<p>The method involves coupling the high frequency (HF) signals from a HF generator (6) and dividing the coupled signals into plasma power and compensation power. The level and phase position of the high frequency power signals is adjusted such that a portion of coupled HF power represents a compensation power for the plasma lines in the region between the lower power limit and the actual power output. A portion of the coupled HF-power represents the compensation power for the plasma power within the provided lower power limit. An independent claim is included for an HF plasma supply device.</p>