"Richard Clark" wrote
"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

Thanks Richard. I have never seen the internal construction of the Radio
Works BalUn, but it is claimed to be a current-type device. It's function
as a choke was the only reason for including it in the designs of my antenna
systems. I see that Reg as well as yourself remind us that is indeed their
primary purpose. Too bad so many may have been fooled into using
voltage-type baluns when that appears to be an inappropriate choice for may
applications. I was curious what applications would benefit from such a
voltage-balancing device.

Jack

Walt, I intended to include a link to your article and looked on your
web site for it before I posted my article. But I didn't find it in the
index. Where is it relative to your home page? I'll add a link to it.

Walt's article was really the first one I ever saw that explained the
phenomenon of currents on the inside and outside of the coax -- my
article is really just an extension of his work.

Roy Lewallen, W7EL

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

Jack Painter wrote:

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"?

No, since I figured out what baluns do and wrote the article, I've never
purchased a balun since I know how to make effective ones myself. When I
wrote the article, the popular commercial baluns were all "voltage
baluns", and I'd like to think that the article was a factor in causing
the gradual changeover of commercial products to "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?

Your question indicates that my article failed to explain one of its
major points. The answer is no, a voltage balun is not more effective
than a current balun in any antenna/feedline application. If the antenna
is perfectly balanced, the third winding in the voltage balun will carry
no current and does nothing. If the antenna isn't balanced, the presence
of the voltage balun's third winding will prevent balanced currents in
the elements. So at best the voltage balun does as well as a current
balun, and otherwise it degrades balance.

Radio Works current baluns the same
kind used in your studies?

Sorry, I've never purchased one and taken it apart. You might try asking
them.

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


You're welcome. I'm surprised and frankly disappointed that so many
people haven't seen the article before. It's been in print for 20 years,
and frequently mentioned on this newsgroup and elsewhere. There are a
lot of other good articles in the _Antenna Compendium_ series -- people
who don't have a set have been missing a lot. But it seems like, more
and more, that the web has become the sole source of information for a
growing number of people. Make that the web, AM talk radio, and Fox news.

Roy Lewallen, W7EL

"Roy Lewallen" wrote
Walt's article was really the first one I ever saw that explained the
phenomenon of currents on the inside and outside of the coax -- my
article is really just an extension of his work.

Roy Lewallen, W7EL

Roy,
Although no credit is given or author claimed, the Radio Works Product
Manual includes a similar drawing and detailed explanation of same. This has
been in print every year for at least the 6 years that I have been buying
products from them. It is the basis for their design, production and
marketing of the current-type baluns. Radio Works also recommends a line
isolator at the transmitter-end, due to near field coupling of antenna
currents onto the coax shield that a Balun cannot prevent. I have never used
that product but it is popular.

Jack

On Sat, 19 Mar 2005 12:35:48 -0800, Roy Lewallen
wrote:

Walt, I intended to include a link to your article and looked on your
web site for it before I posted my article. But I didn't find it in the
index. Where is it relative to your home page? I'll add a link to it.

Walt's article was really the first one I ever saw that explained the
phenomenon of currents on the inside and outside of the coax -- my
article is really just an extension of his work.

Roy Lewallen, W7EL

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
Roy, I changed the address to my web page on 3-13-05 to the one listed
above. I also changed the format somewhat.for better organization. The
new page lists the pertinent categories with links to the individual
chapters from Reflections and its appendices. You'll find the chapter
on baluns under the category "Read Chapters from Reflections 2," with
the title, "Some Aspects of the Balun Problem," Chapter 21 in the
book. Thanks for the assist.

Walt, W2DU

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


"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

Thanks, Jack, for the nice words--they're appreciated.

Walt

On Sun, 20 Mar 2005 03:21:56 GMT, Walter Maxwell wrote:

On Sat, 19 Mar 2005 12:35:48 -0800, Roy Lewallen
wrote:

Walt, I intended to include a link to your article and looked on your
web site for it before I posted my article. But I didn't find it in the
index. Where is it relative to your home page? I'll add a link to it.

Walt's article was really the first one I ever saw that explained the
phenomenon of currents on the inside and outside of the coax -- my
article is really just an extension of his work.

Roy Lewallen, W7EL

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
Roy, I changed the address to my web page on 3-13-05 to the one listed
above. I also changed the format somewhat.for better organization. The
new page lists the pertinent categories with links to the individual
chapters from Reflections and its appendices. You'll find the chapter
on baluns under the category "Read Chapters from Reflections 2," with
the title, "Some Aspects of the Balun Problem," Chapter 21 in the
book. Thanks for the assist.

Walt, W2DU
I forgor to mention that I recently wrote an addition to Chapter 21,
Chapter 21A for Reflections 3, telling what led to the development of
the W2DU balun. It also appears on my web page under the category
"Preview Chapters from Reflections 3," The idea came while fixing a
problem that arose in measuring the radiation patterns of antennas I
developed for use on various spacecraft at the antenna lab of the RCA
Space Center, Princeton, NJ in the 1970s

Walt, W2DU.

A few further comments.

For perfectionists, the attenuation along a twin-line wound on a choke
balun, is appreciably less than a coaxial line of about the same
length.

This is due to the lower Zo of the coax and also due to the very small
inner coaxial conductor diameter and its higher loss resistance.

This is not of great conseqence. The length of line involved is quite
small anyway. Less than 1/8th wavelengths at the highest frequency of
interest.

The power-handling and voltage-handling ability of twin-line is also
greater than coax line.

So, in general, a choke balun wound with Radio Shack, 18 SWG speaker
cable, is cheap, easier to construct, works better, and is more power
efficient than the small-bore coax usually used.
----
Reg, G4FGQ