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Old November 27th 07, 08:56 PM posted to rec.radio.amateur.moderated
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Default Grounding my HF radio equipment

Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

Thanks!

Jim


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Old November 28th 07, 01:46 AM posted to rec.radio.amateur.moderated
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Posts: 149
Default Grounding my HF radio equipment

James Barrett wrote:

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.


Jim,

You'll see numerous references on the web to "single point ground." It
is very, very important stuff. I got nailed on this stuff back in
August, 2003. Here's how it played out:

We had a violent thunderstorm early one morning about 7 A.M. Suddenly
there were three near strikes (simultaneous lightning and thunder)
within a ten second time frame. In addition to telephones, computers
and home entertainment equipment, my four month old Ten-Tec Orion and
numberous shack accessories were zapped. My house ground is a single 8
foot copper plated ground rod. The lightning ground for the shack was
an identical ground rod driven about thirty feet away from the house ground.

When the strikes conducted a surge into my home via the power lines, all
three wires had very high voltage on them. The shack ground was still
at its usual potential (0). The house ground was elevated to high
voltage. There was a potential difference between the shack ground the
the house ground. That potential quickly equalized inside my equipment.

Ten-Tec reported that six boards inside the Orion had their ground
traces evaporated.

For a shack ground, you want the shortest possible distance between your
rig and earth. The house ground will be as close as possible to your
electrical service entrance. If, like me, you have to use two ground
rods, you need to bond the two of them together with a big, fat wire so
that the two can never be at different potentials.

If you have a tower, I'll assume that you have at least one 8 foot
ground rod driven at its base. Bond your coaxial cable sheaths to the
rod at the tower. The sheaths should also be bonded to your shack ground.

Dave Heil K8MN

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Old November 28th 07, 03:21 AM posted to rec.radio.amateur.moderated
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Posts: 64
Default Grounding my HF radio equipment


"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

Thanks!

Jim

my own experence is that using the household ground at hf is marginal at
best

my own result were greatly inproved with aan extrenal seperat e ground


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Old November 29th 07, 12:34 AM posted to rec.radio.amateur.moderated
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Posts: 2
Default Grounding my HF radio equipment

Hi James,

There are several good articles at the www.eham site on this very subject.
If you can read between the lines of some of the muck slinging, you can come
up with several really good solutions.

Just click on the "view more articles" link [at the top of the horizontal
green separator] HTH.

Alain



"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

Thanks!

Jim



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Old November 29th 07, 05:09 PM posted to rec.radio.amateur.moderated
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First recorded activity by RadioBanter: Jun 2006
Posts: 828
Default Grounding my HF radio equipment

Joaquin Tall wrote:
Hi James,

There are several good articles at the www.eham site on this very subject.
If you can read between the lines of some of the muck slinging, you can come
up with several really good solutions.

Just click on the "view more articles" link [at the top of the horizontal
green separator] HTH.

Alain



"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.


There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.

Dealing with the Power ground, you'll want to tie the grounds on the
back of your radios/tuners/amplifiers together. There are a number of
ways to do this. Some folks construct a copper ground plane that has
wires running to it from the equipment needing grounded.

Another possibility is wiring to the grounding bars such as are used for
electrical service. This is the method I use.

Whatever method used, short wires are better working practice.

I'll just go over my own setup as beyond the grounding bar, you'll get a
lot of opinions on what is right. I run heavy gauge wire out to a 8 foot
copper pipe embedded about 7.5 feet into the ground, and have ground
clamps to attach it. Braid is good too.

Some other thoughts:

I install the pipe hydrostatically - I sweat a garden hose adapter onto
the copper pipe, attach a hose to it, and let 'er rip (hopefully no
disclaimers needed here) The water digs a hole for the pipe, which then
sinks into it. It's fun

some folks ground to a water pipe. Not a good idea, as modern plumbing
does not always have continuity - there might be a piece of PVC in the
line somewhere.

I have my Arrester going to that pipe also. I'm using a "spark gap" type
arrester, but I would really recommend one of the gas discharge types.
They are quick to respond, and better protection in general.

