[HBR] HBR with switched coils

[Ian Wilson]

You can vary the inductance of toroids slightly by squashing some
of the turns together. This is not particularly easy to do when the
toroids have been built into whatever assembly you are using. I
usually measure toroids after winding, and adjust to the required
inductance.

I don't know how much excess gain the front end has on the
various bands (i.e. how far into regeneration you can move the
RF amplifier). Something to experiment with...

73, ian K3IMW


On Tue, Feb 3, 2015 at 7:18 AM, john_wilkinson3 at sky.com <
john_wilkinson3 at sky.com> wrote:

> Thank you for the help.I did think of using toroids for the RF stage, but
> I was worried how to vary the coupling from the transformer primaries.As I
> understand, in the original design the coupling was varied to just below
> the point of re-gen, to give the maximum selectivity. How would I do this
> using toroids? does anyone have experience of trying to do this?
> Also How would I vary the inductance of toroids when aligning them?
> regards,John
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