[Antennas] Vertical question re current balun

[DJED1 at aol.com]

"What, if any, advantage would there be by putting a current balun  a
quarter wave from the feedpoint of a vertical?"
 

Not much benefit to a balun on an unbalanced antenna.  When you've  got a 
dipole strung up, the balun forces the current to feed the two halves of  the 
dipole, and discourage the current from going down the coax.  When  you've got a 
vertical with a ground plane, one side of the coax feeds the  vertical, and 
the shield feeds the ground plane (radials, ground screen,  etc).  Since, in 
general, the coax is on the ground, there is no reason for  the current to prefer 
the coax to the ground plane.  And it doesn't matter  much whether the 
current flows along the ground on the coax or the radials. So,  no real need for a 
balun.  
Now if you have an elevated ground plane vertical there might be some  reason 
to suppress current on the coax.  Then a current suppressing choke  might be 
of some benefit.
Ed WB2LHI