Topband: Shunt feeding the Skyneedle - new developments

[Roger D Johnson]

It may not be obvious but often you can get better bandwidth by NOT tuning
for 1:1 at the desired frequency! Those familiar with the Smith chart probably
already know this.

A narrow band antenna will produce a curve between a "U" and a "V" on the
Smith chart. If you tune for a 1:1 SWR, you bring the nose of the curve to the
center of the chart. This often leaves the "tails" outside the desired SWR
circle. If you continue until the nose goes to the opposite side of the SWR
circle, it brings more of the tails into the circle. The resulting SWR curve is
a "W" shape. It won't be 1:1 at any frequency but more of the curve will lie
within the chosen SWR circle.

73, Roger


On 2/22/2014 11:03 AM, Charlie Cunningham wrote:
> Well, I agree with all that, Carl. But Carl Braun, was reading "dead-flat"
> 1:1 at the transmitter end of his cable. I believe he is done!! The antenna
> Q is what it is! As for "improving his 2:1 VSWR bandwidth" he could reduce
> his radial field and increase his ground losses to improve his 2:1 "BW" -
> but I believe that to be self-defeating!! I'm not "missing your point" - I
> just don't see what you'd change to improve on a "flat" line! Carl is well
> past the point of "diminishing returns"!
>
> The math doesn't "lie"!
>
> Charlie, K4OTV
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