Topband: K9AY Loop Revisited

[K9AY]

de W8JI...

> There isn't any evidence that a short metal mast hurts performance,
> but there is strong evidence the antenna is dependent on a moderately
> good ground and that the feedline shield should NEVER be connected to
> the same ground as the antenna. Neither should the mast.
>

Feedline isolation will rarely be needed with the K9AY loop. In the several
installations of my personal versions, the feedline and antenna have both
been connected to ground, with no ill effects (I use a 4-foot ground rod of
1/2"
copper tubing). The ground connection of the K9AY loop has two main
purposes: 1) decoupling the feedpoint and termination, allowing them to be
located adjacent to one another for easy switching, and 2) connection to the
"ground image" or counterpoise that is part of the antenna.

In cases where the local ground is so poor that the feedline becomes
the antenna's primary "ground," the main problem is distortion of the
pattern due to the asymmetry of this one-wire counterpoise. The preferred
solution is to improve the ground system.

73, Gary
K9AY