Wondering if it's possible in any practical sense for
the windings to change on their own, or with
vibrations from mobile/portable operation.
Not just for the K3, but any toroid of similar
construction and mounting.
================
We used to go to Baskin-Robbins for "hand-packed" ice
cream because everyone knows it tastes better. ;-)
>>We carefully hand-adjust the windings after the
toroids are mounted.
================
[Elecraft] K3 Toroids: Why some have uneven turns
spacing (It's intentional!)
wayne burdick n6kr at elecraft.com
Mon Nov 19 19:52:35 EST 2007
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
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