There seems to be a problem serving the request at this time. Output Power. The distance traveled with radio equipment makes the HF amplifier suitable for aviation needs and live radio broadcasts. The essence of HF provides long-distance control over your audio output through an amplifier. This flexibility results in the manufacturing of enclosed boards and those that are exposed for further enhancement or direct installation into HAM radio equipment. All types are made as a closed circuit that captures an audio signal in the form of electricity. An exposed board will reveal these transistors, which have the drum-space for holding electrical charges in.