On 12 sep, 20:17, Owen Duffy wrote:
lu6etj wrote :

Hello boys, good day for you

Is it Carolina Windom a balanced load to justify the name "balun"? We
could think in a device to transform Z and another device to block
feed line current. What do you think about it?

Miguel,

Sometimes the language we use doesn't well describe the thing we are
thinking about, and this is a case.

We could well apply a meaning to balanced, that either the currents are
equal in magnitude but opposite in phase; or that the voltages wrt some
sensible accessible reference are equal in magnitude but opposite in
phase. One does not imply the other without constraining the load
characteristic.

When we speak of unbalanced, we commonly think of a configuration where
one side is 'grounded' and the other 'active'.

The problem is that many situations in antenna systems are not purely
either, they are not balanced by one or other of the meanings above, and
they are not unbalanced by the meaning above.

So, they need to be dealt with by the more general method of considering
that there are non-zero common mode and differential voltages and
currents.

It would be most unlikely that a Carolina Windown would be balanced, or
near to it, by any defintion. The antenna is born out of a quest to sell
the disadvantage of Windom feedline radiation as a positive feature.

The way I like to explain a balun is that it *facilitates* connection of
a not-balanced device to a balanced device. A practical balun does not,
of itself, eliminate (meaning make zero) common mode current or common
mode voltage... yet we commonly use absolute words to describe its
action.

To a certain extent, that is saying that they are not ideal or perfect
devices. Some of the rules we hams have made for baluns pretty much
assure mediocre performance. Like for example what I refer to as Rule
500, that the minimum choking impedance of a current balun is ten times
the differential characteristic impedance (commonly 50, hence Rule 500).

I know English is not your first language, but be wary of applying the
meaning of words absolutely.

Owen

Hello Owen, it is a pleasure to meet you again.

Oh, yes, of course here we use our words with freedom too. I confess I
call "baluncitos" (little baluns) the little toroid transformers,
specially binocular ones, but in this newsgroup a lot of good people
is very strict with wording and precision of terms :) then I thought
it was no exaggeration from me ask whether it is correct use the term
"balun" when both sides are "un", hi hi.

However certainly many times in our hobby words are a true trap for
novice (and not so novices), then, why not to call things with more
proper name?, if a balun do not "baluning", well... call them "seudo-
balun" or another similar pointer to true behaviour (as our known
"pseudo-Brewster angle"). There is not a languages translation issue
here Owen, you and we, in english and spanish, missuse the same words
and concepts, the "thing" it is "globalized".
I am far of being a purist of the tongues, but you know, we hams have
misleading words, a majority of you are true experts in RF and it is
difficult you can become confussed. Anyway, is not something to worry
so much either, the mine It was a casual comment, blame to Roy by take
us to the hard theory

Greetings

Miguel

lu6etj wrote in
:

....
is very strict with wording and precision of terms :) then I thought
it was no exaggeration from me ask whether it is correct use the term
"balun" when both sides are "un", hi hi.

Perhaps the term 'common mode choke' works?

I did see a raging argument someone online (eham?) just recently where
parties were arguing that a 4:1 Guanella current balun could be wound on
a single toroid, it was the way Guanella intended it they said, but they
argued that use of two ferrite sticks for such a device was wrong.

In fact, Guanella's article describes his 1:1 balun without any magnetic
core material, and the 4:1 balun as a connected pair of 1:1 baluns with
no (ie negligible) magnetic coupling. Yet I have seen commercial sites
selling a Guanella 4:1 current balun on a single core, arguing that
Sevick said it was ok in a certain context... a context that is unlikely
to ever exist in an antenna system. But hey, Sevick is Mr Baluns, so they
sell. That context relates to another dimension of the balanced /
symmetric issue.

Back to the Carolina Windom, a common explanation holds that there is
common mode current on the feedline between the dipole feedpoint and the
'isolator'. The notion that common mode current exists on one side of the
isolator and not on the other is an interesting one, one better explained
by advertising hyperbole than radiocommunications theory.

Owen

On 9/12/2010 7:50 PM, Owen Duffy wrote:
... Yet I have seen commercial sites
selling a Guanella 4:1 current balun on a single core, arguing that
Sevick said it was ok in a certain context... a context that is unlikely
to ever exist in an antenna system. But hey, Sevick is Mr Baluns, so they
sell. That context relates to another dimension of the balanced /
symmetric issue.

Back to the Carolina Windom, a common explanation holds that there is
common mode current on the feedline between the dipole feedpoint and the
'isolator'. The notion that common mode current exists on one side of the
isolator and not on the other is an interesting one, one better explained
by advertising hyperbole than radiocommunications theory.

