[TowerTalk] common mode chokes, baluns and multiband, doublets

Wes Stewart wes_n7ws at triconet.org
Tue Dec 12 13:35:22 EST 2017


On 12/12/2017 10:19 AM, Ward Silver wrote:
> > "Balun", def: the most misused and misunderstood word in all of ham radio.
> My approach, when discussing baluns, is to present the "balun" as a 
> "function," not necessarily a "thing."
> The balun "function" is to transfer power between balanced and unbalanced 
> systems while at the same time providing isolation between them.
> Any "thing" that implements the function can be considered a "balun."  There 
> are lots of "things" that implement the "function."
> For example, here's a list of "things" that are all considered to be "baluns":
> - coil of coax
> - coax wound on ferrite cores
> - coax through ferrite beads
> - quarter-wave sleeve
> - Guanella transmission-line structure (a.k.a. "current balun")
> - Ruthroff transmission-line structure (a.k.a. "voltage balun")
> - half-wave transmission-line structure
> - etc
> Some of the "things" also implement impedance transformation, but impedance 
> transformers don't necessarily perform the balun "function," adding to the 
> general confusion.
> 73, Ward N0AX

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