's to be said, but that's enough for now.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Tue, 05 May 2009 17:10:16 +0200, noname wrote:

On Mon, 04 May 2009, Richard Clark wrote:
A very good description of your set-up. You are already
grounded through a the haphazard path of your AC outlet
- if you chose to use three prong connections, if your outlet
is in fact grounded, if your equipment actually has a safety
ground to chassis. A lot of "ifs," hence my use of "haphazard."

Okay, I have checked each of those. The house was recently inspected
ensure compliance with recent building code requirements, with the
outlets and overall grounding system checked for proper wiring at that
time. The house wiring exceeded current building requirements, which I
was indeed happy to hear.

Hi Steve,

So, in fact your three prong plugs find their way to the panel ground.
Can YOU find that ground?

The radio uses a three-prong cord (a requirement here), with the
chassis apparently connected at several points to the ground of that.
It appears the antenna shield side of the connector is also bolted
directly to that chassis.

So, by this explicit statement, your "balanced" antenna has been
unbalanced at the rig (which only further enforces the unbalance by
virtue of the coax connection).

By deliberately adding a ground wire going to an ad-hoc
ground rod, you can easily introduce problems. (snip)

So you recommend no additional grounding?

This is a loaded question because there are TWO grounds which
discussion often gets mixed. They may both go to the same point of
zero potential, but their paths are what distinguish them. The TWO
grounds are safety ground and RF ground. Any wire that is
significantly long at a wavelength of your operation, will qualify
more as a radiator than it will as a ground wire.

Consider you are sitting at your transmitter, it has a dedicated newly
applied ground wire that runs the shortest distance to what you think
of as ground. Maybe that is all of 10 feet. You are operating on
10M. Ground is a quarterwave away. That puts your equipment at the
high potential end of a wire with zero potential at ground. How
grounded does that sound?

Worse than that. You've basically made a big loop antenna: greenwire
ground to panel, panel to ground rod, ground rod to rig.





The solution there is to add an artificial ground tuner to move that
potential away from you (this would be an attempt to "balance" the
distribution so that your equipment sits at an artificially imposed
neutral - ground of another mother).

Or, easier.. put a choke around the feedline where it comes into the
shack, so that there's no appreciable RF current through the chassis and
green-wire ground.




Thing is, as I said, you already have a ground connection. The safety
ground is a necessity unless you are very practiced in the art of
isolation. You can add another path, and, again, that path may be a
different length to the one you already have. Given that situation,
you may find one path now spilling current into the new one - as
dependant upon the wavelength of operation and the physical path
lengths. When this spilling from one path into the other occurs,
strange things happen compared to if you hadn't added that new path.


Exactly.. one DC/Line frequency path is all that's needed for safety.

Richard Clark wrote:

Hi Steve,


I assume you're talking to me since you replied to my message. My name
is Stewart, not Steve.


So, in fact your three prong plugs find their way to the
panel ground. Can YOU find that ground?


I don't understand your question. The radio chassis is grounded to the
wall outlet. The overall house wiring was recently inspected, with the
grounding checked at that time. It was a thorough inspection which
also included a device plugged into most outlets to check the wiring.
Given that, I don't really know what I'm supposed to find and why.


So, by this explicit statement, your "balanced" antenna
has been unbalanced at the rig (which only further enforces
the unbalance by virtue of the coax connection).


I guess so. Actually, I don't really know. The radio was manufactured
with the chassis grounded to the wall outlet and the antenna was
designed by it's manufacturer to work properly with 50 ohm coax feed
connected (I would assume) to a radio like this. What impact that has
on balanced versus unbalanced is beyond me, and the same is true for
what exactly you want me to do about it.

stewart / w5net

noname wrote:
Thanks for the replies, Dave, Rick, and Jim. Since my ideas didn't go
over so well, perhaps it's best to just describe my setup and then
listen to any suggestions. Since I'm not an electrical engineer, do
try to keep things simple.

As I said earlier, the radio and speaker are both connected to the
house ground through their power cords. I've also installed an
inverted V dipole in the back yard (the only place it will fit). The
center (feedpoint) of the antenna is attached to the roof on the
second floor (about twenty feet above the ground) and the two ends run
out to the two corners of the backyard. That's the best I can
accomplish given local antenna restrictions.

My house is located on a hill with a top floor entrance and living
area. Below that is another floor level with the backyard, with a
basement below that.

The radio will be located in the living room on the top floor, again
one floor above the backyard. The coax (RG-8X) will run out a window
on the second floor to the center (feedpoint) of the antenna attached
to the roof just outside (a run of roughly 15-ft).

Now, where (if any) should I add grounding to that setup? I was going
to add a lightning arrester to the coax just before it enters the
house (fed into two ground rods), but will forego that since none seem
overly thrilled about the idea.

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.

stewart / w5net

Dave

I'm not an engineer either but I have installed ridge top communications
shelters from the Argentine Pampas to Alaska without having lightning
caused down time for the communications equipment that the shelters
contained. You need a single point of ground connection in the shack.
One of the best ones to have is an antenna entry bulkhead made of some
stout aluminum or copper plate. You then run all of the connections
that serve your equipment through or past that bulkhead. You also mount
all of your protectors on or at that bulkhead. From the outside of the
bulkhead you run a ribbon conductor down to the Grounding Electrode that
you install as close to directly below the bulkhead as you can.

If the electrode will be driven rods then buy yourself several rod
couplers to permit you to drive the rods to a depth below the permanent
moisture level. The driving is best accomplished by renting an electric
demolition hammer and a ground rod cup. You will need some means to
measure the grounding electrode resistance to earth. You can rent a
three pole or four pole ground impedance tester or a much easier to use
clamp on ground loop impedance tester. You want the total impedance of
the Grounding Electrode System to be less then twenty five ohms and the
lower you get it the better off you are. If you drive four or five rods
on top of each other then you will have reached between thirty two and
fifty feet into the earth. In most cases you will strike hard pan or
rock before that depth and thus will have to drive additional rods. If
your first stacked rod does not get you down to twenty five ohms or less
you just drive a second stacked rod at least the length of the first rod
away from the first rod. Once you have the Grounding Electrode down to
twenty five ohms or less you bond it to the electrical grounding
electrode using a number four or larger copper conductor that is run
entirely outside the builidng.

For best protection you would run the bonding conductor in the form of a
partial ground ring consisting of a number two copper conductor buried
in trench that is thirty inches deep and runs from the one electrode to
the other around the outside of the home.

If your home is new enough to have a concrete encased electrode for it's
power ground then it may be possible to bond to it by bonding to one end
of any steel beam that was used in the floor support at the basement
ceiling. If the electrician was competent the beam will be bonded to
the concrete encased electrode. You will have to check carefully to
assure that it is so bonded.

It is terribly unlikely that your home has a true Ufer ground because
constructing one involves a mesh of half inch or larger rebar that is
continuous throughout the basement floor and foundation footers with all
junctions double tied and one piece of rebar turned up out of the floor
at the location of the electrical service equipment.

If your not willing to do all of that; and most hams are not; you will
have to choose how much to do. The bulkhead, a one inch braid Grounding
Electrode Conductor, two eight foot driven rods at least their own
length apart, and the number four bonding conductor to bond those to the
electrical service ground is the minimum for lightning protection.
Anything less is a feel good waste of time.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison