radiators
 

On Aug 30, 7:27*pm, "Dale Parfitt" wrote:
"Art Unwin" wrote in message

...

Tom, W8ji *apparently is an expert with antennas *having lectured
at Dayton and has authored many technical articles around antennas,
states that radiators must be straight for maximum efficiency,
apparently

Art,
The only place I have ever read that on Tom's site is related to Beverage
antennas- the statement is true, and for obvious (to most of us) reasons.

Dale W4OP

I know it is considered as obvious to those who resist change.
Obvious as you stated means that there is no possible alternative
available because all is known.

radiators
 

"Art Unwin" wrote in message
...
On Aug 30, 7:27 pm, "Dale Parfitt" wrote:
"Art Unwin" wrote in message

...

Tom, W8ji apparently is an expert with antennas having lectured
at Dayton and has authored many technical articles around antennas,
states that radiators must be straight for maximum efficiency,
apparently

Art,
The only place I have ever read that on Tom's site is related to Beverage
antennas- the statement is true, and for obvious (to most of us) reasons.

Dale W4OP

I know it is considered as obvious to those who resist change.
Obvious as you stated means that there is no possible alternative
available because all is known.

Well, suppose you show us for a given length Beverage antenna, how
configuring it in any other shape but straight makes it a better Beverage.

Dale W4OP

radiators
 

On Aug 30, 7:35*pm, Jeff Liebermann wrote:
On Sun, 30 Aug 2009 17:21:34 -0700, Jeff Liebermann
wrote:

On Sun, 30 Aug 2009 14:54:05 -0700 (PDT), Art Unwin
wrote:

Tom, W8ji *apparently is an expert with antennas *having lectured
at Dayton and has authored many technical articles around antennas,
states that radiators must be straight for maximum efficiency,
Using Google, I couldn't find any statement resembling the "straight
radiators" claim.

Oh wait. *Maybe he was referring to the mounting pole:
http://picasaweb.google.com/lh/photo/HC8B4F-AnCQF6I_u0k3MYg

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

No. As I remember it he stated this to somebody on the Double Helix
question
on QRZ antenna design forum some time back. Last time I looked at that
there was several thousand viewers but nobody challenged him! I
believe it is some three pages back in the archives. I am sure he has
stated same in other places. If you ask him I am sure he will point
out the instances to you.
Regards

radiators
 

On Aug 30, 9:23*pm, Art Unwin wrote:

Exactly because it takes a WL or multiple there of to attain
equilibrium

Art -- how, then, do you account for the fact that a 1/4-wave monopole
and r-f ground system used by many AM broadcast stations produces
radiated fields that have been measured to be within a few percent of
the maximum possible for the applied power?

If "equilibrium" takes a WL or multiple thereof, why are such
fractional wavelength radiators so efficient?

RF

radiators
 

Art Unwin wrote:
Tom, W8ji ... states that radiators must be
straight for maximum efficiency, ...

Why are short helical antennas less efficient than
full-size straight radiators? Is there any way to
fold a full-size straight radiator that results
in increased efficiency?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

radiators
 

The Art of misdirection and obfuscation.

radiators
 

On Aug 31, 6:53*am, Richard Fry wrote:
On Aug 30, 9:23*pm, Art Unwin wrote:

Exactly because it takes a WL or multiple there of to attain
equilibrium

Art -- how, then, do you account for the fact that a 1/4-wave monopole
and r-f ground system used by many AM broadcast stations produces
radiated fields that have been measured to be within a few percent of
the maximum possible for the applied power?

If "equilibrium" takes a WL or multiple thereof, why are such
fractional wavelength radiators so efficient?

RF

One time response
Most hams are aware there are two basic resistances or impedances
involved in any antenna. The d.c. wire resistance is a constant
whether it is above ground or not.
Radiation resistance only occur when radiation is allowed to take
place which usually is considered above ground. When the circuit
cannot radiate such as in a ground plain or similar then the circuit
does not encounter radiation resistance thus the only resistance
encountered is the dc resistance which means it draws less power from
the source.
Thus for a half wave with ground plain it will draw 1/2 the power from
the source that a full wave will. So when talking about efficiency per
unit of energy supplied the only difference
between the two is the wire resistance that is not accompanied by
radiation which is extremely small. So overall efficiency changes of a
radiator is so small it really is of zero significance. What is
important is the ability of an antenna to radiate maximum strength
where you want and the ground plain applies a limitation which many
can live with.
The importance of efficiency is that one is accounting for all forces
that impact it where you enter a different mathematical areana which
opens up clues to the formation of radiation
and possibly other scenarios that can be of benefit in other areas.

