Guy Olinger K2AV wrote:
> Martin has the right instincts, says it feels fishy for this. But it's
> worse than he thinks. And don't even consider using ferrites.
>
> The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to produce
> a
> residual inductance value in the right order of magnitude to cancel a
> typical residual capacitive reactance from a 160 meter 5/16 wave single
> wire folded counterpoise, AND provide enough coupling to make the
> transformer work, AND maintain a low enough loss to operate QRO without
> heating, or especially to operate QRP without further handicapping the
> operator with needless loss. This allows the builder of the "simple
> solution" to prune the wire to get resonance and remain somewhere around
I'm trying to understand here what is magic about powdered iron.
It is true you can't just use any random piece of ferrite.
But if the T300A-2 were replaced with LOW PERMEABILITY ferrite
having the same permeability as a T300A-2 core, it would produce
the required residual inductance. The loss of low permeability
ferrite is extremely low, probably lower than powdered iron.
Coupling is a function of how the turns are wound, not the core material.
Am I missing something?
Rick N6RK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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