Owen

The first part, above, implies that no one has ever constructed such a
balun(s), one on a single core, one on a dual core, used "balanced"
resistances, to serve as loads, then unbalance the loads, and observe
results. I have, when constructed properly, one can be constructed on a
single core. Is the dual core better? Yes ... is it possible to run
the single core balun in conditions where it will fail miserably?; Yes.
Is it possible to run the dual core balun in conditions where it will
fail miserably?; Yes.

As to the second part, I have found a properly constructed balun to be
both, a choke and "impedance-transformer." Indeed, an excellent balun
is optimized to take advantage of both phenomenon.

And, of course, I have found and believe a 160m to 10m balun/unun is
stretching things, probably beyond what one should (but, hey, you can
get by with it), two baluns, a high freq and a low freq are better to
cover such a span ... however, you can carry that to an extreme and
optimize core material/size and windings for each specific band ...

And, radio is an onion, each layer built on a preceding layer. At the
core of all this is the EM transmission theory, and RF is both particles
and waves ... obviously, both have great difficulty being true at the
same time, so "waves of bullets" becomes the explanation ... obviously,
great difficulty is going to be had in having cement solid theory in the
outer layers of this onion. By the time you get to "balance" the errors
are only magnified ... balance is like any balance in life ... you'll
know it when you have it, and benefit from it.

Regards,
JS

On 9/12/2010 8:59 PM, John Smith wrote:
On 9/12/2010 7:50 PM, Owen Duffy wrote:
... Yet I have seen commercial sites
selling a Guanella 4:1 current balun on a single core, arguing that
Sevick said it was ok in a certain context... a context that is unlikely
to ever exist in an antenna system. But hey, Sevick is Mr Baluns, so they
sell. That context relates to another dimension of the balanced /
symmetric issue.
...
Owen

The first part, above, implies that no one has ever constructed such a
balun(s), one on a single core, one on a dual core, used "balanced"
resistances, to serve as loads, then unbalance the loads, and observe
results. I have, when constructed properly, one can be constructed on a
single core. Is the dual core better? Yes ... is it possible to run the
single core balun in conditions where it will fail miserably?; Yes. Is
it possible to run the dual core balun in conditions where it will fail
miserably?; Yes.

As to the second part, I have found a properly constructed balun to be
both, a choke and "impedance-transformer." Indeed, an excellent balun is
optimized to take advantage of both phenomenon.
...

Regards,
JS

This:
http://www.pdftop.com/view/aHR0cDovL...8xQmFsdW4ucGRm

is actually a pretty fair appraisal of it all ... beware line wrapping.

Regards,
JS

On Sep 12, 9:50*pm, Owen Duffy wrote:
Back to the Carolina Windom, a common explanation holds that there is
common mode current on the feedline between the dipole feedpoint and the
'isolator'. The notion that common mode current exists on one side of the
isolator and not on the other is an interesting one, one better explained
by advertising hyperbole than radiocommunications theory.

As you know, common-mode RF obeys the rules of the reflection model.
From an (ideal) physics standpoint, there is nothing technically wrong
with having zero common mode current between the isolator and the
source while having a common mode current maximum (loop) 1/4WL back
toward the antenna feedpoint from the isolator. (Assume an ideal
isolator with an infinite choking impedance.)

Consider the following example:

Source--------1/2WL coax1--------isolator-------1/2WL coax2----------
antenna feedpoint

The net common-mode current on each side of the (ideal lumped)
isolator must be equal to satisfy Kirchhoff. There is no technical
reason why the net standing-wave common-mode current could not be zero
on each side of the isolator where the isolator is causing a standing-
wave current node (minimum). 1/4WL back from the isolator toward the
source, there is no technical reason why the net standing-wave common-
mode current could not be zero. 1/4WL forward from the isolator toward
the antenna, there is no technical reason why the net standing-wave
common-mode current could not be at a high (maximum-loop) value. Since
it is theoretically possible, one should not dismiss it as
"advertising hyperbole" without having performed the measurements to
prove that particular statement applies to the Carolina Windom because
of poor isolator performance, not because it violates Kirchhoff's
laws.

Incidentally, this is the same conceptual error that some folks have
made when they reported measuring no phase shift in the current
through a large air-core 75m loading coil when installed on a standing-
wave antenna. Hint: Pure standing wave current has zero relative phase
shift so it obviously cannot be used to measure phase shift. EZNEC
confirms that fact.
--
73, Cecil, w5dxp.com