nope - only concern yourself with the outside measurement - this is how
many antennas are reinforced 0 with extra inner tubing to strengthwen a
splice or the central portion of the element - doing so will not have
any electrical effect on the elements reaonatinf 0 suspect that is due
to old friend "skin effect"
K4OJ
Dino Darling wrote:
> I have a couple of old Hy-Gain antennas with swagged elements. I get
> these for free when I take down old towers.
>
> Lets say, for argument, that we have two elements. One slides inside
> the other, which is swagged in order to meet the outside diameter of
> the first one.
>
> These two elements can be tuned to different frequencies by adjusting
> the length the first element slides INSIDE the other. To exaggerate,
> lets say the first element is 12" inside the swagged element, but the
> only contact area between the two elements is the few inches where the
> second element is swagged. The rest of the first element is hanging
> out "in free space" (for lack of a better term).
>
> Here is the question...will the element INSIDE the other affect the
> electrical length of the entire assemble due to the extra metal in
> "free space"? Although it is a direct short, will there be any
> capacitance much like a gamma match where one material is suspended
> inside the other?
>
> Dino...k6rix@arrl.net
>
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