However, with no electrical connection (transmission line) existing
between primary/secondary, and the voltage and current only conducted
between these windings by a magnetic flux--I CAN'T see how a "true"
balun can be argued, clearly--as opposed to "rf transformer."


I left out the word "current". My balun is a proper current balun as it
meets the formal definition, which is that it maintains currents at the
output terminals that are equal in magnitude and opposite in phase
regardless of potentials at the output terminals with respect to the ground
connection on the unbalanced side. You can find this definition in less
strict form in the ARRL handbook, such as 1991 pages 16.8-16.9.

The single core Guanella 4:1 current balun meets this definition but
only for floating loads. Anything other than that and the two transformers
need to be on separate cores.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ Sonoran Radio Research
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ IEEE Senior Member #40274515
. ( ) \
'-| )__| :. \ Email:
| | | | \ '. http://www.home.earthlink.net/~christrask
c__; c__; '-..'.__

Graphics by Loek Frederiks

"John Smith" wrote in message
...
Chris:

Well, I certainly can see that your claim it is two 1:1 baluns on a
single core is technically accurate--the primaries are in parallel and
their secondaries are in series... that seems clear enough that it
cannot be argued. I can't imagine all NOT to be in agreement on this
point.

However, with no electrical connection (transmission line) existing
between primary/secondary, and the voltage and current only conducted
between these windings by a magnetic flux--I CAN'T see how a "true"
balun can be argued, clearly--as opposed to "rf transformer."

But, I am giving this thought--as I am sure are others... I never
thought about the humble "balun"/"rf transformer" in some of these ways
before--possibly I am not alone... either and anyway, I enjoy the
thinking you have established here...

John

"Chris Trask" wrote in message
link.net...

1. That it is simply a 2:1 transformer with an isolated primary and
secondary?


No. It is a pair of 1:1 transformers on a single core. I can make
it
work equally well by making the two transformers on separate cores. I
can
also make it with a pair of equal length coaxial cables. Both of
these
realisations defeat his claim that it is a 2:1 transformer. But at
the same
time, neither of them answer his claim that it is impossible to make a
4:1
current balun on a single core with a pair of 1:1 transformers.


2. That it is not a true transmission line transformer, because your
transmission-line windings are not being fed with opposite polarities
across the *same* end?


This isn't even a gray area. We're making a BALUN, in other words
a
transformer that has an UNbalanced port and a BALanced port, and in
this
case fully meeting the definition of a current balun. If we were to
accept
the above statement, then we would have no choice except to conclude
that in
no circumstances could we make a BALUN with transmission line
transformers
because in all cases of BALUNs one port is fed unbalanced.

Making transmission line transformers is not difficult, although
Tom is
making it appear as though it's some sort of great mustery. For a
length of
transmission line that is sufficiently short with respect to
wavelength,
meaning less than an eighth of a wavelength in practice, the following
rules
are observed:

1. The voltage across the one conductor is equal to the
voltage of the other conductor, both in magnitude and
in phase.

2. The current in the one conductor is equal in magnitude
but oppostite in phase to the current in the other
conductor.

These basic understandings of transmission line transformers are well
established and understood. Gary Breed brought the concept down to
the
essentials in:

Breed, Gary, "Transmission Line Transformer Basics," Applied
Microwave & Wireless, Vol. 10, No. 4, May 1998, p. 60.

It all comes down to a difference between what is known by way of
established theory and practice versus trying to convince people that
everything we know is wrong.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ Sonoran Radio Research
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ IEEE Senior Member #40274515
. ( ) \
'-| )__| :. \ Email:
| | | | \ '. http://www.home.earthlink.net/~christrask
c__; c__; '-..'.__

Graphics by Loek Frederiks

"Ian White GM3SEK" wrote in message
...
Chris Trask wrote:

It's not a matter of whether I disagree with him or not. It's a
matter
of him standing on a cybersoapbox and declaring to the world in
numerous
ways that such a thing cannot work and that only his analysis of how
it
can
and cannot work is valid. He can't deny that he claimed that it was
impossible, so now he has to prove that the solution cannot possibly
work
the way that he knows that it cannot work. Whatever.


Please skip the personal rhetoric, and tell us how you respond to his
two main technical points about your transformer:

1. That it is simply a 2:1 transformer with an isolated primary and
secondary?

2. That it is not a true transmission line transformer, because your
transmission-line windings are not being fed with opposite polarities
across the *same* end?


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

I left out the word "current". My balun is a proper current balun as
it
meets the formal definition, which is that it maintains currents at the

output terminals that are equal in magnitude and opposite in phase
regardless of potentials at the output terminals with respect to the
ground
connection on the unbalanced side. You can find this definition in
less
strict form in the ARRL handbook, such as 1991 pages 16.8-16.9.

I agree.It just isn't a transmission line balun, nor an optimum design
for most applications.

The single core Guanella 4:1 current balun meets this definition
but
only for floating loads. Anything other than that and the two
transformers
need to be on separate cores.

I agree again. That's what I've been saying all along.

There we have it. Problem solved except for calling transmission lines
transformers, and transformers transmission lines.

73 Tom