Mark Keith wrote in message
om...
"Chuck" wrote in message

A reduced-noise (E-field loaded) vertical
for 40m with a VSWR bandwidth of 1.3:1
from 7.0 to 7.3 mHz, (it's not a dummy
load as one would generally deduce from
the above description), and has proven to
be as good a performer on DX and local
as my conventional top loaded vertical.

What is E-field loaded? Not sure what you mean with that...

The conventional vertical sees a noise
level here of around S-7 or greater, and
the E-field loaded vertical, around S-3 to
S-5 (on IC-756, normal BW, no NB, no
DSP).

I'd be very leary...Also would depend on the polarization of the
noise, and any possible changes in the pattern...But in general, if a
certain vertical picks up more far field noise than another, it's the
superior vertical. Noise is rf like any other signal. So unless I'm
missing something here, the conventional antenna should also receive
the *desired* signal better than the low noise version. And being
things are generally reciprical, it should probably transmit a better
signal also...How careful have your on the air tests been? Are you
quickly A/B'ing using a switch?
Needless to say, I'm kind of dubious of the claims of equal
performance. Unless the noise was common mode or polarity related,
I've never seen an antenna that received lower noise, outdo one that
picked up more noise. If the change is not efficiency related, that
would leave me to think that your vertical pattern is being skewed
somewhat, and is more horizontally polarized than the other, and thus
, picks up less vertically polarized noise. If thats not the case, I
would think the low noise version is less efficient. Just my opinion
tho...

Neither of these were developed using
computer modeling, though.

Neither were my comments...:/ MK

Hi MK,

When I stated:
(it's not a dummy
load as one would generally deduce from
the above description)
I wasn't joking. The fact that you've
never known a vertical antenna to
behave in this manner, is not surprising.

The purpose of my experiment was to
investigate the possibility of loading
(shortening) an element while still
maintaining a relatively normal BW.

Avoiding parallel wires and coils, the
resulting loading system is what I
call E-field loading (perhaps a poor
choice of terms) - a method of
conductive loading that resulted in
reducing the off-resonance reactance
in the FP. I suspect it is effecting the
susceptance of the voltage loop in
some way. The unexpected bonus, of
course, was a reduced susceptibility
to electrical noise.

73 de Chuck, WA7RAI

You place another element closely (behind usually) to the driven element
such that with a
'critical coupling' the feed impedance increases to the desired level.
It is beyond me why antenna manufactures still ask people to match to a low
impedance
which provides losses, when the antenna can be provided with a feed
impedance of 50 Ohm !

I must be in error ofcourse with the above statement as everything is
already known and utilised

May I also point out that if you allow elements to vary in diameter and
height and still keeping to
a .1 boom length, gain increases until ultimately the elements form a
combined parabolic shape
and progressively place rearward radiation energy into the forward direction
until the ultimate is reached,
where there is no radiation to the rear and F/B is absent. I would remind
you that the top element is
going to be designed to be disconnected and connected to ground to
determine impact on static noise.
It is also my intent to string nylon from one end of the elements to the
other, progresively tightening it
until a suitable bend or bow is put in place such that the beam width
narrows to somewhere in the
range of 30 degrees. (ala point to point to get highes gain together with a
lower take off angle)

I do have a fold over tower by the way over 1/2 acre of clear ground with
embedded wire screen
and I am surrouded by sloping farmland with Drummond soil..The 1 inch
hardline is routed undeground.
The above experimentation is why I have so much fun with antenna
experimenting where in other
ways the experts would say it is useless to try before I even put my shoes
on.

Regards
Art


"Chuck" wrote in message
news:w6bfd.12458$6P5.534@okepread02...

wrote in message
news:08_ed.243129$wV.18192@attbi_s54...

"Chuck" wrote in message
news:B3Ted.11167$6P5.7719@okepread02...

...
A 2:1 VSWR bandwidth over the 20m
phone portion implies a good Q, but
aren't you even a bit curious if the gain is
indeed as high as 13 dBi?

