Yuri, K3BU wrote:
"If anybody cares to discuss the subject, or explain how the conductor
laid on the ground can lose its conductivity, bring it on."

"Lose its conductivity" is likely a mischaracterization.

Conductivity of a wire at a particular temperature and frequency is a
function of the form, size, and material the wire is made of.

Proximity of the earth should not affect conductivity directly.

Loss from an R-F carrying conductor can come from energy coupled into
the surroundings. Obvious source is the R-F in the conductor. Closer the
conductor comes to the earth, the higher its capacitive coupling, and
the more current flows in the lossy earth, especially in the case of an
unbalanced conductor.

The fact that a conductor laid on the ground can lose R-F does not mean
it lost conductivity. It means the conductor has induced loss in the
ground upon which it is laid.

Best regards, Richard Harrison, KB5WZI

Original W8JI post:
"The only thing that prevents people from shooting themselves
in the foot with the wire below the Beverage is the wire
couples to the lossy media below it so well it becomes very
lossy, and of course that means it doesn't help with
stability or termination."


Yuri, K3BU wrote:
"If anybody cares to discuss the subject, or explain how the conductor
laid on the ground can lose its conductivity, bring it on."

"Lose its conductivity" is likely a mischaracterization.

"Becomes very lossy" or paraphrased "lose its conductivity" to make the point?

Conductivity of a wire at a particular temperature and frequency is a
function of the form, size, and material the wire is made of.


QSL.

Proximity of the earth should not affect conductivity directly.

QSL

Loss from an R-F carrying conductor can come from energy coupled into
the surroundings. Obvious source is the R-F in the conductor. Closer the
conductor comes to the earth, the higher its capacitive coupling, and
the more current flows in the lossy earth, especially in the case of an
unbalanced conductor.

I can see conductor (assuming insulated wire) having its electrical length
affected by the capacitance between wire and earth, but wouldn't current stay
close to same along the length? So, like if we have a coax, which has quite a
capacitive coupling between the center conductor and shield, we would lose
(significant) RF current at the other end?

The fact that a conductor laid on the ground can lose R-F does not mean
it lost conductivity. It means the conductor has induced loss in the
ground upon which it is laid.

(or improved conductivity?)
Isn't it really case of two (resistive) conductors in parallel? Wire and dirt,
with less resistance wire taking over? Why do we use radials if the conductors
become lossy? Why does the Beverage laid on the ground work?
I can see conductor as a (resonant) RF circuit becoming "detuned" and affected
by earth proximity, but saying that it "becomes very lossy" is not very
descriptive. With two wire Beverage I can see the interference between two
"antennas" having same physical length, but different electrical lengths
causing deterioration of pattern (which is observed).

Cecil help? :-)


Best regards, Richard Harrison, KB5WZI


Yuri, K3BU

On 27 Aug 2004 03:18:43 GMT, oUsama (Yuri Blanarovich)
wrote:

With two wire Beverage I can see the interference between two
"antennas" having same physical length, but different electrical lengths
causing deterioration of pattern (which is observed).

Hi Yuri,

As this is not demonstrated (significantly) through EZNEC in my
models, perhaps you can provide your model that does?

73's
Richard Clark, KB7QHC

Hi Yuri,

As this is not demonstrated (significantly) through EZNEC in my
models, perhaps you can provide your model that does?

73's
Richard Clark, KB7QHC


I do not have EZNEC model, but you can read up the thread at
http://lists.contesting.com/archives...-08/index.html
and look for 2 wire beverages tec.
Someone tested single wire Beverage and then laid "return" wire underneath on
the ground and noticed deterioration of F/B and higher angle lobes.

Yuri

On 27 Aug 2004 04:32:16 GMT, oUsama (Yuri Blanarovich)
wrote:

I do not have EZNEC model, but you can read up the thread at
http://lists.contesting.com/archives...-08/index.html
and look for 2 wire beverages tec.
Someone tested single wire Beverage and then laid "return" wire underneath on
the ground and noticed deterioration of F/B and higher angle lobes.

Hi Yuri,

This is like offering an encyclopedia and saying an article about some
famous guy is in there.

Never mind. The data speaks for itself - less than a dB difference.