Hope this helps.

- 73 de Mike N3LI -



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Old November 30th 07, 01:30 AM posted to rec.radio.amateur.moderated
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First recorded activity by RadioBanter: Oct 2006
Posts: 55
Default Grounding my HF radio equipment

On Nov 27, 8:46 pm, Dave Heil wrote:
James Barrett wrote:
Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?


I'm still doing my research, but figured it couldn't hurt to ask.


Jim,

You'll see numerous references on the web to "single point ground." It
is very, very important stuff. I got nailed on this stuff back in
August, 2003. Here's how it played out:

We had a violent thunderstorm early one morning about 7 A.M. Suddenly
there were three near strikes (simultaneous lightning and thunder)
within a ten second time frame. In addition to telephones, computers
and home entertainment equipment, my four month old Ten-Tec Orion and
numberous shack accessories were zapped. My house ground is a single 8
foot copper plated ground rod. The lightning ground for the shack was
an identical ground rod driven about thirty feet away from the house ground.

When the strikes conducted a surge into my home via the power lines, all
three wires had very high voltage on them. The shack ground was still
at its usual potential (0). The house ground was elevated to high
voltage. There was a potential difference between the shack ground the
the house ground. That potential quickly equalized inside my equipment.

Ten-Tec reported that six boards inside the Orion had their ground
traces evaporated.

For a shack ground, you want the shortest possible distance between your
rig and earth. The house ground will be as close as possible to your
electrical service entrance. If, like me, you have to use two ground
rods, you need to bond the two of them together with a big, fat wire so
that the two can never be at different potentials.


This whole topic area seems to be eternally confused and confusing and
I'm in the parade of the confused. On a common sense basis I
absolutely agree with your connecting the station grounds to the
'lectric service entrance ground for the reasons you've stated.

But somewhere along the line somebody in the ham groups stated that
the National Electrical Code states that there shall be one and *only
one* grounding point per power drop and the neighborhood code cops and
the insurance companies reportedly get stiff about it.

So is it legal to connect a phalanx of ham station ground rods to the
service entrance ground?? Or not.

If you have a tower, I'll assume that you have at least one 8 foot
ground rod driven at its base. Bond your coaxial cable sheaths to the
rod at the tower. The sheaths should also be bonded to your shack ground.

Dave Heil K8MN


w3rv

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Old November 30th 07, 02:39 AM posted to rec.radio.amateur.moderated
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Posts: 464
Default Grounding my HF radio equipment

In article ,
wrote:

This whole topic area seems to be eternally confused and confusing and
I'm in the parade of the confused. On a common sense basis I
absolutely agree with your connecting the station grounds to the
'lectric service entrance ground for the reasons you've stated.

But somewhere along the line somebody in the ham groups stated that
the National Electrical Code states that there shall be one and *only
one* grounding point per power drop and the neighborhood code cops and
the insurance companies reportedly get stiff about it.

So is it legal to connect a phalanx of ham station ground rods to the
service entrance ground?? Or not.


As I understand it, according to the NEC, you must have only one
grounding *system* per building. This system may include two or more
ground rods, and/or a bare grounding wire buried in a trench around
the outside of the building. The ground rods and wires must be
securely bonded together with heavy-gauge wire... that's what ensures
that it's all one grounding "system".

What's dangerous is, as has been suggested, having separate grounding
rods (or grounding subsystems) which aren't well-bonded together. If
you connect any electrical apparatus to two such grounding points
(e.g. ham radio with a third-prong ground on its line cord, which is
also tied to a separate ground rod via the coax feedline), and a
lightning strike or a hot-to-ground fault occurs, your electrical
apparatus and its wiring can end up carrying a lot of current between
the ground points, thus creating a shock or fire hazard.

The bonding wires create a low-impedance path for such fault currents,
minimizing the voltage differential which exists between the ground
rods and thus helping keep down the flow of fault current through
undesired paths (e.g. your ham rig).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

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Old November 30th 07, 03:25 AM posted to rec.radio.amateur.moderated
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Posts: 21
Default Grounding my HF radio equipment

Michael Coslo wrote:
There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.


