LDG JT-11 Manual - page 8
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Step 7: Unsolder and remove the coaxial cable connecting the FILTER board to the SO-239
connector on the back panel of the radio. Carefully melt the solder, then remove it using either
solder wick or a solder sucker. Repeat until all excess solder is removed and the cable can be
removed from the board and from the SO-239 connector. With the board unscrewed from the
chassis, you can move it around enough to reach the solder side with your soldering iron and
solder wick or solder sucker. Take great care not to damage the small toroid inductor through
which the cable is connected to the FILTER board. Keep the white insulating sleeve for reuse in
the next few steps.
Unsolder the cable from the SO-239 connector in the same way. Again, keep the insulating sleeve
from the shield but discard the cable; it will not be reused.
Step 8: Solder the RF IN cable from the JT-11 to the FILTER board. The RF IN coaxial cable is
the one connected to the front of the JT-11 (that is, the side nearest the front of the radio) through
a small toroid inductor. Connect the other end of this coaxial cable to the FILTER board, exactly
where you removed the cable in Step 7. The center conductor goes through the toroid. Again, take
care not to damage the toroid on the FILTER board. You can nudge the toroid around a little bit
to reveal the solder hole if needed, but the toroid wire is very delicate so be careful. Place the
insulating sleeve from Step 7 over the coax shield before soldering it to the FILTER board.
Step 9: Route the other coax cable (RF OUT) from the JT-11 to the SO-239 connector on the
back of the radio. The RF OUT cable is attached to the back of the JT-11 board to a solder pad
labeled "Antenna". Solder the cable to the connector; the coax center conductor goes to the center
pin of the connector. Again, use the insulating sleeve from Step 7 to insulate the shield before
soldering it to the ground lug on the connector.