73's
Richard Clark, KB7QHC

Hi Yuri,

This is like offering an encyclopedia and saying an article about some
famous guy is in there.

Never mind. The data speaks for itself - less than a dB difference.

73's
Richard Clark, KB7QHC

Not really, it is more like saying there is a word or discussion about 2 wire
beverages on page so and so (last few days). Discussion was quite sizable and
worth looking into for those who only play with "soft" antennas and see what
experiences were gained by those who played with real antennas. It was midnight
here and I was closing the shop for the day in anticipation of getting up
early. I had no time to go and do the digest or get into arguments of what IS
is.
Your data speaks of less than one dB, reality is bit different.
But I know, its me (problem), not the software.
Maybe a little less sarcasm would go longer way?

73 Yuri

Yuri wrote:
"Not really. It is more like saying there is a word or discussion about
2 wire beverages on page so and so (last few days)."

Speaking of pages, there is a nice picture of Yuri Blanarovich, VE3BMV
(formerly OK5BU) on page 81 of the March 1973 edition of CQ magazine.

Many of us may have made a nice picture in 1973.

Best regards, Richard Harrison, KB5WZI

Yuri, K3BU wrote:
"I can see conductor (assuming insulated wire) having its electrical
length affected by the capacitance between wire and earth, but wouldn`t
current stay close to same along the length?"

Depends on distance from the source. Current fades fast close to the
source, but at a great distance, the decline is very slow.

Traveling waves don`t require a complete electrical circuit for
propagation. They travel well in a complete void. So, the volts and amps
far from the wave source don`t need to equal those at the source.

V=frequency times wavelength always prevails. So, capacitance between
wire and earth for a given frequency changes the wavelength because the
velocity of the wave is changed (slowed) by proximity of the earth.

As a traveling wave is free to be attenuated in travel, current must
decline enroute. Brown, Lewis, & Epstein, the 20th Century RCA geniuses,
declared that the place to end extending ground radials is where their
current becomes insignificant.

Yuri also wrote:
"Why do we use radials if the conductors become lossy?"
Yuri also had answered the question before asking. Didn`t Johnny Carson
patent that routine, holding the question envelope to his head while he
gave the answer?
Yuti`s answer: "Wire and dirt, with less resistance wire taking over."

Yuri also wrote:
"Why does the Beverage laid on the ground work?"

Kraus says a wave traveling along a perfect conductor produces an
electric field perpendicular to the conducting surface, but along the
earth the electric field has a forward tilt. The horizontal component of
the vertical wave produced by the tilt is associated with that part of
the wave that enters the surface and is dissipated as heat. The vertical
component of the wave continues to travel along the surface. The emfs
induced along the antenna by the horizontal component made of the tilt,
all add up in the same phase at the receiver. Maximum response is in the
direction of the horizontal wire.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Yuri, K3BU wrote:
"I can see conductor (assuming insulated wire) having its electrical
length affected by the capacitance between wire and earth, but wouldn`t
current stay close to same along the length?"

Depends on distance from the source. Current fades fast close to the
source, but at a great distance, the decline is very slow.

Maybe one could coil the wire into a big helical coil where the
current-in is equal to the current-out. :-)
--
73, Cecil http://www.qsl.net/w5dxp



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Yuri Blanarovich wrote:
"Becomes very lossy" or paraphrased "lose its conductivity" to make the point?

I agree that a wire laid on the ground does not become very lossy
although energy is lost to the lossy medium in proximity to the wire.
What is happening is decreasing ExH power caused by field attenuation
in the ground. In free space, the E-field causes an equal energy H-field
which causes an equal energy E-field, ad infinitum. In the presence of a
lossy medium, like earth, the fields undergo an attenuation factor so
that each field strength is less than the previous cycle. The decrease
of the voltage and the current on/in the wire on the ground is *caused*
by the attenuation of the surrounding fields and would occur even if
the wire were a super-conductor. The wire itself does not "become very
lossy". The ground around the wire becomes very lossy.

Consider the power transferred through a transformer. The primary
has highly conductive insulated wire but "loses" virtually all of
its power, not through conduction, but through induction, to the
secondary. The losses through an insulated wire laid on the ground
are through induction, not conduction.
--
73, Cecil http://www.qsl.net/w5dxp



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