Vectronics VEC-121K - Manual (Page 13)

VEC-121K Owner's Manual Crystal Radio Set Kit
11
Phase 2: Winding the tuning coil
This portion of the assembly involves winding about 66 turns of 18 AWG
enamel coated copper wire over a 2½” area of the PVC plastic coil form. This
will take time, patience, planning and practice! Here are a few suggestions to
help you along.
You will be directed to unwind a length of wire from the 100-foot coil of enamel
wire in several of the following steps. Always unspool the wire, never allow it to
uncoil in Slinky
TM toy fashion. The unspooled length of wire should be laid out
in a straight line—do not allow it to simply pile onto the floor, or you will end
up with a hopeless tangle of wire. After unwinding a length of wire, use two
strips of masking tape to secure the remaining wire on the coil.
The winding on the coil should be smooth and even—with no gaps or kinks. If
the copper wire kinks during handling, smooth it out as best you can before
trying to wind it. We are going to wind a single-layer coil, this is called a
solenoid winding. The winding is done in several steps. You will be instructed
to stop winding after a certain amount of wire is wound. If you have a friend
who is willing to help, ask him to give you a hand winding the coil. Four hands
can be very helpful!
! Remove several 5-inch lengths of masking tape from the roll of tape. Keep
them within arm’s reach while winding the coil.
! Find the PVC coil form and the 100-foot hank of coil wire.
! Unspool about 15’ of wire from the 100-foot coil of wire. Leave wire
attached to the spool—do not cut it! Tape the remaining wire so it will not
unwind and become tangled.
! First, secure the wire at the starting point of the winding. Insert about 16”
of wire into the starting hole, and loop it back out of the adjacent wire hole
and pull tightly. Either end of the form may be used as the starting point.
This will secure the wire. The illustration below shows how to do this: