On Sun, 15 Feb 2004 19:33:27 -0800, Frank Gilliland
wrote:

In ,
wrote:

snip
You guys are all over this topic and it's really blowing my hair
back.

Can you guy's condense it to your opinion of the best/cheapest
way to ground lets say..an omni on a roof-top or tower? Best
being a relative term.

I'm sure the advice will save at least one person from getting
blasted, and make people aware that you can't just put a hunk
of metal in the air without considering lightning.

Thx.


Ok......

First, sink a ground rod at the point where the coax will enter the house. If
you have a basement next to the ground rod, sink a couple more rods so they are
separated by ten feet or more and in the path of the coax. Some people like to
prep the ground by soaking with sal****er, but in my experience that makes the
rod corrode before its time, then the salt leeches away into the ground water,
leaving a very poor ground in a very short time. I use galvanized pipe as
opposed to copper rods because they have a larger diameter (more rod-to-ground
contact = lower resistance), and they last longer. You can also thread the pipe
for a super-neat installation of a waterproof box......

Next is the coax installation. Run the coax down the mast or side of the house
to the ground rod. Don't run the coax near any wiring inside the house. You can
detect house wiring with a cheap metal detector. Avoid sharp turns as much as
possible. At the ground rod it helps to have a waterproof box because you need
to cut the coax, ground the shield, and shunt the center conductor to ground
with a choke (as per the diagram I made yesterday).

About the choke: This serves two purposes. First, it shunts static electricity
from the antenna to ground. Second, it provides a path for lightning if it
should strike. Since the lightning will arc across every loop in the choke, the
inductance value isn't critical just as long as it is high enough to block your
RF (about 1 mH or larger for HF and above), and the wire size is large enough to
handle some current (#14 or larger should be fine). One of those heavy-duty hash
chokes for ignition noise is ok, or you can wind your own -- use a large iron
bolt for a core and wind about 50 turns of #10 or #12 house wire. If you aren't
running much power, you can slit the insulation along the length of the coil so
it will arc at a lower voltage.

Then run the coax up into the house along side the grounding strap. Tie them
together with cable-ties if you want. Again, it's important that you run these
so they don't come close to any house wiring, and they should enter at a
location that is clear of easily combustible stuff. Terminate the ground strap
with a really big alligator clip, jumper cable clamp, or whatever you have that
makes a really good connection and can be easily disconnected. The ground clamp
from an arc welder is almost ideal.

Above the point where the coax and grounding strap enter the house, make a hook
or post where you can hang both when not being used. Remember that if lightning
hits, it's very possible that these will jump straight out from the wall and
dance around like a water hose, so make sure they are held securely in place.

Inside the house, make yourself a grounding bus bar of copper or aluminum. Put
this on the back of your bench and use it to ground all your equipment. To this
you clamp on your grounding strap. When not using your bench, unhook the
grounding strap along with the coax and stow it away. Also, to protect the coax,
use an appropriate socket and short it out before you stow it.

When should you unhook your antenna? There is a thing called the 30-30 rule: If
you hear thunder less than 30 seconds after you see the lightning, unplug. Don't
plug in again until 30 minutes after the last thunder. That's pretty safe. You
can even improve on that by building a lightning detector, many of which will
indicate lightning even before you can hear the thunder.


How's that?

Oh, I almost forgot..... coax length!!!!! The low impedance of the ground will
be reflected at the radio when the length of the coax & ground strap, from the
ground rod to the radio, are 1/2 wavelength. This means 1/2 wavelength -without-
consideration of velocity factor because we want a low impedance -ground-. And
this means -- you guessed it -- 18 feet of coax!



Very nice Frank, The only thing I have different on my setup, is a
ground window where my coax and rotor cables enter the house. That is
a metal plate, a scrap aluminum plate I found at work (12" x 12").
Its mounted over the entrance to the crawl space of my house
(no basements down here) I mounted coax and rotor feed throughs to it.
When are storm is approaching I disconnect my cables outside so that
none of cables enter the house.

From: (Frank=A0Gilliland)
In ,
wrote:
..... We pushed poles in the ground with the bobcat and post hole
digger, mostly for lightning. Out here where I live, by the time the
fire dept gets here with the tanker (no hydrants)you're toast.
_
Here's a little trick if you use a pipe for a ground rod: Thread both
ends of the pipe. On the top put a fitting that will accept a garden
hose. On the bottom put a reduction fitting (to be used as a nozzle).
Hold the pipe vertical, turn on the water full blast, then let the water
drill the hole. When you are done just unscrew the top fitting, and
PRESTO!!! A great ground rod without a lot of fuss.
BTW, this doesn't work very well in areas where there are a lot of large
rocks in the ground.....

