Owen Duffy wrote:
"Walter Maxwell" wrote in
:

"John Smith" wrote in message
...
wrote:
...
deals with a Windom Antenna, his text on the design, construction,
function and implementation of baluns is well worth the read.

Doesn't that article espouse the Guanella 4:1 current balun built on a
single toroid?

The extent to which such a construction works is due to flux leakage,
rather than the principles described by Guanella.

Owen

Owen:

You might have missed this part from the Windom URL:

"As far as the forward power to the antenna is
concerned there is no ferrite core. This is
because we have transmission “through two
transmission lines”. There is no external flux
around transmission lines. However if the
antenna is unbalanced there will be leakage or
common mode current flow through the
balun. These currents are not transmission line
mode currents. These currents will see a
choking reactance presented by the balun and
be stopped or significantly reduced. These
leakage currents if extremely excessive can
cause heating of the balun (but you have
probably got a serious problem that you need
to fix). Very high SWR can cause voltage
dielectric loss and even flashover between the
windings. Again this would indicate a more
serious problem with the antenna."

I should think a single core would be superior in relation to the above
stated phenomenon. Indeed, I suspect it to be preferable to two cores.
However, if such "leakage" is occuring, the author indicates you have
a problem with the antenna proper which needs a fix ...

However, this URL:

http://www.n0ss.net/qrp_4-1_guanella-type_balun.pdf

in the include pick 4-1_schematic.jpg, in the URL, contains a "blurb" on
how to move a single core design on to two cores.

Regards,
JS

Dan wrote:
On Sep 1, 4:20*am, Ian White GM3SEK wrote:
Dan wrote:
On Aug 31, 3:07*pm, Ian White GM3SEK wrote:
Dan wrote:
On Aug 28, 2:26*am, Ian White GM3SEK wrote:

In other words, people with limited antenna opportunities are often the
ones who need a balun - or more accurately, a common-mode choke - the
MOST.
Technically I would have to disagree with calling even a 1:1 balun the
same thing as a common mode choke. *A CM choke is an EMI prevention
device intended to filter out RF components generated in a circuit,
away from the feed of a power source, usually an electrical mains.

That is too far narrow a definition *of a "common mode choke",
especially the reference to electrical mains. The term is widely applied
to transmission line for both digital data and analog RF signals.

A common mode choke is used in RF applications, very true, but it
serves a filtering purpose,
not a conversion of unbalanced to balanced energy transfer or vice
versa. A common mode choke that operates well will turn
unwanted RF into heat or cause it to dissipate in its core or a
resistor etc..

Common-mode chokes, and filters in general, do NOT aim to "turn unwanted
RF into heat"! That is a total misunderstanding of the whole concept.

A CM choke aims to present a high impedence to unintentional RF. Once
"choked" by the high impedance,
the enrgey must either reflect or be aborbed somewhere in the circuit
or the core as real power. What is it that you cannot
understand about the term "choke"?


I'm slightly encouraged that the key word "reflected" has now crept into
your description. It wasn't there in what you wrote previously.

[Snip similar]

In a perfect situation, with a balanced feedline, the only kind of
current and voltage you have IS common mode!


What??? You know that statement didn't come out right, so how much of
the rest did you really mean?

I give up! You need some education in this area.


I give up too - at last, something we can agree about.

My main worry is that anyone *else* might have tried to gain some
education from your confused statements on this particular topic.




--

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

Owen Duffy wrote:
"Walter Maxwell" wrote in
:

"John Smith" wrote in message
...
wrote:
...
deals with a Windom Antenna, his text on the design, construction,
function and implementation of baluns is well worth the read.

Doesn't that article espouse the Guanella 4:1 current balun built on a
single toroid?

The extent to which such a construction works is due to flux leakage,
rather than the principles described by Guanella.

Owen

Here is an article which includes text on the use of ferrite rods in
place of toroids.

Someone who has a couple of rods from some old am radios, etc. may
already have the stuff in his junk box to throw together an introductory
prototype?

Regards,
JS

"John Smith" wrote in message
...
JB wrote:
My take on CM chokes is that they are best on TV coax to keep energy on
the
shield from bringing trouble to the TV chassis. On a transmitting
antenna,
the idea is to enforce a high impedance bump somewhere to set the
resonant
length other than what it wants to be. That might not contribute to
efficiency even if it prevents the coax from being part of the antenna.
If
the antenna is in resonance, there won't be any coax radiation and no
Choke
is really needed. My point is, you are best not needing one, but if
that is
what you need to put the current out on the wire, or out of the shack.
OK.
Of course high gain antennas have a pattern to protect, but does it
matter
all that much for anything up to a 3 element yagi? High currents and
voltages on the coax are to be avoided because that is where your loss
will
be.



