You will need
- Copper wire, frame, winding machine, Shuttle
Determine the type of spool that you intend to make. Depending on the usage conditions and the design coil inductance are divided into low and high frequency. For low frequency coils you'll need to fabricate a magnetic core (core) of steel plates. In the high frequency coils the core is either not used or it is made of a nonmagnetic material. This core allows without changing the turns of the coil to change its inductance.
Pick up the wire for winding coils. As a rule, in coils both types use copper wire of different cross-section (copper has a low resistance). Pick up the wire in the insulation, depending on the purpose of the coil (often the preference should be given to the enamel insulation). The coil used in the high-frequency short-wave range, to reduce losses wound non-insulated wire.For winding coils of high quality factor used, for example, in narrow-band filters, use stranded wire consisting of several twisted together wires with enamel insulation.
Determine the diameter of the wire to evaluate the possibility of its application in the coil. In the absence of micrometer wrap a few dozen turns of wire on a pencil or other suitable rod (tightly, turn to turn), and then measure with a ruler the total length of the winding and divide by the number of turns. The more turns and tighter winding, the more accurate the measurement result.
Fabricate the coil form. At home when constructing improvised apparatus frame can be made from paper, organic glass, cardboard. Small size frames are manufactured from your camera roll, which you must first remove the emulsion. For rigidity, use multiple layers of film. This film fabricated the cheeks of the frame, gluing them celluloid glue.
If you master the contoured coil of the receiver, place it in the screen to protect from external electromagnetic fields. For the manufacture of screen use sheet copper or aluminium. The diameter of the screen, make the diameter of the coil about three times.
Winding wires on the coil produce manually or on a special winding machine (depending on the type of frame and core). The coil is made on a circular ferrite core, winded with a special device (Shuttle).
If you need soldering enameled wire, first remove the enamel. This is easily done by holding the wire in the flame of a burning match, Stripping with a sharp knife or rubbing the wire wool soaked in acetone.