Elecraft K2 Owner's Manual - Manual (Page 73)

72
E
LECRAFT ®
Locate the "binocular" (2-hole) ferrite core for T4. Wind 2 turns
of green-insulated hookup wire (5", 13 cm) through the core as
shown in Figure 6-28. This forms the 1–2 winding. (Do not use
enamel-coated wire.)
Cut and strip the two leads using the lengths shown. Be careful
not to nick the wire.
2
1
1/2” (13mm)
7/8” (22mm)
Figure 6-28
Wind a 3-turn winding (3–4) on top of the 1-2 winding, but with
the wire starting and ending on the opposite side (Figure 6-29). Use 7"
(18 cm) of white-insulated hookup wire (not enamel-coated wire).
Prepare the leads in the same manner as above.
4
3
Figure 6-29
Before installing T4, verify that the screws holding the 2-D
fastener beneath it are tightened, and that #4 internal-tooth lock
washers were used. It is important that these screws not come loose
sometime after T4 has been installed.
Install T4 to the right of T3, inserting leads for the 1–2 and 3–4
windings into their matching numbered holes. T4 should rest directly
on top of the screws that secure the 2-D fastener beneath it. T4 should
also be parallel to the board, not tilted to one side. Pull the leads taut
on the bottom and bend them to hold the transformer in place. Do not
solder T4 yet.
Use two 2" (5 cm) lengths of bare hookup wire to form the 5–6
and 7–8 windings on T4 (Figure 6-30). (These are more accurately
described as links, each being just a single turn.) Route the bare wires
through the core first, then bend them down and insert them into their
numbered holes. Do not solder yet.
8 7
6 5
Figure 6-30
Adjust all of the windings of T4 as needed so that the transformer
is positioned directly above its component outline. Pull the leads tight
on the bottom, then solder.
Inspect all four transformers in the transmitter area closely, on
both top and bottom, for shorts or cold solder joints.