[600MRG] s/c inductor tuning loops

[Bart Lee]

Hello Rudy and all,

Thank you for that experiment.  I passed it on to John Staples (PhD), W6BM,
at the California Historical Radio Society.  I had passed on some earlier
comments of his.  He notes:

[Rudy] used a loop of wire instead of a copper disc at least a skin depth
or two thick.

Maintaining high Q requires low dissipation in the perturber, so a large
current path must
be presented to the circulating current.   (A superconductor would be the
best, of course).

Any sort of connections, like clamps or alligator clips would introduce
additional losses and therefore lower Q.

==  ==

So maybe the disks do not affect Q as much as a wire loop would?

73 de Bart, K6VK ##



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On Tue, May 8, 2018 at 4:13 PM, Rudy Severns <n6lf at epud.net> wrote:

> Hello All,
>
>
>
> Over the past few days there’s been some discussion of floating short
> circuited loops or metal discs placed inside a coil to adjust the
> inductance.  The idea absolutely works but it’s a disaster for the coil Q.
> To illustrate the problem I ran a quick experiment to illustrate the
> problem.  I’ve written a short note on the work which is posted at:
> www.antennasbyn6lf.com .  In due course I’ll expanded this to give a
> detailed explanation of the phenomena and show a similar but not nearly as
> serious effect in variometers but this will have to do for right now.
>
>
>
> GL and 73, Rudy n6LF
>
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