Funnily today I changed the model slightly

snipped


I am curious: how are you handling the
driven element's low input impedance?

...
Keep up the fun...


snipped


Hardly

73 de Chuck, WA7RAI

You place another element closely (behind usually) to the driven element
such that with a
'critical coupling' the feed impedance increases to the desired level.
It is beyond me why antenna manufactures still ask people to match to a low
impedance
which provides losses, when the antenna can be provided with a feed
impedance of 50 Ohm !

I must be in error ofcourse with the above statement as everything is
already known and utilised

May I also point out that if you allow elements to vary in diameter and
height and still keeping to
a .1 boom length, gain increases until ultimately the elements form a
combined parabolic shape
and progressively place rearward radiation energy into the forward direction
until the ultimate is reached,
where there is no radiation to the rear and F/B is absent. I would remind
you that the top element is
going to be designed to be disconnected and connected to ground to
determine impact on static noise.
It is also my intent to string nylon from one end of the elements to the
other, progresively tightening it
until a suitable bend or bow is put in place such that the beam width
narrows to somewhere in the
range of 30 degrees. (ala point to point to get highes gain together with a
lower take off angle)

I do have a fold over tower by the way over 1/2 acre of clear ground with
embedded wire screen
and I am surrouded by sloping farmland with Drummond soil..The 1 inch
hardline is routed undeground.
The above experimentation is why I have so much fun with antenna
experimenting where in other
ways the experts would say it is useless to try before I even put my shoes
on.

Regards
Art


"Chuck" wrote in message
news:w6bfd.12458$6P5.534@okepread02...

wrote in message
news:08_ed.243129$wV.18192@attbi_s54...

"Chuck" wrote in message
news:B3Ted.11167$6P5.7719@okepread02...

...
A 2:1 VSWR bandwidth over the 20m
phone portion implies a good Q, but
aren't you even a bit curious if the gain is
indeed as high as 13 dBi?

Funnily today I changed the model slightly

snipped


I am curious: how are you handling the
driven element's low input impedance?

...
Keep up the fun...


snipped


Hardly

73 de Chuck, WA7RAI

"Chuck" wrote in message

Hi MK,

When I stated:
(it's not a dummy
load as one would generally deduce from
the above description)
I wasn't joking. The fact that you've
never known a vertical antenna to
behave in this manner, is not surprising.

Oh, I have, but the lower noise was always due to increased losses
somewhere in the system...

The purpose of my experiment was to
investigate the possibility of loading
(shortening) an element while still
maintaining a relatively normal BW.

Adding loss would do that...

Avoiding parallel wires and coils, the
resulting loading system is what I
call E-field loading (perhaps a poor
choice of terms) - a method of
conductive loading that resulted in
reducing the off-resonance reactance
in the FP.

Still doesn't say too much...

I suspect it is effecting the
susceptance of the voltage loop in
some way.


Ditto...But I don't know how long the vertical is. Being you need
loading, I'll assume it's shorter than a quarter wave...Dunno...This
just doesn't really add up to me...I've fed verticals in many points,
at the max current, or max voltage points, or in between, and have
never seen this to effect noise pickup. Again, the only thing I've
ever seen to reduce noise, *and* keep the same pattern, was to
increase loss.

The unexpected bonus, of
course, was a reduced susceptibility
to electrical noise.

Due to extra losses? If you reduce susceptibility to far field
electrical noise, you are also reducing the desired signals at those
same angles. Rf is rf...What am I missing here? Myself, I consider the
so called "low noise" antennas to be old wives tails...
Even the shielded electrostatic versions, for the most part. IE:
shielded loops, etc...They are no more quiet than any other well
balanced loop made of normal wire windings. The shielded design is not
to magically reduce noise, it's to ensure balance. I'm not trying to
be ornery, but so far, what I read is not flushing to *me*...But I
don't believe in "low noise" antennas. To me, low far field noise
compared to another vertical antenna at the same angles and same
polarization, means increased loss somewhere if the pattern hasn't
changed. MK

Art Unwin wrote:
"You place another element closely (behind usually) to the driven
element such that with a "critical coupling" the feed impedance
increases to the desired level."

