A homemade antenna tuner can increase the frequency range and transmitting power of your CB radio. The tuner matches the impedance, or resistance to electrical flow, of the antenna to the radio, creating the illusion that the antenna is perfectly tuned to a particular radio frequency. The radio then receives and transmits through the antenna at maximum power when this balance occurs. Build a CB antenna tuner and extend the range of your home or mobile CB conversations.
Drill two 1/8-inch holes 1/4 inch from the end of the PVC tube. Thread the magnet wire through the holes. Tightly wrap the magnet wire around the tube 120 times, twisting the wire into a loop every 10 turns. Drill two 1/8-inch holes after the 120th turn, and thread the magnet wire through, locking the wire in place.
Trim the magnet wire, leaving 3 feet of excess wire on one end. Sand the insulation from the magnet wire loops to expose the wire contacts. Place a dab of epoxy over each set of holes in the PVC to secure the wires permanently.
Drill two 1/4-inch holes in one corner of the board. Insert the screws through these holes from the bottom of the board with the threads facing up. Tighten a nut around each screw to secure it to the board.
Epoxy the PVC tube vertically to a corner of the board adjacent to the screws. Epoxy the capacitor base to a corner of the board with the tuning shaft facing out.
Strip 1/2 inch of insulation from both ends of each 16-gauge wire. Solder a wire to the rear frame of the capacitor. Twist the other end of the wire around a screw. This will be the ground connector screw.
Solder a second wire to the solder tab on the side of the capacitor. Twist the free end of the wire around the empty screw. This screw will connect the antenna.
Crimp the alligator clip to the remaining wire. Twist the free end of the wire to the antenna screw, and clip the other end to a loop on the PVC tube.
Strip 1/2 inch of insulation from the free end of the wrapped magnet wire, and connect it to the external antenna jack of your CB radio. Attach the antenna to the antenna screw, and attach a ground wire to the ground screw. Twist a second nut over each screw to secure the wires in place.
Tune the antenna by adjusting the capacitor knob and clipping different loops on the PVC tube.
Stagger the twisted wire loops around the PVC tube to avoid crowding. Ground both your CB radio and tuner to a cold water pipe or to the chassis of your car for better reception.
Tips and warnings
- Stagger the twisted wire loops around the PVC tube to avoid crowding.
- Ground both your CB radio and tuner to a cold water pipe or to the chassis of your car for better reception.
Things you need
- Variable capacitor, air type, 365 pf
- PVC tube, 1-inch diameter, 3 inches long
- Magnet wire, 24-gauge, 6 feet long
- 3 pieces of electrical wire, 16-gauge, 6 inches long
- Plywood board, 6 inches square, 1/2-inch thick
- 2 machine screws, 1/4 inch by 1 inch
- 4 machine screw nuts
- Alligator clip, solderless
- Wire stripping tool
- Utility knife
- Soldering iron and solder
- Power drill, 1/4- and 1/8-inch bits