Front End and Gain
The right half of the control strip carries five groups: FRONT-END, AGC, AF, and a combined ZOOM · DRIVE · MIC block. On mobile, some of these collapse or move into a settings menu.
Controls the analogue-domain stages of the radio before the ADC.
Toggles the RF preamp ON / OFF. Use it on quiet bands or with lossy antennas; turn it off on crowded HF where strong signals might overdrive the ADC.
On Hermes Lite 2 there is no hardware preamp — the PRE button is hidden on that board.
A combined toggle-button-and-slider:
-
A-ATT(default) — Auto Attenuator. The radio ramps attenuation up when it sees the ADC clipping, and releases it as the signal drops. The slider shows your baseline attenuation; the read-out shows the effective value (baseline + auto offset). -
S-ATT(clickA-ATTto toggle) — Static Attenuator. The slider is the actual attenuation, no auto-ramp.
Range: 0 – 31 dB in 1 dB steps. The read-out turns warning-coloured when an ADC overload event has just been observed — a sign to raise attenuation or disable PRE if you have one.
A single AGC-T slider — the only AGC control in the strip.
- AGC-T (gain-threshold / "top") sets the maximum gain the AGC will apply. Lower it if background hiss is too loud; raise it if weak signals feel buried.
- Range: 0 – 120 dB in 1 dB steps. Default 80 dB (matches Thetis
AGC_MEDIUM).
The current value is echoed in the top bar's AGC-T chip. There are no separate Fast / Med / Slow / Long mode buttons — OpenHPSDR Zeus uses a fixed AGC characteristic.
A single AF-gain slider for the receive audio sent to your speakers/headphones.
- Range: -50 dB to +20 dB in 1 dB steps. Default 0 dB.
- This is the gain applied after WDSP's RX chain, before the audio leaves the backend.
Four small sliders sharing a single row.
Panadapter / waterfall span, 1× to 8× in integer steps (1, 2, 3, 4, 5, 6, 7, 8). Higher zoom = narrower span around the VFO.
Alternative ways to zoom:
- ↑ / ↓ arrow keys (one step at a time).
- The + / − buttons at the top of the panadapter (when QRZ is engaged).
TX drive level, 0 % to 100 %. Interpreted as target wattage as a percentage of the radio's Rated PA Output. So with a 5 W rated HL2, DRV = 50 % targets ~2.5 W on-air.
See PA settings (power calibration) in the README for the rated-watts and PA-gain inputs that turn this slider into a calibrated wattage. Excessive drive triggers ALC limiting — see the Meters page.
A separate "tune-power" slider, 0 % to 100 %, used by the TUNE button on the transport bar. Lets you tune at low power without touching the main DRV setting.
Microphone gain, 0 dB to +20 dB, in 0.5 dB steps. The mic gain adds to the raw input level coming from your microphone; the effective level is shown on the mic meter at the bottom of the screen and on the TX Stage Meters panel.
On viewports narrower than about 900 px the AGC, AF, ZOOM, DRV, TUN, and MIC sliders are hidden from the control strip. Zoom is still available via the ↑ / ↓ keys and via the panadapter buttons.