The AL-811H is a grounded grid linear amplifier developed by Ameritron using low cost 811A power triodes. It operates in class AB2 for SSB and CW. 1. Fast Warm Up Time: The 811A tubes take approximately 10 seconds to warm-up. 2. Long Tube Life: The 811A tubes are long life, reliable transmitting tubes. 811A tubes offer rugged, reliable operation even on RTTY and SSTV. 3. Tuned Input: A Pi-Network tuned input matches the 811A tubes to 50 ohm exciters. 4. Two Illuminated Panel Meters: The AL-811H has two illuminated panel meters. The Grid Current meter provides a continuous reading of the 811A grid current to indicate proper loading of the amplifier. The other meter switches between high Voltage (HV) and Plate Current (Ip). 5. Multi-voltage Heavy Duty Transformer: A unique "buck-boost" winding allows adjustment of primary voltages to match a wide range of line voltages centered on 110 and 230 volts. This versatile Ameritron feature allows the user to maintain optimum voltages on the tubes and other components to obtain maximum performance and life. 6. Vernier Plate and Load Adjustments: Both tuning controls have vernier 6:1 reduction drives for smooth tuning logging scales for accurate and rapid tune-up. 7. Safety interlock: AC input power is removed from the transformer when the cover is removed. Never attempt to defeat this switch. 8. Operate/Standby Switch: Used to remove the amplifier from the RF line while filament and plate voltages are maintained during "barefoot" operation. 9. XMT Indicator LED: Provides a front panel indication of proper amplifier keying by the exciter. 10. ALC: The drive level is detected to provide a control voltage for the exciter. ALC prevents over-driving of the linear and reduces distortion from excessive drive power. 11. Neutralization Circuit: Reduces unwanted feedback to improve performance.