Elecraft KXAT1 User Manual
Page 5
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Install L1 vertically on the PC board as shown by its component outline, then pull the leads taut on
the bottom of the board.
Trim and solder the leads of L1. When soldering, make sure that the solder binds well to the leads. If
the lead appears to be an "island" in a small pool of solder, chances are it is not making good contact.
Measure from pad to pad using an ohmmeter to verify the connection (low resistance).
Wind and install L2 and L3 using the same procedure you used for L1. The number of turns and wire
length for each inductor is shown below.
__ L2, 17 turns (11" [28 cm])
__ L3, 25 turns (15" [38 cm])
Fold C10 down toward K6 and L3, but not so far that it touches the leads of these components.
T1 is wound on a ferrite toroidal core (gray, FT37-43; may have an orange dot). Cut two 10" (25 cm)
lengths of #26 enamel wire, one red and one green. Inspect the wires closely to make sure the enamel
coating is not chipped or broken.
Twist the two wires together, crossing over each other about 3 to 4 times per inch (1-2 times per cm).
Wind the twisted wires onto the core as shown below, using 10 turns. Each pass through the core
counts as one turn, and turns spacing should closely resemble the illustration.
i
As shown below, the wires labeled (1) and (3) should originate from below the core, and
wires (2) and (4) from above it. This will ensure that the transformer has the correct phasing.
3 (RED)
1 (GRN)
2 (GRN)
4 (RED)
Trim the leads of T1 to about 1/2" (12 mm) long. Then completely remove the insulation from T1's
leads up to the edge of the core, using a solder pot, hot soldering iron tip, sand paper, or by scraping with
an X-acto knife. Do not attempt to burn off the insulation using a match or lighter, as the flame may
fuse the pairs of wire together, causing them to become shorted.