[Elecraft] H.e.l.p!!

[Tom Hammond]

Hi Jim:

>The last time I wound a coil, it was on an oatmeal box.

Well, THAT sez a lot!  Heheheh!

>Questions
>
>1. How tightly do you wind the wire around the torroid.

Tightly-wound windings are generally NOT REQUIRED. However, this having 
been said, when I wind 'em, I pull the wire tightly around all four sides. 
In fact, I take extra care to try to make the winding snug.

A fairly easy way to accomplish this is, once the wire (a 'turn') has been 
pulled thru the core, pull it tight and straightened out to remove 
bends/curves, then FORM the wire around the last inside edge of the core 
and around the two outside corners so the wire takes a 'set' before you 
thread the next turn thru the core. Thread the next turn thru the core and 
repeat this step.

Once all turns have been laid on, then go back with a fingernail and spread 
out the turns so they're nicely spaced around the periphery of the core, to 
cover about 80%-85% of the circumference. This 'spreading' will also help 
to take up a small bit of excess wire 'slop' if any exists.

2) Install the wires into the PC board snuggly and solder then into place. 
Then, using needle nose pliers, grip a lead and pull on it WHILE reheating 
the pad. Hold it in place until the joint has cooled. This, combined with 
tightly-wound turns, should ensure that the core is held decently snug. A 
small amount of 'flop' is not a problem.

>2. Is there plenty of wire for a few mistakes, or should I go ahead and 
>order more?

Generally Elecraft will have you wind the smaller (fewer turns) inductors 
first. So, if you botch one or two, there will be more than ample wire for 
the task. I generally wind up with well over a foot (or three) left.

REMEMBER to do a PREMIUM job of stripping and tinning the leads of your 
toroidal inductors. Poorly tinned toroid leads (PTTLs) still account for a 
SIGNIFICANT part of the service problems with Elecraft kits.

73,

Tom Hammond    N0SS