What is the correct adjustment for the LOAD or COUPLING control of a vacuum tube RF power amplifier?

Tuning a vacuum tube RF power amplifier requires adjusting both the TUNE (Plate) and LOAD (Coupling) controls. The LOAD control specifically adjusts the impedance matching between the amplifier tube and the antenna system, determining how much power is transferred out of the amplifier. The correct procedure is to adjust the LOAD control to achieve the desired RF power output. During this process, you must carefully monitor the plate current meter to ensure it never exceeds the manufacturer's maximum allowable rating, as excessive plate current can quickly destroy the vacuum tube. Students often confuse this with the proper adjustment for the TUNE (or Plate) control. The TUNE control is adjusted to find a 'dip' or minimum in plate current, which indicates resonance. The LOAD control, however, is adjusted for power output while keeping that current within safe limits.