[Elecraft] Winding Toroids

[W7is at aol.com]

I  just finished building K2 #5600 and I found winding the  toroids to be   
extremely easy  ------  if you follow a few simple  rules.   Its true you  
have  to take great care when winding the toroids.   If you follow the 
directions in the manual exactly, you wont have any  trouble.    
Here is what I  found works best.   
1.  All toroids are wound in the same direction.  If you look closely at  
the  picture of the first toroid -- and wind it exactly as shown, all  other 
toroids will be wound in the same direction.  Make sure your wires 
exit the toroid exactly as in the picture.  Wind all the other toroids  
--  including the dual winding toroids in the same direction.  I kept the  
wire  pretty tight against the core so that the wires dont flop around  
on  the core.   
2. I  started by scrapping the enamel of the wire using a small knife  
and  that worked fine up until I got to the toroids with the dual  windings. 
Then  I needed to find a better way to clean off the enamel.    
After  experimenting with some extra wire I found that if you turn the 
heat of your soldering station to its maximum 850F,  heating the wire 
at the same time as you apply solder.  The high heat will vaporize  the 
paint and tin the wire perfectly.  Start at the end of the wire—dragging  
the  soldering tip towards where you want to end the tinning.  
Applying  liberal amounts of solder as you drag the tip.    I found this 
process works perfectly to remove the paint and tin  at the same time.   
Try it on  some test samples of wire until you get the hang of it.    
The secret is  having your soldering station set to maximum temp.   
This is  where you really need a variable temperature soldering station.  
If  you have your soldering station set to medium heat, it simply wont  work. 
3.  If you follow the winding directions exactly as specified in the manual,  
and  you count the number of turns exactly, you wont have any trouble with  
the  toroids.   The last step is to  count the number of turns a second time  
before you trim the wires.   I used a tooth pick to count the  number of 
turns 
outside the core.  But you need to experiment to be sure  your counting the  
turns correctly as noted in the manual.     
4.   When it came time to twist the dual wires together per the  
instructions,   
I gave the wires  slightly more twists than specified per inch.   Its 
important  
your  wires stay together for better mutual coupling.    Especially on T6.  
If  you wind T6 funky, that can effect your receiver performance in a way  
you might not appreciate.  
When  it came time to wind the toroid for the VCO shielding kit, I followed 
the directions exactly as specified and I didn’t  even have to fiddle with 
the 
winding spacing during the testing.  Trust the manual and follow the  
instructions 
exactly and you wont have any trouble.