> Anyone have any experience with toroid tank coils? Is
> efficiency normally
> poor on the higher bands?
I'd never use a torrid in a wide frequency range tank
circuit. If the toroid behaved perfectly as in theory it
would not work at all over wide frequency ranges.
This is because in a normal pick up and hold tank switching
system, without significant flux leakage in the toroid the Q
would go to zero along with the inductance on higher bands.
The only way around that problem is to not short unused
turns, and then you would get into a switch arcing problem
on higher bands!
In practice most lower mu physically large toroids will
barely have enough flux leakage to work in circuits
requiring low Q when turns are shorted. I suspect that is
the reason for your low efficiency.
73 Tom
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