Art wrote:
"I have determined that coupling of elements which means parasitic
elements is wasteful."

A parasitic element is normally constructed of low-loss material and
re-radiates all the energy it absorbs from the radio wave. If it is
placed and phased right it can reinforce radiation in the desired
direction.

Kraus in the 3rd edition of "Antennas" has his close-spaced all-driven
W8JK array and a wide-spaced all-driven 2-dipole array in the same
figure, Fig. 6-12, on page 184. The gain of either antenna is about 6
dB, supposedly with respect to an isotropic, or about 4 dB with respect
to a dipole. Both arrays are bidirectional.

Arnold Bailey catalogs a version of the W8JK close-spaced all-driven
array on page 511 of "TV and Other Receiving Antennas". On page 516 is a
1/2-wave radiator with a 1/2-wave parasitic reflector 1/4-wave behind it
(a simple Yagi).

Bailey gives the W8JK a resistance of 7 ohms and a gain of 4 dBd (6
dBi).

Bailey gives the parasitic array a resistance of 28 ohms and a gain of 5
dBd 7dBi). The parasitic array is slightly unidirectional while the
pattern of the W8JK is symmetrical.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

...
A parasitic element is normally constructed of low-loss material and
re-radiates all the energy it absorbs from the radio wave.
...

Although this is nit-picking, the above is impossible, some percentage
of rf MUST be lost as heat (poor joints in elements/booms can GREATLY
enhance loss also) ...

The rest of your text seems to be generally accepted ...

Regards,
JS

On 26 Apr, 09:37, (Richard Harrison) wrote:
Art wrote:

"I have determined that coupling of elements which means parasitic
elements is wasteful."

A parasitic element is normally constructed of low-loss material and
re-radiates all the energy it absorbs from the radio wave. If it is
placed and phased right it can reinforce radiation in the desired
direction.

Kraus in the 3rd edition of "Antennas" has his close-spaced all-driven
W8JK array and a wide-spaced all-driven 2-dipole array in the same
figure, Fig. 6-12, on page 184. The gain of either antenna is about 6
dB, supposedly with respect to an isotropic, or about 4 dB with respect
to a dipole. Both arrays are bidirectional.

Arnold Bailey catalogs a version of the W8JK close-spaced all-driven
array on page 511 of "TV and Other Receiving Antennas". On page 516 is a
1/2-wave radiator with a 1/2-wave parasitic reflector 1/4-wave behind it
(a simple Yagi).

Bailey gives the W8JK a resistance of 7 ohms and a gain of 4 dBd (6
dBi).

Bailey gives the parasitic array a resistance of 28 ohms and a gain of 5
dBd 7dBi). The parasitic array is slightly unidirectional while the
pattern of the W8JK is symmetrical.

Best regards, Richard Harrison, KB5WZI

I did a quick scan of your response and only see book references so I
suppose that is the end of that since I also have books of my own.
Art

Richard Harrison wrote:


Bailey gives the W8JK a resistance of 7 ohms and a gain of 4 dBd (6
dBi).


I've always wondered how he managed to have "NO SIGNAL RESPONSE IN THIS
PLANE" for yz though. He must have built and balanced things really
well.

tom
K0TAR

Tom Ring, K0TAR wrote: "I`ve always wondered how he managed to have "NO
SIGNAL RESPONSE IN THIS PLANE" for yz though. "

I guessed that Arnold Bailey just assumed perfection in some instances
for practical purposes. My own experience has been that differences of
less than one dB were not to be confided in. Reg Edwards used to speak
of "delusions of accuracy", and I think he grasped a lot of wisdom
there.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

I guessed that Arnold Bailey just assumed perfection in some instances
for practical purposes. My own experience has been that differences of
less than one dB were not to be confided in. Reg Edwards used to speak
of "delusions of accuracy", and I think he grasped a lot of wisdom
there.

Best regards, Richard Harrison, KB5WZI


I was being a bit facetious, Richard. I couldn't resist after looking
at the page, and knowing that there really could not have been "no
response".

tom
K0TAR

On 5 Mar, 14:14, "Wayne" wrote:
Wayne wrote:
When the subject of antenna efficiency comes up, it often involves a
discussion of ground losses on verticals. What about, for example, a
dipole? Could one calculate "power out/power in" by measuring the VSWR
and declaring that everything not reflected was transmitted? It would
seem more accurate to actually measure power out and power in, but that
introduces inaccuracies by having to calibrate the setup. Thoughts?
"Roy Lewallen" wrote in message

...

There's no direct way to measure the total power being radiated other than
sampling the field at many points in all directions and integrating.
"Reflected" power is not power that isn't transmitted. You can find the
power being applied to the antenna by subtracting the "reverse" or
"reflected" power from the "forward" power, but that tells you nothing
about what fraction is radiated and what fraction lost as heat.

Roy Lewallen, W7EL

Thanks for the reply. My dipole example is intended to avoid transmission
line issues by not having one, and the elements are assumed to be reasonably
low loss. If I do some quick back-of-the-envelope calculations, for a VSWR
of 1.3:1, I get an efficiency of about 98.3% (using the equation
1-gamma^2). Assuming a resistance of 1 ohm in the dipole conductors the
efficiency I calculate is about 98.6% (72/73).

