[RFI] Current balun construction?

[Jim Brown]

On Sun, 22 Feb 2009 09:26:56 -0600, Peter Laws wrote:

>Is there any magic to the spacing of the beads when you build a
>current balun?  I bought a kit from Palomar a while back in an attempt
>to cure some issues.  It's just a series of beads and some shrink
>tubing to hold it in place - pretty slick, less than $20.  

The only thing that's slick is the guy who sold it to you for five times 
what it cost him. It's a LOUSY excuse for a common mode choke.

>Stuck it on
>a length of LMR400 or 9913 and stuck some PL259s on it.  No sweat.
>Didn't operate as desired, but that wasn't the fault of the balun.

Yes, it IS the fault of the so-called balun. Study 

http://audiosystemsgroup.com/RFI-Ham.pdf 

>Question is, if I thought I needed more choking, could I just assemble
>another one and add it in to the feedline?  Or would it be better to
>take the existing unit apart and rebuild it with all the beads
>"touching"?

The best thing you can do with what you bought is put them in your junkbox 
for a rainy day. 

73,

Jim Brown K9YC