PA Settings

PA Settings (Power Calibration)

OpenHPSDR Zeus maps the drive / tune slider to an on-air wattage using a two-input formula lifted from Thetis and pihpsdr:

1. Rated PA Output (W) — the amplifier's rated max power at full drive.
2. PA Gain (dB), per band — the amplifier's forward gain from DUC output to the antenna (not a trim; the amplifier's physical gain).

Slider 100% targets the rated wattage; slider 50% targets half that wattage. The per-band gain corrects for the fact that different HF bands need different drive bytes to produce the same on-air watts.

Defaults

Fresh installs seed the Rated PA Output per board class:

Radio class	Rated PA Output (default)
Hermes Lite 2	5 W
Hermes / Metis / Griffin / ANAN-10	10 W
ANAN-100 / 100B / 8000D (Angelia)	100 W
ANAN-100D / 200D (Orion)	100 W
ANAN-7000D / G1 / G2 (OrionMkII)	100 W

Per-band PA Gain defaults are seeded from Thetis's per-board calibration tables (see Zeus.Server/PaDefaults.cs).

Upgrading from an older OpenHPSDR Zeus install? The per-board default only applies on first run — if you've used OpenHPSDR Zeus before, the pa_globals record is already stored with PaMaxPowerWatts = 0, which silently forces the legacy linear mode (PA Gain is ignored). Open the Settings menu → PA tab, set Rated PA Output (W) to 100 for a G2 / ANAN or 10 for a Hermes, and click Apply. Or delete ~/.local/share/Zeus/zeus-prefs.db to start fresh and pick up the new defaults automatically.

Applying changes

PA settings require an explicit Apply click to persist. After editing any value in the Settings menu's PA tab, click the Apply button at the bottom of the tab — changes only take effect on the radio at that moment. Closing the Settings modal without clicking Apply discards pending edits.

See also

• Front-End and Gain — DRV / TUN sliders that are calibrated by these settings.
• TX Controls — MOX / TUNE behaviour.
• Meters — TX stage meters used to verify on-air output.