"Baluns: What They Do and How They Do It", from the _ARRL Antenna
Compendium_, Vol. 1 is now available on line at
http://eznec.com/Amateur/Articles/Baluns.pdf.

Roy Lewallen, W7EL

Thanks Roy, your article is a keeper. I'm gonna fire up the soldering iron,
grab some #43 cores, and build me up a current balun or two for my listening
setup.

73,
John


"Roy Lewallen" wrote in message
...
"Baluns: What They Do and How They Do It", from the _ARRL Antenna
Compendium_, Vol. 1 is now available on line at
http://eznec.com/Amateur/Articles/Baluns.pdf.

Roy Lewallen, W7EL

"Roy Lewallen" wrote in message
...
"Baluns: What They Do and How They Do It", from the _ARRL Antenna
Compendium_, Vol. 1 is now available on line at
http://eznec.com/Amateur/Articles/Baluns.pdf.

Roy Lewallen, W7EL

Thanks Roy

You are a truely helpfull guy and I appreciate your efforts.

Jerry

Thanks, but I want to thank the ARRL. I recently enquired and discovered
they generously grant blanket permission for authors of articles in
their publications to reproduce the articles on their own web sites. So
I'll be adding more to my web site as I have time to scan them in. I
hope the articles will prompt some readers to buy some of the
publications to see some of the other interesting and informative things
which have been and are being written. And to support the League's
ability to continue publishing. Contrary to growing popular belief, only
a tiny fraction of the good information that exists is on the web.

Roy Lewallen, W7EL

Jerry Martes wrote:
"Roy Lewallen" wrote in message
...

"Baluns: What They Do and How They Do It", from the _ARRL Antenna
Compendium_, Vol. 1 is now available on line at
http://eznec.com/Amateur/Articles/Baluns.pdf.

Roy Lewallen, W7EL


Thanks Roy

You are a truely helpfull guy and I appreciate your efforts.

Jerry

Roy Lewallen wrote:
"Baluns: What They Do and How They Do It", from the _ARRL Antenna
Compendium_, Vol. 1 is now available on line at
http://eznec.com/Amateur/Articles/Baluns.pdf.

Roy Lewallen, W7EL


Well, thank you so much Roy! It's appreciated.

You are an asset to the radio community.

Lee C. KA0FPJ

Excellent article! It really did a good job of explaining why the
current path on the outside of the coax exists and causes problems.
Also an excellent description of the various types of baluns that had
this rookie puzzled.

More please!

jtm

On 19 Mar 2005 08:37:07 -0800, "Jim Miller" wrote:

Excellent article! It really did a good job of explaining why the
current path on the outside of the coax exists and causes problems.
Also an excellent description of the various types of baluns that had
this rookie puzzled.

More please!

jtm
Yes, Roy's article in the Compendium is excellent, as are all of Roy's
contributions to our art. In his article he referenced my work with
baluns, which appeared in QST for March 1983. This article is also
available on my web page at www.w2du.com for those who don't have a
copy of that issue of QST.

Walt Maxwell, W2DU

"Walter Maxwell" wrote
Yes, Roy's article in the Compendium is excellent, as are all of Roy's
contributions to our art. In his article he referenced my work with
baluns, which appeared in QST for March 1983. This article is also
available on my web page at www.w2du.com for those who don't have a
copy of that issue of QST.

Walt Maxwell, W2DU

Walt & Roy, thank you both very much for your lifetime of service to radio.
Have either of you analyzed any the numerous popular Radio Works "Current
Baluns"? I was advised many years ago that the current-type balun was more
effective for use with a dipole, and have used Radio Work's baluns on both
dipole and random wires with success. But my measure of success is not
analytical, as your studies have been. Operating a center-fed dipole at it's
resonant frequency, slightly below that, and significantly above it, are the
specific inquiries wrt current baluns - would a voltage balun be more
effective in any of those conditions? Radio Works current baluns the same
kind used in your studies?

Thanks for your comments, and the great participation of all in this group.

Jack Painter
Virginia Beach, Virginia

On Sat, 19 Mar 2005 14:38:32 -0500, "Jack Painter"
wrote:

would a voltage balun be more effective in any of those conditions?

Hi Jack,

The typical Voltage BalUn is constructed in such a way that one lead
violates the isolation offered by the Current BalUn method. There are
examples found for the same application of the 4:1. One is the
Guanella, the other is the Ruthroff. If you examine the Ruthroff
model, you will notice that one lead of the load (antenna) is
connected directly to the source without a choking intervention. On
the other hand, both leads are choked by the Guanella.

By common usage, the Guanella is generally described as a Current
type, where as the Ruthroff is described as a Voltage type BalUn.
Current or Voltage, the more important feature is in the choking.

73's
Richard Clark, KB7QHC

Roy and Walter,

CHOKE BALUNS.

Keep it simple. Why make a song and dance about it?

The pair of wires wound on a choke balun behave as an inductive choke
for longitudinal currents and as a transmission line for balanced
currents.

The two circuits, line and choke, behave independently of each other.

The actual current on a wire, if anyone should ever wish to know, is
just the arithmetical sum of the other two.

All authors omit to say that the the pair of transmission line wires
need not be coaxial. They can be a balanced twin line such as a length
of stranded flexible speaker cable. Or just a pair of insulated wires
laid alongside each other. Or twisted.

Not only is the twin-line mechanically more convenient to construct,
it has electrical advantages. Its Zo is intermediate between the high
and low terminating impedances. Typically Zo is about 120 -130 ohms.
The geometric mean of 50 and 300 ohms is 122 ohms. Not that this
matters very much because the device is never terminated in its
nominal impedances.

Twin line also has a higher velocity factor than 50-ohm coax.

The length of line wound on the choke behaves as an impedance
transformer. So it seriously, but not harmfully, affects the impedance
presented to the tuner. The tuner LC settings may be beneficially
affected. Otherwise the transformation ratio, which heavily depends on
frequency, is not of consquence.

Preferably, the length of twin-line wound on the choke should be less
than 1/8th of a wavelength long at its own velocity at the highest
operating frequency.

It is not too difficult to construct a choke balun which has
sufficient inductive choking reactance at 1.8 MHz without the
transmission line exceeding 1/8 wavelengths at 30 MHz.
----
Reg, G4FGQ