Please DO NOT adjust the turns on any of the toroids in the K3 to make
them "look nicer" :)
In some circuits, we need to hold 2% or better tolerance on inductances
to meet filter passband cutoff or ripple criteria. We carefully
hand-adjust the windings after the toroids are mounted, because it's
not practical to control them to this tolerance at the winding house. A
lot of very expensive test equipment is brought to bear on this as we
sweep for best return loss (lowest SWR) and the required passband
shape.
Having the turns spacing slightly irregular may not look as pretty, but
trust me, they're where they need to be. This is one reason for the
large-gauge wire on toroids in the low-pass filters. And it has no
significant impact on their self-shielding characteristics in our
applications.
We'll be adding a note about this to the assembly manuals.
73,
Wayne
N6KR
---
http://www.elecraft.com
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