"Richard Clark" wrote
On Sat, 22 Jan 2005 06:59:07 -0600, "Richard Fry"
wrote:
A coax feedline that does not project on a
radial normal to the dipole feedpoint will have current induced on its
outer
conductor by coupling to the dipole -- whether or not a balun is used.
...Their discussion and my own comprise a general solution that
responds to the necessary correlative:
What is the degree of coupling?
__________________
I will email you* a NEC study showing two surface patterns from a 1/2-wave
dipole; one with no feedline, and one having a conductor approaching within
2" of the center of the dipole and not attached to it, and not perpendicular
to the longitudinal axis of the dipole.
The second pattern simulates a dipole fed by a sloping coax cable connected
to the dipole feedpoint through a balun -- a fairly typical scenario for the
coax feedline.
You can judge the affect for yourself.
*and any others wanting to see it
RF
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