Are there any other loss issues missing in this example.

I would say you are close enough to say you are correct. Because you
chose a dipole which is in a state of equilibrium and thus particles
projected from the dipole cannot collide with other particles from
other parasitic radiators. Aren't you not basically refering to the
foundations of Poyntings vector which like Gauss is refering to an
item in equilibrium when subjected to a time variable of zero value ?
If the item is not in a state of equilibrium collision
of particles may well occur without a radiation field reaction thus
one cannot calculate the resultant field since energy transfer due to
particle collision prevents the return of particles to the mother
radiator.

"art" wrote:

I would say you are close enough to say you are correct. Because you
chose a dipole which is in a state of equilibrium and thus particles
projected from the dipole cannot collide with other particles from
other parasitic radiators. Aren't you not basically refering to the
foundations of Poyntings vector which like Gauss is refering to an
item in equilibrium when subjected to a time variable of zero value ?
If the item is not in a state of equilibrium collision
of particles may well occur without a radiation field reaction thus
one cannot calculate the resultant field since energy transfer due to
particle collision prevents the return of particles to the mother
radiator.

I've been reading Art's posts for some time now, mostly for the
entertainment value. Some of the recent posts were starting to make
sense, and this was causing me some concern: that my bafflegab
filter in the computor (sic) had gone out. Well, the above quote was
a wakeup call... I don't have a clue what he's saying. Can someone
translate, please.

Mike W5CHR

"Mike Lucas" wrote in message
...

"art" wrote:

I would say you are close enough to say you are correct. Because you
chose a dipole which is in a state of equilibrium and thus particles
projected from the dipole cannot collide with other particles from
other parasitic radiators. Aren't you not basically refering to the
foundations of Poyntings vector which like Gauss is refering to an
item in equilibrium when subjected to a time variable of zero value ?
If the item is not in a state of equilibrium collision
of particles may well occur without a radiation field reaction thus
one cannot calculate the resultant field since energy transfer due to
particle collision prevents the return of particles to the mother
radiator.

I've been reading Art's posts for some time now, mostly for the
entertainment value. Some of the recent posts were starting to make
sense, and this was causing me some concern: that my bafflegab
filter in the computor (sic) had gone out. Well, the above quote was
a wakeup call... I don't have a clue what he's saying. Can someone
translate, please.

Mike W5CHR


Maybe if you put this in a word blender and spun long enough, maybe you
could get one sentence that would make some sense. :-)
I gave up way back when I could not understand what is the POLARITY in
antennas, which end up? So I guess humanity has to evolve for few more
centuries to catch up with "antenna wizard" and understand and appreciate
his piosneering work.
Judging by some other posts on other more earthly subjects, looks like there
are some missing gears in the gear box. What you expect from inventor that
has a patent on reflector beeing director and vice-voica. Looks like that
one will not ever be copyright violated. So take it with grain of salt and
enjoy the mumbo-jumbo-entoitenmeint. :-)

73 bada BUm

On 29 Apr, 04:48, "Mike Lucas" wrote:
"art" wrote:

I would say you are close enough to say you are correct. Because you
chose a dipole which is in a state of equilibrium and thus particles
projected from the dipole cannot collide with other particles from
other parasitic radiators. Aren't you not basically refering to the
foundations of Poyntings vector which like Gauss is refering to an
item in equilibrium when subjected to a time variable of zero value ?
If the item is not in a state of equilibrium collision
of particles may well occur without a radiation field reaction thus
one cannot calculate the resultant field since energy transfer due to
particle collision prevents the return of particles to the mother
radiator.

I've been reading Art's posts for some time now, mostly for the
entertainment value. Some of the recent posts were starting to make
sense, and this was causing me some concern: that my bafflegab
filter in the computor (sic) had gone out. Well, the above quote was
a wakeup call... I don't have a clue what he's saying. Can someone
translate, please.

Mike W5CHR

Mike, you must first understand that that two unlike particles in
combination from the same radiator creates radiation. Lock that into
your mind. Other collisions or combinations do not creat radiation so
their energy has to be ascertained so they do not finish up on the
radiation side of the equation. If the radiating article is in
equilibrium there is no other radiator in competition in the same
space to create radiation thus the single radiator is free to emit
particles in isolation where errent collisions or combinations can not
occur. You must also note that all particles emitted from a single
radiator do not all finish up on the radiation side of the equation
since some return to the mother element with the same kinetic impact
that was imparted on them in the first place and thus these must be
accounted for in any equation. If one is to ascertain the final
arrangement of any energy transfer from a black box it is desirable
not to introduce energy exchange phenomina by introducing rival or
cumulative exchanges which cannot be accounted for. All equations that
do not allow for the unit of time are purely mathematical exercises of
theory thus one must be absolutely sure that the numbers add up on
both sides of the equation to justify the addition of that very
important symbol called equal. That is why the subject of ther terms
of "time" and "equilibrium" is important to transform an equation from
a fantasy form to one of reality in both Poyntings vector and the
Gaussian equation.
Art