A linear amplifier increases or delivers more power into the electrical load, or the source from which the output of sound is delivered. So, when a musical note, for instance, is being produced to be broadcast over a huge area, it needs to be carried to its larger audience or destination. This is done through amplification, and often through the use of a linear amplifier.
To understand a linear amplifier, break the words down by their roots. To amplify something is to increase its volume. An amplifier in the field of acoustics is something that increases the volume of sound. Amplifiers receive input, such as input from a microphone or other electrical signal, and boost the original signal to make it louder. A linear amplifier is a specific type of amplifier that affects radio waves.
Radio waves have different frequencies that are transmitted into instruments such as a radio or television. A linear amplifier is a kind of radio frequency power amplifier that performs the primary role of amplifying a transmitter’s output to a much higher level. It helps amplify radio waves, allowing wider distribution, by reducing distortion in the transmission.
This type of amplifier allows the broadcast of amateur radio, which requires a smaller frequency than public broadcasting. In amateur radio terminology, a linear amplifier is referred to as a "brick." Targeted output sources are usually selected to receive these radio signals. It is available for frequencies ranging from 1.8 MHz to over one GHz.
Linear amplifiers come in two varieties: solid state and vacuum tube amplifiers. Each of these varieties has different technical features and different benefits and detriments. Primarily, the differences are in the usage and output the two options can deliver.
When a broadcaster wants to communicate to a wider audience and is not as concerned about the money that goes into buying an amplifier, a solid state amplifier is a good option. It is well suited for high frequency and very high frequency work. An amateur ham, for instance, can expect to communicate a lot of information and connect very well with lots of contacts in the network. However, this is more costly than a vacuum tube amplifier.
For limited usage and network connections, a vacuum tube linear amplifier is a good bet. A beginner can start with a used set, which is incredibly cheap to buy and operate. This will allow transmission of radio waves to a smaller number of output sources, but can still amplify radio waves.