[Elecraft] Ferrite transformer losses, 43-foot vertical and the K3

[Jim Brown]

On Sat, 20 Sep 2008 20:25:51 -0500, Sandy wrote:

>When a high VSWR exists with a toroid ferrite balun due to a high inductive 
>or capacitive reactance and the toroid begins to heat, the losses will rise 
>to quite unacceptable losses and can possibly destroy the balun itself, even 
>tough the tuner used appears to have reduced the VSWR on the input side of 
>the circuit to a very low value.

The word "balun" is far too broad and confusing in the context of this 
statement. Dissipation in a common mode choke wound with coax, whether on a 
toroid or only a string of beads (both are so-called "current baluns") is 
UNRELATED TO SWR. It is DIRECTLY related to IMBALANCE in the antenna. Further, 
the higher the choking impedance, the lower the dissipation. 

There appear to be significant gaps in your understanding of baluns and common 
mode chokes. My tutorial includes an extensive discussion of common mode chokes 
wound with coax. http://audiosystemsgroup.com/RFI-Ham.pdf  

73,

Jim K9YC