[Elecraft] Toroids - Effect of Winding Spacing on Inductance andDistributed Capacitance

[Ron D'Eau Claire]

The link doesn't work for me either.  

There is a reason the Elecraft manuals clearly show the placement and
spacing of turns on the inductors. Unless the text says otherwise (such as
optimizing the output filter in the KX1) they should be wound just as shown:
spacing and number of turns. But it's not high precision work. If the coils
*look* like the pictures with about the right amount of core exposed in the
gap, and you have *exactly* the number of turns (counting the number of
times the wire passes through the center hole), the coil will work FB. 

One mistake many builders make is in thinking the wire must lie tight
against the toroid core all the way around in each wrap, or turn. That's not
so. A small gap between the wire and core is fine. Indeed, it's preferable
to pulling the wire so tightly the enamel gets scrubbed off or the wire
breaks! 

The second mistake is worrying too much about small breaks in the enamel
coating. The core is *not* conductive! Bare wire touching it is not a
problem. The problem is when two adjacent turns short out, usually where the
wire passes through the center hole, because bare copper on adjacent turns
touches. Not only can that cause trouble from the start, if it's a poor
contact between turns it can cause an intermittent that is very frustrating
to locate later. Again, don't be too aggressive about pulling the wire too
tight around the cores. Allow a natural, small, gap to form between the wire
and the core as you wind with moderate pressure on the wire.  

Ron AC7AC

-----Original Message-----
Jack,

Sounds interesting but the link in your e-mail 
(http://g4oep.atspace.com/coil/coil.htm) does not work for me.

Tom KG3V