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Winding a 1 to 49 transformer on a FT-140-43 core

This page was last updated : 21-Oct-24 22:29:34

This page describes how to wind a 1 to 49 transformer for the DG1JAN XOTA on a FT140-43 core.

Step 1

Cut 2 pieces of wire. one of 18 cm and one of 115 cm and strip them both on one end of the enamel for 2 cm.

Step 2

Tin the exposed wire and solder them together. 

 

Step 3

Use a combination plier to clamp the wire aprx 14 cm from the end leaving at least 2 cm of wire from the primary wire free.

 

Step 4

While clamping the wire use another plier to twist the wire on the solder part (right in the picture below) to get a even twist. 12 to 15 twist should be OK (image below shows 12 twists).

 

Step 5

Bend the soldered together wire to a 90 dgr angle and wind the first turn. 

 

Step 6

Pull the wire 2 times more through the core as shown below.

 

Step 7

Leave the short wire point outside the core and make a additional 18 winding's through the core.

 

Step 9

Trim the long wire to aprx 5 cm and strip both the primary and the secondary wire aprx 5mm outside the core from it's enamel and tin it. 

 

Step 10

Use needle nose pliers to make a loop from 0.6 mm silver wire (or any wire you have) which is big enough the hold the twisted wire.

 

Step 11

Test if it fits in the GND soldering hole (trust me, I made the mistake of not testing before). 

 

Step 12

Bend the 2 wires aprx 3 mm from the side of the core for 90 dgr as show below and when needed trim them to aprx 2 cm.

 

Step 13

Lift the silver wire loop, pull the twisted through it, fit the single wires through the in and ant hole, and pull the loop wire through the PCB and guide when needed the single wires to place the core on the PCB. 

Other side for reference.

 

After a final inspection, you can use the tie wraps to fixate the core on the PCB and solder the GND, ANT and IN wires.

Now have a refreshment, cup of thee, coffee etc, sit down, relax and appreciate your work. 

 

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