[Elecraft] What Vertical Antenna Do I Need?

[Vic K2VCO]

Stuart Rohre wrote:
> They are coax 
> fed,with bead chokes on the coax so that bringing off the coax from the 
> center is not a problem.

This isn't true.  The bead balun solves the problem of current flow on 
the outside of the coax which occurs when the feedline length is such 
that the outside of the coax has a low impedance compared to the 
impedance of the line (that is, the common mode impedance is not much 
higher than the differential mode impedance).  It does *not* prevent 
imbalance caused by capacitive coupling between the outside of the line 
and one of the legs of the vertical dipole.

It's still a good idea to try to reduce such coupling.  Having said 
that, it probably doesn't matter much in practice unless you run the 
coax parallel to the antenna for some distance.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco