Buzz
Embark on the journey of making a crystal radio, a delightful and relatively straightforward endeavor enabling you to tune in to nearby AM radio stations. Besides the essential germanium diode and earpiece, you can fashion the radio using commonplace household items: cardboard tubes from toilet paper and paper towels, masking tape, screws, wires, and bits of scrap metal and wood. The process entails fashioning a capacitor, coils, a holder, and then interconnecting them all with wires.
Guiding Steps
Creating the Capacitor
Constructing the Coils
Fabricating a Holder
Linking Everything Together
Prepare your materials:
- Obtain a long wire for the antenna (at least 15 to 20 feet, or longer in areas with weaker signals).
- Acquire a germanium diode (1N34, 1N34A or equivalent), available at electronics stores or online.
- Secure a high impedance earpiece or headphones (at least 2000 Ohms) (an antique telephone earpiece will suffice).
- Prepare a ground wire (any long wire will suffice).
- Ensure a ground connection (metal posts or pipes reaching into the ground, such as those under sinks or radiators).
- Procure wire for the tuning bar (12 inches is ample).
Understanding Wire Connections: To connect wires, tightly twist together the bare (uninsulated) parts. If multiple wires need connecting, repeat the process for each one.
- You can connect wires individually or twist them together simultaneously, whichever is easier for you.
- Thicker wires are easier to twist onto smaller ones than vice versa.
Creating a Ground Wire Connection: Attach a bare part of the wire to clean, bare metal that leads to the ground. Common sources include cold water pipes, faucets, and steel support beams.
- If using pipes, locate uninsulated or uncoated sections close to the wall. You may need to scrape away some insulation to expose metal for better conductivity.
Secure the ground wire firmly on the left side of the base. This wire will connect to the adjustable side of the capacitor and the wires from the right ends of the 25- and 90-turn coils. Place it accordingly on the base.
Fasten a wire to the tuning bar. Loosen the screw holding the tuning bar in place, wrap the bare end of a wire around the screw, and then gently tighten the screw. Ensure the wire makes contact with the tuning bar.
- Both ends of this wire should be bare as they will conduct energy from the tuning bar to the ground wire.
Connect the following capacitor and coil wires to the ground wire. Securely twist them together.
- Wire on the adjustable paper-foil side of the capacitor (located on the left side of the base)
- Wire on the bottom (right end) of the primary, 25-turn coil
- Wire on the bottom (right end) of the secondary, 90-turn coil
- Wire attached to the tuning bar
Fix the antenna wire securely on the left side of the base. It will connect to the top (left end) of the primary, 25-turn coil, so position it accordingly on the base.
- The antenna can be any wire, insulated or bare, although insulated is preferable.
- It's crucial for the antenna to be as tall and long as possible, and it must not be grounded (i.e., connected to any ground sources such as basement floors or pipes. If attaching to a tree, metal post, etc., use a short piece of plastic rope).
Join the top, left end of the 25-turn coil to the antenna. Twist the two wires tightly together.
Secure the germanium diode to the right side of the base. Utilize masking tape for this task. Ensure the grey stripe on the diode faces upwards and outwards, towards the edge of the base rather than towards the coils.
- Ensure the diode’s wires protrude from beneath the tape, as you will connect them to other wires.
- Position the diode in alignment with the right end of the capacitor (the side covered with paper towel that cannot be extended), as this is where you will attach it.
Connect the following wires to the top wire of the diode. These wires will connect to the side of the diode without the grey line:
- Wire on the right (fixed) side of the capacitor
- Wire from the top, left side of the secondary, 90-turn coil
Attach the earpiece to the ground and diode wires. Connect one wire of the earpiece to the group of ground wires, and the other end of the earpiece to the free diode wire (i.e., the one not already connected to the 90-turn coil and the capacitor).
- You will attach the earpiece to the side of the diode with the grey line closer to it.
Start enjoying the radio! You may need to adjust the tuning wand and capacitor before hearing anything. Begin by adjusting the wand, then delicately pull out the paper-foil side of the capacitor to increase the volume.
Troubleshooting
Helpful Pointers
Cautions
- Do not plug your radio into a wall outlet or household wiring. This is hazardous and could lead to electrocution.
- Avoid power lines when installing the outdoor antenna. Contact with power lines, especially with a metal ladder, can result in electrocution.
- Do not operate the radio with an outdoor antenna during a thunderstorm.
- Ensure that when positioning your antenna, it doesn't pose a safety risk for people to bump into.
Essential Materials
- Empty and clean paper towel roll
- Two 6-inch-by-6-inch pieces of aluminum foil
- One 7-inch-by-7-inch piece of white paper (printer paper is suitable)
- Two 1-foot-long pieces of wire
- Masking tape or any other non-conductive tape
- X-ACTO blade or wire strippers
- Scissors
- One toilet paper roll
- Wire (recommend 60 ft of 26-gauge enamelled magnet wire or similar)
- Masking tape or any other non-conductive tape
- Sandpaper
- One piece of wood for the base (at least 8 inches wide by 12 inches long)
- Two pieces of wood to support the capacitor (at least 6 inches long and approximately 1.5 inches wide to fit inside the capacitor)
- One small piece of wood to mount the tuning bar (about 1 inch thick by 2 inches long)
- Piece of metal for the tuning bar (a strip from a paint can works)
- Pliers for bending metal
- Screws for connecting wooden pieces
- Screwdriver
- Insulated wire for antenna (at least 15 to 20 feet, longer in weaker signal areas)
- High impedance earpiece (piezo earpiece) or high impedance headphones (at least 2000 Ohms) (an earpiece from an antique telephone is suitable)
- Germanium diode (1N34, 1N34A, 1N60, 1N91, 1N119, 1N270, 1N277, or 1N283 will work)
- Ground wire (any long wire will suffice)
- Wire for tuning bar (12 inches will be more than enough)
