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Old March 28th 07, 01:52 AM posted to rec.radio.amateur.antenna
art art is offline
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On 27 Mar, 15:12, (Richard Harrison) wrote:
Art wrote:

"I have his (Kraus`) second edition (Antennas) and I find no mention of
radiation from the beginning where current is applied onward."

I think I have that edition too. If you review the chapter on "Point
Sources" you`ll find: power patterns, a power theorem and its
application to isotropic sources, rediation intensity, source with
hemispheric power pattern, unidirectional cosine power pattern, etc.,
etc..

snip.

Being uncertain of what Art really wants, doesn`t stop me from advising

snip

Bingo
Just as I thought, you are bull****ting like the rest of them. All you
have is the answer for the question you want me to ask so you can then
look good.
When you give that same answer to any question that I actually ask it
sure removes any possible credability.
If you all had been nice to the MIT guy he may have come back and give
you a tutorial again to set you straight, but I suspect he left for
the same reasons that other experts left. I accept that none on the
thread has a clue
so it is reasonable to close down this thread to allow you to get back
to badger Walt. I believe that each poster has provided an average of
ten posts
on Walt's article which suggest that Walt is having a bad time with
communicating his message like me. My bet is that half of the posts
aren't even relavent to the subject at hand! That's tough for
anybody.Richard you have posted four times with lots of words on this
thread but at the very end you admit that you have no idea what the
thread was all about. So what were your answers meant to apply to so I
can oblige you with supplying the question that you want... to the
answer you have already so you can spout off.
No ........forget it.
............FINI..........
Art



Best regards, Richard Harrison, KB5WZI



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Old March 28th 07, 02:16 AM posted to rec.radio.amateur.antenna
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I readily admit I have not discovered whhat Art asked for. My first
guess was: Why are most antennas either horizontal or vertical. I tried
to give a thoughtful and honest answer. Sorry it didn`t satisfy.

Best regards, Richard Harrison, KB5WZI

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Old March 28th 07, 03:25 AM posted to rec.radio.amateur.antenna
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"Richard Harrison" wrote in message
...
I readily admit I have not discovered whhat Art asked for. My first
guess was: Why are most antennas either horizontal or vertical. I tried
to give a thoughtful and honest answer. Sorry it didn`t satisfy.

Best regards, Richard Harrison, KB5WZI


I looked up the references, seems good to me.

Jimmie.


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Old March 31st 07, 10:36 PM posted to rec.radio.amateur.antenna
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On 27 Mar 2007 16:39:52 -0700, "art" wrote:

On 27 Mar, 15:12, (Richard Harrison) wrote:
Art wrote:

"I have his (Kraus`) second edition (Antennas) and I find no mention of
radiation from the beginning where current is applied onward."

I think I have that edition too. If you review the chapter on "Point
Sources" you`ll find: power patterns, a power theorem and its
application to isotropic sources, rediation intensity, source with
hemispheric power pattern, unidirectional cosine power pattern, etc.,
etc..

The new, now available 3rd ed. of "Antennas" by Kraus, Marhefka, and a
host of others is greatly expanded and improved. It is worth the
investment.

Being uncertain of what Art really wants, doesn`t stop me from advising
him to start by having a look at the famous Sommerfeld formula on page
804 of Terman`s 1955 opus.
It predicts 1 kilowatt will produce 186 mv per m at a distance of 1 mile
from a short vertical transmitting antenna given a certain ground
conductivity and other conditions.

Best regards, Richard Harrison, KB5WZI


Richard, I have lots of books but as yet have not found the answer
even tho many have posted none appear to really have an answer other
than to throw stones. You apparently have found the answer! Could you
quote from the books that you are refering to the angle of radiation
relative to the radiator, thats it ? If you can't understand that then
relay to me the angle of a radiation front relative to a radiator, I'm
sure some other people are interested in what you found. Even better,
let me know the TOA of a dipole in free space and how much it varies
to that of the same dipole over a perfect ground. Use a computor
program if you like, anything that sheds light on the matter . The
books say that a horizontal "v" antenna should be tipped for max gain,
doesn't that raise your interest about the reasoning and mathematics
behind this? Jimmie D asked me to state this angle but I have only a
expensive computor program that doesn't give the math with the answer.
Please read off the angle and the specifics so we all can move on, I
don't want a 160 thread postings some thrust upon Walt
Art


The take-off angle of a dipole in free space? The angle with respect to what?

