Radio waves are light waves.
FM radio remains a popular medium for news, information, and entertainment. Radio waves are not sound waves, but light waves. They make up part of the electromagnetic spectrum, and can be exploited to produce sound with the use of a receiver and amplifier. Even if you don't have an engineering background, you can design and build your own simple FM radio transmitter.
Instructions
1. Plug in a light soldering iron that is limited to a power of 25 Watts. Make sure the tip is clean. Let the soldering iron heat up.
2. Clean the component leads using a small piece of emery paper. The component leads are the small, copper-colored metallic pieces on the green circuit board into which pieces are soldered. Bend each component to fit the component's body and insert it into the circuit board. Use a mini drill to slightly widen the holes if the components don't fit.
3. Place the tip of the soldering iron on the component lead while holding the solder wire where the lead comes out of the board. Touch the tip very slightly to the board and cover the area evenly with flux. The joint surface should have a bright metallic sheen and smooth edges.
4. Set the audio frequency input on your frequency dial at point 1 (ground) and point 2 (signal). Connect the power supply to points 3 (negative) and point 4 (positive) with wire and solder. Connect the antenna to points 5 and 6. Connect the frequency dial to point 7. The frequency can be adjusted by hand within a range of 88 to 108 megahertz. The power supply uses a 12-18 volt direct current (DC) adapter for an output of 4 watts.
5. Set the FM transmitter on a clear, blank space. Secure the screw-adjustable trimmer capacitor, followed by the 0.1 uf, .01 uf, and 30 pf variable capacitors. Capacitor strength is measured in microfarads (uf) or picofarads (pf). These capacitors are referred to as connecting capacitors because they are placed on the circuit board and conduct the signal through the receiver.
6. Align the Radio Frequency (RF) stages in order to optimize transmission. Turn on the transmitter and connect the Standard Wave Radio (SWR) meter to the antenna. Adjust the other capacitors until the SWR meter gives readings for the desired output.
Tags: circuit board, soldering iron, component leads, dial point, frequency dial