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Old July 17th 04, 05:30 PM
Bob Miller
 
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Default Buried ground wire, insulated or bare?

I can't find this in any of my books, so thought I ask the group:

For my general station ground, I have a copper pipe that goes down
about one foot -- then hits rock or limestone or whatever.

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?

Tnx,

Bob
k5qwg

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Old July 17th 04, 05:57 PM
 
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Bob Miller wrote:
I can't find this in any of my books, so thought I ask the group:


For my general station ground, I have a copper pipe that goes down
about one foot -- then hits rock or limestone or whatever.


I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?


Or should I go buy some bare solid copper wire?


Tnx,


Bob
k5qwg


This has been hashed over many times. A google search will provide all
the details.

Bottom line:

If you want a DC ground, bare wire or bury your ground rod in a trench.

If you want a RF ground, it doesn't matter.

--
Jim Pennino

Remove -spam-sux to reply.
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Old July 18th 04, 01:34 AM
J999w
 
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Default

Why buy more wire ... don't you have a knife?

jw
K9RZZ
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Old July 18th 04, 06:13 AM
Richard Clark
 
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On Sat, 17 Jul 2004 10:30:16 -0500, Bob Miller
wrote:

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?


Hi Bob,

Insulated will make a poor 60Hz safety ground (which you should
connect this ground to anyway). Insulated wire will make a perfectly
good RF ground (upwards to 5 orders of magnitude frequency shift makes
a considerable difference in what ground "means"). The pipe, on the
other hand, serves very little purpose. It is inadequate for a safety
ground, and useless for RF and maybe just suitable for providing a
mast base. It does give you a physical reference point - kinda like a
big solder lug.

Use up all your wire and enjoy - another 500 or 5000 feet won't bring
as much return as the first 500. For radials, try 10 X 50 feet, or 50
X 10 feet or something in between.

73's
Richard Clark, KB7QHC


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Old July 18th 04, 02:56 PM
Bob Miller
 
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On Sun, 18 Jul 2004 04:13:37 GMT, Richard Clark
wrote:

On Sat, 17 Jul 2004 10:30:16 -0500, Bob Miller
wrote:

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?


Hi Bob,

Insulated will make a poor 60Hz safety ground (which you should
connect this ground to anyway). Insulated wire will make a perfectly
good RF ground (upwards to 5 orders of magnitude frequency shift makes
a considerable difference in what ground "means"). The pipe, on the
other hand, serves very little purpose. It is inadequate for a safety
ground, and useless for RF and maybe just suitable for providing a
mast base. It does give you a physical reference point - kinda like a
big solder lug.

Use up all your wire and enjoy - another 500 or 5000 feet won't bring
as much return as the first 500. For radials, try 10 X 50 feet, or 50
X 10 feet or something in between.


Question -- is there a problem in using a safety ground as an rf
ground, too? If I connected 10x50-ft bare, buried radials to my little
pipe, and used it as a safety ground for the station, and also as a
ground to work an inverted "L" against, would that be a problem, or
should I have separate ground points?

Tnx to all who have replied so far...

Bob
k5qwg


73's
Richard Clark, KB7QHC


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Old July 18th 04, 07:11 PM
Richard Clark
 
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On Sun, 18 Jul 2004 07:56:32 -0500, Bob Miller
wrote:
Question -- is there a problem in using a safety ground as an rf
ground, too? If I connected 10x50-ft bare, buried radials to my little
pipe, and used it as a safety ground for the station, and also as a
ground to work an inverted "L" against, would that be a problem, or
should I have separate ground points?


Hi Bob,

The Safety ground as RF ground will be ONE radial equal in path to all
copper it is connected to (your plumbing in other words, provided it
is not plastic) - not bad, but not any great shakes. It was never
designed nor installed to serve RF, just to keep 60Hz tamed around
home, shop and garden.

You can build a separate Safety ground into your antenna ground
system, but code demands you then connect both Safety grounds (to keep
you, children, small animals, and your neighbors alive - this is not
just a tedious bureaucratic exercise). The wire between them must be
continuous (no splices). This also has the added advantage of cutting
down on nasty noise problems called "ground loops" (the hum that
refuses to go away or the strange operation of other electronics while
you are transmitting).

