On Mon, 3 Aug 2009 02:58:29 GMT, "KJ4NTS" wrote:

I have about a 50 foot run from my radio to the outside ground rod. What's the minimum gauge wire
that is acceptable for this connection?
The last time I checked the minimum wire size for a ground intended to
protect from lightning is #6.

50 feet of any wire will not work as an RF ground for anything other
than a quarter wave at 50 feet!

Your next question is about driving another ground rod: If you do, the
second ground must be tied to the first with a minimum of #6 wire or
you set up a dangerous ground loop.

On 3-Aug-2009, Michael Coslo wrote:

http://tinyurl.com/ns7jjd

Is a nice station grounding pdf from Polyphasor. Sorry for the tinyurl,
the original url is a mile long.

Everyone should have a copy, and the writer should get an award for his
or her clarity.

That's a good article, but it is focused on grounding for lightning protection. I am interested in
that, but I am also interested in having an effective RF ground.

I've been able to get a total of 16 feet of ground rod down in the form of 4 four-foot rods, but I
have a 50 foot run from my office to the ground rods, and I'm concerned about RF impedance in that
connection.

On 3-Aug-2009, John Ferrell wrote:

I have about a 50 foot run from my radio to the outside ground rod. What's the minimum gauge
wire
that is acceptable for this connection?
The last time I checked the minimum wire size for a ground intended to
protect from lightning is #6.

50 feet of any wire will not work as an RF ground for anything other
than a quarter wave at 50 feet!

OK. Would it work to construct a radial counterpoise in the crawl space under my office? It would
only be about a 5 foot run to the center of the counterpoise.

If I lay wires on the dirt floor of the crawl space, how many radials would be required and what
would the length be to handle 6-40 meters?

On Mon, 3 Aug 2009 17:52:13 GMT, "KJ4NTS" wrote:

I'm concerned about RF impedance in that connection.

Add a capacitor.

In article ,
"KJ4NTS" wrote:

On 3-Aug-2009, Michael Coslo wrote:

http://tinyurl.com/ns7jjd

Is a nice station grounding pdf from Polyphasor. Sorry for the tinyurl,
the original url is a mile long.

Everyone should have a copy, and the writer should get an award for his
or her clarity.

That's a good article, but it is focused on grounding for lightning
protection. I am interested in
that, but I am also interested in having an effective RF ground.

I've been able to get a total of 16 feet of ground rod down in the form of 4
four-foot rods, but I
have a 50 foot run from my office to the ground rods, and I'm concerned about
RF impedance in that
connection.

The two are pretty much Mutually Exclusive. What makes for Good
Lightning Protection, really doesn't have ANYTHING to do with RF
Grounding, especially if your using an End Feed Vertical, for an
Antenna. Lightning Protection is a Ground Rod that meets NEC.
Low Impedance RF Grounding System design is a Science and Art all in
itself.

--
Bruce in alaska
add path after fast to reply

On Aug 3, 3:09*pm, Bruce in alaska wrote:
In article ,



*"KJ4NTS" wrote:
On *3-Aug-2009, Michael Coslo wrote:

http://tinyurl.com/ns7jjd

Is a nice station grounding pdf from Polyphasor. Sorry for the tinyurl,
the original url is a mile long.

Everyone should have a copy, and the writer should get an award for his
or her clarity.

That's a good article, but it is focused on grounding for lightning
protection. *I am interested in
that, but I am also interested in having an effective RF ground.

I've been able to get a total of 16 feet of ground rod down in the form of 4
four-foot rods, but I
have a 50 foot run from my office to the ground rods, and I'm concerned about
RF impedance in that
connection.

The two are pretty much Mutually Exclusive. *What makes for Good
Lightning Protection, really doesn't have ANYTHING to do with RF
Grounding, especially if your using an End Feed Vertical, for an
Antenna. Lightning Protection is a Ground Rod that meets NEC.
Low Impedance RF Grounding System design is a Science and Art all in
itself.

