[TowerTalk] Johnson Matchbox Question

[Mickey Baker]

The KW Matchbox that I have is a simple device with a single inductor with
8 taps that all connect back to a 2 gang band switch.  I can’t speak to any
mods made.

W0QE has a comprehensive video:
https://youtu.be/OvRI1m4bBjQ

Mickey N4MB

On Sun, Mar 13, 2022 at 1:27 PM Tom Hellem <tom.hellem at gmail.com> wrote:

> I have a Johnson KW Matchbox that doesn't seem to be working quite right.
> It's very hard to accomplish a perfect match at times even though the load
> is well within the claimed capability of the tuner. The RF input from the
> TX is injected into an approx. 5 turn coil which surrounds a smaller
> diameter coil of many more turns. Looking at the 5 turn coil I can see that
> some previous owner had tried tapping different points on it for injecting
> the RF.
> Question- how critical is the tap point on this coil for proper operation
> of the tuner?
> The 5 turn coil is grounded on one end and open on the other, and is
> currently tapped approx. 1-1/4 turns from the grounded end.
> Does anybody know where Johnson tapped this coil when they built the tuner?
>
> Any input gratefully accepted.
>
> Tom
> K0SN
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