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
|