_
The hose in the pipe method works very well. It is standard procedure
down here to do what you suggested when installing
pvc sprinkler systems that must pass under walkways, driveways, etc.
You mentioned sal****er...folks have been known to pour bagged salt
around their tower, as well, although down here you really don't need
it, as the water table is easily accessible at 3 to 5 feet. It's
practically impossible to have a rod here that ISN'T in the water
table....but I prefer dragging the copper line in the Gulf behind the
boat,,,,.remember,,,, N3CVJ said if you're gonna break the law, (dxing
is technically against the law on cb) 'tis better to do it from a
portable station than from your home.

In ,
(Twistedhed) wrote:

From: (Frank*Gilliland)
In ,
wrote:
.... We pushed poles in the ground with the bobcat and post hole
digger, mostly for lightning. Out here where I live, by the time the
fire dept gets here with the tanker (no hydrants)you're toast.
_
Here's a little trick if you use a pipe for a ground rod: Thread both
ends of the pipe. On the top put a fitting that will accept a garden
hose. On the bottom put a reduction fitting (to be used as a nozzle).
Hold the pipe vertical, turn on the water full blast, then let the water
drill the hole. When you are done just unscrew the top fitting, and
PRESTO!!! A great ground rod without a lot of fuss.
BTW, this doesn't work very well in areas where there are a lot of large
rocks in the ground.....

_
The hose in the pipe method works very well. It is standard procedure
down here to do what you suggested when installing
pvc sprinkler systems that must pass under walkways, driveways, etc.
You mentioned sal****er...folks have been known to pour bagged salt
around their tower, as well, although down here you really don't need
it, as the water table is easily accessible at 3 to 5 feet. It's
practically impossible to have a rod here that ISN'T in the water
table..


Now isn't that just special..... as if anyone cares about your mud.


..but I prefer dragging the copper line in the Gulf behind the
boat,,,,.remember,,,, N3CVJ said if you're gonna break the law, (dxing
is technically against the law on cb) 'tis better to do it from a
portable station than from your home.


And, of course, there is no reason to doubt his word on the subject.







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Oh, I almost forgot..... coax length!!!!! The low impedance of the ground will
be reflected at the radio when the length of the coax & ground strap, from the
ground rod to the radio, are 1/2 wavelength. This means 1/2 wavelength -without-
consideration of velocity factor because we want a low impedance -ground-. And
this means -- you guessed it -- 18 feet of coax!

18 feet? Are you sure? I thought 18 feet was only a convenient
length for mobile antennas and could never have any electrical
significance.

(Twistedhed) wrote:
N3CVJ said if you're gonna break the law, (dxing
is technically against the law on cb) 'tis better to do it from a
portable station than from your home.

Where did he say that you lying sack of dog poop?

If in sandy loom, then a single ground rod may not be
sufficient. Neighborhood history will apply. Previous
lightning damage in the last ten years? If so, then the
single point ground may be expanded with more rods; spaced as
Frank suggests and to comply with NEC. Other alternatives
include looping the house with a buried bare copper wire. But
again, this is typically only required for high 'strike
frequency' locations - more a function of neighborhood
geology.

A problem with the water idea is a loose ground rod. A
ground rod must be firm in ground when installed. A loose
ground rod is not earthed. Ground rod is further compromised
if using threaded joints. Ground rod should be monolithic
until well below frost line.

If antenna is not located near to service entrance and
single point ground, then antenna may require its own earth
ground. This in addition to the coax ground. IOW either the
antenna is part of your structure and earthed at the service
entrance ground; or antenna is earthed as if a lightning
rod. If the antenna connection to earth ground is
significantly shorter than connection to service entrance,
then antenna must also have its own earth ground rod located
as directly under the antenna as possible. This so that
lightning takes a short path to earth; does not seek
alternative paths via other items such as chimney or interior
wire.

If installing for commercial broadcaster reliability, then
the inductor from center core is additional protection. But
most industry professionals say the center conductor will leak
sufficiently to the outer shield making no center conductor
connection necessary. IOW that ground block sold in Home
Depot or Radio Shack (to earth only outer shield to single
point earth ground) is more than sufficient protection for
most residences. Again, neighborhood history will apply.
Inductor adds only minor improvement; a function of local
history and other considerations.

