On Fri, 10 Apr 2009 06:29:24 -0700 (PDT), Art Unwin
wrote:

"Ignoring the obvious" is a nonsense aproach,
as is scale and wavelength.

This is a curious defense of poor practice. The results fully follow
the obvious problem of ignoring scale and wavelength. Fundamentals
have been violated - it doesn't take a PhD nor a research grant to
figure that out. No models are necessary, but they would show the
failure too.

73's
Richard Clark, KB7QHC

On Fri, 10 Apr 2009 14:35:26 +0100, Ian Jackson
wrote:

No baluns are used

That alone is at least one thing wrong with the design.

Do you use a balun with a helix and a dish reflector? Surely that bit at
least is right!

Hi Ian,

What has been done right is arguable in the face of failure. The
simple testimony easily reveals very simple problems of a fundamental
nature.

Hoisting the design 40 feet only added to the inefficiency of the
exercise (use common sense before muscles - much in the sense of
"measure twice, cut once").

73's
Richard Clark, KB7QHC

On Fri, 10 Apr 2009 07:54:41 +0100, Brian Howie
wrote:

Diffraction off the edge of the reflector. It causes backlobes. It's
not a fault.

Hi Brian,

You have hit the nail on the head. More, you have pushed in the tack
with a 10# sledge. This design we are talking about suffers immensely
from the violation of observing what you comment upon.

It is very much a fault.

73's
Richard Clark, KB7QHC

Maybe the coax ground is insufficent and a seperate ground from mother earth
is required.....Maybe


"Art Unwin" wrote in message
...
I made a helical end fed antenna that is inside a cone shaped
reflector
The reflector is made from 1/2" mesh steel with an aluminum foil liner
and connected to the braid of the feed coax. No baluns are used, just
direct connections.
I was surprised to hear signals from the rear!
I thought that a dish reflector prevented such signals getting to the
receiver. So what can be wrong with the reflector or can signals get
reflected back from the frontal area? Antenna is at a 40 foot height
Any ideas as to what the fault could be?
Regards
Art
I have no experience with dishes thus the question Note, the helical
antenna does not protrude beyond the dish envelope.
Art

On Apr 10, 1:07*pm, "Rollie" wrote:
Maybe the coax ground is insufficent and a seperate ground from mother earth
is required.....Maybe

"Art Unwin" wrote in message

...

I made a helical end fed antenna that is inside a cone shaped
reflector
The reflector is made from 1/2" mesh steel with an aluminum foil liner
and connected to the braid of the feed coax. No baluns are used, just
direct connections.
I was surprised to hear signals from the rear!
I thought that a dish reflector prevented such signals getting to the
receiver. So what can be wrong with the reflector or can signals get
reflected back from the frontal area? Antenna is at a 40 foot height
Any ideas as to what the fault could be?
Regards
Art
I have no experience with dishes thus the question Note, the helical
antenna does not protrude beyond the dish envelope.
Art

Rollie
I checked.
The coax ground and the reflector is grounded at the same place at the
top of the tower. All horizontal coax is buried. Seems like the dish
reflector does not get a lot of attention from ham operators !
Art

Art Unwin wrote:
On Apr 10, 1:07Â*pm, "Rollie" wrote:
Maybe the coax ground is insufficent and a seperate ground from mother earth
is required.....Maybe

"Art Unwin" wrote in message

...

I made a helical end fed antenna that is inside a cone shaped
reflector
The reflector is made from 1/2" mesh steel with an aluminum foil liner
and connected to the braid of the feed coax. No baluns are used, just
direct connections.
I was surprised to hear signals from the rear!
I thought that a dish reflector prevented such signals getting to the
receiver. So what can be wrong with the reflector or can signals get
reflected back from the frontal area? Antenna is at a 40 foot height
Any ideas as to what the fault could be?
Regards
Art
I have no experience with dishes thus the question Note, the helical
antenna does not protrude beyond the dish envelope.
Art

Rollie
I checked.
The coax ground and the reflector is grounded at the same place at the
top of the tower. All horizontal coax is buried. Seems like the dish
reflector does not get a lot of attention from ham operators !
Art

Hmmm, I guess this guy just talks to himself.

http://www.signalone.com/kb2ah/KB2AHantennas.html


--
Jim Pennino

Remove .spam.sux to reply.

