[TowerTalk] Current Choke for Ladder Line

[Patrick Greenlee]

My by-the-numbers OCF dipole (Carolina Windom) is approx 90 ft on the  
short side and 180 ft on the long side and uses the "right kind" of 
balun at the top where the dipole legs converge selected to NOT choke 
out the common mode current on the outside of the 22 ft of vertical coax 
hanging down to the other balun which is between the 22 ft of coax which 
radiates and is part of the antenna and the coax feedline.  This lower 
balun DOES prevent common mode current from flowing on the outer surface 
of the coax feedline and getting back toward the shack. I can operate 
just about any segment of any band (using a tuner) from 160-10m.  
haven't actually tried it on 6m.

With the exception of the 22 ft of coax which is supposed to radiate I 
don't see any common mode problem between the lower balun and the shack 
up to the max power I have available (about 1000-1200 watts PEP)  which 
I never use except for tests.  I typically  run the amp at or below 
7-800 watts.

I can't say if I am just lucky or if OCF dipoles like  mine with the two 
different but appropriate baluns don't have common mode radiation 
problems but mine doesn't.

Patrick     NJ5G

On 5/12/2015 3:14 PM, Bry Carling AF4K wrote:
> I would think that the OCF is FAR more likely to radiate off the feedline than a conventional
> dipole in most circumstances.
>
>