>
> This morning, in conversation with a professional pilot,
he has
> suggested that if the central core of the coax cable is
connected
> to the part of the dipole pointing down, that may well
account
> for some of the reported problems [distorted audio],
especially
> when the aircraft is on the ground.
He said what? In coaxial transmission line theory, the
shield does what the center conductor does. That is...if
the line is balanced (i.e., ferrite bead "balun" added). If
not, the coax shield is radiating, so it's possible that
flipping the connections will improve....or make things
worse, where the problem is ground reflections.
On the common NAV antenna (cat's whiskers on a vertical
fin), using the common type coax "balun," the center
conductor is not electrically connected to anything. It
just...ends! It works because of....the above mentioned
theory.
Fred F.
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