On Apr 10, 10:15*am, wrote:
Dale Parfitt wrote:

"Art Unwin" wrote in message
...
I made a helical end fed antenna that is inside a cone shaped
reflector
The reflector is made from 1/2" mesh steel with an aluminum foil liner
and connected to the braid of the feed coax. No baluns are used, just
direct connections.
I was surprised to hear signals from the rear!
I thought that a dish reflector prevented such signals getting to the
receiver. So what can be wrong with the reflector or can signals get
reflected back from the frontal area? Antenna is at a 40 foot height
Any ideas as to what the fault could be?
Regards
Art
I have no experience with dishes thus the question Note, the helical
antenna does not protrude beyond the dish envelope.
Art

There is a lot of very important information missing here.
What frequency are we talking about and what is the dish diameter?
Do you have any idea as to what your edge taper is or sidelobes?

Dale W4OP

The last time he talked about it, it was "designed" to operate on the
160 meter band and the "reflector" was 3 meters in diameter.

No, those numbers are not typos.

--
Jim Pennino

Remove .spam.sux to reply.

That antenna was when I used an old parabolic satellite dish which was
unsuitable.
Scanning past antenna papers point to the use of a cone shape similar
to a horn of 2 metres diameter
produces better results. The antenna needs a longer mast so at the
moment I can't compare
F/R. Either way, with the radiator within the reflector envelope it is
difficult to understand what creates
a rearward lobe regardles of scale or frequency of use with respect to
receive. At the moment I see nothing that points away from the
Rutherford particle experiments with foil .ie penetration when at
right angles , deflection at other angles.

On Apr 10, 8:35*am, Ian Jackson
wrote:
In message , Richard Clark
writesOn Thu, 9 Apr 2009 20:05:20 -0700 (PDT), Art Unwin
wrote:

No baluns are used

That alone is at least one thing wrong with the design.

Do you use a balun with a helix and a dish reflector? Surely that bit at
least is right!



--
Ian

Ian;
I specifically mentioned the absence of a balun. I stated that since
it doesn't seem relevent, especially when one reviews published
patterns. In a way I knew that Richard would pile up his postings of
olde english prose in the shape of riddles that provide nothing, But
one has to get used to him and his pals kb9....and others who smear
this group with a foul smell as they are wired very differently from
the rest of us.

On Fri, 10 Apr 2009 19:30:03 GMT, wrote:

Hmmm, I guess this guy just talks to himself.

For himself.

Artifice: I have a novel and mysterious design emploiting Rutherford
partical evasion without baluns and using a gauss reflectionater.

Ham: What is its front to back rejection?

Artifice: I gets signals in all directions! Not just front or back.

Ham: Then why do you say it -um- evades something or other (sigh)?

Artifice: Well, this is not part of the design of not getting the
forward proceeding back signals.

Ham: So, it doesn't work.

Artifice: It works perfectly, just not as well as gaussian
reflectionating mechanics would expect unless these particals are
accelerated to high speeds by the weekend force.

Ham: So, why doesn't my antenna get this kind of signal?

Artifice: Because you read books from the libraries of the hooded
priests who refuse to backnowledge my inventions!

Ham: Why would I want to listen to these signals if I read your
books?

Artifice: Then you could enjoy the Fill-harmonic richness of my
single channel stereoid transmissions.

73's
Richard Clark, KB7QHC

That antenna was when I used an old parabolic satellite dish which was
unsuitable.
Scanning past antenna papers point to the use of a cone shape similar
to a horn of 2 metres diameter
produces better results. The antenna needs a longer mast so at the
moment I can't compare
F/R. Either way, with the radiator within the reflector envelope it is
difficult to understand what creates
a rearward lobe regardles of scale or frequency of use with respect to
receive. At the moment I see nothing that points away from the
Rutherford particle experiments with foil .ie penetration when at
right angles , deflection at other angles.

As usual Art you are avoiding answering the questions and choose to confuse
the issues
with you own preconceived ideas and terminology. The fact that the feed is
totally within the "reflector envelope" tells you or us nothing about
sidelobes and edge taper.
I really don't think you want answers, but I'll try once mo
1. What frequency
2. What is the dish diameter
3. What is the dish focal length to diameter ratio (F/D)

Dale W4OP