QRP PROJECT Blue Cool Radio, Руководство пользователя

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Rev:Nobember 20. 2006
17
Building the current transformer and the SWR/Power measuring unit.
You now will handle the first torroid in this kit. It is the smallest one you
have to deal with, it is only 4,5x1,9x2mm and it is made from N30
material, that´s a ferrite. Wind exactly 22 turns trough the ring. I know,
there ares some mistery tales about torroids to hear in the field, but it is
absolutey easy. Just count INSIDE the ring, thats the hole secret. Spread
the 22 turns over the whole ring. This is the secondary winding. The primary
winding consists of only 1 turn. Actually 1 turn does not look like a turn
because it is only a piece of wire through the ring, but that is the trick with
torroids: because all the magnetic field is concentrated inside the ring, it
doesn´t matter what happenes at the outer side of the ring. You may use a
cut of from a resistor to form the primary, because it is easier to solder
then the laquered wire. However, solder the 1 turn primary firs and the thin
secondary after it because you may damage the thin wire if you do it
opposite.
[ ] Tr3 Ringkern N30 4,5x1,9x2 G-1 prim.1 turn 0,5mm wire / sec.22 turns
0,1mm laquered wire.
Ok, that was for training purpose ;-)
If you have done the small transformer with success, you will not have any
problems with the Low Pass Filter Torroids.
ATTENTION: Do not wind or Install L6 and L7 if you plan to install the
80m Option. use the description of L6 only as reference for L9
L6 is a simple Torroid coil wound with 0,4mm laquered wire. If you look at
the holes on the pcb for L6, you will see, that you must take care to wind
these Torroids in the correct direction to meet the layout. How? If you feed
the wire from back to front through the ring, wind the next turns clockwise.
If you feed the wire front to back through the ring, wind the next turns
counterclockwise. The picture shows such a torroid with 8 turns.
OK, lets start. Wind L6 on a yellow Torroid. Count inside the ring, wind 13
turns 0,4mm laquered wire. All turns should be
tautly (tight?) on the ring, if all 13 turns are
made spread them over 2/3 of the ring.
The enamel wire supplied with the kit can be
heat-stripped. A good method to do this is to
place a small amount of solder (a „blob“) on the
end of your soldering iron, then insert the wire into the hot solder
for a few seconds. Avoid scraping insulation off with a razor blade, as this
may nick the wire. Strip and tin the leads of the toroid before you mount it
to the board. You should remove the enamel from the leads up to about 3
mm from the core. You should see only bare wire (no insulation) on the side
to be soldered. Now install the torroid. While soldering hold it tigh against
the board to give it a stable position. Do NOT glue the Torroid to the board.
[ ] L6 Amidon T37-6 13Wdng 0,4mm CuL F/G-2
Now L9, it is wound the same way as L6. Use the same direction for the
winding, use the
0.5mm wire .
[ ] L9 Amidon T37-6 (yellow) 11 turns 0,5mm CuL H-2
The next 2 Torroids must be wound the opposite direction due to the
geometrie of the board. We didn´t do this to annoy you, the geometrie is
the result of some RF rules which claim the wire length of coils to be as
short as possible.
Do not wind L7 if you plan to install the 80m option, use text as
reference forr L8.
Make L7: L7 gets 17 turns of 0,4mm laquered wire on a yellow ring .
Attention, take care the geometrical aspect. If you wind from back to
front, this time wind counterclockwise. If you wind front to back, this time
wind clockwise.
[ ] L7 Amidon T37-6 yellow 17 turns 0,4mm wire F/G-2
To make L8 use the same technik as for L7, but use 0,5mm wire.
[ ] L8 Amidon T37-6 yellow 10turns 0,5mm wire
H-2
Ok, now some remaining parts and this section is complete. Remember how
to handle BB12 diodes, avoid shorts by placing them too close down to the
board.