That`s not the way it works. More coupling lowers the feed impedance.

Check under "Close-spaced Arrays -- Super-=gain Antennas" on page 906 of
Terman`s 1955 edition:
"A characteristic of all close-spaced arrays is that as the ratio of
size to antenna gain is reduced, the radiation resistance also goes
down;---." The Yagi antenna of Fig.23-39, and the corner reflector,
represent almost the best that can be achieved in a compact array."

Notice that Terman said "almost". There`s always hope, but looking for
more gain by element spacing changes has been thoroughly investigated.
This is akin to to drilling in a field which is already overdrilled in
the search for oil.

Moving elements closer together brings the radiation resustance down.
The elements don`t know if a coupled element is ahead of the driven
element or behind it. It brings the drivepoint impedance down for the
driven element. Impedance adjustment is done through transformation.

Best regards, Richard Harrison, KB5WZI

Mark Keith wrote in message
om...
"Chuck" wrote in message

...

I suspect it is effecting the
susceptance of the voltage loop in
some way.


Ditto...But I don't know how long the vertical is. Being you need
loading, I'll assume it's shorter than a quarter wave...


Hi Mark,

Yes, its vertical height is 23 ft. It is elevated
6' above ground with elevated horizontal radials.
The input Z at the junction of the radials and DE
is 50 ohm j0 with no matching system. There is
a current un-un at the feedpoint, thus no
common-mode, and the Tx line is 1wl electrical.

The experiments with this type of loading was
begun around '95 - '96, and this vertical antenna
was erected in '98. It has been through near I/2
solar cycle, and all seasons. Time has a way of
dispelling illusions, and don't think for a moment
that I ignored the "loss" question.

To me, low far field noise

Do not assume all noise is the same or
that all originates in the 'far field' as EM
particle-waves.

73 de Chuck, WA7RAI

wrote in message
news:vYcfd.314858$3l3.210855@attbi_s03...
...

May I also point out that if you allow elements to vary in diameter and
height and still keeping to
a .1 boom length, gain increases until ultimately the elements form a
combined parabolic shape
and progressively place rearward radiation energy into the forward direction
until the ultimate is reached,
where there is no radiation to the rear and F/B is absent. I would remind
you that the top element is
going to be designed to be disconnected and connected to ground to
determine impact on static noise.
It is also my intent to string nylon from one end of the elements to the
other, progresively tightening it
until a suitable bend or bow is put in place such that the beam width
narrows to somewhere in the
range of 30 degrees. (ala point to point to get highes gain together with a
lower take off angle)

I do have a fold over tower by the way over 1/2 acre of clear ground with
embedded wire screen
and I am surrouded by sloping farmland with Drummond soil..The 1 inch
hardline is routed undeground.
The above experimentation is why I have so much fun with antenna
experimenting where in other
ways the experts would say it is useless to try before I even put my shoes
on.

Regards
Art

Many years ago - before computer modeling -
I was talking with a fellow down under (VK or
ZL, I can't recall) who was experimenting with
parabolic elements. Like you, he was using
fishing line to achieve the shape.

Don't let banal criticism get under your skin...
not everyone feels secure when venturing to
the outer edge of the envelope g

73 de Chuck, WA7RAI

Then the book is incorrect assuming you are using statements corectly
Art
"Richard Harrison" wrote in message
...
Art Unwin wrote:
"You place another element closely (behind usually) to the driven
element such that with a "critical coupling" the feed impedance
increases to the desired level."

That`s not the way it works. More coupling lowers the feed impedance.

Check under "Close-spaced Arrays -- Super-=gain Antennas" on page 906 of
Terman`s 1955 edition:
"A characteristic of all close-spaced arrays is that as the ratio of
size to antenna gain is reduced, the radiation resistance also goes
down;---." The Yagi antenna of Fig.23-39, and the corner reflector,
represent almost the best that can be achieved in a compact array."

Notice that Terman said "almost". There`s always hope, but looking for
more gain by element spacing changes has been thoroughly investigated.
This is akin to to drilling in a field which is already overdrilled in
the search for oil.

Moving elements closer together brings the radiation resustance down.
The elements don`t know if a coupled element is ahead of the driven
element or behind it. It brings the drivepoint impedance down for the
driven element. Impedance adjustment is done through transformation.

Best regards, Richard Harrison, KB5WZI

No Chuck, that is not going to happen.When you are an experimentor you don't
have to be hindered by diminishing returns as it is the chase that is the
most rewarding part. There has been many oilfields and silver mines that
have been abandoned ONLY because of diminishing returns which is usually
because of greed and not for the joy of doing what one likes to do.
For those who quote from books without a real understanding of what is being
said are doomed to only quoting books
without the self determination needed to explore new frontiers. A book is to
be used to explore the past but to explore the
future one has to avoid generating bed sores and procrastination and explore
what the future holds for those who are willing to move without fear of
failure.
On diminishing rear radiation, that can only go so far as the efficiency
relates heavily to the ratio of the element diameters
relative to spacing of elements on the reflective medium, so one can easily
be disapointed when stacking two 2 element beams using only 4 elements
instead of the many required for a "dish", but the low take off angle can
still be reproduced as well as a narrow beam with extra gain if the
corrective reflective contour can be obtained. Sure beats argueing about
current decline versus current drop versus current flow or what pack of
wolves to join.
By the way, do you know if dish antennas suffer from static like dipole
arrays? I would think they would be immune
but I really don't know.
Regards
Art KB9MZ XG



"Chuck" wrote in message
news:hSwfd.12591$6P5.1429@okepread02...

wrote in message
news:vYcfd.314858$3l3.210855@attbi_s03...
...

May I also point out that if you allow elements to vary in diameter and
height and still keeping to
a .1 boom length, gain increases until ultimately the elements form a
combined parabolic shape
and progressively place rearward radiation energy into the forward
direction
until the ultimate is reached,
where there is no radiation to the rear and F/B is absent. I would
remind
you that the top element is
going to be designed to be disconnected and connected to ground to
determine impact on static noise.
It is also my intent to string nylon from one end of the elements to the
other, progresively tightening it
until a suitable bend or bow is put in place such that the beam width
narrows to somewhere in the
range of 30 degrees. (ala point to point to get highes gain together
with a
lower take off angle)

I do have a fold over tower by the way over 1/2 acre of clear ground
with
embedded wire screen
and I am surrouded by sloping farmland with Drummond soil..The 1 inch
hardline is routed undeground.
The above experimentation is why I have so much fun with antenna
experimenting where in other
ways the experts would say it is useless to try before I even put my
shoes
on.

Regards
Art

Many years ago - before computer modeling -
I was talking with a fellow down under (VK or
ZL, I can't recall) who was experimenting with
parabolic elements. Like you, he was using
fishing line to achieve the shape.

Don't let banal criticism get under your skin...
not everyone feels secure when venturing to
the outer edge of the envelope g

73 de Chuck, WA7RAI

Art Unwin wroyte:
"Then the book is incorrect assuming you are using statements
correctly."

I included page numbers to make it easy to check the accuracy of my
translation.

Art said elements are "critically coupled". Critical coupling is defined
as maximum energy transfer at the resonant frequency.

Coupling additions (more loads) to a feedpoint lowers the impedance
unless additional measures (transformations) are taken. Coupling more
loads to a feedpoint is tantamount to paralleling resistors. Terman is
right.

Best regards, Richard Harrison, kB5WZI