[TowerTalk] current balance in ladder line?

[jimlux]

On 1/18/11 8:46 AM, Andy wrote:
>> Why is the current into the antenna balanced?
>
> Well, it isn't always.  You are right to question that assumption.

If there's only two terminals, the current is, by definition, balanced 
at that point.

What might not be balanced is the current *distribution* and any 
currents that are induced on nearby objects (e.g. the outside of the 
shield of the feedline, or common mode current in a balanced line)

>
> An OCF (off-center fed) dipole does not have balanced currents at the
> feedpoint,

Not true, from basic circuit theory.  *at the feedpoint* the current 
into one terminal will be exactly the opposite of the current into the 
other terminal.

What's not symmetric is what happens after that.  The current 
distribution will likely not be symmetric, so any conductor in the 
vicinity will see a different contribution from the two sides, and, so, 
will have some current induced in it.