The AMERITRON AL-84 is a grounded grid class AB linear power amplifier that operates on 1.8 through 22 MHz. Four inexpensive 6MJ6 beam tetrodes are driven through an impedance compensating and power swamping network that eliminates instabilities common to parallel tube amplifiers while providing a low SWR to the exciter throughout the frequency range of the amplifier. The pi-network output exceeds FCC harmonic specifications and provides full tuning coverage of all amateur, MARS and international frequencies below 22 MHz. An illuminated meter reads plate current and voltage. Twelve volts is available to operate external lights or other low current (200 ma or less) loads. The AL-84 will deliver a minimum of 400 watts of RF output power with 100 watts of drive.