--
Bruce in alaska
add path after fast to reply

Atta boy Bruce!
A ground plane or counterpoise is part and parcel of a antenna all of
which does not necessarily radiate and it is not of the same potential
of the true ground that should be at the lowest potential of them all.
It is for this reason the transmitter chassis is grounded and
separated from the radiator system which has it's own closed circuit
and where the potential is above that of true ground. In this way your
transmitting circuit does not have a ground loop which is the last
thing that you want.
Lightning tries to get to the true ground by the shortest route and
the requirement is for you to not be part of it's route, even if your
radio has to be the sacrificial lamb if you haven't pulled the plug.

"Art Unwin" wrote in message
...
On Aug 3, 3:09 pm, Bruce in alaska wrote:
In article ,
It is for this reason the transmitter chassis is grounded and
separated from the radiator system which has it's own closed circuit
and where the potential is above that of true ground. In this way your
transmitting circuit does not have a ground loop which is the last
thing that you want.

i don't know where you get your radios, but in all of them here the coax
connector is connected to the transmitter chassis which also has a lug for
going to the safety ground.

Lightning tries to get to the true ground by the shortest route and
the requirement is for you to not be part of it's route, even if your
radio has to be the sacrificial lamb if you haven't pulled the plug.

there ain't no such thing as 'true ground', tis all relative.

On Aug 3, 4:51*pm, "Dave" wrote:
"Art Unwin" wrote in message

...
On Aug 3, 3:09 pm, Bruce in alaska wrote:

In article ,
It is for this reason the transmitter chassis is grounded and
separated from the radiator system which has it's own closed circuit
and where the potential is above that of true ground. In this way your
transmitting circuit does not have a ground loop which is the last
thing that you want.

i don't know where you get your radios, but in all of them here the coax
connector is connected to the transmitter chassis which also has a lug for
going to the safety ground.


By golly, I believe you are correct! I thought that was a bad
practice! Are all electronics at the same potential in the U.S. as
its container? So with a ground connection at the electrical supply
point and a provided connection for another generated "ground", is
that not an invitation for ground loops?



Lightning tries to get to the true ground by the shortest route and
the requirement is for you to not *be part of it's route, even if your
radio has to be the sacrificial lamb if you haven't pulled the plug.


there ain't no such thing as 'true ground', tis all relative.

H'mm, the ground point with the lowest potential relative to other
ground potentials in the same system is the "true" ground of the
system. Now can you tell me which "ground" is protected and from
what? And RF ground; is that protected from lightning? Lightning is
multi frequency oriented so it would appear to me it would gyrate
towards a radiator.
What about just one wire to the antenna and let the earth be the
return line to close the circuit! Seems like the definitions have gone
awry without involvement of a chassis ground
but then it is you that is electrically educated and the better judge.

On Aug 4, 3:52*am, "KJ4NTS" wrote:
.. *I am interested in
that, but I am also interested in having an effective RF ground.

I've been able to get a total of 16 feet of ground rod down in the form of 4 four-foot rods, but I
have a 50 foot run from my office to the ground rods, and I'm concerned about RF impedance in that
connection.

That's about a quarter wave at 5MHz. It sure isn't an effective
ground.You'd need a tuner on the ground wire as well.

KJ4NTS wrote:
On 3-Aug-2009, Michael Coslo wrote:

http://tinyurl.com/ns7jjd

Is a nice station grounding pdf from Polyphasor. Sorry for the tinyurl,
the original url is a mile long.

Everyone should have a copy, and the writer should get an award for his
or her clarity.

That's a good article, but it is focused on grounding for lightning protection. I am interested in
that, but I am also interested in having an effective RF ground.

I've been able to get a total of 16 feet of ground rod down in the form of 4 four-foot rods, but I
have a 50 foot run from my office to the ground rods, and I'm concerned about RF impedance in that
connection.

Gathering from your other posts, you are in a difficult situation. RF
grounding from a non ground floor or basement location is an issue. The
problem is proportional to the frequency and wavelength, which is to say
that at 10 meters, your RF ground won't.

Is there any possibility of putting in a balanced antenna? Or one of the
so called no-ground verticals? All antenna setups are a compromise of
one sort or another. Your setup will be a little bit more of a compromise.

This isn't to say there is no solution. There is always a solution of
some sort.

- 73 de Mike N3LI -