[Elecraft] Toroids frequency range and baluns

[Solosko, Robert B (Bob)]

Jim,

	Why are choke baluns wound as a coil vastly superior to choke
baluns made with a sting of ferrite beads? With the coil type, you're
adding additional coax loss... What am I missing here?

73,

Bob W1SRB

 

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Brown
Sent: Saturday, September 20, 2008 4:17 AM
To: elecraft at mailman.qth.net
Subject: RE: [Elecraft] Toroids frequency range and baluns

On Fri, 19 Sep 2008 20:45:57 -0700, Ron D'Eau Claire wrote:

>"Balun" is an unfortunate, all-inclusive and misleading term. One 
>so-called "balun" may be as different from another "balun" in its 
>requirements and application as a motorcycle is different from railroad
locomotive.

Yes, it really is. 

>I stand by my statement when talking about a "choke balun" consisting 
>of a string of ferrite beads on some coax or a coaxial line on a coil 
>form such as I  described. The only losses caused by such a balun will 
>be those of the transmission line itself, which cannot be ignored if
the SWR is high.

Yes on all counts. BUT -- the chokes wound as a coil are vastly
superior. 

>So-called "baluns" that transform impedances are, typically, 
>transformers -- often transmission-line transformers. They're a whole 
>different animal and can be very unpredictable, especially when they 
>use ferrite or powdered iron cores and are exposed to a wide range of
impedances.

Yes. Again, poor use of words by the industry. 

73,

Jim K9YC


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