[Elecraft] KAT100 with Ladder Line

[Goody K3NG]

Using any balun with an unbalanced tuner to feed balanced line can be 
bad news (your mileage may vary, standard disclaimers apply).  Under 
highly reactive loads, a balun used like this can become quite lossy.  
There's a couple articles in publications and on the Internet on this, 
but Cebik's article is one that comes to mind ( 
http://www.cebik.com/link/l-bal.html ).  It's better to run a real 
balanced tuner like a Johnson Matchbox, the MFJ Balanced Line tuner, or 
others, if you can.

Don Wilhelm wrote:
> Curt,
>
> There seems to be a misconception among hams that when using 450 
> ladder line, a 4:1 balun is the best thing to use.  While that may be 
> true in some cases, in many other cases, a 1:1 balun will serve 
> better.  It all depends on the feedpoint impedance of the feedline at 
> the shack end, and that has little relationship with the fact that 450 
> ohm line is being used - i.e. the  feedpoint impedance is *not* the 
> characteristic impedance of the transmission line in most cases.  The 
> feedpoint impedance looking into the shack end of a multiband antenna 
> can vary from extremely low to extremely high - it all depends on the 
> length of the antenna and the length of the feedline.
-- 

Blog: http://thek3ngreport.blogspot.com/