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A [[Citizen Band]] or CB radio signal without modulation is a carrier wave. When you speak into the microphone the AM carrier wave is increased or modulated relative to the level of your voice. The modulation can be increased by speaking more loudly or using a power microphone. The more the wave amplitude is modulated, the virtual output power will seem higher, thus achieving a noticeable power boost in your transmission. Beyond what can be achieved at the microphone it is possible to further increase modulation by internal modification of an adjustable resistor known as a potentiometer, and possibly by removal of a modulation limiting resistor. Most CB radios have a speaker on the bottom. It is the bottom case cover that is typically removed to gain access to the internal components. When removing the bottom case lid take care not to pull the cover away from the radio such that the speaker wires are jerked off of the speaker or board. Turn clockwise or counter-clockwise? It depends on the radio. The way it has the furthest to turn is probably the wrong way. The logic follows that there should be less room to turn it up as opposed to down as modulation is typically factory set above 50% of the potentiometer adjustment value. Make note of the position prior to making an adjustment. It will not turn more than 360 degrees (it is not multi-turn) and you will likely not have far to turn it before achieving maximum modulation. Turn clockwise or counter-clockwise? It depends on the radio. The way it has the furthest to turn is probably the wrong way. The logic follows that there should be less room to turn it up as opposed to down as modulation is typically factory set well above 50% of the potentiometer adjustment value. In fact, it will typically be turned over three-quarters of the way at about 85% relative modulation. Make note of the position prior to making an adjustment. It will not turn more than 360 degrees (it is not multi-turn) and you will likely not have far to turn it before achieving maximum modulation. At this point you will want to speak into the microphone and if the reading constantly peeks you are probably over modulated. Back off the modulation until speech is no longer distorted.Increased modulation is typically desirable, however, maximum modulation is often counterproductive. Turn it up all the way and then back it off just slightly. At this point you will want to speak into the microphone and if the reading constantly peeks you are probably over modulated. Back off the modulation until speech is no longer distorted. If over-modulated, you will sound distorted and your radio can cause interference to adjacent channels or on other frequency harmonics. There is also a modulation limiter resistor on some CB radios. A modification known as "clipping the modulation limiter" is the removal or bypass of this resistor to achieve even higher modulation. In some radios the limiter may be a diode. There are CB radios that do not have an adjustable potentiometer for modulation, and simply use a fixed resistor. The resistor can be replaced with a jumper made of wire or solder, or a resistor of a lower value.CB radio people tend to refer to the potentiometer or pot as a "can" and they will talk about tuning the cans.*CB radio people tend to refer to the potentiometer or pot as a "can" and they will talk about tuning the cans.*The potentiometer may be referred to as a "trimmer" or "trim pot." The potentiometer is simply an adjustable or variable resistor. Trimmers can actually be variable resistors (potentiometers), variable capacitors, or trimmable inductors.*CB radio people tend to refer to the final stage transistor as a "pill" and will talk about burning out the pills.CB radio people tend to refer to the final stage transistor as a "pill" and will talk about burning out the pills.Some of the "export model" CB radios have more than one final stage transistor. Modern export models have two MOSFET type final transistors. These models are not legal for use in the United States. Export models with a high and low power setting will also have two potentiometers that may be modified for audio modulation and two potentiometers to modify for power output, making a total of four potentiometers that may be adjusted.