That is so bizarre; I just don't know where to begin in the description
of how and how much!

Regards,
JS

Ya I know, I didn't get into the how. How much is the first thing you need
to be aware of.

JB wrote:

...
Ya I know, I didn't get into the how. How much is the first thing you need
to be aware of.



Then this work:

http://www.hep.princeton.edu/~mcdona...andards_93.pdf

by Jerry Sevick, may be of significant interest to you ...

Regards,
JS

JB wrote:

...
Ya I know, I didn't get into the how. How much is the first thing you need
to be aware of.



You may also find this picture of a 1:1 guanella balun of interest.
Notice the "crossover" which alters the direction of the common winding
between sides of the core ...

Regards,
JS

On Aug 28, 5:10*pm, John Smith danced
around naked pulling on his meat:
snip a lot of John Smiths bull**** diatribe

Now, I am off to watch my momma crawl about ...

Momma still selling her pussy on the corner huh John? I bet she still
has nightmares over your conception from the guy that donated her his
half of your egg! I guess the old saying that you get what you pay
for is true and its a shame your momma had to pay for the other half
from some old whino in Bakersfield, living under the freeway ramp in a
box!

Regards,
JS

John Smith wrote:
On Aug 28, 5:10 pm, John Smith danced
around naked pulling on his meat:
snip a lot of John Smiths bull**** diatribe
Now, I am off to watch my momma crawl about ...

Momma still selling her pussy on the corner huh John? I bet she still
has nightmares over your conception from the guy that donated her his
half of your egg! I guess the old saying that you get what you pay
for is true and its a shame your momma had to pay for the other half
from some old whino in Bakersfield, living under the freeway ramp in a
box!
Regards,
JS


Does make you wonder:

1) Some disgruntled ham with mental problems?

2) Some wino with a stolen laptop and wifi link?

3) Individual that is a product of the current school system?

4) Local/county/state/federal politician?

5) Religious devotee of the arrl?

6) Someone bored with the traffic on a moderated news group?

7) Retarded relative/family-member of a group member here--sneaking
about and gaining unauthorized access to his/her computer?

8) ...

plonk ...

Regards,
JS

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

...
Ya I know, I didn't get into the how. How much is the first thing you
need
to be aware of.



You may also find this picture of a 1:1 guanella balun of interest.
Notice the "crossover" which alters the direction of the common winding
between sides of the core ...

Regards,
JS

There ya go.
One of the problems of breaking up the path to ground on the shield is that
now static can build up. If you can provide a way to bleed off the charges
that build up on both halves, while breaking up the shield currents, now you
have made it worthwhile. But when you guys start discussing off center fed
dipoles, I step aside. I have computers in the shack. I have better luck
with fan dipoles. Also running a Butternut vertical. Works a lot better
than a 4btv, but a pain to get it right on all bands.

Thanks

Also liked the other pdfs presented. I never have time to read them all
because of constant interruption around here. Back to work.

JB wrote:

...
There ya go.
One of the problems of breaking up the path to ground on the shield is that
now static can build up. If you can provide a way to bleed off the charges
that build up on both halves, while breaking up the shield currents, now you
have made it worthwhile. But when you guys start discussing off center fed
dipoles, I step aside. I have computers in the shack. I have better luck
with fan dipoles. Also running a Butternut vertical. Works a lot better
than a 4btv, but a pain to get it right on all bands.

Thanks

Also liked the other pdfs presented. I never have time to read them all
because of constant interruption around here. Back to work.



OCF antennas were not fully appreciated by me, a few of Cecils' helpful
insights and encouragement and I built one and was rather surprised ...
I do not have one right now but that is only due to neighbors/property
constraints.

Here is a URL for design/implementation of "non-standard"
baluns/transformers, but of a highly useable and desirable nature--or,
Dr. Sevick strikes again!:

http://www.highfrequencyelectronics....104_Sevick.pdf

Fig. 6(A) is very interesting. A 5-winding, 1:1.56 bootstrap
transformer which provides 50/75 ohm connections/substitutions. Perfect
for allowing one to use 75 ohm "junk" (or found in dumpsters) tv coax in
place of more expensive 50 ohm coax.

I have made good use of this since I have thousands of feet of NEW 75
ohm coax I purchased from a scrap dealer for next-to-nothing! A lot of
large dia coax and hard-line mixed in!

Regards,
JS