Ham & Amateur Radio Amplifiers

The Right Amplifier Can Be an Asset to Your Radio Setup

When you are trying to communicate with the world via your ham radio, you need a good linear amplifier to help get your message across. You may have a wonderfully worded phrase to impart or a pithy comment to make on the world situation, but if no one can hear you or read your comments, you might as well have not communicated at all. While having a good antenna is the first step in acquiring the desirable radio strength, adding a linear amplifier to your radio system can definitely extend your range.

A linear amplifier is a radio frequency (RF) power amplifier that provides highly linear power with the input and output keeping, their relationship proportional all the while. Linear amplifiers are focused to concentrate on linearity in all types of load situations. Linear amplifiers are most often used in amateur radio, laboratory equipment, and audio equipment. They can have either vacuum tubes or use solid state technology. Most ham radio systems use linear amplifiers with vacuum tubes that can boost the RF transmission amplification by 10 to 20 times in the one to two kilowatt range.

Amplifier classes are designations of the amount of output within the amplifier circuit for one cycle of operation, and you can find several classes to choose from on eBay. The classification ranges from a wholly linear process with low efficiency to a non-linear process that possesses a higher efficiency, while other classes lie somewhere in the middle. These are the classifications:

• Class A - The class A amplifier possesses the highest linearity and thus is rated as a linear amplifier. A class A amplifier is always on and is inefficient in its use of power.
• Class B - A class B amplifier has no DC base bias current, so the power output is small, but it has a higher efficiency than an amplifier in the A class. There is less linearity as a result.
• Class AB - Each of the transistors conducts for a little more than the conduction half cycle in class B but less than class A full conduction cycle.
• Class C - A class C amplifier is the most efficient but possesses the lowest linearity.

An amplifier is an electrical component that increases the current or voltage of a signal. Power output and efficiency are the main considerations. Power output is measured in watts, and efficiency is the ratio of power output to total power input.