Toroids

About Winding Toroids

The TAK-40 makes use of toroidal transformers and inductors. Here are winding instructions.

L204 has two windings, the primary (input side) is bifilar, 12 turns #30
enameled wire with alternate ends connected to form a center tap. The
secondary is just 8 turns of #30 enameled wire. The core is a FT37-43

L301 - 52 turns #26 enameled wire on a T50-2 core. Remove turns as necessary
to put the VFO in the right range.

L401 has been changed for better PA drive: Wind 2 windings on a FT50-43 or
FT37-43 core, one with 8 Turns of #26 enameled wire, 1 with 2 turns #26
enameled wire. Remove the enamel from the wire ends (all four) and connect
on end of the 8 turn winding to 1 end of the 2 turn winding. This junction
connects to L401's center tap (12 VDC, C407). The other end of the 8 turn
winding goes to the Drain of Q401. The other end of the 2 turn winding goes
to C402.

L402 is wound on a FT50-43 core I call out 16 turns but it works with as
little as 5 turns of #26 enameled wire bifilar wound, with alternate ends
connected to form a center tap.

L403 - A single winding of #26 enameled wire on a FT50-43 core 15-20 turns.

L404 - A single winding of #22 enameled wire on a T50-2 core, 10 turns


How to clean insulation from toroid wires

Contributed by KG8RV

Here are some pictures of how I clean insulation off of toroid wires.
Take a puddle of solder on a big soldering iron (40w maybe) and run the wires
through it until the insulation is burnt off of it. When done, you have a nice
tinned and clean connection to solder to.

Solder puddle examples:

Click for a higher quality picture
001 002 014

Tinned wires:

Click for a higher quality picture
003tinned

An example of my bifiler winding (9 turns):

Click for a higher quality picture
012bifilar

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License