Small Wonder Labs
PSK-40 Transceiver Kit 03/09/10
2000
20
Group 9 Assembly:
Group 9 assembly installs the transmitter final
amplifier and lowpass filter.
Using a 16" (40 cm) length of magnet wire
supplied with the kit , wind 18 turns on one of
the 1/2" (1.2 cm) diameter
yellow
toroids.
After passing the wire through the center hole
each time, pull it snug against the toroid as
you proceed. Make sure that each turn lays
flat on the core- 'crossed' or scramble-wound
turns must be avoided.
Doublecheck the turns count, adjust the
spacing between turns for a uniform
appearance.
Trim the excess wire length to 3/8" (1cm)
and strip the insulation off the lead ends using
a sharp knife. This needs to be fairly
thorough- rotate the core as you scrape until
the bare copper is visible around the lead.
Install at L11 and solder.
Using a second 16" wire length and yellow
toroid , repeat the above sequence and install
this 18-turn toroid at L13 (nearest to board
corner).
Using a third 16" wire length and the last
yellow toroid, wind 19 turns and install at L12
(
mounts at right angles to the two toroids
already installed
).
Find the 5" (12 cm) length of heavy wire
bundle supplied with the kit. Nick the
insulation jacket slightly to expose one or
more individual wires- pull these out of the
jacket (discard the jacket).
Select any 2 of the 4 wires and pass both
through the hole in the toroid.
Wrap this wire-pair snugly around the toroid
for one complete turn. It should look like
this:
Proceed to thread the wire pair through the
hole again and draw it snug . Repeat this
threading operation twice more (a total of 4
wire-pair turns through the hole in all).
Caution:
The wires must not cross over each other
as they are laid down on the core (i.e.,
there are no 'twists' built into the wire. If
(color 1) is on the leading edge in the
direction you're winding, it must continue
on the leading edge for all 4 turns.
'Clockwise' and 'counterclockwise' winding
senses are non-critical- either one is fine.
Here's what the result looks like:
Note the way the color-pairs are arranged as
they proceed around the core.
As you look through the toroid hole (as
shown above, confirm that the 2 (first color)
leads protruding are on the left and the 2
(other color) are on the right.
Cut the protruding leads to a length of 1/2",
strip these with the wirestripping tool and
install at
T2
. Doublecheck the insulation
colors before soldering this component
down.-
Install C40 and C43 (330 pF monolithic caps ,
'331J').
Install C41 and C42 (680 pF monolithic caps ,
'681J').
