Elecraft KX1 Manual - Manual (Page 41)

40
E
LECRAFT
i
In the following steps you’ll wind and install toroidal
inductors L1 and L2. They must be wound as exactly indicated in
the instructions or the transceiver will not operate correctly.
3
Turn the board bottom face up with J1 in the upper right corner.
Locate the printed outlines for L2 and L1 in the upper left corner near
J2.
Locate the four toroid cores. There are two yellow T37-6 cores
and two dark gray FT37-43 cores. Use the yellow cores to make L1
and L2.
i
Although the yellow and gray cores look similar, they have
very different electrical properties. You must use the yellow cores
for L1 and L2. The transceiver will not work if you use the wrong
cores. See Identifying Toroid Cores, page 9, for more information.
Wind L2 first as follows:
_ Cut a 13” (33 cm) length of red enameled wire.
_ “Sew” the long end of the wire through the hole in the core
for a total of 14 turns as shown in Figure 16. Count one
“turn” each time the wire passes through the center of the
core. There are no “half” or “quarter” turns when winding a
toroid. Match the winding direction shown in the figure or the
leads won’t line up with the solder pads on the circuit board.
_ Spread the turns around the core so the finished result looks
like Figure 16.
3 Prewound toroids are available from an Elecraft-approved source. See
www.elecraft.com for details.
REMOVE INSULATION
(SEE TEXT)
Figure 16. Toroidal Inductor L2.
i
In the next step the toroid leads will be stripped and
tinned. The leads must be prepared correctly to provide good
electrical contact when installed.