Tricks for working with Toroids
When mounting toroids to the circuit board leave a little extra length on the leads. When you install it on the board twist the wires on the bottom of the board together. This will hold the toroid in place. Once it is soldered, just cut off the extra wire. Sure makes keeping the coil where you want it when soldering.
To twist wire together for Bifilar and Trifular Windings Cut the wires to the same length, I like to use a different color wire for each if I have it on hand. Tie a knot in one end holding all the wires together. Chuck the knot in a drill chuck, and turn until you get about 5 or 6 turns per inch.
Links to info on Toroids
Winding Toroids by WT9W (Includes table to calculate wire length)
Securing Toroids with Common Materials
Toroid Inductance Charts
Amidon Associcates, Specifications
A Toroid Tutorial
Assessing unknown Ferrite Toroids
Kits and Parts.com has some nice software and information on their web site
Software to calculate all kinds of stuff on coils including Toroids.
Sources for Toroids
I purchase most of my toroids from
Kits And Parts . com