Disconnecting to protect equipment is unreliable because
humans are not reliable. Humans are only available only 1 in
three hours - and that assumes humans are home often.
Protection must be installed virtually 24 hours every day and
must be fully sufficient even when using the equipment.
Disconnecting is just convenient extra protection made
unnecessary by properly earthing.

Again, you have soil that typically makes poor earth
grounds. This will be especially a problem if more conductive
earth lies beneath - such as limestone. Ground rod would need
be deeper to make contact with that limestone. If geology
changes beneath building, then that too can create earthing
problems. Point being the best earth ground must be the
single point earth ground.

If using multiple rods, then those rods need be connected by
buried bare copper wire. Some do this by digging a hole, then
driving ground rod into bottom of that hole. A four or six
inch plastic pipe lines the hole. Buried bare copper wire
clamps to earth ground rod AND can be inspected through that
covered plastic pipe. Integrity of that wire to rod clamp is
important.

Forget about salting the earth. Some have lined 'buried
copper wire' trench with better material such as trailings
from a steel mill. This tends to improve the transition from
buried copper wire to earth while not destroying the copper.
Tailings are a superior idea to salt since salt will leach
away before the year is gone. But most don't bother. They
simply bury the wire.

Notice the concept. The most critical and essential feature
of any protection 'system' is defined by that single point
earth ground. The quality of that earth ground and how
connections are made to that central earth ground determines
system effectiveness. Single point grounding is the most
critical component in a protection system.

wrote:
That's a slick idea, we're sandy loam and clay around here. Next
time I sink a ground rod I'll remember the water.

--
Go 40 42 12

A benchmark in this technology is Polyphaser. These
application note applies to your questions:
http://www.polyphaser.com/ppc_PEN1002.asp
http://www.polyphaser.com/ppc_PEN1024.asp
http://www.polyphaser.com/ppc_PEN1026.asp
http://www.polyphaser.com/ppc_PEN1025.asp
http://www.polyphaser.com/ppc_PEN1003.asp

wrote:
That's a slick idea, we're sandy loam and clay around here. Next
time I sink a ground rod I'll remember the water.

In , w_tom wrote:

If in sandy loom, then a single ground rod may not be
sufficient. Neighborhood history will apply. Previous
lightning damage in the last ten years? If so, then the
single point ground may be expanded with more rods; spaced as
Frank suggests and to comply with NEC. Other alternatives
include looping the house with a buried bare copper wire. But
again, this is typically only required for high 'strike
frequency' locations - more a function of neighborhood
geology.


Sandy loam is better than average not just for grounding, but also for
ground-wave propogation and gardening. Regardless, it's the subsoil that really
matters. Unless you live in the desert, one good rod is enough to provide a
direction for the lightning to travel, which is the basic purpose. Any ground,
even one in poor soil, can be improved by running radials from the rod, which is
far better at dissipating a lightning strike than using multiple ground rods.
The only exception to this is, as I stated before, when the main ground rod is
located next to a basement. In that case, tie the ground rods together, but
maintain a central grounding point at the main ground rod ('star' grounding).
And avoid loops!


A problem with the water idea is a loose ground rod.


Again you are talking about things about which you know nothing. Most of the
dirt that is displaced by the rod doesn't make it to the surface, although you
do get wet while going down those first couple feet. The resulting mud settles
down into the gap and hardens like concrete. Once you turn off the water and let
it set for an hour or so, you couldn't pull the blasting thing out with a
backhoe. And there is only about a foot or two near the surface that needs to be
filled which is easily done by rinsing the muddy splatter back into the hole.


A
ground rod must be firm in ground when installed. A loose
ground rod is not earthed. Ground rod is further compromised
if using threaded joints.


If the threads were exposed it would probably -improve- the efficiency of the
ground by increasing the surface area. But since they aren't, the point is moot.


Ground rod should be monolithic
until well below frost line.


Pipes burst when water is trapped as it freezes. Both the top and bottom of the
pipe are open, therefore no bursting. And since the bottom is open, there should
be no standing water to freeze -- unless you put it there just to make your life
more complicated.


If antenna is not located near to service entrance and
single point ground, then antenna may require its own earth
ground. This in addition to the coax ground. IOW either the
antenna is part of your structure and earthed at the service
entrance ground; or antenna is earthed as if a lightning
rod.


