Grounding for Gable end bracket & mast.
 

Szczepan Bialek wrote:

"K1TTT" wrote
...
On Aug 13, 8:42 am, "Szczepan Bialek" wrote:

Your antenna is a high voltage AC system.
The loss is a loss of electrons.
Try to measure it.

there is no net charge build up on an antenna due to rf.

So we are at the beginning.
Try then to work without ground.
S*

Antennas work just fine without ground.

Have you ever heard of airplanes, radiosondes and spacecraft?



--
Jim Pennino

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Grounding for Gable end bracket & mast.
 

Szczepan Bialek wrote:

"K1TTT" wrote
...
On Aug 13, 5:19 pm, "Szczepan Bialek" wrote:

So we are at the beginning.
Try then to work without ground.

antennas work just fine without a ground. how do they work in
airplanes? how about spacecraft? yes, i know, you like plasmas that
provide the free electrons... but you are wrong. take a transmitter,
encase it in rubber, put it in a vacuum chamber and pump out all the
air, and you will still receive it.

See at the fig. 1: http://amasci.com/tesla/tmistk.html
Can it work without Gnd?

You can use a chassis.
Transmitter is only a oscillating pump. Such must has a tank.
S*

Gibberish and nonsense based on ancient crap.

Connect an RF source through a transformer with the secondary connected to
a dipole and hang it from a balloon; works fine and no ground or chassis.


--
Jim Pennino

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Grounding for Gable end bracket & mast.
 

On Aug 13, 5:55*pm, "Szczepan Bialek" wrote:
*"K1TTT" ...
On Aug 13, 5:19 pm, "Szczepan Bialek" wrote:



So we are at the beginning.
Try then to work without ground.
antennas work just fine without a ground. *how do they work in

airplanes? *how about spacecraft? *yes, i know, you like plasmas that
provide the free electrons... but you are wrong. *take a transmitter,
encase it in rubber, put it in a vacuum chamber and pump out all the
air, and you will still receive it.

See at the fig. 1:http://amasci.com/tesla/tmistk.html
Can it work without Gnd?

You can use a chassis.
Transmitter is only a oscillating pump. Such must has a tank.
S*

the best quote from that web page: "electromagnetism is
electromagnetism", nuff said.

Grounding for Gable end bracket & mast.
 

wrote ...
Szczepan Bialek wrote:

Transmitter is only a oscillating pump. Such must has a tank.

Gibberish and nonsense based on ancient crap.

Connect an RF source through a transformer with the secondary connected to
a dipole and hang it from a balloon; works fine and no ground or chassis.

Start thinking. The dipole is a very long wire. The electrons are emitted
from the ends only. The rest of the wire is the chassis.
The very short dipole (0.05 wavelengh) should not work fine without ground.

All antennas are the same:

"In conventional ICP (or TCP) reactors, a rf power is inductively coupled to
an antenna placed outside a plasma vessel. Such an external coupling system
is known to have several disadvantages. In order to avoid these
disadvantages, a new internal coupling system has been developed in which a
bare metal antenna is directly immersed in a plasma, thus forming a full
metal reactor. This is accomplished by generating magnetic field lines
around an antenna conductor, which effectively suppress the electron loss at
the antenna and hence suppress the anomalous rise of plasma potential.
Magnetic fields near the antenna are formed by superposing a dc current on a
rf current along the antenna. This type of ICP enables rf discharges at
rather low pressures such as ?3×10-4 Torr due to the magnetron effect. Other
characteristics of internal metal antennas are also discussed".

"the electron loss" and "the anomalous rise of plasma potential." apply to
all antennas.
S*

Grounding for Gable end bracket & mast.
 

On Aug 14, 8:03*am, "Szczepan Bia³ek" wrote:
....

Szczepan Bialek wrote:

Transmitter is only a oscillating pump. Such must has a tank.

Gibberish and nonsense based on ancient crap.

Connect an RF source through a transformer with the secondary connected to
a dipole and hang it from a balloon; works fine and no ground or chassis.

Start thinking. The dipole is a very long wire. The electrons are emitted
from the ends only. The rest of the wire is the chassis.
The very short dipole *(0.05 wavelengh) should not work fine without ground.

All antennas are the same:

"In conventional ICP (or TCP) reactors, a rf power is inductively coupled to
an antenna placed outside a plasma vessel. Such an external coupling system
is known to have several disadvantages. In order to avoid these
disadvantages, a new internal coupling system has been developed in which a
bare metal antenna is directly immersed in a plasma, thus forming a full
metal reactor. This is accomplished by generating magnetic field lines
around an antenna conductor, which effectively suppress the electron loss at
the antenna and hence suppress the anomalous rise of plasma potential.
Magnetic fields near the antenna are formed by superposing a dc current on a
rf current along the antenna. This type of ICP enables rf discharges at
rather low pressures such as ?3×10-4 Torr due to the magnetron effect. Other
characteristics of internal metal antennas are also discussed".