A case in point. If one has a vertical then the radiation pattern is
donut shaped ie it has a hole that is devoid of radiation which is not
so good for military servalance. This is because the radiator is
oriented opposite to the gravitational force only. If one wants to
account for ALL forces involved then one must include with gravity the
Corriolis force without which NOTHING can be stable on Earth. One must
include it when considering the Earths forces within a arbitrary
boundary to achieve equilibrium. Thus to be in equilibrium a radiator
must be tipped to include the Coreolis force which then allows for a
spherical radiation pattern ala Poynting's vector where the forces
within the boundary equals ( and opposite) that outside the boundary
and is in a state of equilibrium Thus when a radiator is tipped it now
fills up the hole in the donut to obtain radiation that is equal in
all directions( equilibrium) which is what a military installation
would prefer as possible observation is 100 %. Thus starting with a
single radiator that is in equilibrium you are starting from a
different point to a planar mode when proceeding with array designs
which then becomes educational with respect to possible occurances
that are not available to systems outside that of the equilibrium.
NUFF SAID

radiators
 

"Art Unwin" wrote in message
...
On Aug 30, 7:27 pm, "Dale Parfitt" wrote:
"Art Unwin" wrote in message

...

Tom, W8ji apparently is an expert with antennas having lectured
at Dayton and has authored many technical articles around antennas,
states that radiators must be straight for maximum efficiency,
apparently

It would assist us if you would cut and paste the quote from Tom' site.
As I said before, the only place I ever saw this was with reference to
Beverages- the statement is true and obvious to everyone except perhaps you
Art.
The onus is upon you to prove that a Beverage in any other deployment
except straight would be better. I don't want to hear about your theories
that only you embrace- a simple EZNEC model will be sufficient.

Dale W4OP

radiators
 

Art Unwin wrote:

Thus to be in equilibrium a radiator
must be tipped to include the Coreolis force which then allows for a
spherical radiation pattern ala Poynting's vector where the forces
within the boundary equals ( and opposite) that outside the boundary
and is in a state of equilibrium Thus when a radiator is tipped it now
fills up the hole in the donut to obtain radiation that is equal in
all directions( equilibrium) which is what a military installation
would prefer as possible observation is 100 %
____________

Then by your theory does the radiation launched by a vertical, 1/2-
wave, center-fed dipole have a different pattern shape when that
dipole is tipped away from the vertical plane?

I'm referring to the radiation pattern of the dipole itself, not
including any reflections.

RF

radiators
 

On Aug 31, 12:40*pm, "Dale Parfitt" wrote:
"Art Unwin" wrote in message

...
On Aug 30, 7:27 pm, "Dale Parfitt" wrote: "Art Unwin" wrote in message

....

Tom, W8ji apparently is an expert with antennas having lectured
at Dayton and has authored many technical articles around antennas,
states that radiators must be straight for maximum efficiency,
apparently

It would assist us if you would cut and paste the quote from Tom' site.
As I said before, the only place I ever saw this was with reference to
Beverages- the statement is true and obvious to everyone except perhaps you
Art.
The onus *is upon you to prove that a Beverage in any other deployment
except straight would be better. I don't want to hear about your theories
that only you embrace- a simple EZNEC model will be sufficient.

Dale W4OP

Dale I am happy with the responses of the group. Seems like they are
united against the idea that radiators must be straight for maximum
efficiency. I never mentioned anything about Beverages, that was
somebody else. As far as Eznec is concerned I am not familiar with it
as I use a program equiped with an optimiser that tries to bring your
inputs in line with Maxwells equations. For instance, Eznec is only a
calculator devised to provide answers to that supplied with additions
to handle planar forms that are not in compliance. When you have an
optimiser and your input is not pre guided ,such as a planar input,
the optimiser will respond with a non planar design that includes
the
Coriolis force such that Maxwells equations are enforced , and that
requires equilibrium.
That also means the programs costs more but all antenna design
companies use them as they recognise the true value of adherence to
Maxwell's laws.
The above justifies my position on radiators unless you want to
declare "garbage in garbage out". I have a simple sample printed of a
computerized array that shows the above in the patent request that is
presently due for extinction. The military uses tipped radiators in
many places to gain coverage of the donut hole as I have shown, but
you will not see printed matter on the subject except from me. The WWW
changes a lot of things regarding secrecy. Remember, when Tesla died
he was working on a cheap energy system. The FBI raided his lab and
took every thing which even now has not seen the light of day!
I know. YOU now want me to provide a copy of the statement to you but
then,. you can choose to believe or not to believe and use free speech
to demand any thing. But I am not in your employ.