73's
Richard Clark, KB7QHC
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Old July 19th 04, 04:01 AM
Hal Rosser
 
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Reminds me of the cartoon of the lineman whose job changed to running
underground service - he said the hardest part was getting the holes deep
enough to bury the power poles.
You got a lot of good advice already - I vote for bare copper - and use the
ground rod and its ground clamp as a solderless lug to distribute the buried
ground wires.

"Bob Miller" wrote in message
...
I can't find this in any of my books, so thought I ask the group:

For my general station ground, I have a copper pipe that goes down
about one foot -- then hits rock or limestone or whatever.

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?

Tnx,

Bob
k5qwg



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Old July 19th 04, 08:05 PM
Jack Painter
 
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Default

"Bob Miller" wrote

For my general station ground, I have a copper pipe that goes down
about one foot -- then hits rock or limestone or whatever.

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?
---
and then Bob added:

Question -- is there a problem in using a safety ground as an rf
ground, too? If I connected 10x50-ft bare, buried radials to my little
pipe, and used it as a safety ground for the station, and also as a
ground to work an inverted "L" against, would that be a problem, or
should I have separate ground points?
--

Hi Bob, can you be more clear on what you meant by "general station ground"?

Since you're in thunderstorm country it could be you mean a lightning
protection ground. But you also mention safety ground and RF ground so it
appears you have multiple requirements here.

Conductor choices vary according to the function of the system so it is
difficult to generalize about stranded v. solid wire until you can be more
specific in your requirements. In some cases neither kind of wire is
appropriate, with wide/heavy gage copper strap being the best choice.

However many purposes your ground system fulfills, and from however many
places it connects to ground rods, one standard always applies: you must
always bond all of your earth-references (ground rods) to your station
equipment AND the main entrance ground of utility wires coming into your
home. Preferably that station single point ground and the Utility single
point ground are the same place. Unfortunately few of us are so lucky as to
be able to locate our station right at the main Utility service entrance.
When the two are far apart that creates problems. With a lot of help from
this group, and professional engineer review, I completed a station
grounding and lightning protection system that accounted for those problems.
The complete site construction plans are listed at:
http://members.cox.net/pc-usa/station/grounding.htm

Hope this helps,

Jack Painter
Virginia Beach, VA


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Old July 19th 04, 09:33 PM
Jack Painter
 
Posts: n/a
Default

"Bob Miller" wrote

For my general station ground, I have a copper pipe that goes down
about one foot -- then hits rock or limestone or whatever.

I'd like to enhance the pipe with a few buried radials. I happen to
have a 500' roll of 14-guage stranded *insulated* copper wire. Will
the insulation keep the wire from becoming "one with the dirt"?

Or should I go buy some bare solid copper wire?
---
and then Bob added:

Question -- is there a problem in using a safety ground as an rf
ground, too? If I connected 10x50-ft bare, buried radials to my little
pipe, and used it as a safety ground for the station, and also as a
ground to work an inverted "L" against, would that be a problem, or
should I have separate ground points?
--

Hi Bob, can you be more clear on what you meant by "general station ground"?

Since you're in thunderstorm country it could be you mean a lightning
protection ground. But you also mention safety ground and RF ground so it
appears you have multiple requirements here.

Conductor choices vary according to the function of the system so it is
difficult to generalize about stranded v. solid wire until you can be more
specific in your requirements. In some cases neither kind of wire is
appropriate, with wide/heavy gage copper strap being the best choice.

However many purposes your ground system fulfills, and from however many
places it connects to ground rods, one standard always applies: you must
always bond all of your earth-references (ground rods) to your station
equipment AND the main entrance ground of utility wires coming into your
home. Preferably that station single point ground and the Utility single
point ground are the same place. Unfortunately few of us are so lucky as to
be able to locate our station right at the main Utility service entrance.
When the two are far apart that creates problems. With a lot of help from
this group, and professional engineer review, I completed a station
grounding and lightning protection system that accounted for those problems.
The complete site construction plans are listed at:
http://members.cox.net/pc-usa/station/grounding.htm

Hope this helps,

Jack Painter
Virginia Beach, VA



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