Which wire? Which winding?
From the picture above we can see how to identify the polarity or magnetic sense of the
toroidal transformer.
If we were to use this toroid, where does the RED wire go? Where does the
WHITE wire go?
The answer is that in this case it does not matter so long as we are consistent!
So, say we pick the RED wire at the top of the transformer (the wires that are dotted on
the schematic and that on the physical toroid are pictured on the right-hand side) to go
to a 100nF coupling capacitor then it follows that the RED wire from the left-hand side of
the windings must go to the other 100nF capacitor.
Continuing, it then follows that the WHITE top wire should be connected directly to the
output. Whereas, the WHITE bottom wire (left-hand side of the windings) must be
soldered to ground.
Remember
Remember that we will not be winding a big ‘easy to see’ toroid with two different
coloured wires.
Instead, we will be winding 10 twisted bifilar turns of 33 SWG
enamelled copper wire onto a black FT37-43.
Winding these toroids is easy when you stay totally focused on the job. Once the 33
SWG wire has been twisted together, we treat it as though its one wire. We then wind
ten turns onto the toroid using the same counter-clockwise method shown earlier.
No excuses!
The toroid is smaller, but this is no excuse at all for making hard work out of what
is really easy to do. Indeed, there are far smaller toroids that you might have to
wind!
ASSEMBLY INSTRUCTIONS
RFLEGO Active Antenna Receiving Loop
page 59 of 66