"the electron loss" and "the anomalous rise of plasma potential." apply to
all antennas.
S*

no they don't. that discusses a rather unique situation of an antenna
in a very low pressure plasma. another case where google supplied
irrelevant information because of your ignorance of the actual physics
involved.

Grounding for Gable end bracket & mast.
 

"Szczepan Bia?ek" wrote:

wrote ...
Szczepan Bialek wrote:

Transmitter is only a oscillating pump. Such must has a tank.

Gibberish and nonsense based on ancient crap.

Connect an RF source through a transformer with the secondary connected to
a dipole and hang it from a balloon; works fine and no ground or chassis.

Start thinking. The dipole is a very long wire. The electrons are emitted
from the ends only. The rest of the wire is the chassis.
The very short dipole (0.05 wavelengh) should not work fine without ground.

Babbling nonsense contradicted by about a hundred years of empirical
observation.


--
Jim Pennino

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Grounding for Gable end bracket & mast.
 

The NEC only requires 5.261 (mm)2 for the protective down conductor
and 13.30 (mm)2 for the bonding conductor between electrodes. Since
those sizes are at best a bad joke I was hoping to elicit best
practice advise on what size the conductors should actually be as well
as advise on how to accomplish the bonding of the interior single
point grounding buss bar to the exterior grounding conductors and
Grounding Electrode System.
--

In what way is #6 a "bad joke?"

Do you expect it to vaporize and set your roof on fire?

Grounding for Gable end bracket & mast.
 

"John Gilmer" wrote in
net:

Do you expect it to vaporize and set your roof on fire?

Well, engineering of lightning protection is about design of a protection
system that will, amongst other things, survive most events so as to
continue to provide protection, and to minimise incidental damage.

So, yes, down conductors adequately sized to manage the risk of the
conductor "vapourising" is part of the scope, and physical design to
minimise the risk of side flash causing damage is also part of the scope.

It is interesting, no confusing, that you have two guides that give such
different guidance. In Australia, we too have a standard for house wiring,
and another standard for lightning protection, but they are not in conflict
and our standard for lightning protection is well aligned with NFPA 780 on
the downconductor size issue.

Owen

Grounding for Gable end bracket & mast.
 

Owen Duffy wrote:
"John Gilmer" wrote in
net:

Do you expect it to vaporize and set your roof on fire?

Well, engineering of lightning protection is about design of a protection
system that will, amongst other things, survive most events so as to
continue to provide protection, and to minimise incidental damage.

So, yes, down conductors adequately sized to manage the risk of the
conductor "vapourising" is part of the scope, and physical design to
minimise the risk of side flash causing damage is also part of the scope.

It is interesting, no confusing, that you have two guides that give such
different guidance. In Australia, we too have a standard for house wiring,
and another standard for lightning protection, but they are not in conflict
and our standard for lightning protection is well aligned with NFPA 780 on
the downconductor size issue.

Owen




The thing is, AWG 6 wire won't vaporize or even melt or even get warm to
the touch. There's not enough "action" (I^2 T) in a lightning stroke to
do it. Remember that the current is high, but only lasts a matter of a
50-100 microseconds.

Say you are using AWG 10 wire which has a resistance of 1 milliohm per
foot. a 50 kA strike will dissipate 50E3^2*1E-3 = 2.5 MegaWatts.. which
is big.. but for 50 microseconds, that's only 150 joules. That same
foot of wire weighs about 1/2 an ounce (I'm sorry for the customary
units, but they are what I remember off the top of my head AWG 10 is
1/10th inch in diameter, 1 ohm/kft, and 32 ft/lb).. or about 14 grams.

Specific heat of copper is 0.38, so we have deltaT = 150/14 * 0.38
let's call it about 4 degrees C.

I should note that this is a bit optimistic.. the AC resistance for a 50
microsecond pulse will be higher than for DC because of skin effect
(skin depth at 1 MHz is 65 microns, 2.5E-3 inches, and it goes as the
square root, so even at 100kHz, it's still not much more).. so the
dissipation will be higher.

But, you've got a long ways from 30C to 1000C (melting point of copper)
and even farther to "vaporization"...

(as a practical matter, you need kiloJoules to explode a 1 meter AWG 30
copper wire.. hundreds of joules just "melts" it. )

(note also that while the peak current might be 50kA or 100kA, the
average current is substantially less..)

Mechanical stresses from magnetic fields are a bigger concern, as well
as "sideflash".