[Elecraft] Winding my first torroid

[Leigh L. Klotz, Jr.]

Chris,
Here are some things about toroids.

1. Everybody tells you to count the turns as you go through the toroid, 
but nobody ever tells you how to check it afterwards.  Once you've 
wound, count the number of turns on the inside of the ring and you can 
verify the number to make sure it's right.

2. There's two ways to wind them and they "wind up" being mirror 
images.  Sometimes it doesn't matter, but usually you have to do it the 
right way or else it won't line up with the holes.  Start out either 
left on top or right on top, and keep it that way.  Once you've wound it 
and it doesn't fit the board, flipping the toroid itself over won't help.

3. Pay careful attention to getting the enamel insulation off the ends 
of the wire, up to and just past the point where the wire goes into the 
board.  Any insulation that touches the PC board is a recipe for 
trouble.  Don't wear shorts when you're tinning the leads.  (Not that I 
have any experience with that...)

4. If there are pictures, make the toroid windings look like the 
pictures.  If not, make it take up 80% of the core.  See also #2 if 
there are pictures.

5. Always double and triple check to make sure none of the windings 
cross over each other or get "knotted" up.  (Remember in Ghostbusters 
when they said, "Never cross the streams!"  They didn't say why, but my 
guess is that it has to do with flux linkages.)

6. And finally, if you want to eliminate that asymmetric wire, you can 
run center the wire in the toroid before winding by holding both ends of 
the wire, making it into a U and, and dangling the toroid from the 
center of the wire like a necklace or a charm bracelet. Then wind back 
both ways, (N-1)/2 turns. The wire will always come out centered. 
Unfortunately, you have to think harder to deal with #2 if you do this, 
because everything winds up backwards from how you start. Obviously this 
works out best for odd-numbered turns counts.  For even counts of turns, 
give one side an extra turn and start it out longer by 1/2" for T30 and 
1" for T50. 

73 es GL,
Leigh/WA5ZNU

> Hi all,
>
> I'm at the point with my KX1 build to wind my first
> torroid and I have a question.
>
> In the man it says to cut 13" of red wire, after
> winding 14 turns on a yellow core, I still have a lot
> of extra wire.
>
> Almost 2" on one side and about 4.5" on the other. 
>
> Is this the norm?
>
> Just want to make sure things are right before I trim
> and tin.
>
> Thanks
> -chris
>
>