[Boatanchors] Kilowatt Matchbox w/directional coupler- SWR calibration?

[Tom Osborne Sr.]

How far apart is the coupler in the Matchbox and the SWR meter you are
reading the SWR?  There can be a difference between the 2 meters if there
is any distance between them.  73
Tom W7WHY


On Tue, Sep 8, 2020 at 3:55 PM Brad Councilman <bc at councilman.com> wrote:

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> Finally testing after an arduous cleaning and reassembly process.
>
> Brings 155' of wire close to 1:1 on 75m.  Those old timers knew their
> stuff.
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> In SWR mode the meter dips like it should, but reads 3:1 when actual is
> close to 1:1
>
> Anyone have experience with these?  Wondering if the problem is within the
> directional coupler or the .01 mfd ceramic caps which are across both the
> meter and the 2k pot which adjusts the meter for full deflection before
> switching to SWR mode.
>
> Or is it a problem?  Did they intend for the indicated SWR to be accurate
> on a random wire?  Have yet to test it using both sides of my 600 ohm
> ladder line or with a coax fed antenna.
>
> Just curious.  Not sure I'm up for taking it apart again.  A bear to get
> the shafts to line up with the front panel.
>
> Thanks,
>
> --Brad  W1BCC
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>