Short wave radios receive high frequency (3,000-30,000 kHz) radio signals. The term "shortwave" refers to the wavelength of the radio waves being transmitted. Compared to medium and low frequency radio waves, the high frequency waves are rather short and originally were not used to transmit signals. However, amateur radio users in the 20s were able to send radio signals across the Atlantic Ocean. Since then, short wave radio has been a standard for sending voice and music across the planet.
Download a circuit schematic of a short wave radio receiver from a free Internet site. Circuit schematics diagram the circuit you are building by using symbols and marked values to represent specific electronic components and their specifications (see Resources).
Use your schematic to determine what electronic components your short wave radio requires. Make a list of all the parts represented by symbols in your schematic. All components in short wave radios are available from electronics dealers (see Resources). The basic short wave radio consists of common electrical elements (capacitors, resistors, knobs, audio jacks) and additional specialised items such as coil receivers.
Purchase the necessary electronic components as indicated by your circuit schematic and pre-assemble the short wave radio circuit. Orient electronic components on your blank circuit board in a manner which reflects the circuit schematic. Bend the metal connectors of each component as you place it into the circuit board to keep each component in place.
Solder each component to the blank circuit board by touching rosin-core solder to the joint where the circuit board and bent electronic connector meet and applying heat from the tip of your 25-watt soldering iron. A small amount of molten solder applied to each joint is sufficient. Working from left to right assures no component is missed and avoids accidental contact between finished components and the soldering iron. Allow each soldered joint five minutes to cool and cut off the excess metal connector of each electronic component with wire cutters.
Use the wiring pencil to draw the connections between electronic components as represented in your original circuit schematic. The wiring pencil functions similar to a soldering iron, except instead of creating small points of molten solder, the wiring pencil creates lines of conductive copper between electronic components. Simply draw the lines conductive copper lines directly on the circuit board as drawn in your schematic.
Use a simple length of wire as an antenna. Enclose your short wave radio inside a project box or cardboard container.
Always use a soldering iron and wiring pencil in a ventilated area due to the possibility of toxic fumes emitted during use.
Tips and warnings
- Use a simple length of wire as an antenna.
- Enclose your short wave radio inside a project box or cardboard container.
- Always use a soldering iron and wiring pencil in a ventilated area due to the possibility of toxic fumes emitted during use.