Walt, W2DU


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Old April 1st 07, 12:42 AM posted to rec.radio.amateur.antenna
art art is offline
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On 31 Mar, 14:36, Walter Maxwell wrote:
On 27 Mar 2007 16:39:52 -0700, "art" wrote:





On 27 Mar, 15:12, (Richard Harrison) wrote:
Art wrote:


"I have his (Kraus`) second edition (Antennas) and I find no mention of
radiation from the beginning where current is applied onward."


I think I have that edition too. If you review the chapter on "Point
Sources" you`ll find: power patterns, a power theorem and its
application to isotropic sources, rediation intensity, source with
hemispheric power pattern, unidirectional cosine power pattern, etc.,
etc..


The new, now available 3rd ed. of "Antennas" by Kraus, Marhefka, and a
host of others is greatly expanded and improved. It is worth the
investment.


Being uncertain of what Art really wants, doesn`t stop me from advising
him to start by having a look at the famous Sommerfeld formula on page
804 of Terman`s 1955 opus.
It predicts 1 kilowatt will produce 186 mv per m at a distance of 1 mile
from a short vertical transmitting antenna given a certain ground
conductivity and other conditions.


Best regards, Richard Harrison, KB5WZI


Richard, I have lots of books but as yet have not found the answer
even tho many have posted none appear to really have an answer other
than to throw stones. You apparently have found the answer! Could you
quote from the books that you are refering to the angle of radiation
relative to the radiator, thats it ? If you can't understand that then
relay to me the angle of a radiation front relative to a radiator, I'm
sure some other people are interested in what you found. Even better,
let me know the TOA of a dipole in free space and how much it varies
to that of the same dipole over a perfect ground. Use a computor
program if you like, anything that sheds light on the matter . The
books say that a horizontal "v" antenna should be tipped for max gain,
doesn't that raise your interest about the reasoning and mathematics
behind this? Jimmie D asked me to state this angle but I have only a
expensive computor program that doesn't give the math with the answer.
Please read off the angle and the specifics so we all can move on, I
don't want a 160 thread postings some thrust upon Walt
Art


The take-off angle of a dipole in free space? The angle with respect to what?

Walt, W2DU- Hide quoted text -

- Show quoted text -


Always zero Walt since it takes two dipoles to tango.

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Old April 1st 07, 05:33 PM posted to rec.radio.amateur.antenna
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Art wrote:
"Even better, let me know the TOA of a dipole in free space and how much
it varies to that of the same dipole over perfect ground."

If possible, look at Terman`s1955 opus page 882:
"Effect of Ground on the Directional Pattern of Ungrounded Antennas -
Image Antennas."

In free space, no reflecting surface is nearby to distort the pattern of
a radiator.

Terman gives the familiar radiation of a 1/2-wave dipole in space in
Fig. 23-4(a) on page 867.

Terman says on page 883:
"For purposes of calculation, it is convenient to consider that the
reflected wave is generated, not by reflection, but rather by an "image"
antenna located below the surface of the ground."

The summation of the direct and reflected waves from a horoizontal wire
above the earth often has serious consequences as Terman notes on page
885:
"Consequently, to obtain strong radiation in directions approaching the
horizontal using a horizontally polarized radiating system, it is
necessary that the height of the antenna above the earth be in the order
of one wavelength or more."

Terman shows the vertical radiation patterns for a horizontal wire at
various heights above the earth in Fig. 23-21 on page 884. Note that
half-wave elevation concentrates most energy into a good elevation angle
for sky wave reflection at some frequencies and distances.

Best regards, Richard Harrison, KB5WZI

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Old April 1st 07, 05:34 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jul 2006
Posts: 588
Default Why?

Art wrote:
"Even better, let me know the TOA of a dipole in free space and how much
it varies to that of the same dipole over perfect ground."

If possible, look at Terman`s1955 opus page 882:
"Effect of Ground on the Directional Pattern of Ungrounded Antennas -
Image Antennas."

In free space, no reflecting surface is nearby to distort the pattern of
a radiator.

Terman gives the familiar radiation of a 1/2-wave dipole in space in
Fig. 23-4(a) on page 867.

Terman says on page 883:
"For purposes of calculation, it is convenient to consider that the
reflected wave is generated, not by reflection, but rather by an "image"
antenna located below the surface of the ground."

The summation of the direct and reflected waves from a horoizontal wire
above the earth often has serious consequences as Terman notes on page
885:
"Consequently, to obtain strong radiation in directions approaching the
horizontal using a horizontally polarized radiating system, it is
necessary that the height of the antenna above the earth be in the order
of one wavelength or more."

Terman shows the vertical radiation patterns for a horizontal wire at
various heights above the earth in Fig. 23-21 on page 884. Note that
half-wave elevation concentrates most energy into a good elevation angle
for sky wave reflection at some frequencies and distances.

Best regards, Richard Harrison, KB5WZI

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Old April 1st 07, 10:01 PM posted to rec.radio.amateur.antenna
art art is offline
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Posts: 1,188
Default Why?

On 1 Apr, 09:34, (Richard Harrison) wrote:
Art wrote:

"Even better, let me know the TOA of a dipole in free space and how much
it varies to that of the same dipole over perfect ground."

If possible, look at Terman`s1955 opus page 882:
"Effect of Ground on the Directional Pattern of Ungrounded Antennas -
Image Antennas."

In free space, no reflecting surface is nearby to distort the pattern of
a radiator.

Terman gives the familiar radiation of a 1/2-wave dipole in space in
Fig. 23-4(a) on page 867.

Terman says on page 883:
"For purposes of calculation, it is convenient to consider that the
reflected wave is generated, not by reflection, but rather by an "image"
antenna located below the surface of the ground."

The summation of the direct and reflected waves from a horoizontal wire
above the earth often has serious consequences as Terman notes on page
885:
"Consequently, to obtain strong radiation in directions approaching the
horizontal using a horizontally polarized radiating system, it is
necessary that the height of the antenna above the earth be in the order
of one wavelength or more."

Terman shows the vertical radiation patterns for a horizontal wire at
various heights above the earth in Fig. 23-21 on page 884. Note that
half-wave elevation concentrates most energy into a good elevation angle
for sky wave reflection at some frequencies and distances.

Best regards, Richard Harrison, KB5WZI


Very good, all accepted, I am now in a position to ask the real
question of "why" where the starting point is acceptable to all.
..
I model a dipole in free space to obtain its impedance, this dipole
was resonant at right angles to the ground and resting on the ground.
I also modelled another dipole over the ground and tipped it over
about 5% of its WL but letting the length grow until the dipole was
resonant over ground ( ground means perfect ground as per Mininec) I
then placed this tipped dipole in free space and noted its impedance.
In all cases the impedance in free space was the same though not
resonant! In all cases over ground the dipoles were resonant. Why were
both dipoles over ground resonant? Why did the program model the
dipole at a tipped angle for resonance when given total freedom
instead of modeling a dipole at right angles to ground?
Regards
Art


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Old April 1st 07, 10:37 PM posted to rec.radio.amateur.antenna
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"art" wrote in message
oups.com...
On 27 Mar, 15:12, (Richard Harrison) wrote:
Art wrote:

"I have his (Kraus`) second edition (Antennas) and I find no mention of
radiation from the beginning where current is applied onward."

I think I have that edition too. If you review the chapter on "Point
Sources" you`ll find: power patterns, a power theorem and its
application to isotropic sources, rediation intensity, source with
hemispheric power pattern, unidirectional cosine power pattern, etc.,
etc..

The new, now available 3rd ed. of "Antennas" by Kraus, Marhefka, and a
host of others is greatly expanded and improved. It is worth the
investment.

Being uncertain of what Art really wants, doesn`t stop me from advising
him to start by having a look at the famous Sommerfeld formula on page
804 of Terman`s 1955 opus.
It predicts 1 kilowatt will produce 186 mv per m at a distance of 1 mile
from a short vertical transmitting antenna given a certain ground
conductivity and other conditions.

Best regards, Richard Harrison, KB5WZI


Richard, I have lots of books but as yet have not found the answer
even tho many have posted none appear to really have an answer other
than to throw stones. You apparently have found the answer! Could you
quote from the books that you are refering to the angle of radiation
relative to the radiator, thats it ? If you can't understand that then
relay to me the angle of a radiation front relative to a radiator, I'm
sure some other people are interested in what you found. Even better,
let me know the TOA of a dipole in free space and how much it varies
to that of the same dipole over a perfect ground. Use a computor
program if you like, anything that sheds light on the matter . The
books say that a horizontal "v" antenna should be tipped for max gain,
doesn't that raise your interest about the reasoning and mathematics
behind this? Jimmie D asked me to state this angle but I have only a
expensive computor program that doesn't give the math with the answer.
Please read off the angle and the specifics so we all can move on, I
don't want a 160 thread postings some thrust upon Walt
Art


The V antenna is a terminated traveling wave antenna the dipoles that you
have been refering to are standingwave antennas. You are comparing apples
and oranges. The best I can tell is that all other references you made to
tilt have been perpedicular to the direction of the wave front. The V
antenna is tilted in the direction of the wave front, more apples and
oranges. Throw in some grapes and pineapple and we will have fruit salad.

Jimmie


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