What is modulation on a cb radio

Therefore sideband is more susceptible to background noise and an overpowering mic gain adjustment is counter productive. In understanding how to adjust your audio on sideband you must first know what the receiver AGC automatic gain circuit does as it receives a sideband signal. The AGC has the job of varying the receivers gain to prevent overloading from strong signals. Without it, signals from around S-5 and above would start or completely overload the receiver rendering the signal unintelligible.

The AGC has a recovery delay time that varies from radio to radio. This delay keeps the gain according to last signal received. If a weak signal comes in after a strong one, the first word or two may be very low or completely missed. We can use the reverse for an example. If we cut the output power in half we loose 3db of signal. Receiving an 18 watt signal at S-9 we would receive a S-8 at 4. The background is desensitizing the receive with the AGC kicking in, making your peaks have less impact or punch.

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. Use the built in display to determine what your modulation swing is before and after the modification. 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. Another modification that can easily be made by adjustment of a potentiometer is to increase transmit power. This potentiometer is typically located close to the amplification transistor often referred to as the final stage amplification transistor or the final.

Make sure you identify the correct potentiometer prior to making an adjustment. Other potentiometers perform functions related to alignment and the operation of the receiver. You can create problems with your CB radio which can seriously inhibit the functionality of the unit or cause damage to other components inside the radio.

Then, in addition to that modification they will add a very high gain microphone that amplifies their voice to very high levels creating overly strong input into the modulation circuit of their radio. Overmodulation will make the CB operator sounds scratchy or may add static type sounds to their transmission. While everyone wants to sound loud and clear when talking on the CB radio, there is a clear maximum level for modulation. Going over this level will result in overmodulation and will have multiple negative and unwanted effects on your transmission.

How can you tell which side is the component side? The speakers are attached directly to the bottom cover with screws and then have two small wires that run to your PC board.

Now you can see the guts and components of your radio. But how do you determine where the modulation potentiometer is when there are so many similar parts on the board? Well the truth is, there is no easy way, but luckily there were people before you who figured it out and the information is readily available on the internet for you to look up.