The is probably the biggest point of confusion for me. What do you mean
by "RF ground"? The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground? Because I
thought that the power ground was the three prong plug.


Jim

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Old November 30th 07, 07:08 AM posted to rec.radio.amateur.moderated
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Posts: 464
Default Grounding my HF radio equipment

In article ,
James Barrett wrote:

The is probably the biggest point of confusion for me. What do you mean
by "RF ground"? The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground? Because I
thought that the power ground was the three prong plug.


The intent of the third prong on the power plug is to provide a safe
path from the equipment chassis, back to the power panel (where the
neutral and hot are bonded together). This ensures that if there's a
fault inside the equipment, and a "hot" wire touches the chassis, the
stray current will immediately flow back to the panel via this ground
connection (and likely cause a fuse to blow or a breaker to trip very
quickly). It ensures that you don't end up with a chassis which is
"hot", and isolated from ground... just waiting for somebody to touch
it, accidentally complete a path to ground via their body, and get
themselves mildly dead.

The intent of the ground terminal on the back of the radio is to let
you tie the radio chassis to a good RF ground, so that if any RF
reaches the chassis via conduction (e.g. coming back down the
feedline) it doesn't leave you with a chassis which is RF-hot compared
to grounded objects nearby (this could cause an RF burn if you touch
the chassis, or sneak back into the microphone wiring and cause weird
squawking sounds when you transmit). It's also necessary if you plan
to use a random-wire or similar unbalanced antenna which is designed
to work against the station ground (e.g. radials or counterpoises).

It's normally the practice to bond *all* of the equipment in your
shack together with good (short, heavy) grounding wire or braid...
once again, ensuring that different pieces of equipment have their
chassis at the same (or nearly the same) AC and RF potential. By
doing so, you are in effect bonding together your power/safety ground,
and your station RF ground, creating a single ground system.

Because this in-the-station ground bonding isn't really designed to
handle massive amounts of fault current (e.g. from lighting) and since
it's in an area where you really don't want such fault current to flow
(e.g. your shack), it's still important to bond your station's "RF
ground" rod, and your house's service-panel ground rod, together as
per NEC.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

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Old November 30th 07, 02:15 PM posted to rec.radio.amateur.moderated
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First recorded activity by RadioBanter: Jun 2006
Posts: 828
Default Grounding my HF radio equipment

James Barrett wrote:
Michael Coslo wrote:
There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.


The is probably the biggest point of confusion for me. What do you mean
by "RF ground"?


It is confusing, so you're not alone.

RF grounds can be related to Power grounds, but only so far. On say a
ground plane antenna, where you have a vertical center rod connected to
the coax center conductor, and some angled rods connected to the coax
shield, those angled rods are serving as a ground plane. They aren't
connected to actual earth.

This is where a lot of the confusion comes in. The ground plane is more
of a counterpoise, or to look at it as a circuit, a place for the other
part of the current to go.

Now if we look at say a vertical HF antenna of the 1/4 wave variety,
typically this antenna will have "grounding" by way of many radial
lengths of wire that are either buried in the earth at a shallow depth,
or even just stapled to the surface of the earth.

This is "Kind of-sort of" like a power ground, in that it is in the
earth, but its doing something different. It is operating very similarly
to that ground plane. It gives the RF current a place to go.

I didn't go into things like impedence to avoid confusing the issue, but
that would be next in the discussion.



The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground?


The ground terminals on your equipment are part of the power ground,
that you would attach to the pipe in the yard. Explanation of that
below. Any RF ground would be considered to be on the shield of the coax
connectors.

Because I
thought that the power ground was the three prong plug.


Yes, generally. One of the reasons that we put in a separate ground rod
from house ground for a power ground is that there can be currents on it
after going around the house. It's still mostly neutral, but with
hundreds of feet of that green wire running around the house, you can
still get some currents.


Some people can "get away with" not having a station power ground.
Kinda. I highly recommend one especially for some place to send your
lightning protection.

- 73 de Mike N3LI -



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