Depends on the antenna.


If the antenna connection to earth ground is
significantly shorter than connection to service entrance,
then antenna must also have its own earth ground rod located
as directly under the antenna as possible. This so that
lightning takes a short path to earth; does not seek
alternative paths via other items such as chimney or interior
wire.


First off, if the line from the antenna to the grounding rod is shorter than the
line from the grounding rod to the shack, it might be time to do a little
research on alternative antenna systems. Second, and it seems you missed this
point the first three times, electricity (lightning included) will take ANY AND
ALL paths to ground that are available. It will easily jump from an antenna to a
chimney, interior wire, plumbing vent, phone line, or anything else it finds to
be a convenient path to earth AS WELL AS the antenna! Anytime the voltage in the
path = the spark-gap potential it WILL arc, and to whatever it arcs WILL become
a parallel current path. If you think that all the current will go to the
closest ground rod and ignore any electrically connected ground path further
away, or any other potential ground path connected or not, then you have
ABSOLUTELY NO CLUE what you are talking about regarding electricity.


If installing for commercial broadcaster reliability, then
the inductor from center core is additional protection. But
most industry professionals say the center conductor will leak
sufficiently to the outer shield making no center conductor
connection necessary.....


Well, I'm going to stop here because this is worse than beating a dead horse.
You clearly don't know what you are talking about, and you are very bad at
making stuff up to try and hide your ignorance. I don't know what your
motivation is to spew your BS but there is no excuse for it. Even if you are a
vampire and the public library is only open during daylight hours, or you are
permanently confined to your bubble, or too fat to get out your front door, you
can still have a friend get some educational materials for you. Or have you
****ed off all your friends by feeding them the same BS that you are trying to
pass off in here? Don't bother answering, because I really don't care and it
would probably be more BS anyway.

Just a word of advice: Most of the people in this newsgroup aren't as
technically gullible as you might think (at least not any more). If you want to
show people how intelligent you -really- are, quit with the BS and learn a
little more about the subject.







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In , w_tom wrote:

A benchmark in this technology is Polyphaser. These
application note applies to your questions:
http://www.polyphaser.com/ppc_PEN1002.asp
http://www.polyphaser.com/ppc_PEN1024.asp
http://www.polyphaser.com/ppc_PEN1026.asp
http://www.polyphaser.com/ppc_PEN1025.asp
http://www.polyphaser.com/ppc_PEN1003.asp


Lot's of theory but no practical value. The use of a star ground ("Single Point
Ground") system for lightning protection of the whole building + tower requires
the use of an isolated or 'floating' power supply; i.e, an isolated generator or
dedicated pole-pig. Marconi discovered this a century ago. And for the record,
all high-tech gizmos designed to compensate for the inductive reactance of power
and transmission lines during a lightning strike have failed miserably because
lightning has no fixed frequency. You can verify this with your local power
company or public library.








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From: (I=A0Am=A0Not=A0George)
(Twistedhed) wrote:
N3CVJ said if you're gonna break the law, (dxing is technically against
the law on cb) 'tis better to do it from a portable station than from
your home.

Where did he say that you lying sack of dog

poop?


Let's see....N3CVJ wrote:


Peaking a radio is NOT recommended. It's

more trouble than it's

worth. Go with the small 2 pill amp, and let IT

do the work.

Dave

"Sandbagger"



Whhoops...no, ,,that's not it,,,this is where he advocates using a
linear instead of tweaking an export radio.






That's an export radio, so he's already a

criminal. So go ahead and

modify the clarifier!

Dave

"sandbagger"


Shux,,,taht's not it either,,,just more hypocrisy...



I'll stick with my TS amp. It seems to continue

to run with the best

of them....

Dave

"Sandbagger"

N3CVJ


Aw man,,I know it is here somehwere,,,,
Let's try again...


it is much safer for a CBer to run power from

the mobile. That way you never interfere with

the same people for very long.

Dave

"Sandbagger"



There ya' go,,,,read the entire thread if your communication deficit and
mild retardation prevents you from reading what he not only inferred,
but actually said, wrote and posted.
_

LOL..he also said this,,,,

Only people that

have something to hide need

to fear this loss of anonimity. (SIC)


LOL...you wear it well.....lmao!

The likelihood of one individual being correct increases in a direct
proportion to the intensity with which others try to prove him wrong