Topband: Effect of DC on Ferrite Toroids?

[Jim Brown]

On Tue, 09 Jan 2007 11:56:42 -0500, David Sinclair wrote:

>Remember, cause
>a device to run non- linear, and you might get it to work as a crude
>rectifier or mixer. Not good. A small core running near saturation could
>possibly introduce signal distortion in some cases.

YES!  And a LARGE core running near saturation could also introduce 
distortion -- that is, INTERMOD!  This could be a VERY big deal in a 
voltage balun, because the core carries the entire output of the 
transmitter. I'm beginning to suspect this as a reason why some stations 
running good gear are broader than others. 

It is NOT a big deal in a sufficiently beefy choke (current) balun, 
because the current balun sees only the common mode current, and if it's 
sufficiently beefy, is reducing that current to a very small value (and 
thus staying below non-linearity). 

I'm wondering if anyone has measured significant intermod in a voltage 
balun that is being driven hard?  Tom?

73,

Jim Brown K9YC